JPH04338657A - Connecting structure connecting method and connecting device between chip part and substrate - Google Patents

Abstract

PURPOSE:To provide a connecting structure, a connecting method and a connecting device between a substrate and a chip part permitting high-density connection and high reliability at a low cost by shortening the wiring pitch intervals. CONSTITUTION:A solder bump 23 formed on a connecting pad 22 of IC chip part 21 is firmly touched to a wiring conductor 12 on a film substrate 11. At this time, a predetermined pressure is applied to the top of the solder bump 23, and all the solder bumps 23 are arranged to the same height. This pressure is reduced or a non-pressure stated is brought about, and then the solder bumps 23 are heated and melted. At this time, the gap between a chip part 21 and substrate 11 is adjusted, the solder bumps 23 are extended longer than the height before melting, and almost a straight drum form or a tabor form is created. Under this condition, the solder bumps 23 are cooled off and solidified, and then a connected structure is obtained which has the chip part 21 connected to a wiring conductor 12 on the substrate 11 with almost drum-shaped or tabor- shaped solder bumps 23.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a connection structure, a connection method, and a connection device of a chip component to a wiring conductor on a board using molten metal. The present invention relates to a high-density connection structure, connection method, and connection device for chip components on a substrate.

0002

2. Description of the Related Art In recent years, as chip components such as ICs and LSIs have become smaller, more highly integrated, and have more pins, it has become essential to establish high-density connection technology for these chip components to substrates.

Conventionally, ceramic substrates, glass substrates,
As a method for connecting chip components such as ICs to wiring conductors formed on an epoxy resin substrate or the like, a self-alignment connection method using reflow using solder bumps is generally used. In this method, approximately spherical solder bumps are formed in advance on connection pads of chip components or wiring conductors formed on a board, and the chip components are placed on the wiring conductors of the board via the solder bumps. The solder bump is heated through the molten solder bump, and the chip component is positioned on the wiring conductor by the action of the surface tension of the molten solder bump. On the other hand, as a method for connecting chip components such as ICs to a film substrate, a thermocompression method or a wire bonding method is generally used in which gold bumps and tin plating patterns are thermocompression bonded under high temperature and pressure.

0004

[Problem to be Solved by the Invention] In the reflow connection method, since the solder bumps are subjected to pressing force due to the weight of the chip component, as shown in FIG.
When melted, the solder bumps 3 on the connection pads 2 connect to the wiring conductors 4 on the substrate (not shown) and the connection pads 2 on the chip component 1.
It is cooled and solidified while being crushed into a barrel shape. Therefore, there is a high risk that the adjacent bumps 3, 3 will come into contact with each other and form a bridge. In order to avoid contact between the bumps 3, 3, it is necessary to widen the arrangement pitch of the connection pads 2 and the wiring conductors 4, making it difficult to achieve high-density connections.

[0005] Furthermore, in a structure in which a chip component and a board are connected using molten metal such as solder, the problem of thermal fatigue caused by the difference in the coefficient of thermal expansion between the chip component and the board when subjected to a temperature cycle load can be avoided. Although it is necessary to consider this, the barrel-shaped connection solder 3 formed by the reflow connection method has a small connection height ratio to the cross-sectional area, so conduction failure due to thermal fatigue is likely to occur early, and high reliability can be ensured. is becoming difficult.

Furthermore, chip components such as ICs and LSIs connected to a substrate are generally sealed with resin for the purpose of preventing oxidation of the conductor surface, ensuring insulation, and improving impact resistance, but reflow connection methods are not recommended. As mentioned above, the barrel-shaped connection solder 3 formed by the connection solder 3 has a small connection height ratio to the cross-sectional area, so the resin does not easily wrap around the gap between the chip component 1 and the board, causing air bubbles to form in the gap. A problem has arisen in that a sufficient sealing effect cannot be obtained due to the remaining voids.

On the other hand, with the above-mentioned thermocompression bonding method, high-density connections with a wiring pitch of about 100 μm are possible, but there is a risk of damaging chip components such as ICs and LSIs due to high temperature and high pressure. The disadvantage is that the cost is high due to the use of Furthermore, a high-precision, high-rigidity device is required, and there is a problem in that simultaneous connection of 300 or more pins would require too large a pressurizing load and would be difficult to realize. Further, as shown in FIG. 5(b), the gold bumps 5 connecting the connection pads 2 on the chip component 1 and the wiring conductors 4 on the substrate (not shown) are crushed into a plate or film under high pressure. Therefore, the same problems as the reflow connection method occur with respect to thermal fatigue due to the difference in thermal expansion coefficient between the chip component 1 and the substrate when subjected to temperature cycle load, and sealing with resin. .

