JPH06295936A - Mounting method of semiconductor device - Google Patents

Abstract

PURPOSE:To minimize the contact resistance for enhancing the reliability by abutting a bonding plate a larger than an IC chip against the IC chip. CONSTITUTION:Patterns are formed on a circuit substrate 1 thereby enabling the central parts of plural pads whereon a semiconductor chip 2 is mounted to be coated with a bonding agent 3. The bumps 4 of the semiconductor chip 2 in such a state are aligned with the pads so as to tack-fix the semiconductor chip 2. Next, a bonding resin solution 6 is dripped to cover the semiconductor chip 2. Next, a bonding plate 8 a size larger than the semiconductor chip 2 is abutted against the semiconductor chip 2. Finally, the bumps 4 of the semiconductor chip 2 are junctioned with the pads by feeding thermal or photo energy while pressurizing the bonding plate 8 using a pressurizing jig simultaneously setting the bonding resin solution 6 so as to bond the bonding plate 8 onto the circuit substrate 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a flip chip type I.
A method of mounting C on a circuit board. Semiconductor integrated circuits (ICs) have advanced in integration degree and LSI and VLSI have been put into practical use, and further integration degree has advanced, and ULSI has been put into practical use. To mount these semiconductor elements on a circuit board, In many cases, a flip chip type mounting method is adopted.

That is, the back surface of the semiconductor element is initially made of gold.
After bonding to the circuit board using a metal braze such as a tin (Au-Sn) eutectic alloy or an adhesive, the bonding pad and thin film forming technology and photo-etching technology (photo A circuit connection method has been adopted in which wire bonding is performed using a gold wire or the like with a bonding pad that has been patterned on a circuit board using (lithography) or the like. A flip-chip type mounting method in which a large number of bumps such as solder balls are formed on the back surface of the formed semiconductor substrate (chip) and circuit connection is performed using these as extraction terminals is the mainstream.

[0003]

2. Description of the Related Art Flip-chip type ICs differ depending on their specifications. In many cases, gold (Au) bumps with a thickness of about 20 μm are formed on the back surface of a semiconductor element by plating or the like. After aligning the pads on the pattern formed on the circuit board, pressurizing them with a pressure welding jig and fixing them by pressing them together, but the adhesive strength is insufficient by itself, so use resin. The reliability is secured by adhering the semiconductor chip to the circuit board, adhering and fixing it by the shrinkage force of the resin, and further covering it with a moisture resistant resin.

Specifically, an adhesive resin such as an epoxy resin is dropped onto a pad of a circuit board to be mounted by using a dropping device such as a dispenser, and then a semiconductor chip is aligned on the pad of the circuit board. Then, the bumps of the semiconductor chip are pressed against the pads using a pressing jig, and heating or ultraviolet irradiation is performed to cure the resin. Next, a means for securing moisture resistance by supplying a resin having excellent moisture resistance such as a silicone resin so as to cover the semiconductor chip mounted on the circuit board and heating and curing the resin is adopted.

However, when such an adhesive method is adopted, an increase in contact resistance is often observed because the bumps and pads are pressed against each other by pushing away the adhesive, and moisture resistance is ensured. Since the semiconductor chip may be deformed due to the shrinkage force of the resin used for this purpose, improvement was necessary.

[0006]

As described above, in the conventional mounting method of the flip chip type IC on the circuit board, the adhesive resin liquid is previously supplied to the pad position of the circuit board,
The bumps of the semiconductor chip are aligned with this pad, and in this state they are pressed together and the resin is cured at the same time.
Increasing contact resistance between bumps and pads is unavoidable,
Another problem is that the semiconductor chip is easily deformed into a concave shape due to the shrinkage of the moisture-resistant resin applied on the semiconductor chip.

[0007]

SUMMARY OF THE INVENTION The above-mentioned problems include a step of temporarily aligning each bump of a flip-chip type IC with each pad formed on a circuit board for mounting an IC chip by patterning. , A step of supplying an adhesive resin liquid onto the IC chip and wrapping the temporary fixing position of the IC chip with the adhesive resin liquid, and a step of abutting an adhesive plate slightly larger than the IC chip on the IC chip While applying pressure to the adhesive plate using a pressure jig, heat energy or light energy is supplied to bond the bumps of the IC chip to the pads and to cure the adhesive resin liquid, thereby separating the circuit board and the adhesive plate. This can be solved by adopting a method of mounting the semiconductor device to be bonded.

[0008]

The present invention eliminates the interposition of a resin solution for completely adhering the bumps of the semiconductor chip to the pads of the circuit board, and also prevents the semiconductor chip from being deformed by the stress due to the curing shrinkage of the moisture-resistant resin. The adhesive plate is used instead of the moisture resistant resin.

FIG. 1 is a cross-sectional view showing a mounting method according to the present invention. First, a pattern is formed on a circuit board 1, and the semiconductor chip 2 is mounted on the center portion of a plurality of pads. The adhesive 3 is applied, and in this state, the bumps 4 of the semiconductor chip 2 are aligned with the pads of the circuit board 1 to temporarily fix the semiconductor chip 2. (As shown in FIG. 1A) Next, the adhesive resin liquid 6 is dropped from the dispenser 5 to cover the semiconductor chip 2 and wet the mounting portion of the circuit board 1. (The above B in the same figure) Next, in a state where the resin liquid 6 for bonding is not dried, the bonding plate 8
Is brought into contact with the semiconductor chip 2.

The adhesive plate 8 is the semiconductor chip 2
It is composed of a ceramic, metal, or glass plate having a larger area, and when the adhesive plate 8 is in contact, the adhesive resin liquid 6 on the semiconductor chip 2 is extruded to wrap the semiconductor chip 2 for adhesion. The eaves of the plate 8 and the semiconductor chip 2 are almost filled. Next, the pressure jig 9 is brought into contact with the adhesive plate 8 to apply pressure to bond the bumps 4 and the pads to each other, and at the same time, when the adhesive resin liquid is an ultraviolet curing type, it is irradiated with ultraviolet rays, and the ordinary heat curing In the case of a mold, the adhesive resin liquid 6 is cured by heating. Next, except for the pressing jig 9, the upper part of the semiconductor chip 2 is wrapped with the adhesive plate 8 and the side surface is wrapped with the resin 10 to complete the mounting. (As shown in FIG. 4D) In this way, since the semiconductor chip 2 is uniformly pressed and fixed by the adhesive plate 8, it is not deformed, and the resin is interposed between the bump 4 and the pad. Therefore, the contact resistance can be minimized, and the conventional problems can be solved.

[0011]

【Example】

Example 1 (corresponding to claim 1 and FIG. 1) A semiconductor chip having an area of 3 × 3 mm and a thickness of 0.4 mm was mounted on a glass-epoxy circuit board having a conductor line made of copper (Cu).

First, an adhesive is applied to the center of a semiconductor chip mounting position of a circuit board on which a large number of pads are formed in a square pattern, and the semiconductor chip 2 is applied to the adhesive in the same manner as the conventional method.
The bumps 4 were aligned and temporarily fixed.

Next, the epoxy resin liquid 6 is dispensed from the dispenser.
Then, an adhesive plate 8 made of a glass plate having a size of 5 × 5 mm and a thickness of 0.5 mm was brought into contact with the semiconductor chip 2 with the centers thereof aligned and then contacted with a pressure jig 9 for 5 kg.・ F
The adhesive plate 8 was pressed by the above pressure and heated at 150 ° C. for 20 seconds to cure the adhesive resin liquid 6.

The semiconductor device thus formed is made of resin 10
Adheres the adhesive plate 8 and the circuit board 1,
In addition to reinforcing the bonding between bumps 4 and pads, resin 10
Has a sufficient moisture-proof structure because it surrounds the semiconductor chip 2, and since the adhesive plate 8 uniformly presses the semiconductor chip 2, the semiconductor chip 2 is not deformed. Second Embodiment (corresponding to claim 2 and FIG. 2) In many cases, a large number of semiconductor chips 2 are mounted on a circuit board 1 arranged in a matrix on an electronic circuit. In such a case, since the individual semiconductor chips are minute, it is advantageous in terms of man-hours to collectively carry out the bonding and to press the adhesive plates 8 individually.

