JP2000286302A - Semiconductor chip assembling method and assembling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assembling method with high production efficiency, in which curing of an underfill resin and electrical connection between electrodes of a semiconductor chip and a circuit board are continuously performed. SOLUTION: An underfill material 4A is attached so as to cover a region where a solder bump 3A is formed on a circuit board 1,
The circuit board 1 to which the underfill material 4A is adhered is baked, the solder bumps 3A and the electrodes 7 of the semiconductor chip 6 are aligned, and the semiconductor chip 6 is pressed against the circuit board 1 to bond the solder bumps 3A and the electrodes 7 together. Then, the underfill material 4A is heated and cured at a first temperature via a semiconductor chip 6 by a thermocompression jig 8 to form an underfill resin 4B, and a solder bump 3A is formed at a second temperature. Heat to melt. The electrodes of the semiconductor chip 6 and the electrodes of the circuit board 1 are welded to each other by the cured solder bumps 3B, so that electrical connection can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an assembling method for mounting a semiconductor chip such as an LSI on a circuit board and assembling the same, and an assembling apparatus used at that time.

[0002]

2. Description of the Related Art As one of methods for mounting a semiconductor chip on a circuit board, a so-called flip chip bonding method has been proposed. In this flip chip bonding method, solder bumps are mounted on electrodes on the chip side in advance, and the chip is superposed on a circuit board in a face-down state, and the solder bumps are matched with the electrodes on the circuit board side. In this state, the electrodes are soldered by melting the solder bumps by applying the required heating and pressing force in this state, thereby enabling high-density mounting. Further, the above-mentioned circuit board and the semiconductor chip have different thermal expansion coefficients. Due to this, in a product in which the circuit board and the semiconductor chip are integrated, warpage occurs due to heating, and problems such as an increase in connection resistance and damage at the electrode junction occur. Therefore, in order to solve such a problem, the gap between the circuit board and the semiconductor chip is filled with a resin material, and the two are adhered with the filled resin. Thereby, the occurrence of the above-described inconvenience caused by the difference in the coefficient of thermal expansion is suppressed, and the reliability of the product is improved. Further, as a method of filling a resin material between a circuit board and a semiconductor chip, for example, the following method has been proposed. First, there is a liquid resin dispensing method in which after a semiconductor chip is mounted on a circuit board, a liquid resin material is dispensed between the two as an underfill material and filled by a capillary phenomenon, and the filled resin material is cured. Next, after attaching a film containing metal plating resin particles to a circuit board in advance, mounting a semiconductor chip on the circuit board, and heating and curing the film, the ACF (A
nisotropic Conductive Film) method. Next, an ESC (Epoxy Encapsulated Solder C) for dispensing a liquid thermosetting resin material on a circuit board in advance, mounting a semiconductor chip on the circuit board, and curing the thermosetting resin material.
onnection) method.

[0003]

In a conventional method of filling a resin material between a circuit board and a semiconductor chip, for example, in the above-described liquid resin dispensing method, a flux or the like used at the time of mounting the semiconductor chip is removed. The production efficiency is poor due to the necessity of a washing step for cleaning, the fact that it takes a long time to fill the resin, and the necessity of curing the filled resin. Further, it has been pointed out that a dedicated flux coating device, an underfill device, a curing device, and the like are required, thereby increasing the cost of the device. Also,
The above-mentioned ACF method has an advantage that the flux application step and the dispensing step are not required, but the cost of the film containing the metal plating resin particles used in this method is expensive and the connection resistance between the electrodes is low. Problems have been pointed out that there are many variations and that the connection resistance increases under high temperature and high humidity. In addition, the above ES
In the method C, the flux application step becomes unnecessary,
Although there is an advantage that the resin filling time is shortened, a problem has been pointed out that in order to achieve high-efficiency production of a product having high quality, the performance largely depends on the dispenser.

In order to assemble a flip chip, as described above, a step of electrically connecting a semiconductor chip to a circuit board and a step of filling a gap between the connected circuit board and the semiconductor chip with a resin material to fill a resin material are performed. Therefore, it is necessary to go through a processing step of bonding the two. In view of the above, the present invention achieves high production efficiency by filling a gap between a circuit board and a semiconductor chip with a resin material in a short time without using a dispenser, thereby achieving high curing efficiency of the filled resin. Semiconductor chip assembly that can reduce the cost of the device by making electrical connection between the electrodes using the same device, and can stably secure a low connection resistance by using a hot-melt protruding electrode. It is a primary object to provide a method. Further, a second object of the present invention is to provide an assembling apparatus capable of simultaneously performing curing of a filling resin and electrical connection between electrodes.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, a method for assembling a semiconductor chip according to the present invention comprises a first electrode of a semiconductor chip and a heat-meltable material of a circuit board. A method for assembling a semiconductor chip in which a protruding second electrode is opposed to and electrically connected to a semiconductor chip, wherein a sheet-like resin is placed on a region of the circuit board where the second electrode is formed and pressed. Attaching the sheet-shaped resin to the circuit board, positioning the first electrode and the second electrode so as to face each other, and contacting the semiconductor chip and the circuit board via the sheet-shaped resin. Contacting the first electrode with the second electrode by pressing at least one of the semiconductor chip or the circuit board; and contacting the first electrode with the second electrode in a state where the first electrode and the second electrode are in contact with each other. 1 depending on the temperature Heating and curing the resin to compress the semiconductor chip onto the circuit board; and, in a state where the semiconductor chip is pressed onto the circuit board, applying the second electrode at a second temperature higher than the first temperature. The method includes a step of heating and melting, and a step of welding the first electrode and the second electrode by curing the melted second electrode.

In the method for assembling a semiconductor chip according to the present invention, in the above-mentioned assembling method, in the step of attaching the sheet-like resin, the sheet-like resin is placed on a circuit board in a reduced-pressure atmosphere and pressed. It is characterized by doing.

Further, in the semiconductor chip assembling apparatus according to the present invention, the first electrode of the semiconductor chip and the heat-meltable and projecting second electrode of the circuit board are opposed to each other and electrically connected to each other. A semiconductor chip assembling apparatus used in the process, wherein a sheet-like resin is placed and pressed in a region where a second electrode is formed on a circuit board in a reduced-pressure atmosphere, and the sheet-like resin is removed. Attaching means for attaching to the circuit board; positioning means for positioning the first electrode and the second electrode so as to face each other; placing the semiconductor chip on the sheet-like resin; Pressing means for pressing at least one of the semiconductor chip or the circuit board placed on the first electrode and the first electrode and the second electrode, and a second temperature after heating the sheet-like resin at the first temperature. Add a second electrode It is characterized in that a heating means for melting.

In the above-described assembling apparatus, the first temperature may be a temperature sufficient to cure the sheet-like resin and the second temperature may be equal to the second temperature.
The second temperature is a temperature at which the electrodes are not melted.
The temperature is sufficient to melt the electrodes and maintain the state of the cured sheet-like resin.

[0009]

According to the semiconductor chip assembling method of the present invention,
The semiconductor chip is pressed against the circuit board by heating and curing the sheet-shaped resin at a first temperature, and the first electrode in a heat-fusible and protruding shape is melted by heating at a second temperature. Therefore, a step of forming an underfill resin by curing and pressing a semiconductor chip onto a circuit board, and a step of making electrical connection between electrodes,
It can be easily realized by changing the heating temperature continuously using the same device. Further, since the sheet-like resin is attached to the circuit board in a reduced-pressure atmosphere, good adhesion between the circuit board and the sheet-like resin can be maintained. Therefore, no void is generated inside the underfill resin formed by curing, so that the reliability of the sealing resin can be improved. Further, according to the assembling apparatus according to the present invention, the generation of voids in the underfill resin is prevented, the semiconductor chip is pressed on the circuit board at the first temperature, and the electrical connection between the electrodes is performed at the second temperature. Connections can be made continuously.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor chip assembling method according to the present invention will be described below with reference to the drawings. FIG.
(1) to (5) are cross-sectional views showing respective steps of the semiconductor chip assembling method according to the present embodiment.

First, in FIG. 1A, on a land 2 of a circuit board 1, a solder bump 3A as a protruding electrode is provided. Then, a sheet-like underfill material 4A made of a thermosetting resin such as an epoxy resin is placed above the circuit board 1 so as to completely cover the area of the circuit board 1 where the solder bumps 3A are provided. Hold. The underfill material 4A is previously adhered to a tape-shaped base film 5 which is easy to peel, and has not yet been cured at room temperature. That is, the underfill material 4A is supplied in a state of being attached to the tape-shaped base film 5.

Next, in FIG. 1 (2), after the underfill material 4A is attached to the circuit board 1 by pressing and heating,
The base film 5 is peeled and removed. Thus, the surface of the circuit board 1 on which the solder bumps 3A are formed is covered with the underfill material 4A. Further, the circuit board 1 to which the underfill material 4A is attached is baked in a high-temperature atmosphere to remove moisture from the underfill material 4A. Here, the underfill material 4 is provided on the circuit board 1.
A may be applied in an atmosphere reduced in pressure by a vacuum pump. Thereby, the adhesion between the underfill material 4A and the circuit board 1 is improved, so that it is possible to prevent the generation of voids when the underfill material 4A is cured in a later step.

Next, in FIG. 1C, the semiconductor chip 6 is held above the circuit board 1 to which the underfill material 4A is attached. Here, the semiconductor chip 6 is held after the electrodes 7 of the semiconductor chip 6 and the solder bumps 3A on the circuit board 1 are opposed to each other and aligned.

Next, referring to FIG.
Is used to press the semiconductor chip 6 against the circuit board 1. Thereby, the solder bumps 3A on the circuit board 1
However, it breaks through the uncured underfill material 4 </ b> A and comes into contact with the electrode 7 of the semiconductor chip 6. Then, under pressure, the underfill material is applied from the back surface of the semiconductor chip 6 (the surface opposite to the surface on which the electrodes 7 are formed) using the thermocompression jig 8 via the semiconductor chip 6 at a first temperature. Heat 4A. Here, the first temperature is set to a temperature that is sufficient to cause the underfill material 4A made of a thermosetting resin to be gelled and then cured and that does not melt the solder bumps 3A, for example, 175 ° C. Keep it. Therefore, the underfill material 4A between the circuit board 1 and the semiconductor chip 6 is gelled and cured by heating at a first temperature for a predetermined time, for example, 50 seconds in the pressed state. The resin 4B can be formed. Then, the semiconductor chip 6 and the circuit board 1 are pressure-bonded with the cured underfill resin 4B.

Next, in FIG. 1 (5), while maintaining the state where the semiconductor chip 6 is crimped to the circuit board 1, the thermocompression jig 8 is used to apply a second temperature through the semiconductor chip 6 through the semiconductor chip 6. The solder bump 3A is heated for a predetermined time. Here, the second temperature is set to a temperature that is sufficient to keep the underfill resin 4B cured and to melt the solder bumps 3A, for example, 250 ° C. Therefore, with the underfill resin 4B cured,
The solder bump 3A is heated and melted at the second temperature for a predetermined time, for example, 60 seconds, and then cured by natural cooling to form the cured solder bump 3B. Thus, the electrodes 7 of the semiconductor chip 6 and the lands 2 of the circuit board 1 can be welded and securely connected by the cured solder bumps 3B.

As described above, according to the semiconductor chip assembling method according to the present invention, the sheet-like underfill material 4A is attached to the circuit board 1, and after the semiconductor chip 6 is pressed against the circuit board 1, Using a thermocompression bonding jig 8, the underfill material 4A is gelled by heating at a first temperature and then cured to form an underfill resin 4B, which is then heated at a second temperature to form the solder bumps 3A. Melts. Further, the solder is hardened by natural cooling to form the hardened solder bumps 3B, and the electrodes of the circuit board 1 and the semiconductor chip 6 are welded and electrically connected. Thus, the underfill material 4A can be provided between the circuit board 1 and the semiconductor chip 6 in a short time without using a dispenser. After the underfill material 4A is cured, that is, cured, by the thermocompression bonding jigs 8, the electrical connection between the electrodes of the circuit board 1 and the semiconductor chip 6 by melting and curing of the solder bumps 3A is continuously performed. You can do it. Accordingly, since the formation of the underfill resin and the electrical connection between the electrodes are continuously performed by the same assembling apparatus without using a dispenser, a semiconductor chip assembling method that improves production efficiency and reduces apparatus costs can be realized. . Furthermore, since the electrical connection is performed by melting and hardening the solder bumps and welding the electrodes to each other, a low connection resistance can be stably obtained and the mechanical strength of the product can be improved. Can be realized.

Hereinafter, an assembling apparatus according to the present invention will be described with reference to FIGS. 1 (4) and 1 (5). Fig. 1 (4),
The thermocompression bonding jig 8 in (5) has a built-in ceramic heater (not shown) and is formed such that the lower surface is a plane corresponding to the size and shape of the semiconductor chip 6. The temperature of the ceramic heater is controlled by a temperature controller. Further, the atmosphere around the thermocompression bonding jig 8 can be reduced in pressure by a vacuum pump (not shown). When assembling a semiconductor chip, the surrounding atmosphere is first reduced in pressure by a vacuum pump. Next, the thermocompression bonding jig 8 is pressed against the circuit board 1 after adsorbing the semiconductor chip 6. Next, the thermocompression bonding jig 8 is heated to a first temperature by a built-in ceramic heater, and further heated to a second temperature after a lapse of a predetermined time. Here, the first temperature is set to a temperature that is sufficient to cause the underfill material 4A made of a thermosetting resin to gel and then harden, and to a temperature that does not melt the solder bumps 3A, for example, 175 ° C. Is set. And
The second temperature is preset to a temperature sufficient to keep the underfill resin 4B in a cured state and to melt the solder bumps 3A, for example, 250 ° C. Thereby, the thermocompression bonding jig 8 cures the underfill material 4A to form the underfill resin 4B and
And the circuit board 1 are crimped, and then the solder bumps 3A are melted. Further, in the thermocompression bonding jig 8, when the power supply to the ceramic heater is stopped and the temperature of the thermocompression bonding jig 8 is reduced, the solder is hardened to form the hardened solder bump 3 </ b> B.

According to the assembling apparatus of the present invention, the underfill material 4A is attached to the circuit board 1 in a reduced-pressure atmosphere, and the attached underfill material 4A is cured, that is, cured to cure the semiconductor chip 6. And the circuit board 1 are crimped, and the electrodes of the semiconductor chip 6 and the circuit board 1 can be electrically connected to each other. Thereby, it is possible to prevent the generation of voids in the underfill resin 4B, and since the curing of the underfill resin and the electrical connection between the electrodes are continuously performed, it is possible to improve the production efficiency and reduce the apparatus cost. An assembling device is obtained which enables this.

It should be noted that in the above description, pressure is applied from the back surface of the semiconductor chip 6 (the surface opposite to the surface on which the electrodes 7 are formed).
Heated, but instead of this, the back of circuit board 1 (electrode 2
Pressing and heating can also be performed from the surface opposite to the surface on which is formed.

Although the underfill material 4A is supplied in a state of being attached to the tape-like base film 5, the invention is not limited to this, and each underfill material may be supplied alone.

Furthermore, the circuit board corresponding to one semiconductor chip has been described. However, the present invention is not limited to this, and the semiconductor chip can be assembled using the following board.
That is, a semiconductor chip is assembled by using a so-called multi-piece substrate which can divide one substrate to form a plurality of circuit boards. As an assembling method in this case, first, solder bumps are collectively formed in a region corresponding to each circuit board of a large number of boards. Next, the underfill material corresponding to each area is supplied in a state of being attached to a base film in the form of a sheet or a wide tape, and is applied to each area by pressing and heating all together. Then, for one of each region,
After the semiconductor chips are aligned and pressed against each other, the underfill material is heated at a first temperature, the solder bumps are heated and melted at a second temperature, and then cooled and hardened. Then, the steps from the alignment of the semiconductor chip to the curing of the solder bumps are sequentially performed for each region, and after the curing of the solder bumps for the semiconductor chips in all regions is completed, the substrate is cut or divided. According to this assembling method, when assembling a plurality of semiconductor chips, forming solder bumps in each region of a large number of substrates and attaching an underfill material to each region are collectively performed. Will do. Therefore, the semiconductor chip can be more efficiently assembled.