[0008] The wire bonding method performs bonding in one
The bonding process takes a long time because it is done one by one. Therefore, it is not suitable for connecting multi-pin chip components.

In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a low-cost and highly reliable connection structure between a chip component and a board, which enables high-density connection by shortening the wiring pitch interval. It is in.

Another object of the present invention is to provide a method for connecting a chip component to a substrate, which enables high-density connection by shortening the wiring pitch interval and realizes a highly reliable connection structure between the chip component and the substrate at low cost. and to provide connecting devices.

[0011]

[Means for Solving the Problems] The invention as set forth in claim 1 connects a chip component and a wiring conductor on a substrate via molten metal bumps formed on the chip component or on the wiring conductor on the substrate. In the connection structure between a chip component and a substrate, the molten metal bump is solidified between the chip component and the substrate to form a substantially straight body shape or a drum shape.

[0012] In the above structure, preferably the molten metal bumps are solder bumps. Further, as the substrate, any one of a film substrate, a ceramic substrate, a glass substrate, or a resin substrate can be used.

The invention according to claim 4 brings the chip component into contact with the wiring conductor on the substrate through the molten metal bump formed on the chip component or the wiring conductor on the substrate, and the molten metal bump is brought into contact with the wiring conductor on the substrate. In a method for connecting a chip component and a substrate, the chip component and the wiring conductor on the substrate are connected via a molten metal bump by heating and melting the wiring conductor on the substrate and then cooling and solidifying the molten metal bump. The present invention is characterized in that, when the metal bumps are melted, the gap between the chip component and the substrate is adjusted to be greater than the height of the molten metal bumps before melting.

[0014] In the above structure, preferably, when the molten metal bump is melted, the gap between the chip component and the substrate is adjusted so that the molten metal bump has a substantially straight body shape or a drum shape.

[0015] According to the sixth aspect of the invention, the chip component and the wiring conductor on the substrate are brought into contact via the molten metal bump formed on the chip component or the wiring conductor on the substrate, and the molten metal bump is In a method for connecting a chip component and a substrate, in which the chip component and the wiring conductor on the substrate are connected via the molten metal bumps by heating and melting the molten metal bumps, and then cooling and solidifying the molten metal bumps. When the chip component and the wiring conductor come into contact, a predetermined pressure is applied to the tops of the molten metal bumps to make all the molten metal bumps the same height, and then before heating the molten metal bumps to a melting temperature, It is characterized by reducing the pressurizing force or making it in a non-pressurized state.

[0016] The invention according to claim 7 includes a bonding stage that holds one of the chip component and the substrate, and a bonding stage that presses the other of the chip component and the substrate, and presses the other of the chip component and the substrate. a bonding tool that brings the chip component into contact with a wiring conductor on the board through the formed molten metal bump; and a heating unit that heats the molten metal bump to a melting temperature through at least one of the chip component or the board. In the connection device for connecting a chip component and a substrate, the bonding stage or the bonding tool reduces the height of the molten metal bump before melting by reducing the gap between the chip component and the substrate when the molten metal bump is melted. It is characterized by being equipped with a fine adjustment mechanism for adjusting the dimensions beyond the size.

In the connecting device configured as described above, preferably, the bonding tool includes a pressurizing mechanism that applies a predetermined pressurizing force to the top of the molten metal bump, and a pressurizing mechanism that applies a predetermined pressurizing force to the top of the molten metal bump, and a pressurizing mechanism that applies a predetermined pressurizing force to the top of the molten metal bump. A pressure reducing mechanism is provided to reduce the pressure applied or to make it into a non-pressurized state.

Furthermore, the invention according to claim 9 includes a bonding stage that holds one of the chip component and the substrate, and a bonding stage that presses the other of the chip component and the substrate, and presses the other of the chip component and the substrate to bond the wiring conductor on the chip component or the substrate. A bonding tool that brings the chip component into contact with the wiring conductor on the board through the molten metal bump formed thereon, and heating that heats the molten metal bump to a melting temperature through at least one of the chip component or the board. A connecting device for connecting a chip component and a substrate, comprising: a pressurizing mechanism in which the bonding tool applies a predetermined pressurizing force to the top of the molten metal bump; and a pressurizing mechanism in which the molten metal bump is heated to a melting temperature. The present invention is characterized in that it includes a pressure reducing mechanism that reduces the pressure applied by the pressure mechanism or makes it in a non-pressurized state before the pressure is applied.

