JP2001291805A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flip-chip packaging semiconductor device, wherein the bonding reliability is not degraded even when a semiconductor element is made larger. SOLUTION: A semiconductor element 20 is mounted on a substrate 10 with its face down, and a gap between the substrate 10 and the semiconductor element 20 is filled with a rubber/resin composite. In this semiconductor device, the central portion of the gap between the substrate 10 and the semiconductor element is mainly filled with a first rubber/resin composite, and the periphery is mainly filled with a second rubber/resin composite having a modulus of flexural elasticity lower than that of the first rubber/resin composite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device used for various electronic devices, and more particularly, to a semiconductor device in which a semiconductor element is mounted face down on a substrate.

[0002]

2. Description of the Related Art In recent years, as the technology of the field of electronic equipment manufacturing has improved, the size of semiconductor elements has been increasing. Flip-chip mounting is increasingly used.

That is, in the flip chip mounting, typically, a projection called a bump is provided on an electrode of a semiconductor element, and the bump is faced down to face a wiring board to join the mutual electrodes. It has the feature that high-density mounting is possible as compared with bonding mounting and the like. Various methods are known for flip-chip mounting, such as providing bumps on the wiring board side, or bonding via conductive particles without providing bumps.

In general, in flip-chip mounting, a semiconductor element circuit surface is protected from an external environment, and the semiconductor element and a wiring board are mechanically bonded to each other.
Alternatively, an epoxy resin or an anisotropic conductive material may be placed in the gap between the semiconductor element and the wiring board for the purpose of, for example, reducing the concentration of thermal stress caused by the difference in the coefficient of thermal expansion between the semiconductor element and the wiring board at the electrode joint. Is filled.

[0005] However, as the size of the semiconductor element increases, simply filling the resin as described above requires
The semiconductor element and the wiring board cannot sufficiently cope with the thermal stress caused by the difference in the coefficient of thermal expansion, and peeling occurs between the semiconductor element and the resin or between the wiring board and the resin, and in some cases, conduction may be impaired. .

[0006]

As described above, in the conventional flip-chip-mounted semiconductor device, there is a problem that when the size of the semiconductor element is increased, the reliability of bonding between the semiconductor element and the wiring board becomes insufficient. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional technical problem. For example, in a flip-chip mounted semiconductor device, even if a semiconductor element is enlarged, the bonding reliability is reduced. It is an object to provide a semiconductor device without any.

[0008]

The present inventor has conducted intensive studies to achieve the above object, and as a result, as a material to be filled in the gap between the semiconductor element and the substrate, a material having a different elastic modulus as described later is used. It has been found that the above objects can be achieved by using various types of rubber / resin compositions, and the present invention has been completed.

That is, in order to solve the above-mentioned problems, the invention according to claim 1 of the present application is directed to a semiconductor device in which a semiconductor element is mounted face-down on a substrate, and a gap between the substrate and the semiconductor element is formed of a rubber-resin composition. A central portion of a gap between the substrate and the semiconductor element is primarily filled with a rubber / resin composition, and a peripheral portion is mainly filled with the first rubber / resin composition. It is characterized by being filled with a second rubber / resin composition having a low flexural modulus.

[0010] In order to solve the above-mentioned problems, claim 2 of the present application.
According to the invention described in the first aspect, in the semiconductor device according to the first aspect, the flexural modulus of the second rubber / resin composition is 0.9 times or less of the modulus of elasticity of the first rubber / resin composition. And

[0011] In order to solve the above-mentioned problems, a third aspect of the present invention is described.
The invention according to claim 1, wherein in the semiconductor device according to claim 1 or 2, the flexural modulus of the first rubber-resin composition is 6 GPa.
-15 GPa, and the second rubber-resin composition has a flexural modulus of 1 GPa-10 GPa.

[0012] In order to solve the above-mentioned problems, claim 4 of the present application.
The semiconductor device according to any one of claims 1 to 3, wherein an electrical junction between the substrate and the semiconductor element is provided at a peripheral portion mainly filled with the second rubber / resin composition. It is characterized by having.