[0022]

According to the present invention, the step of pressing a semiconductor chip on a circuit board and the step of making electrical connection between electrodes are performed by changing the heating temperature by continuously using the same apparatus. It can be easily realized. Further, since the sheet-like resin is attached to the circuit board in a reduced-pressure atmosphere, it is possible to prevent voids in the cured resin. Therefore, according to the method of assembling a semiconductor chip of the present invention, it is possible to improve the reliability of a product, to improve the production efficiency and to reduce the cost of the apparatus, and to achieve an excellent practical effect. . According to the present invention, the sheet-like resin is attached to the circuit board in a reduced-pressure atmosphere, and the semiconductor chip is bonded to the circuit board at the first temperature, and then the electrical connection between the electrodes is performed at the second temperature. Can be continuously performed. Therefore, according to the assembling apparatus of the present invention, it is possible to improve the reliability of the product by preventing the occurrence of voids in the cured resin, thereby improving the production efficiency and reducing the apparatus cost. It has a practical effect.

[Brief description of the drawings]

FIGS. 1 (1) to 1 (5) are cross-sectional views showing respective steps of a semiconductor chip assembling method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2 Land 3A Solder bump (2nd electrode) 3B Solder bump after hardening 4A Underfill material (sheet resin) 4B Underfill resin 5 Base film 6 Semiconductor chip 7 Electrode (1st electrode) 8 Thermocompression bonding jig

Claims (4)

[Claims] 1. A method of assembling a semiconductor chip, wherein a first electrode of a semiconductor chip and a heat-fusible and projecting second electrode of a circuit board are opposed to each other and electrically connected to each other, A step of placing and pressing a sheet-like resin on an area of the circuit board where the second electrode is formed, and attaching the sheet-like resin to the circuit board; and the first electrode and the second electrode And positioning the semiconductor chip and the circuit board through the sheet-shaped resin, and pressing at least one of the semiconductor chip and the circuit board to thereby form the first electrode. Contacting the first substrate with the second electrode; and heating and curing the sheet-like resin at a first temperature in a state where the first electrode and the second electrode are in contact with each other, thereby curing the circuit board. To A step of crimping the semiconductor chip; a step of heating and melting the second electrode at a second temperature higher than the first temperature in a state where the semiconductor chip is crimped on the circuit board; A step of welding the first electrode and the second electrode by hardening the molten second electrode. 2. The method for assembling a semiconductor chip according to claim 1, wherein, in the step of attaching the sheet-like resin, the sheet-like resin is placed on the circuit board in a reduced-pressure atmosphere and pressed. A method for assembling a semiconductor chip. 3. An assembling apparatus for a semiconductor chip used when a first electrode of a semiconductor chip and a heat-fusible and projecting second electrode of a circuit board are opposed to each other and electrically connected to each other. An attaching means for placing and pressing a sheet-like resin on a region of the circuit board where the second electrode is formed in a reduced-pressure atmosphere, and attaching the sheet-like resin to the circuit board. Positioning means for positioning the first electrode and the second electrode so as to face each other, and mounting the semiconductor chip on the sheet-shaped resin; and positioning the semiconductor chip on the sheet-shaped resin. Pressing means for pressing at least one of the semiconductor chip or the circuit board and bringing the first electrode and the second electrode into contact with each other; and heating the sheet-like resin at a first temperature and then at a second temperature. The second electrode The semiconductor chip assembly device being characterized in that a heating means for heating and melting. 4. The apparatus for assembling a semiconductor chip according to claim 3, wherein the first temperature is a temperature sufficient to cure the sheet-like resin and a temperature at which the second electrode is not melted. The semiconductor chip assembling apparatus according to claim 2, wherein the second temperature is a temperature sufficient to melt the second electrode and maintain a state of the cured sheet-like resin.