[0019]

[Operation] In the connection structure between the chip component and the substrate according to claim 1, after the molten metal bump is melted between the chip component and the substrate, it does not bulge or constrict in a substantially straight shape, that is, in the center. Since it is solidified in an unformed shape or a constricted center part like a drum, there is no risk of short circuits between adjacent connection pads or wiring conductors due to contact between molten metals, and the wiring pitch interval can be reduced. High-density connections are possible by shortening the length. Furthermore, since the connection height ratio to the cross-sectional area of the molten metal increases compared to the case where molten metal bumps of the same volume are crushed into a barrel shape and solidified, it is possible to suppress the occurrence of conduction failure due to thermal fatigue. In addition, since the gap between the chip component and the substrate can be increased, when sealing the chip component with resin after connecting the chip component, the resin can easily wrap around the gap and completely seal the chip component with resin. Enables sealing.

In the method for connecting a chip component and a substrate according to claim 4, when the molten metal bump is melted, the gap between the chip component and the substrate is adjusted to be greater than or equal to the height of the molten metal bump before melting. Therefore, the molten metal bump solidified by cooling has a maximum cross-sectional area smaller than the maximum cross-sectional area before melting. Therefore, there is no risk of short-circuiting between adjacent connection pads or wiring conductors due to contact between molten metals, and high-density connections can be achieved by shortening the wiring pitch interval. In addition, compared to the case where molten metal bumps of the same volume are crushed into a barrel shape and solidified, the ratio of connection height to the cross-sectional area of molten metal increases, resulting in a connection structure between chip components and substrates with excellent thermal fatigue resistance. can be realized at low cost.

[0021] In the above method, when the gap between the chip component and the substrate is adjusted so that the molten metal bump has a substantially straight body shape or a drum shape when the molten metal bump is melted, the gap between the chip component and the substrate is adjusted. The molten metal bumps that are cooled and solidified become approximately straight-shaped or drum-shaped, making it possible to realize a connection structure between chip components and substrates that enables higher-density connections and has excellent thermal fatigue resistance at a lower cost. Become.

According to the method described in claim 6, when the molten metal bumps formed on the chip component are brought into contact with the wiring conductors on the substrate, a predetermined pressure applied to the molten metal bumps causes the molten metal bumps to melt. Since variations in the height of the metal bumps can be eliminated, all the molten metal bumps can be heated uniformly. In addition, since the pressurizing force is reduced or no pressure is applied before the molten metal bump is heated to the melting temperature, the compressive stress inside the molten metal bump is extremely small, or the molten metal bump is melted with no compressive stress occurring. Metal bumps can be melted. Therefore, it is possible to reduce the lateral spread of the molten metal bumps during melting, and to reduce the risk that adjacent molten metal bumps will come into contact with each other and form a bridge. Therefore, the reliability of the connection can be further improved. Further, since the lateral spread of the molten metal bumps can be suppressed to a small extent, high-density connections can be achieved by shortening the wiring pitch interval. Furthermore, by suppressing the lateral spread of the molten metal bumps, it is possible to suppress a decrease in the connection height ratio to the cross-sectional area of the solidified molten metal bumps, resulting in chip components and substrates with excellent thermal fatigue resistance. This makes it possible to realize a connection structure with.

[0023] In the connection device according to claim 7,
When the molten metal bump is melted, the gap between the chip component and the substrate is adjusted to be greater than or equal to the height of the molten metal bump before melting, so the molten metal bump solidified by cooling has a maximum cross-sectional area smaller than the maximum cross-sectional area before melting. It has a cross-sectional area. Therefore, the risk of short-circuiting between adjacent connection pads or wiring conductors due to contact between molten metals is reduced, and high-density connections can be achieved by shortening the wiring pitch interval. In addition, compared to the case where molten metal bumps of the same volume are crushed into a barrel shape and solidified, the ratio of connection height to the cross-sectional area of molten metal increases, resulting in a connection structure between chip components and substrates with excellent thermal fatigue resistance. can be realized at low cost.

In the apparatus configured as described above, the bonding tool includes a pressure mechanism that presses the top of the molten metal bump with a predetermined pressure, and a pressure mechanism that reduces the pressure of the pressure mechanism before the molten metal bump is heated to the melting temperature. Alternatively, in the case where a decompression mechanism is provided to bring the pressure to a non-pressurized state, the predetermined pressure applied by the pressure mechanism can eliminate variations in the height of the molten metal bumps and uniformly heat all the molten metal bumps. In addition, before the molten metal bump is heated to the melting temperature, the pressurizing force of the pressurizing mechanism is reduced by the depressurizing mechanism or the compressive stress in the molten metal bump is extremely small, or the compressive stress inside the molten metal bump is extremely small. It is possible to melt the molten metal bump in a state where the molten metal bump is not generated. Therefore, the lateral spread of the molten metal bumps during melting can be reduced, and the risk of adjacent molten metal bumps coming into contact with each other to form a bridge can be reduced. Therefore, the reliability of the connection can be further improved.

