JP3220739B2 - Electronic component manufacturing method - Google Patents

Abstract

PURPOSE: To cut a time required for resin sealing, improving reliability of quality and enlarge a selection range of resin by adopting a method such as to forcibly suck and fill liquid sealing resin supplied around a flip chip in a gap between the flip chip and a substrate on vacuum inside the gap. CONSTITUTION: After a flip chip is mounted on a substrate through a bump, liquid sealing resin is filled into a gap 5 between a substrate and a flip chip and an electronic component is manufactured. In the process, after a circumference of the gap 5 is sealed by liquid sealing resin supplied around a flip chip, it is placed under a depressurized condition. Thereby, air in the gap 5 and in sealing resin is sucked and exhausted to an outside while keeping it sealed by sealing resin and an interior of the clearance 5 is evacuated simultaneously. Thereafter, sealing resin is forcibly sucked and filled into the clearance 5 based on vacuum in the gap 5 by releasing decompression. For example, viscosity of liquid sealing resin is made within a range of 10 to 10000 voids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic component on which flip chips are mounted.

[0002]

2. Description of the Related Art When manufacturing the above electronic components,
The mounting of the flip chip is performed by connecting and fixing the electrodes of the flip chip and the electrodes of the substrate via bumps, and the gap between the substrate and the flip chip mounted on the substrate is based on a pump. Gaps occur. The gap is filled with a sealing resin for the purpose of improving the thermal cycle life.

Conventionally, such a sealing resin is filled with a predetermined amount of liquid sealing by discharging from a dispenser on the side of a flip chip 2 'mounted on a substrate 1', as schematically shown in FIG. This is performed by supplying a sealing resin 3 'and then impregnating the resin 3' into the gap 5 'between the substrate 1' and the flip chip 2 'by utilizing the capillary phenomenon. The conventional method has the following problems.

(A) A considerable amount of time is required for the sealing resin 3 'to penetrate into the gap 5' and completely fill it, and this is the most time-consuming step in the mounting process.
This is a cause of a decrease in production efficiency. In particular, recently, the gap 5 'has become considerably narrower, for example, 20 to 100 [mu] m, and the size of the flip chip 2' tends to increase. I have.

(B) Flip chip 2 'due to high density
Since the number of bumps on the lower surface increases, and the bumps prevent the sealing resin 3 'from flowing into the gap 5', many bubbles remain in the sealing resin and the reliability of quality becomes poor.

(C) The viscosity of the sealing resin is usually limited to 100 poises or less, since it is difficult to fill the resin if the viscosity is not reduced. Therefore, the content of the filler in the sealing resin must be suppressed to, for example, 60% by weight or less, and the expansion coefficient increases to 30 ppm or more. In addition, due to restrictions on viscosity, the types of resins and curing agents that can be used are restricted, which hinders the development of high-quality and highly reliable sealing resins.

[0007] The present invention has been made to solve such a conventional problem.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing an electronic component in which a flip chip is mounted on a substrate via bumps, and then a liquid sealing resin is filled in a gap between the substrate and the flip chip. In the method, after the periphery of the gap is sealed with the liquid sealing resin supplied around the flip chip, by placing under reduced pressure, the air in the gap and in the sealing resin is sealed by the sealing resin. By sucking and discharging to the outside while maintaining the state and making the inside of the gap a vacuum at the same time, and then releasing the decompression,
The present invention relates to a method for manufacturing an electronic component, wherein the sealing resin is forcibly filled into the gap based on the vacuum in the gap.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 schematically shows the structure of a main part A of an electronic component to be subjected to resin sealing. The main part A is composed of a substrate 1 and a flip chip mounted on the substrate 1 via bumps 2. 3
And the lower end of the bump 2 is electrically connected to the circuit 4 on the substrate 1. In the figure, 5 is a substrate 1 and a flip chip 3
The gap 5 is filled with a sealing resin as described below. Such a structure of the main body portion A does not substantially differ from a conventional product, and may be manufactured according to a conventional method.

