JPH09213738A - Method for manufacturing semiconductor device and substrate holder for mounting semiconductor element - Google Patents

Abstract

(57) [Abstract] (Modified) [PROBLEMS] Semiconductor device and circuit board are more reliably and stably electrically connected to each other, whereby a semiconductor device having extremely stable quality and high productivity, and a manufacturing method thereof. I will provide a. A semiconductor device (3) having a circuit board (1) and a protruding electrode (4) having an uncured conductive adhesive (5) applied on its tip is formed on an electrode terminal (3a) in advance, and the semiconductor device (3) is mounted. After mounting the circuit board 1 on the board holders 2a and 2b in order to flatten the shape of the semiconductor element mounting area of the circuit board 1, the semiconductor element 3 is mounted face down on the semiconductor element mounting area on the circuit board 1. Then, the uncured conductive adhesive 5 is cured, and the space between the semiconductor element 3 and the surface of the circuit board 1 is covered with a sealing material and cured, and then the circuit board 1 is removed from the board holders 2a and 2b. A method for manufacturing a semiconductor device, which comprises sequential steps.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a semiconductor device,
In particular, the present invention relates to a semiconductor device manufacturing method using a flip chip mounting technique and a holder for holding a circuit board for mounting the semiconductor device.

[0002]

2. Description of the Related Art In recent years, the degree of integration of semiconductor elements has increased,
As the miniaturization of semiconductor devices and the narrower pitch of connection terminals have progressed,
For this reason, semiconductor devices using flip chip mounting technology have been actively developed. Hereinafter, an example of a semiconductor device using a conventional flip chip mounting technique will be described with reference to the drawings.

FIG. 7 shows a sectional view of a semiconductor device using a conventional flip-chip mounting technique. Aluminum electrode terminals 102 are formed on the element formation surface of the semiconductor element 101, and the portions other than the aluminum electrode terminals 102 are covered with an insulating film 103 made of a Si oxide film, a nitride film, or the like. Bumps (projection electrodes) 104 made of a conductive metal material such as Au or Cu are formed on the surface of the aluminum electrode terminal 102.
On the other hand, a desired circuit pattern 106 and electrode terminals 107 are formed on the main surface of the circuit board 105. In addition,
As a substrate material of the circuit board 105, a ceramic material having insulation and rigidity, which is unlikely to be deformed (having a thickness of 0.4 mm or more), and having good flatness accuracy is mainly used. The terminal electrode 107 is connected to the circuit pattern 106 and electrically connected to the semiconductor element 101 during flip-chip mounting. Bump (projection electrode) 104 and electrode terminal 1
07 is electrically connected by a conductive adhesive 108. The conductive adhesive 108 is an adhesive containing a powder of a conductive metal material such as Ag, Cu or Ni in a resin. The gap between the semiconductor element 101 and the circuit board 105 is filled with an insulating resin (sealing material) 109. Insulating resin 1
When 09 is hardened, the hardening shrinkage stress bonds the semiconductor element 101 and the circuit board 105, and then strongly attracts and fixes them. Therefore, the mechanical strength of the connection between the semiconductor element 101 and the circuit board 105 in the semiconductor device can be increased and the stability can be maintained.

A conventional method of manufacturing a semiconductor device having the above structure will be described with reference to the process diagram of FIG. First, a semiconductor element 101 in which a desired element or wiring and an insulating film 103 are formed in a normal semiconductor process
A semiconductor wafer having a large number of formed is manufactured. Next, after a probe is brought into contact with the aluminum electrode terminal 102 to perform an electrical inspection to determine the quality of the semiconductor element 101, a bump (protruding electrode) 104 is formed, and then pressed against a flat plate having good plane accuracy. Then, flattening processing is performed to make the bump height uniform. Further, the semiconductor wafer is cut into individual semiconductor elements 101. On the other hand, the circuit board 105 made of an insulating material is used in advance by using a conductive metal material such as Au or Cu.
A desired circuit pattern 106 and an electrode terminal 107 are formed on the circuit board 105, and a conductive adhesive 108 is formed on the circuit board 105.
Via a predetermined electrode terminal 107 and bump (projection electrode)
The semiconductor element 101 is arranged face down so that the semiconductor elements 101 can be brought into contact with each other for electrical connection. After that, heat treatment is performed to cure the conductive adhesive 108, and an electrical inspection is performed to confirm the operating state. After confirming the normal operation, a liquid epoxy resin 109 having an insulating property is filled between the semiconductor element 101 and the circuit board 105 by utilizing the capillary phenomenon. After the filling is completed, heat treatment or the like is performed to cure the insulating resin 109 and flip-chip mounting is performed.