According to the apparatus configuration described in claim 9, when the chip component and the wiring conductor on the board are brought into contact through the molten metal bumps formed on the chip component or the wiring conductor on the board, By applying a predetermined pressure force applied by the pressure mechanism, it is possible to eliminate variations in the height of the molten metal bumps and uniformly heat all the molten metal bumps. Also,
Before the molten metal bump is heated to the melting temperature, the pressurizing force of the pressurizing mechanism is reduced by the depressurizing mechanism or the pressure is left unpressurized, so the compressive stress in the molten metal bump is extremely small or no compressive stress occurs. It is possible to melt a molten metal bump without using a molten metal bump. Therefore, the lateral spread of the molten metal bumps during melting can be reduced, and the risk of adjacent molten metal bumps coming into contact with each other to form a bridge can be reduced. Therefore, the reliability of the connection can be further improved. Further, since the lateral spread of the molten metal bumps can be suppressed to a small extent, high-density connections can be achieved by shortening the wiring pitch interval. Furthermore, by suppressing the lateral spread of the molten metal bumps, it is possible to suppress a decrease in the connection height ratio to the cross-sectional area of the solidified molten metal bumps, resulting in chip components and substrates with excellent thermal fatigue resistance. This makes it possible to realize a connection structure with.

[0026]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 4 show an embodiment of a connection structure between a chip component and a substrate according to the present invention. First, referring to FIGS. 1 and 2, in this embodiment, a film substrate 11 is used as a substrate, and a wiring conductor 12 is formed on the film substrate 11. As a method for forming the wiring conductor 12 in a desired pattern shape,
Although not particularly limited, it is possible to employ a method in which a copper foil is bonded and formed on the film substrate 11 with the adhesive 13 in advance, and then the copper foil is etched through a mask. Further, it is preferable that the surface of the wiring conductor 12 be plated with molten metal such as solder in advance.

As shown in FIGS. 1 and 4, IC, LS
The chip component 21 such as I has a connection pad 22,
The connection pad 22 and the wiring conductor 12 are connected via a solder bump 23 which is shaped like a drum and has a constricted center. The solder bumps 23 are formed in advance on the connection pads 22 of the chip components 21 or on the wiring conductors 12 on the substrate 11 by fusion bonding, and when they are formed on the connection pads 22 or the wiring conductors 12, the solder bumps 23 are bonded by surface tension. Although it has an almost spherical shape, after being heated and melted on the wiring conductor 12, the chip component 2
By adjusting the gap between the substrate 1 and the substrate 11, the substrate 11 is cooled and solidified in a stretched state in the shape of a drum. For example, when using solder bumps 23 with a bump diameter of 70 to 80 μm, the gap between the chip component 21 and the substrate 11 is increased by 20 to 30 μm or more when the solder bumps 23 are melted. It can be formed into a roughly drum shape.

In the connection structure of the above embodiment, since the solder bumps 23 are melted between the chip component 21 and the substrate 11 and then solidified into a drum shape, the solder bumps 23 are solidified in the shape of a drum. There is no risk of short circuit between the wiring conductors 12, 12 due to contact between the solder bumps 23, 23. In experiments, it was confirmed that by employing the above configuration, high connection reliability could be obtained even when the wiring pitch interval was 100 μm or less. Furthermore, since the ratio of the connection height to the solder cross-sectional area is increased compared to the case where solder bumps of the same volume are crushed into a barrel shape and solidified, it is possible to suppress the occurrence of conduction failure due to thermal fatigue. Furthermore, since the gap between the chip component 21 and the substrate 11 can be increased, as shown in FIG. The resin 24 can easily flow inside, making complete sealing possible.

Although solder bumps were used as the molten metal bumps in the above embodiments, other alloy bumps made of alloys with a melting point as low as solder may also be used. Further, the solder bump 23 may be solidified in a straight body shape between the chip component 21 and the wiring conductor 12 of the substrate 11. Further, as the substrate, in addition to the above-mentioned film substrate, a ceramic substrate, a glass substrate, and a resin substrate such as epoxy can be used.