[0013] In order to solve the above problems, claim 5 of the present application.
According to a fourth aspect of the present invention, in the semiconductor device according to the fourth aspect, the electrical junction includes a bump provided on at least one electrode of the substrate and the semiconductor element.

In the semiconductor device according to the first aspect of the present invention, the peripheral portion of the gap between the substrate and the semiconductor element is mainly filled with a rubber / resin composition having a lower bending elastic modulus than that of the central portion. Even if the size of the semiconductor element becomes large, it is possible to secure a bonding force enough to withstand thermal stress caused by a difference in thermal expansion coefficient between the semiconductor element and the wiring board,
It is possible to prevent a reduction in the reliability of electrical and mechanical bonding between the semiconductor element and the substrate.

In the semiconductor device according to the second aspect of the present invention, the rubber / resin composition mainly filled in the peripheral portion of the gap between the substrate and the semiconductor element is used as the rubber / resin composition mainly filled in the center portion. By using a material having a flexural modulus of 0.9 or less, the electrical and mechanical bonding between the semiconductor element and the substrate can be made even more reliable.

In the semiconductor device according to the third aspect of the present invention, the rubber / resin composition mainly filled in the center of the gap between the substrate and the semiconductor element has a flexural modulus of 6 GPa to 15 GPa.
GPa, and, as the rubber / resin composition mainly filled in the peripheral portion of the gap between the substrate and the semiconductor element, the flexural modulus of 1 Gpa to 10 Gpa was used, whereby the semiconductor element and the substrate were used. And electrical and mechanical bonding with the substrate can be made even more reliable.

In the semiconductor device according to the fourth aspect of the present invention, an electrical junction between the substrate and the semiconductor element is provided in a portion mainly filled with a rubber / resin composition having a low flexural modulus. In such a semiconductor device, when the size of the semiconductor element is increased, the reliability of electrical and mechanical bonding between the semiconductor element and the substrate is more significantly improved.

According to a fifth aspect of the present invention, in the semiconductor device according to the present invention, the electrical junction has a bump, and the reliability of the electrical and mechanical junction between the semiconductor element and the substrate when the semiconductor element is enlarged. The improvement is more remarkable.

In the present invention, as the rubber / resin composition, as described in claim 6, butadiene rubber, nitrile rubber, urethane rubber, silicone rubber,
Examples of the composition include a composition containing as a main component at least one selected from polystyrene, polyvinyl alcohol, methacrylic resin, polyamide, phenolic resin, melamine resin, epoxy resin, and unsaturated polyester resin.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments.

FIG. 1 is a schematic sectional view showing an embodiment of the semiconductor device of the present invention.

In FIG. 1, reference numeral 1 denotes a substrate 10 such as a printed wiring board on which connection electrodes (not shown) are formed on the upper surface. On this substrate 10, a semiconductor element 20 faces down, that is, An electrode (not shown) formed on the semiconductor element 20 is mounted so as to face the connection electrode of the substrate, and a bump 30 is interposed between the connection electrode and the electrode. In this embodiment, the bump 30
Are arranged on the periphery of the mounting surface of the semiconductor element 20.
Then, the semiconductor element 20 thus mounted and the substrate 1
Between zero and two, two types of resin compositions having different flexural modulus are filled.

That is, the central portion of the gap between the semiconductor element 20 and the substrate 10 is mainly filled with a resin composition having a high flexural modulus (first resin composition). The peripheral portion that is included is mainly filled with a resin composition having a low flexural modulus (second resin composition). In FIG. 1, reference numeral 41 denotes a first resin filling portion mainly filled with a first resin composition, and reference numeral 42 denotes a first resin filling portion mainly filled with a second resin composition. Here, it is preferable that the second resin composition has a flexural modulus of 0.9 times or less of the first resin composition in order to obtain the effect of the present invention, and the first resin composition Is more preferably 6 GPa to 15 GPa, and the flexural modulus of the second resin composition is in the range of 1 GPa to 10 GPa. In addition, as long as it satisfies such a condition, the type is not particularly limited, and a material that satisfies the above condition is selected from those usually used as a filler of this type. Can be used. Specific examples include resin compositions based on thermoplastic resins such as polystyrene, polyvinyl alcohol, methacrylic resins, and polyamides, and thermosetting resins such as phenolic resins, melamine resins, epoxy resins, and unsaturated polyester resins. These may be used alone or as a mixture of two or more. In the present invention, a rubber composition such as butadiene rubber, nitrile rubber, urethane rubber, and silicone rubber can be used.