As described above, the semiconductor device using the flip chip mounting technique has been manufactured.

[0006]

However, in the above-described conventional semiconductor device structure and manufacturing method, as shown in FIG. 9, the base material of the circuit board 105a is made of a resin substrate made of an organic material or an inorganic material. Even in the case of a ceramic substrate or the like, a relatively thin plate (a substrate having a thickness smaller than 0.4 mm) is less rigid and easily deformed as compared with the conventionally used thick circuit board 105, For example, it is known that deformation due to uneven thermal stress generated by unevenly existing formations such as asymmetrically and non-uniformly drawn such as the circuit pattern 106 causes local warpage or undulation. Has been.

FIG. 10A is a schematic diagram of the warp amount of the semiconductor element mounting region 110 on the circuit board 105, and FIG. 10B is a histogram of the warp amount in the semiconductor element mounting region of the conventional substrate (ceramic substrate). FIG. 10C shows a histogram of the amount of warpage in the semiconductor element mounting region on the resin substrate (glass epoxy substrate). Here, as shown in FIG. 10A, the warp amount is a value indicating how much the semiconductor element mounting region 110 on the circuit board 105 is warped in a vertical direction from a horizontal plane.

In FIGS. 10 (b) and 10 (c), the horizontal axis of the graph shows the amount of warpage, and the vertical axis shows the distribution ratio in percentage. As can be seen from these figures, the warp amount of the conventional substrate (for example, a ceramic substrate having a thickness of 0.4 mm or more) is 10 μm or less, but the resin substrate (for example, a glass epoxy substrate or
Ceramic substrates thinner than 0.4 mm) exhibited a relatively large warpage distribution of 8 to 30 microns.

Due to the warp and undulation localized in the circuit board 105a, the height variation between the electrode terminals 107 on the circuit board side located in the semiconductor element mounting region becomes large. Therefore, when the semiconductor element 101 is mounted face down, the electrode terminals 107 located in the recesses are placed.
There is a problem that the bonding layer of the conductive adhesive 108 cannot reach the surface, resulting in poor electrical connection. FIG. 11 shows an example of the incidence of connection failure between the semiconductor element and the circuit board with respect to the warp amount of the circuit board. From the experimental result of FIG. 11, the warp amount as shown in FIG.
It can be seen that when a circuit board having a large warp or waviness of a micron or more is used, the incidence of defective connection of semiconductor elements increases rapidly, which is not suitable for mounting semiconductor elements.

The values in the graph shown in FIG. 11 are values that change due to various factors such as the bump shape, the properties of the conductive adhesive, and the transfer amount.

Further, the occurrence of local warpage or undulation due to thermal stress occurs not only in the circuit board manufacturing process but also in the heating process such as hardening of the conductive adhesive or the sealing material during the flip chip process. For example, at the time of mounting a semiconductor element, after the bonding layer of the conductive adhesive 108 has been successfully reached, until the curing of the sealing material is completed, local warping or swell exceeding the limit may occur. However, there is also a problem that connection failure may occur.

The present invention has been made to solve the above-mentioned problems of the prior art, and by electrically connecting the semiconductor element and the circuit board more reliably and stably, the productivity is extremely stable and the quality is high. It is an object of the present invention to provide a good semiconductor device and a manufacturing method thereof.

[0013]

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention comprises a circuit board and a protruding electrode having an uncured conductive adhesive applied to the tip thereof on an electrode terminal. A step of preparing the formed semiconductor element in advance,
A surface shape of a mounting region of the circuit board on which the semiconductor element is to be mounted is substantially parallel to the electrode terminal forming surface of the semiconductor element, and a step of holding the circuit board so as to be a flat surface, Mounting the semiconductor element on the input / output electrode terminals provided in the mounting area on the circuit board face down with the uncured conductive adhesive while holding the circuit board; The step of curing an uncured conductive adhesive, the step of filling a sealing material between the semiconductor element and the circuit board, and the step of curing the sealing material are performed to cure the sealing material. After that, the holding for flattening the circuit board is released.

Further, as a holding method for flattening the circuit board, the circuit board is placed on a board supporting base having a recess for mounting the circuit board, and at least the mounting area of the circuit board is provided. The circuit board is flattened by aligning and fixing the circuit board fixing base having the opening of the size with the circuit board supporting base so as not to block the mounting area of the circuit board. It is characterized by holding.

The semiconductor element mounting substrate holder of the present invention is a circuit board for mounting a semiconductor element face down, wherein the semiconductor element mounting area surface of the circuit board is the semiconductor element mounting surface. It is characterized in that the circuit board is held so as to be substantially parallel and flat with the electrode terminal forming surface.