FIG. 6 is a process diagram showing an embodiment of the method for connecting a chip component and a substrate according to the present invention. Although the wiring conductor 12 on the substrate 11 is illustrated in an exaggerated manner in the figure, the thickness of the wiring conductor 12 made of copper foil, for example, is about 20 to 30 μm. Referring to FIG. 6, in this embodiment, the solder bumps 23 formed on the connection pads 22 of the chip component 21 are connected to the wiring conductors 1 on the film substrate 11.
The connection pads 22 on the chip components 21 and the wiring conductors 12 on the substrate 11 are connected via solder by heating and melting the solder bumps 23 and then cooling and solidifying them. It is characterized in that the gap between the component 21 and the substrate 11 is adjusted to be greater than the height of the solder bump 23 before melting.

To explain in more detail, in this example,
First, the film substrate 11 is pressurized from behind (step (a)
), the wiring conductor 12 on the film substrate 11 is pressed against the approximately spherical solder bump 23 formed on the connection pad 22 of the chip component 21 (step (b)).
) ). As described above, it is preferable that the surface of the wiring conductor 12 be plated with a low melting point metal such as solder in advance. In the pressurizing process, a predetermined pressurizing force is applied to the top of the solder bump 23, thereby making it possible to eliminate variations in the height of the solder bump 23.

Next, after the pressure applied to the solder bumps 23 is reduced or no pressure is applied, the solder bumps 23 are heated to a melting temperature, thereby melting the solder bumps 23 ( Step (c)).

In this heating step, the solder bumps 23 are heated through at least either the substrate 11 or the chip component 21, but as described above, all the solder bumps 23 are aligned at the same height in advance. Therefore, all the solder bumps 23 are uniformly heated and melted at a uniform temperature. Further, in this embodiment, the solder bump 23
Since the solder bumps 23 are melted through a pressurizing process, the solder bumps 23 can be reliably bonded to the wiring conductors 12 even if flux, which is required in reflow solder connections, is omitted.

Furthermore, in this embodiment, as described above, after the pressure applied to the solder bumps 23 is reduced or no pressure is applied, the solder bumps 23 are heated to the melting temperature. The solder bump 23 can be melted while the compressive stress within the solder bump 23 is extremely small or no compressive stress is generated. Therefore, the lateral spread of the melted solder bumps 23 can be reduced, and the risk of adjacent solder bumps coming into contact with each other and forming a bridge can be reduced.

FIG. 7 shows an example in which the solder bump 23 is heated to the melting temperature while applying pressure to the solder bump 23.
This is shown for comparison with the above example. Pressure step (steps (a) and (b)) in this comparative example
is the same as steps (a) and (b) shown in FIG. 6, but in this comparative example, the solder bump 23 is heated while the pressure is applied to the solder bump 23 in the heating step (step (c)).
3 is melted, the solder bump 23 widens laterally, increasing the risk of contact with adjacent solder bumps.

[0037] In the above embodiments of the method of the present invention,
In order to minimize the thermal influence on the chip components, it is preferable to use pulse heat heating as the heating method. Further, it is preferable to preheat the chip component 21 in order to shorten the heating time to the melting temperature.

Still referring to FIG. 6, in the above embodiment of the method of the present invention, when the solder bumps 23 melt, the substrate 1
1 or chip component 21 (in this embodiment, chip component 21
) is adjusted so that the gap between the chip component 21 and the substrate 11 is equal to or larger than the height of the solder bump 23 before melting. The chip component 21 and the substrate 11 are
(step (d)). Then, the solder bumps 23 are cooled and solidified while maintaining the adjusted gap size.

As described above, in this embodiment, when the solder bumps 23 are melted, the gap between the chip component 21 and the substrate 11 is adjusted to be greater than the height of the solder bumps 23 before melting, so that the gap is adjusted to be greater than the height of the solder bumps 23 before melting. The solidified solder bump 23 has a maximum cross-sectional area smaller than the maximum cross-sectional area before melting. Therefore, adjacent connection pads 22,
22 or between the wiring conductors 12 and 12 due to contact between solder bumps, and high-density connection is possible by shortening the wiring pitch interval. In addition, compared to the case where solder bumps of the same volume are crushed and solidified into a barrel shape, the ratio of the connection height to the cross-sectional area of the solder increases, making it possible to reduce the connection structure between chip components and the board, which has excellent thermal fatigue resistance. This can be achieved at low cost.

In particular, as in this embodiment, the solder bump 2
The chip part 21 is arranged so that 3 has a substantially straight body shape or a drum shape.
When the gap between the chip component 21 and the substrate 11 is adjusted, the solder bump 2 is cooled and solidified between the chip component 21 and the substrate 11.
3 has a substantially straight body shape or a drum shape, it is possible to realize a connection structure between a chip component and a substrate that can be connected at a higher density and has excellent thermal fatigue resistance at a low cost.