The semiconductor device of this embodiment can be manufactured, for example, as follows.

A first resin composition is applied to a central portion of a place where the semiconductor element 20 is mounted on the substrate 10 on which the connection electrode is formed on the upper surface, and then the first resin composition is applied inside the connection electrode formation region. The second resin composition is applied so as to surround the application portion of the first resin composition applied to the first resin composition. After the application, the semiconductor element having the bumps 30 formed on the electrodes in advance is mounted with the bump 30 side facing the substrate 10 and heated and pressed. As a result, the applied resin composition spreads on the substrate 10, and FIG.
As shown in the figure, the center of the gap between the semiconductor element and the substrate is
A semiconductor device is obtained in which the first resin composition is mainly used and the peripheral portion including the bump arrangement position around the first resin composition is mainly filled with the second resin composition.

In the semiconductor device thus obtained, the periphery of the gap between the substrate 10 and the semiconductor element 20 is mainly
Filled with a resin composition having a lower flexural modulus than that at the center, and even if a thermal cycle is applied, the filling resin at the peripheral portion has a low flexural modulus, so that the thermal expansion coefficient of the semiconductor element and the substrate is reduced. Large thermal stress caused by the difference can be absorbed. On the other hand, since the filling resin at the center has a high flexural modulus, a sufficiently high bonding strength can be obtained. Therefore, even if the size of the semiconductor element is increased, it is possible to sufficiently cope with the semiconductor element and to have high bonding reliability.

The above embodiment is an example in which the present invention is applied to a semiconductor device in which a semiconductor element is flip-chip mounted via bumps. However, the present invention is not limited to such an example. Needless to say, the present invention can be widely applied to a semiconductor device in which a semiconductor element is flip-chip mounted via conductive particles, and a semiconductor device in which a semiconductor element is mounted face down on various substrates.

According to the present invention, the size of the semiconductor device is 15 mm × 15
It is particularly useful when it exceeds mm.

[0029]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following description, “parts” means “parts by weight”.
Means

Example 1 100 parts of a bisphenol A type epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy), 20 parts of an aminopolyamide resin (trade name: G-725, manufactured by Toto Kasei Co., Ltd.)
A resin composition A was prepared by uniformly mixing 5 parts of 2 dimethylimidazole and 1 part of γ-glycidoxypropyltrimethoxysilane with a homogenizer. When the flexural modulus of this resin composition A was measured, it was 2.5 GPa.

Further, bisphenol A type epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy)
100 parts, 20 parts of aminopolyamide resin (trade name: G-725, manufactured by Toto Kasei), 5 parts of 1,2 dimethylimidazole, γ-
Resin composition B was prepared by uniformly mixing 1 part of glycidoxypropyltrimethoxysilane and 100 parts of silica (average particle size: 1.0 μm) with a homogenizer. When the flexural modulus of this resin composition B was measured, it was 8 GPa.

About 10 mg of the above resin composition B was placed at the center of a semiconductor element mounting position on a printed wiring board (0.8 mm thick glass epoxy board FR-4, copper foil thickness 18 μm) having an Au / Ni plating on the electrode surface. Then, about 6 mg of the above resin composition A was applied to the periphery. Next, a 15 mm x 15 mm x 0.7 mm silicon chip (chip size 15 mm x 15 mm x 0.7 mm, bump size 80 m x 80 m x 25 m, bump number 360, bump spacing 80 m) with an Au plating bump formed on the periphery Using a bonding machine for 180
Under a condition of 10 ° C. and 10 kg / cm ² , heating and pressurizing were performed for 2 minutes to integrally bond, thereby obtaining a sample for property evaluation.

Example 2 Phenoxy resin (trade name: YP-50, manufactured by Toto Kasei) 10
0 part and 100 parts of methyl ethyl ketone were uniformly mixed with a homogenizer to prepare a resin composition C. When the flexural modulus of this resin composition C was measured, it was 1 GPa.

About 10 mg of the resin composition B used in Example 1 was applied to the center of the semiconductor element mounting position on the printed wiring board as in Example 1, and the resin composition C was applied to the periphery thereof. 12 mg was applied and dried at room temperature. Next, a silicon chip similar to that of Example 1 was further heated and pressed under the conditions of 180 ° C. and 10 kg / cm ² for 2 minutes using a bonding apparatus to integrally bond the silicon chip to obtain a sample for property evaluation. Was.

Comparative Example 1 About 16 mg of the resin composition B used in Example 1 was applied to the same mounting position of the semiconductor element on the printed wiring board as in Example 1,
Next, a silicon chip similar to that of Example 1 was further heated and pressed under the conditions of 180 ° C. and 10 kg / cm ² for 2 minutes using a bonding apparatus to integrally bond the silicon chip to obtain a sample for property evaluation. Was.

Comparative Example 2 About 16 mg of the resin composition A used in Example 1 was applied to a mounting position of a semiconductor element on a printed wiring board similar to that in Example 1,
Next, a silicon chip similar to that of Example 1 was further heated and pressed under the conditions of 180 ° C. and 10 kg / cm ² for 2 minutes using a bonding apparatus to integrally bond the silicon chip to obtain a sample for property evaluation. Was.

With respect to the sample for property evaluation obtained in each of the above Examples and Comparative Examples, the initial adhesive strength of the silicon chip was measured, and a thermal cycle acceleration test (-40
C. to 125.degree. C., 1000 cycles), and the adhesive strength and conduction were measured. Table 1 shows the results.

[Table 1]

As is clear from Table 1, in the embodiment,
In each case, the initial adhesive strength was sufficient, and the conduction did not become OPEN even after the thermal cycle test, and the initial adhesive strength was maintained. In Comparative Example 1, however, the adhesive strength after the thermal cycle test was large. The peeling was observed between the silicon chip and the resin composition, and the conduction was poor. Further, in Comparative Example 2, although no decrease in the adhesive strength due to the thermal cycle was observed, the initial adhesive strength was insufficient, and the conduction after the thermal cycle was poor.

[0039]

As described above, according to the present invention,
Since the periphery of the gap between the substrate and the semiconductor element is filled with a rubber / resin composition having a lower flexural modulus than the central part, high bonding reliability can be obtained even when the size of the semiconductor element increases. it can.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a semiconductor device of the present invention.

[Explanation of symbols]

 10 Substrate 20 Semiconductor element 30 Bump 41 First resin filled part 42 First resin filled part

Claims (6)

[Claims] 1. A semiconductor device in which a semiconductor element is mounted face down on a substrate, and a gap between the substrate and the semiconductor element is filled with a rubber / resin composition. The center of the gap is mainly the first
And a peripheral portion mainly filled with a second rubber / resin composition having a lower flexural modulus than the first rubber / resin composition. 2. The semiconductor device according to claim 1, wherein the flexural modulus of the second rubber / resin composition is not more than 0.9 times the modulus of elasticity of the first rubber / resin composition. . 3. The flexural modulus of the first rubber / resin composition is 6 GPa to 15 GPa, and the flexural modulus of the second rubber / resin composition is 1 GPa to 10 GPa. Item 3. The semiconductor device according to item 1 or 2. 4. The semiconductor device according to claim 1, further comprising an electrical connection portion between the substrate and the semiconductor element at a peripheral portion mainly filled with the second rubber / resin composition. 13. The semiconductor device according to claim 1. 5. The semiconductor device according to claim 4, wherein the electrical junction includes a bump provided on at least one electrode of the substrate and the semiconductor element. 6. The first and second rubber / resin compositions comprise butadiene rubber, nitrile rubber, urethane rubber, silicone rubber, polystyrene, polyvinyl alcohol,
The composition according to any one of claims 1 to 5, wherein the composition is a composition mainly containing at least one selected from methacrylic resin, polyamide, phenolic resin, melamine resin, epoxy resin, and unsaturated polyester resin. 13. The semiconductor device according to claim 1.