FIG. 2 shows an example in which two semiconductor chips 2 are pressure-bonded and fixed by a single adhesive plate 8. As in the case of the first embodiment, the semiconductor chips 2 are temporarily fixed with an adhesive 3 and epoxy is applied with a dispenser. The resin liquid 6 was dropped, and an adhesive plate 8 made of a glass plate having a partially recessed position where it comes into contact with the semiconductor chip 2 in a wet state around the semiconductor chip 2 of the circuit board 1 was brought into contact.

Here, since the area of the semiconductor chip 2 is 3 × 3 mm, the recess provided in the glass plate is 3.2.
The size is set to 3.2 mm, and the depth is set to 0.1 mm because the height of the semiconductor chip 2 is about 0.4 mm. Then, the pressure-sensitive jig was used to press the adhesive plate 8 at a pressure of 5 kg · f / chip and at 150 ° C. for 20 seconds to cure the adhesive resin liquid 6. This way,
The joining reinforcement of the semiconductor chip 2 to the circuit board 1 is sufficient, and it also has a sufficient moisture resistant structure. Embodiment 3: (corresponding to claim 3 and FIG. 3) The feature of this embodiment is that the elastic film 12 is interposed between the semiconductor chip 2 and the adhesive plate 8 to equalize the pressing force. In this case, neoprene with a thickness of 0.3 mm was used. Here, the elastic film is required to have the same size as the semiconductor chip 2. If the elastic film is larger than the semiconductor chip 2, the contact area between the adhesive plate 8 and the adhesive resin liquid 6 decreases, and That is, the joining reinforcement to the circuit board 1 becomes insufficient. Fourth Embodiment (Corresponding to Claim 4 and FIG. 4) The feature of this embodiment is that when the bumps 4 of the semiconductor chip 2 are aligned with the pads of the circuit board 1 and temporarily fixed, a frame 13 is provided around the chip 2. Is provided to prevent the adhesive resin liquid 6 from flowing under the semiconductor chip 2, thereby eliminating the possibility of resin intervening in the joint portion when the bump 4 and the pad are joined. Can be any heat-resistant insulator, in which case the wall pressure is 0.1 mm and the height is 0 mm.
Using a 3.2 mm square polycarbonate frame with a size of 3 mm,
The semiconductor chip 2 was temporarily fixed to the circuit board 1 and then inserted. The subsequent steps are the same as in Example 1.

[0017]

By implementing the present invention, problems such as deformation of the semiconductor chip and an increase in contact resistance between the bump and the pad can be eliminated when mounting the flip chip type IC chip on the circuit board. By using the adhesive plate, it is possible to eliminate the use of the conventional sealing resin.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mounting method according to the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2 Semiconductor chip 3 Adhesive 4 Bump 6 Adhesive resin liquid 8 Adhesive plate 9 Pressure jig 10 Resin 12 Elastic film 13 Frame body

Claims (4)

[Claims] 1. A step of aligning each bump of a flip-chip type IC with each pad patterned on a circuit board for mounting the IC chip and temporarily fixing the bumps, and bonding the bumps onto the IC chip. Supply the resin liquid,
The step of wrapping the temporary fixing position of the IC chip with an adhesive resin liquid, the step of abutting an adhesive plate slightly larger than the IC chip on the IC chip, and the adhesive plate using a pressure jig While pressurizing, supplying heat energy or light energy to bond the bumps of the IC chip to the pads, cure the adhesive resin liquid, and adhere the circuit board and the adhesive plate. Method of mounting semiconductor device. 2. A plurality of I temporarily fixed on a circuit board.
When the adhesive plate is brought into contact with the C chip, one adhesive plate including a plurality of depressions corresponding to the positions of the plurality of IC chips is aligned and brought into contact with the plurality of IC chips. The method for mounting a semiconductor device according to claim 1, wherein: 3. An IC chip temporarily fixed to a circuit board, when an adhesive plate is brought into contact with the IC plate, an elastic film having the same shape as that of the IC chip is used to intervene. 2. The method for mounting the semiconductor device according to 2. 4. An adhesive resin liquid is supplied onto an IC chip temporarily fixed on a circuit board, and when the temporary fixing position of the IC chip is wrapped with the adhesive resin liquid, the adhesive resin liquid is higher than the IC chip. The method of mounting a semiconductor device according to claim 1, wherein the IC chip is surrounded by a low frame.