Note that in one embodiment of the method of the present invention, if the solder bumps 23 are previously formed to a uniform height on the chip component 21 or on the wiring conductor 12 of the substrate 11, the bump processing shown in FIG. The pressure step (step (b)) can be omitted. Furthermore, in another aspect of the method of the present invention,
The fine movement step (step (d)) shown in FIG. 6 may be omitted. In the case of the latter embodiment, the above-mentioned effect of shortening the wiring pitch interval or increasing the connection height ratio due to the tension of the solder bumps 23 cannot be obtained, but the horizontal spread of the melted solder bumps 23 can be suppressed to a small extent. Since the risk of adjacent solder bumps contacting each other and forming a bridge can be reduced, the reliability of the connection can be increased. Furthermore, since the lateral spread of the solder bumps 23 can be suppressed to a small extent, high-density connections can be achieved by shortening the wiring pitch interval. Furthermore, by suppressing the lateral spread of the solder bumps 23 to a small extent, it is possible to suppress a decrease in the connection height ratio to the cross-sectional area of the solidified solder bumps 23, thereby improving chip components and substrates with excellent thermal fatigue resistance. This makes it possible to realize a connection structure with.

FIGS. 8 to 10 show an embodiment of a connecting device for carrying out the above-described connecting method. First, referring to FIGS. 8 and 9, the connecting device is equipped with a bonding stage 31 that holds a chip component 21. Above the bonding stage 31, a guide roller is placed with a band-shaped film substrate 11 facing the chip component 21. 32, 33, etc., to maintain tension. Above the film substrate 11 is a film substrate 11.
A bonding tool 34 is provided for pressing from behind to bring the molten metal bumps 23 formed on the connection pads 22 of the chip component 21 into contact with the wiring conductors 12 on the substrate 11.

The bonding tool 34 chucks a pressure cylinder 35 forming a pressure mechanism, a bonding head 36 provided at the tip of a movable rod 35a of this pressure cylinder 35, and stops the movement of the movable rod 35a. The bonding tool 34 further includes a pulse heat heating section 37 for pulse heat heating the solder bump 23 to a melting temperature via the bonding head 36 and the film substrate 11. .

[0044] The bonding stage 31
1 and the bonding table 38 on which the bonding table 3 is mounted.
8 with respect to the bonding head 36 in the X-axis direction, a Y-axis adjustment mechanism 40 with which to adjust the position of the bonding table 38 in the Y-axis direction with respect to the bonding head 36, and a solder bump. The chip component 21 is slightly moved in the Z-axis direction when the chip component 23 is melted.
and a Z-axis fine adjustment mechanism 41 for adjusting the gap between the molten metal bump 23 and the film substrate 11 to be greater than the height of the molten metal bump 23 before melting. Further, in this embodiment, a preheating section (not shown) for preheating the chip component 21 is incorporated in the bonding table 38. Here, the Z-axis fine adjustment mechanism 41 uses a pulse motor 41a and a ball screw shaft/nut mechanism (not shown) that converts the rotation of the motor into linear motion,
The bonding table 38 is configured to be slightly moved through the shaft adjustment mechanisms 39 and 40, and the Z
It may also be one that allows slight movement in the axial direction.

Referring to FIG. 10(a), the inside of the pressurizing cylinder 35 is divided into an upper chamber and a lower chamber, and the drive control system for the pressurizing cylinder 35 is controlled by a pressurized air supply source 42.
, a first switching valve 43 that controls the supply and discharge of pressurized air to and from the upper chamber, and a second switching valve 44 that controls the supply and discharge of pressurized air to and from the lower chamber. , constitutes a pressure reduction mechanism for reducing the pressure applied by the pressure cylinder 35 or making it non-pressurized before the solder bump 23 is heated to the melting temperature.

Next, with reference to FIGS. 8 to 10, the operating steps of the above connection device when implementing the connection method shown in FIG. 6 will be described. First, as shown in FIG. 10(a), pressurized air is supplied to the upper chamber of the cylinder 35 via the first switching valve 43, and the lower chamber of the cylinder 35 is opened to the atmosphere. As a result, the movable rod 35a descends, the film substrate 11 is pressed by the bonding head 36 at the tip of the movable rod, and the wiring conductor 12 (FIG. 9) on the substrate 11 comes into contact with the solder bump 23 on the chip component 21. And FIG. 10(b)
As shown in FIG. 2, a predetermined pressing force F is applied to the solder bumps 23.