In the manufacturing method of the present invention, in order to fill the gap 5 between the substrate 1 and the flip chip 3 with the sealing resin, first, as shown in FIG. The liquid sealing resin 6 is supplied so as to surround the entire circumference without a gap, and the gap 5 is sealed at the outer peripheral portion by the sealing resin 6. The supply of the sealing resin 6 is shown in FIGS. As described above, the present invention can be implemented by applying a stencil printing means.

That is, in the state shown in FIG. 3, the squeegee 7 is actuated so that the circumferential gap 9 between the through hole 8a of the stencil 8 and the flip chip 3 housed concentrically in the through hole 8a. After the liquid sealing resin 6 is pressed and filled therein as shown in FIG. 4, the movable side, for example, the stencil 8 is moved up and down to a predetermined position, so that the intermediate product A _{1 as} shown in FIG. Is obtained.

The supply of the sealing resin by such a stencil printing means is disclosed in, for example, Japanese Patent Application Laid-Open No.
No. 5390 can be performed by applying a known stencil printing means.

When the sealing resin 6 is supplied by the stencil printing means, the supply of the sealing resin 6 to the upper surface of the flip chip 3 is performed as follows.
There are cases where this is performed and cases where it is not performed, and FIGS. 3 and 4 show the latter case.

3 and 4, reference numeral 8b denotes a through hole 8 of the stencil 8;
a lid portion left at the upper end portion of the chip 3 so as to be flush with the upper surface of the stencil 8, and the lid portion 8b has a planar shape slightly larger than the flip chip 3; And is supported by the stencil 8 through a narrow bridge (not shown) at the end face of the peripheral side portion.

The intermediate product A ₁ shown in FIG. 2 is placed under reduced pressure by operating the vacuum generator 11 in a state where the intermediate product A ₁ is housed in a chamber 10 kept airtight as shown in FIG.

The air forming the air bubbles 12 in the sealing resin 6 and the air in the gap 5 are sucked and discharged outside through a layer of the sealing resin 6 while being placed under reduced pressure. At the same time, the inside of the gap 5 is evacuated.

If the degree of vacuum in the chamber 10 is too low, vacuuming becomes insufficient, and if it is too high, the sealing resin 6 may lose its shape and the sealing property may be impaired. 10 Torr or less, for example, about 1 to 10 Torr is appropriate.

After the defoaming process and the evacuation are completed, the operation of the vacuum generator 11 is stopped, and as shown in FIG. A pressure difference occurs between inside and outside. Therefore, the sealing resin 6 is forcibly sucked and / or pressed and filled in the gap 5 as shown in FIG. By this forcible filling, the filling time is shortened, the filling can be performed without any trouble even in a narrow gap, and the fillable viscosity of the sealing resin is reduced to 10 to 10,
000 poise, and the content of filler is 30-90
Each can be expanded up to% by weight. Furthermore, since the filling viscosity can be increased, the range of choice of the resin and the curing agent is widened, and highly reliable resin compounding becomes possible.

Table 1 shows the results of the comparative tests of the present invention and comparative examples. Test sample Substrate size 32mm × 32mm × 0.4mm Flip chip size 10mm × 10mm × 0.4mm Length of gap between substrate and flip chip 50μm Type of sealing resin a), b, c a) Bisphenol type epoxy resin ( Epoxy equivalent 190) 100 parts Methyl tetrahydrophthalic anhydride 90 parts 2P4MZ (imidazole, Shikoku Chemicals) 1 part Carbon black 1 part KBM-403 (silane coupling agent, Shin-Etsu Chemical Co., Ltd.) 1 part Silica (average particle) (Diameter: 5 μm) to obtain a sealing material having a filler amount of 60 wt% and a viscosity of 80 poise.

B) A sealing material having a viscosity of 150 poise was obtained with the same composition as in a) except that 65 wt% of silica was filled.

C) A sealing material having a viscosity of 300 poise was obtained with the same composition as in a) except that 70 wt% of silica was filled.