Further, the substrate holder for mounting a semiconductor element of the present invention has a substrate support having a recess for mounting a circuit board, and a substrate having at least an opening having a size corresponding to the mounting area of the circuit board. It is characterized by comprising a fixed lid.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic diagram showing a method of holding a circuit board using a semiconductor device mounting board holder according to Embodiment 1 of the present invention.

According to this method, the circuit board 1 is sandwiched between a board support 2a made of two metal plates and a board holder made of a board fixing lid 2b, and vertical pressure is applied to the circuit board 1 to fix the circuit board 1 in place. It is a method of holding it flat.

The substrate support base 2a of the substrate holder shown in FIG.
Has a structure in which a groove (recess) for easily fixing the circuit board 1 in a fixed position is provided, and the board fixing lid 2b has an opening provided in a portion corresponding to the semiconductor mounting area 1a of the circuit board 1. It has a structure. Further, screw holes are provided in the outer peripheral portions of the substrate support base 2a and the substrate fixing lid 2b.

A method of holding a circuit board using the board holder of the first embodiment will be described below.

First, the circuit board 1 is placed with the semiconductor element mounting surface facing upward in a groove (recess) provided in the central portion of the board support base 2a, and the opening provided in the board fixing lid 2b is positioned above the circuit board 1. The board fixing lid 2b is placed so as to surround the outside of the mounting area 1a of the board 1.

After that, the substrate support base 2a and the substrate fixing lid 2b
Insert the screw 2c into the screw hole provided on the outer periphery of the
By tightening c, pressure is applied in the vertical direction to hold the circuit board 1.

FIG. 2 is a sectional view of the circuit board 1 fixed to a board holder. FIG. 3 shows the results of measuring the amount of warp in the semiconductor element mounting region 1a of the circuit board 1 in this state and the amount of warp in the semiconductor element mounting region 1a of the circuit board 1 before fixing the substrate holder.

FIG. 3 shows the circuit board 1 before and after fixing the board holder.
The warp amount distribution in the semiconductor element mounting area 1a of (0.8 mm thick glass epoxy substrate) is shown, and the warp in the semiconductor element mounting area 1a of the circuit board 1 is held by holding the board holder. It shows that the quantity is getting smaller.

Next, a semiconductor element coated with a conductive adhesive is mounted face down on the semiconductor element mounting area 1a of the circuit board 1 held by the board holder, and then the semiconductor element is electrically conductive at a temperature of 130 ° C. in an oven. Cure the adhesive. FIG. 4 (a)
4B is a cross-sectional view showing a state in which the semiconductor element 3 is mounted in the semiconductor element mounting region 1a of the circuit board 1 held by the board holder, and FIG. 4B is the same as the circuit board 1 and the semiconductor element 3 in FIG. It is the figure which expanded a part of connection part of.

In FIG. 4B, the bumps (projection electrodes) 4 formed on the aluminum electrode terminals 3a on the semiconductor element 3 and the input / output electrode terminals 1b formed on the circuit board 1 are made of a conductive adhesive 5. Are joined through. Here, when not held by the board holder, the surface accuracy of the mounting area 1a of the circuit board 1 is not good, so that the conductive adhesive 5 is applied to the input / output electrode terminals on the circuit board 1 when the semiconductor element 3 is mounted. There is a portion that does not contact 1b.

Further, in the state where the conductive adhesive 5 is slightly contacted, the contact portion is separated due to thermal deformation of the circuit board 1 when the conductive adhesive 5 is cured, and electrical connection cannot be obtained.

However, the above problem can be solved by mounting the semiconductor element by the method shown in the first embodiment.

Next, a sealant material is injected between the semiconductor element 3 of the circuit board 1 and the surface of the circuit board 1 after the conductive adhesive 5 is cured, and the sealant material is heated in an oven at a temperature of 130 ° C. To cure and coat.

After the encapsulant material is hardened, the adhesive force between the semiconductor element 3 and the circuit board 1 increases, so that the electrical connection at the connection point is secured even if the circuit board 1 is removed from the board holder.

In the first embodiment, SUS-304 is used as the material of the substrate holder, but a metal material such as copper or aluminum may be used, or a ceramic material such as alumina may be used.

(Second Embodiment) FIG. 5 is a view showing a state in which a circuit board is held by a semiconductor element mounting substrate holder according to the second embodiment of the present invention, (a) is a sectional view, and (b) is a sectional view. Is a top view.

The board holder according to the second embodiment is for holding the circuit board on which a plurality of semiconductor element mounting regions are formed flat.

The substrate support base 2a of the substrate holder shown in FIG.
Has a structure in which a groove (recess) for facilitating fixing of the circuit board 1 at a fixed position is provided as in the first embodiment, and the board fixing lids 2b are formed on the circuit board 1. Corresponding to each semiconductor element mounting region 1a, an opening is provided in a portion corresponding to each mounting region 1a, and an opening is also provided in the circuit measurement terminal portion. Further, screw holes are provided in the outer peripheral portions of the substrate support base 2a and the substrate fixing lid 2b.

The method of holding the circuit board 1 using the board holder according to the second embodiment is similar to that of the first embodiment in that the semiconductor element mounting surface faces upward in the groove provided in the central portion of the board support base 2a. The circuit board 1 is placed on the board fixing lid 2b so that the openings provided in the board fixing lid 2b surround the outsides of the semiconductor element mounting regions 1a of the circuit board 1 respectively.
Put. After that, the screw 2c is inserted into the screw holes provided on the outer peripheral portions of the substrate support base 2a and the substrate fixing lid 2b, and the screw 2c is tightened to apply pressure in the vertical direction to the circuit substrate 1 to hold the circuit substrate 1. .

FIG. 6 shows the circuit board 1 before and after fixing the board holder.
FIG. 3 is an enlarged view of the semiconductor element mounting surface of the circuit board 1 so that the warp amount in the semiconductor element mounting region 1a of (0.8 mm thick glass epoxy substrate) can be visually recognized. As is clear from FIG. 6, the amount of warpage in the semiconductor element mounting region 1a of the circuit board 1 is reduced by holding the substrate by the substrate holder, and flattening is realized.

Next, the circuit board 1 held by the board holder.
The semiconductor element coated with the conductive adhesive is mounted face down on the semiconductor element mounting region 1a, and then the conductive adhesive is cured at a temperature of 130 ° C. in an oven. Next, a sealant is injected between the semiconductor element of the circuit board after the conductive adhesive is cured and the surface of the circuit board, and the sealant material is cured and coated at a temperature of 130 ° C. in an oven. After the encapsulant material is cured, the adhesive force between the semiconductor element and the circuit board increases, so that the electrical connection at the connection point is maintained even if the circuit board is removed from the board holder.

In this embodiment, aluminum is used as the material of the substrate holder, and the surface is subjected to alumite treatment so that the circuit board has an insulating property and the circuit board can be inspected for continuity while being held. You may coat with insulating resin.

In this embodiment, a board holder made up of a board support base 2a and a board fixing lid 2b is used to flatten the circuit board, and the screws are tightened in the direction perpendicular to the circuit board. Although pressure was applied to hold the circuit board, the means for flattening the circuit board is not limited to this board holder, and for example, the circuit board is placed on the board support table while the circuit board is placed on the board support table. It is also possible to use a method of sucking with air or the like from below, or flattening the semiconductor element mounting region of the circuit board by magnetic force.

[0041]

As described above, the method of manufacturing a semiconductor device according to the present invention includes a circuit board and a semiconductor element in which a protruding electrode having an uncured conductive adhesive applied to the tip thereof is formed on an electrode terminal in advance. The step of preparing and the surface shape of the mounting region of the circuit board on which the semiconductor element is to be mounted are substantially parallel to the electrode terminal formation surface of the semiconductor element, and the circuit board is formed so as to be a flat surface. The step of holding, and the state where the circuit board is held, the semiconductor element is mounted face down on the input / output electrode terminals provided in the mounting area on the circuit board with the uncured conductive adhesive. And a step of curing the uncured conductive adhesive,
Further, a step of filling a sealing material between the semiconductor element and the circuit board, and a step of curing the sealing material,
After hardening the sealing material, the holding for flattening the circuit board is released, and the substrate holder for mounting a semiconductor element of the present invention is for mounting a semiconductor element face down. The circuit board of claim 1, wherein the circuit board is held so that a surface of the circuit board on which the semiconductor element is mounted is substantially parallel to and flat with an electrode terminal forming surface of the semiconductor element. With this, it is possible to eliminate the local warp and undulation of the semiconductor mounting region surface of the circuit board, reduce the height variation between the respective electrode terminals provided on the semiconductor element side and the circuit board side, It is possible to eliminate a defective electrical connection when mounting a semiconductor element.

Further, the local warpage and undulation that occur during the heat treatment in the flip chip mounting process are also suppressed by the method of the present invention.

Therefore, electrical connection can be made extremely stably, and a semiconductor device with high productivity and high quality can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method of fixing a circuit board using a semiconductor element mounting board fixing jig according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the circuit board according to Embodiment 1 of the present invention is fixed to a fixing jig.

FIG. 3 is a circuit board before and after fixing the board holder according to Embodiment 1 of the present invention (a glass epoxy board having a thickness of 0.8 mm).
Figure showing the warp amount distribution in the semiconductor element mounting area of

FIG. 4A is a sectional view showing a state in which a semiconductor element is mounted in a semiconductor element mounting region of a circuit board fixed by a jig according to the first embodiment of the present invention. FIG. Partly enlarged view

5A is a cross-sectional view of a state in which a circuit board is fixed by a semiconductor element mounting board fixing jig according to Embodiment 2 of the present invention, and FIG. 5B is a top view of the same state.

FIG. 6 is a circuit board before and after fixing the board holder according to Embodiment 2 of the present invention (a glass epoxy board having a thickness of 0.8 mm).
FIG. 2 is an enlarged view of the semiconductor element mounting surface of the circuit board so that the amount of warp in the semiconductor element mounting area 1a can be visually recognized.

FIG. 7 is a sectional view of a semiconductor device using a conventional flip chip mounting technique.

FIG. 8 is a process diagram showing a conventional method for manufacturing a semiconductor device.

FIG. 9 is a cross-sectional view showing a mounting failure of a semiconductor element due to a warp of a circuit board in a semiconductor device using a conventional flip chip mounting technique.

10A is a schematic diagram showing the amount of warpage in a semiconductor element mounting region on a circuit board, and FIG. 10B is a diagram showing a histogram of the amount of warpage in a semiconductor device mounting region on a conventional substrate (ceramic substrate). Shows a histogram of the amount of warp in the semiconductor element mounting area on the resin substrate (glass epoxy substrate)

FIG. 11 is a diagram showing an example of a rate of occurrence of defective connection between a semiconductor element and a circuit board with respect to a warp amount of the circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 circuit board 1a semiconductor element mounting area 1b input / output terminal electrode 2a board support 2b board fixing lid 2c screw 3 semiconductor element 3a aluminum electrode terminal 4 bump (protruding electrode) 5 conductive adhesive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Bessho 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshihiro Tomura, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Masahiro Ono 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (11)

[Claims] 1. A step of preparing a semiconductor device in which a circuit board and a protruding electrode having an uncured conductive adhesive applied to the tip thereof are formed on electrode terminals, and a step of mounting the semiconductor device. The surface shape of the mounting area of the circuit board is substantially parallel to the electrode terminal forming surface of the semiconductor element, and a step of holding the circuit board, and in a state of holding the circuit board, A step of mounting the semiconductor element face down on the input / output electrode terminals provided in the mounting area on the circuit board with the uncured conductive adhesive; and curing the uncured conductive adhesive. And a step of filling a sealing material between the semiconductor element and the circuit board, and a step of curing the sealing material, and after the sealing material is cured, planarization of the circuit board is performed. Holding for A method for manufacturing a semiconductor device, characterized in that 2. The circuit board material of the circuit board is resin.
The manufacturing method of the semiconductor device described in the above. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the circuit board is made of resin and glass. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the substrate material of the circuit board is ceramic. 5. A circuit board is mounted on a circuit board support having a recess for mounting a circuit board, and a circuit board fixing lid having an opening at least the size of a mounting area of the circuit board is provided. The semiconductor device according to claim 1, wherein the circuit board is kept flat by aligning and fixing the circuit board so that the mounting area of the circuit board is not blocked. Device manufacturing method. 6. A circuit board for mounting a semiconductor element face down, wherein a mounting area surface of the semiconductor element of the circuit board is substantially parallel to and flat with an electrode terminal forming surface of the semiconductor element. A substrate holder for mounting a semiconductor element for holding the circuit board. 7. A substrate supporting base having a recess for mounting a circuit board, and a substrate fixing lid having an opening having a size at least the mounting area of the circuit board. 6. The semiconductor element mounting substrate holder according to item 6. 8. The substrate holder for mounting a semiconductor element according to claim 6 or 7, which is made of a metal material or a metal material whose surface is subjected to an insulation treatment. 9. The substrate holder for mounting a semiconductor element according to claim 7, wherein the substrate support base and the substrate fixing lid are aligned and fixed by screwing. 10. The substrate holder for mounting a semiconductor element according to claim 6, wherein the holding for flattening the circuit board is performed by a suction force. 11. The substrate holder for mounting a semiconductor element according to claim 6, wherein the holding for flattening the circuit board is performed by magnetic force.