Thereafter, as shown in FIG. 10(c), pressurized air is supplied to the lower chamber of the cylinder 35 through the second switching valve 44, so that the pressurizing force applied to the solder bumps 23 is reduced. The pressure is reduced or the pressure is not applied. Then, as shown in FIG. 10(d), the pulse heat heating section 37 (FIG. 8) is energized with the movable rod 35a locked by the locking mechanism 35b until the solder bump 23 reaches the melting temperature. Heated by pulse heat. Next, when the solder bumps 23 are in a molten state, the chip component 21 is in the Z state as shown in FIG. 10(e).
It is finely moved downward by the axis fine adjustment mechanism 41 (FIG. 8) to adjust the gap between the chip component 21 and the substrate 11. In this way, the solder bumps 23 are cooled and solidified while being stretched in the vertical direction.

FIG. 11 shows the process of heating and melting the solder bump 23 while applying pressure to the solder bump 23, for comparison with the operation process of the above-described apparatus. As shown in FIGS. 11(b) to 11(c), when the movable rod 35a is chucked by the locking mechanism 35b while applying the pressure F to the solder bump 23, the inside of the movable rod 35a etc. below the chucking portion is Since compressive stress remains, even if pressurized air is subsequently supplied to the lower chamber of the cylinder 35, a residual pressure load f will be applied to the solder bump 23, as shown in FIG. 11(d). The melted solder bumps 23 spread widely laterally.

In contrast, according to the apparatus of the embodiment of the present invention, spreading of the solder bumps 23 can be prevented by reducing or not applying pressure as shown in FIGS. 10(c) and 10(d). This makes it possible to prevent the formation of bridges between adjacent solder buns.

According to the apparatus of the above embodiment, by going through the process shown in FIG. It has a columnar shape with a constricted center like a straight trunk or a drum. Therefore, the risk of short-circuiting between adjacent connection pads 22 or wiring conductors 12 due to contact between solders is reduced, and high-density connections can be achieved by shortening the wiring pitch interval. Additionally, compared to the case where solder bumps of the same volume are crushed into a barrel shape and solidified, the ratio of the connection height to the cross-sectional area of the molten metal increases, so the connection structure between chip components and the board with excellent thermal fatigue resistance can be achieved. It can be realized at low cost.

[0051] In the above embodiment, the fine adjustment mechanism 41 in the Z-axis direction is provided on the bonding stage 31 side, but a similar fine adjustment mechanism may be provided on the bonding tool 34 side instead. Further, the pressure applying mechanism and the depressurizing mechanism may be configured using a pulse motor and a pressure sensor such as a load cell. Furthermore, the bonding stage 31 may be used to press the film substrate 11 from below toward the chip component 21. The bonding tool 34 may be arranged upside down from the above embodiment. Furthermore, when a ceramic substrate, a glass substrate, a resin substrate, or the like is used as the substrate, the bonding tool may hold the substrate and press the substrate toward the chip component.

[0052]

[Effect of the invention] As is clear from the above explanation, claim 1
According to the configuration described in , it is possible to provide a low-cost and highly reliable connection structure between a chip component and a substrate, which enables high-density connection by shortening the wiring pitch interval.

Further, according to the configurations described in claims 4 and 6, a connection structure between a chip component and a substrate that enables high-density connection and realizes a highly reliable connection structure between the chip component and the substrate at low cost. A connection method can be provided.

Furthermore, according to the configurations described in claims 7 and 9, a chip component and a substrate can be connected to each other, which enables high-density connection and realizes a highly reliable connection structure between the chip component and the substrate at low cost. A connecting device can be provided for connecting.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an embodiment of a connection structure between a chip component and a substrate according to the present invention.

FIG. 2 is a schematic plan view of the connection structure shown in FIG. 1, viewed from above.

3 is a schematic side view showing an example in which the chip component of the connection structure shown in FIG. 1 is sealed with resin.

4 is a perspective view of a main part showing the solder connection relationship between the wiring conductor on the board and the chip component of the connection structure shown in FIG. 1; FIG.

FIG. 5 is a perspective view of a main part showing a connection state between a wiring conductor on a board and a chip component in a conventional connection structure between a chip component and a board, in which (a) is formed by a reflow soldering method; (b) shows a connection formed by thermocompression bonding using gold bumps.

FIG. 6 is a process explanatory diagram showing an example of a method for connecting a chip component and a substrate according to the present invention.

FIG. 7 is a process explanatory diagram showing a comparative example of a method of connecting a chip component and a board.