In the present invention, three kinds of sealing resins are applied to predetermined portions of a test sample as shown in FIG.
After applying the stencil printing means shown in 4 and supplying, it is kept at 5 mmHg or less for 2 minutes in a defoamer, and then returned to normal pressure.
Cured at 130 ° C. for 2 hours.

Comparative Example A test sample was heated to 60 ° C., and the three types of sealing materials a) to c) of the example were packed in a syringe, and the degassed one was poured out to one side of a flip chip. Waiting for the resin to spread sufficiently on the lower surface and around the chip,
C./2 hours.

[0025]

[Table 1]

As is clear from Table 1, in the present invention, the sealing time is set to 5 when the viscosity is low (sealing resin a: 80 poise).
From 3 minutes to 3 minutes. In the case of medium viscosity (sealing resin b: 150 poise), it can be shortened from 12 minutes to 3 minutes. In the case of high viscosity (sealing resin c: 300 poise), sealing is performed in the comparative example. While it is impossible, it can be filled in a short time as in the case of low and medium viscosity in the present invention. Further, in the present invention, there are no bubbles, and the quality is far superior to the comparative example.

[0027]

According to the present invention, the following effects can be obtained.

Since the gap 5 can be forcibly filled with the liquid sealing resin 6 by utilizing a pressure difference, the time required for resin sealing can be reduced by at least about 40% as compared with the conventional method using the capillary phenomenon.

Since the vacuum filling method is employed, no bubbles are contained in the sealing resin, and the reliability of quality can be improved.

The applicable viscosity range of the liquid sealing resin can be expanded, so that the range of choice of the resin and the curing agent is widened, and a highly reliable resin compounding becomes possible.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a structure of an electronic component body used for resin sealing in the manufacturing method of the present invention.

FIG. 2 is a partial vertical sectional side view schematically showing a supply state of a liquid sealing resin around a flip chip in the manufacturing method of the present invention.

FIG. 3 is a partially longitudinal side view showing a state in which the supply of the liquid sealing resin is performed by applying a stencil printing means, and before the supply of the sealing resin.

FIG. 4 is a partially longitudinal side view schematically showing a state after the supply.

FIG. 5 is an explanatory view showing the state of a degassing step in the production method of the present invention.

FIG. 6 is an explanatory diagram showing a step of returning to atmospheric pressure.

FIG. 7 is an explanatory view showing a state at the time of completion of filling of the liquid sealing resin.

FIG. 8 is an explanatory diagram of a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Bump 3 Flip chip 4 Circuit 5 Gap 6 Liquid sealing resin 7 Squeegee 8 Stencil 9 Peripheral gap 10 Room 11 Vacuum generator 12 Bubbles

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-54-11696 (JP, A) JP-A-4-233742 (JP, A) JP-A-2-205390 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/60 311 H01L 21/50

Claims (5)

(57) [Claims] 1. A method of manufacturing an electronic component, comprising: mounting a flip chip on a substrate via bumps; and filling a liquid sealing resin in a gap between the substrate and the flip chip. After sealing with the liquid sealing resin supplied around the flip chip, by placing it under reduced pressure, the air in the gap and in the sealing resin is externally kept in a state where the sealing resin is kept sealed. An electronic component characterized in that the gap is evacuated and at the same time a vacuum is formed in the gap, and then the pressure is released, whereby the sealing resin is forcibly suction-filled into the gap based on the vacuum in the gap. Manufacturing method. 2. The method according to claim 1, wherein the supply of the liquid sealing resin around the flip chip is performed by applying stencil printing means. 3. The liquid sealing resin has a viscosity of 10 to 10,000.
2. The method according to claim 1, wherein the range is 0 poise. 4. The method according to claim 3, wherein the liquid sealing resin contains 30 to 90% by weight of a filler. 5. The method according to claim 1, wherein the suction and discharge of air in the gap and in the sealing resin to the outside is performed under a degree of vacuum of 10 Torr or less.