FIG. 8 is a schematic perspective view of a main part showing an embodiment of a connecting device for connecting a chip component and a substrate according to the present invention.

9 is a partially cross-sectional side view schematically showing a state in which the molten metal bump on the chip component and the wiring conductor on the substrate are brought into pressure contact with each other using the apparatus shown in FIG. 8;

10 is a process explanatory diagram showing the work steps up to connecting the molten metal bumps on the chip component and the wiring conductors on the board using the apparatus shown in FIG. 8;

FIG. 11 is a process explanatory diagram showing the work steps up to connecting the molten metal bumps on the chip component and the wiring conductors on the board in a comparative example of the connection device.

[Explanation of symbols]

11 Film substrate 1
2 Wiring conductor 21 Chip component
22 Connection pad 23 Solder bump 31 Bonding stage 34 Bonding tool 35
Pressure cylinder (pressure mechanism) 37 Pulse heat heating section 41
Z-axis fine adjustment mechanism 43 first switching valve
44 Second switching valve (pressure reducing mechanism)

Claims (9)

[Claims] 1. A connection structure between a chip component and a substrate in which a chip component and a wiring conductor on a substrate are connected via a molten metal bump, wherein the molten metal bump is connected substantially directly between the chip component and the substrate. A connection structure between a substrate and a chip component, characterized by being solidified in the shape of a drum or drum. 2. The connection structure according to claim 1, wherein the molten metal bumps are solder bumps. 3. The connection structure according to claim 1, wherein the substrate is any one of a film substrate, a ceramic substrate, a glass substrate, or a resin substrate. 4. The chip component and the wiring conductor on the board are brought into contact via molten metal bumps formed on the chip component or the wiring conductor on the board, and the molten metal bump is heated and melted, and then cooled. In a method for connecting a chip component and a substrate, in which a chip component and a wiring conductor on a substrate are connected via a molten metal bump by solidifying the molten metal bump, a gap between the chip component and the substrate is formed when the molten metal bump is melted. A method for connecting a chip component and a substrate, characterized in that the height of the molten metal bump is adjusted to be greater than or equal to the height of the molten metal bump before melting. 5. The gap between the chip component and the substrate is adjusted so that when the molten metal bump is melted, the molten metal bump has a substantially straight shape or a drum shape. Connection method. 6. The chip component and the wiring conductor on the substrate are brought into contact via the molten metal bumps formed on the chip component or the wiring conductor on the substrate, and the molten metal bump is heated and melted, and then cooled. In a method for connecting a chip component and a wiring conductor on a board via a molten metal bump, the chip component and the wiring conductor are connected via the molten metal bump by solidifying the chip component and the wiring conductor on the board. At the time of contact, a predetermined pressure is applied to the molten metal bumps to make all the molten metal bumps the same height, and then, before heating the molten metal bumps to the melting temperature, the pressure is reduced or the pressure is not applied. A method for connecting a chip component and a board, characterized by: 7. A bonding stage that holds one of the chip component and the substrate, and a bonding stage that presses the other of the chip component and the substrate, and a bonding stage that presses the other of the chip component and the substrate, and a molten metal bump formed on the chip component or the wiring conductor of the substrate. a bonding tool that brings the chip component and the wiring conductor on the board into contact with each other; and a heating section that heats the molten metal bump to a melting temperature via at least one of the chip component or the board, The bonding tool
characterized by having a fine adjustment mechanism for adjusting the gap between the chip component and the substrate to be greater than the height dimension of the molten metal bump before melting when the molten metal bump is melted,
Connection device for connecting chip components and substrates. 8. The bonding tool comprises a pressurizing mechanism that applies a predetermined pressurizing force to the top of the molten metal bump, and the pressurizing force of the pressurizing mechanism is reduced or eliminated before the molten metal bump is heated to a melting temperature. 8. The connection device according to claim 7, further comprising a pressure reduction mechanism that brings the device into a pressurized state. 9. A bonding stage that holds one of the chip component and the substrate and presses the other of the chip component and the substrate to bond the molten metal bumps formed on the chip component or the wiring conductor on the substrate. a bonding tool that brings a chip component into contact with a wiring conductor on a board through the substrate; and a heating section that heats the molten metal bump to a melting temperature through at least one of the chip component or the board, the bonding tool comprising: A pressure mechanism that applies a predetermined pressure to the top of the molten metal bump, and a pressure reduction mechanism that reduces the pressure of the pressure mechanism or puts it into a non-pressurized state before the molten metal bump is heated to the melting temperature. A connection device for a chip component and a board, characterized in that: