JPH1135800A - Resin composition and resin-sealed semiconductor device made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having low viscosity during injection of resin, low coefficient of thermal expansion after molding, and high power of adhering to a frame and a chip surface by blending an epoxy resin, a curing agent, a cure accelerator, an inorganic filler, a mold release agent comprising mainly an aliphatic compound, and a thermoplastic organic material comprising a low-molecular organic material having a steroid structure. SOLUTION: The epoxy resin (A) used comprises the one having at least two epoxy groups in the molecule, for example, a bisphenol A epoxy resin. The curing agent (B) used comprises, e.g. a phenolic novolak resin. The cure accelerator (C) used preferably comprises a phosphorus compound. The inorganic filler (D) used comprises, e.g. fused silica, in which the contents of U and Th are each at most 0.5 ppb. The mold release agent (E) used comprises, e.g. a paraffin wax. The thermoplastic organic material (F) used comprises, e.g. cholesterol. The component C accounts for 0.05-5 wt.% of the total resin components, and the component F accounts for 0.5-20 wt.% of the component E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition suitably used as a sealing material for a semiconductor chip, and a resin-sealed semiconductor device using the same.

[0002]

2. Description of the Related Art With the development of an advanced information society, integrated circuits (ICs) using semiconductors have been required to have higher capacity and more multifunctional performance. In order to meet such demands, the unit element size in a semiconductor chip has recently become smaller, and the degree of integration of an IC chip has been increasing. However, the demand for improving the performance of ICs exceeds the speed of miniaturization due to the improvement of the degree of integration, and as a result, the chip size of ICs is gradually increasing.

At present, the mainstream of IC chip packages is:
A silicon IC chip is mounted on an iron-nickel alloy frame called Alloy 42, and a first bonding pad formed on the IC chip is connected to a second bonding pad formed on the lead frame by bonding with an aluminum or gold wire. This is a method of molding a semiconductor component assembled by using an epoxy-based thermosetting resin composition. This manufacturing process was low in cost and high in productivity, and the packaged IC was excellent in reliability.

However, as the chip size of ICs has increased, it has become clear that thermosetting resin molds have the following problems. This is because stress is generated between the resin composition and the IC chip (or frame) inside the package due to the difference in the coefficient of thermal expansion between the resin composition after thermal curing and the IC chip (or frame), and This is a problem that separation occurs between the two. Such peeling is particularly noticeable when a solder reflow process is performed on the package IC. As a measure for preventing peeling, by changing the composition of the filler (filler) of the resin composition, specifically, by increasing the ratio of the filler contained in the resin composition, the coefficient of thermal expansion can be reduced by an IC.
A method of approaching the coefficient of thermal expansion of the chip has been adopted. For example, in the latest resin composition containing a quartz filler, the filler weight ratio has reached about 90%.

Although the problem of the coefficient of thermal expansion can be solved by increasing the filler composition ratio in this way, a new problem has arisen in the process of molding a package using such a resin composition. That is, when the ratio of the filler in the resin composition is increased, the viscosity does not sufficiently decrease when the resin composition is injected into a molding die in transfer molding or injection molding. For this reason, the bonding wire connecting the IC and the lead frame is deformed due to the viscous resistance of the resin composition, thereby causing a problem that leads to contact between the wires and disconnection of the wire. As a countermeasure against defects such as wire breakage, by changing the epoxy resin contained in the resin composition to a low-viscosity resin represented by a biphenyl-based or bisphenol-F-based resin, even a resin composition containing about 90% of a filler,
A method of achieving a minimum viscosity (as a specific guideline, a minimum viscosity of 70 Pa · s or less) that does not cause inconvenience such as wire breakage has been taken.

However, a resin composition containing a low-viscosity resin has a problem in that the adhesion between the resin and the surface of the frame or chip is insufficient, and the reflow resistance is insufficient. Adhesive strength can be increased by blending an adhesive strength enhancer, but many of the adhesive strength enhancers have an effect of accelerating curing, causing an increase in viscosity and storage stability at room temperature. Is reduced.

[0007]

As described above, although many characteristics are required for a resin for encapsulating a semiconductor element, a resin composition satisfying all of them has not yet been obtained. Is the current situation.

Accordingly, the present invention provides a resin composition having a low viscosity at the time of resin injection, a low coefficient of thermal expansion after molding, and a high adhesive strength to the frame and chip surfaces, and its reliability, especially resistance to It is an object of the present invention to provide a resin-sealed semiconductor device having high reflow properties.

[0009]

In order to solve the above-mentioned problems, the present invention provides an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and a release agent containing aliphatic as a main component. , Containing a thermoplastic organic material, wherein the thermoplastic organic material,
Provided is a resin composition characterized by being a low molecular weight organic material having a steroid structure.

The present invention also provides an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a release agent containing an aliphatic component as a main component, and a thermoplastic organic material. The organic material provides a resin composition having at least an alicyclic structure having 6 or more carbon atoms and a methylene chain having 12 or more carbon atoms.

Further, the present invention comprises a semiconductor element and a resin layer for encapsulating the semiconductor element, wherein the resin layer uses a cured product of the above resin composition. A semiconductor device is provided.

Hereinafter, the present invention will be described in more detail. The epoxy resin that can be blended in the epoxy resin composition of the present invention is not particularly limited, as long as it has two or more epoxy groups in one molecule. Specifically, bisphenol A type epoxy resin,
Bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthol type novolak type epoxy resin, bisphenol A novolak type epoxy resin,
Epoxidized tris (hydroxyphenyl) alkane, epoxidized tetra (hydroxyphenyl) alkane obtained by epoxidizing a condensate of phenol or alkylphenol and hydroxybenzaldehyde,
2,2 ′, 4,4′-tetraglycidoxybenzophenone, triglycidyl ether of paraaminophenol,
Examples include polyallyl glycidyl ether, 1,3,5-triglycidyl ether benzene, 1,2,3-triglycidyl ether benzene, and glycidyl ether of phenol aralkyl resin. These epoxy resins can be used alone or in combination of two or more.

As the curing agent in the epoxy resin composition of the present invention, a phenol resin can be used. Specifically, a phenol novolak resin, a cresol novolak resin, a nonylphenol resin, a nonylphenol novolak resin, a bisphenol F type novolak resin, Novolak type phenol resins such as bisphenol A type novolak resin and naphthol type novolak resin, 2,2 ′
A phenol aralkyl resin of a condensation polymerization compound of -dimethoxy-p-xylene and a phenol monomer, a biphenyl phenol aralkyl resin, a naphthalene phenol aralkyl resin, a dicyclopentadiene phenol polymer, hydroquinone, resorcinol, catechol,
1,2,3-trihydroxybenzene, and 1,3
5-trihydroxybenzene and the like. These phenolic resins can be used alone or in combination of two or more.

In the resin composition of the present invention, the mixing ratio of the epoxy resin component and the phenol resin component is determined by the ratio of the number of phenolic hydroxyl groups of the phenol resin as a curing agent to the number of epoxy groups of the epoxy resin (the number of phenolic hydroxyl groups / It is desirable to adjust so that the number of epoxy groups) is in the range of 0.5 to 1.5. If this value is less than 0.5, the curing reaction is unlikely to occur sufficiently, while if it exceeds 1.5, the curing properties, especially the moisture resistance, tend to deteriorate.

In the resin composition of the present invention, as a curing accelerator, amine-based, phosphorus-based, boron-based, and phosphorus-based
Although a boron-based or the like can be used, among these, a resin composition containing a phosphorus-based curing accelerator is particularly preferred.
Since it has excellent moisture resistance after curing, it is suitable for sealing semiconductor elements. The compounding amount of the curing accelerator is preferably 0.05 to 5% by weight of the entire resin component. This is because when the amount of the curing accelerator is less than 0.05 wt%, it is difficult to exert its effect sufficiently, and when it exceeds 5 wt%, the gel time becomes too short and unfilling occurs. This is because there is a fear.

Examples of the inorganic filler include fused silica, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, and mica. These may be used alone or as a mixture of two or more. it can.
Note that a fused silica, a crystalline silica, or the like is particularly preferably used because a composition having a low hygroscopicity and a low melt viscosity can be obtained. The shape of fused silica or crystalline silica includes crushed and spherical silica, and these may be combined and combined.

In any of the inorganic fillers, the content of uranium (U) and thorium (Th) in the filler is desirably 0.5 ppb or less in order to prevent soft errors.

The amount of the inorganic filler as described above is
70 to 95% by weight, and more preferably 8 to 80% by weight based on the whole resin composition.
The content is preferably set to 5 to 92% by weight. If it is less than 70 wt%, it is difficult to obtain sufficient thermal shock resistance, while 9
If it exceeds 5% by weight, the melt viscosity of the composition may increase and the moldability may decrease.

Examples of the release agent blended in the resin composition of the present invention include natural waxes such as paraffin wax, rice wax, carnauba wax and candelilla wax; petroleum waxes such as polyethylene wax and polyethylene oxide wax; Examples include higher aliphatic ketones, higher aliphatic esters, higher fatty acids, higher aliphatic alcohols, and the like. These may be used alone or in a mixture of two or more. The amount of the release agent is 0.1 to 2.5 parts by weight based on 10 parts by weight of the epoxy resin.

The thermoplastic organic materials used in the present invention include the following two types. First
Is a low molecular weight organic material having a steroid skeleton, and the second thermoplastic organic material has at least an alicyclic structure having 6 or more carbon atoms and a methylene chain having 12 or more carbon atoms. . The alicyclic structure having 6 or more carbon atoms in the second thermoplastic organic material has a steroid structure,
It can be selected from an adamantane structure and a norbornene structure. Specific examples of the thermoplastic organic material include cholesterol, cholesterol stearate, norbornenol pehenate, and adamantanol behenate.

The amount of the thermoplastic organic material is 0.5 to 2 parts by weight based on the weight of the release agent in the resin composition.
It is preferably 0% by weight. If the amount is less than 0.5% by weight, the effect of blending the thermoplastic resin cannot be sufficiently obtained, while if it exceeds 20% by weight, the effect of the release agent may be impaired.

Further, in addition to the above-mentioned components, the resin composition of the present invention may further contain a pigment such as carbon black and titanium dioxide; a surface treating agent such as a silane coupling agent; a flame retardant auxiliary such as antimony trioxide; Etc. may be appropriately added.

In the resin composition of the present invention, the above-mentioned components are melted and kneaded by a heating roll, a kneader or an extruder, mixed by a special mixer capable of being finely pulverized, or by appropriately combining these methods. Can be manufactured more easily.

In sealing a semiconductor element using the resin composition of the present invention, low pressure transfer molding is most commonly used, but is not limited thereto. That is, the semiconductor element can be sealed by any method such as injection molding, compression molding, and casting. After sealing, it is desirable to perform after-curing at a temperature of 175 ° C. or higher.

It should be noted that the semiconductor chip sealed in the present invention is not particularly limited, and any chip according to the purpose or application can be sealed. Since the thermoplastic organic material blended in the resin composition of the present invention has compatibility with any of the epoxy resin, the curing agent, and the release agent composed of an aliphatic resin, it is separated from the resin that originally undergoes phase separation. It exists at the interface with the agent and has the effect of improving its dispersibility. Therefore, it was possible to suppress the release agent from excessively adhering to the frame during resin molding, and as a result, a resin composition having excellent adhesion to the frame or chip surface and having a combination of release properties was obtained. . In addition, since the viscosity of the above-mentioned thermoplastic organic material after melting is low, it is effective for reducing the viscosity of the resin composition.

Furthermore, since the above-mentioned thermoplastic organic material has both crystalline and amorphous properties (or an ordered state and a disordered state), it has an effect of relieving the stress inside the resin by a structural change. . Therefore, particularly in the sealing of a chip having a large area, the load on the element under the cooling / heating cycle or the heating under pressure can be reduced. Therefore, by sealing a semiconductor element with the resin composition of the present invention, a resin-sealed semiconductor device having significantly improved reflow resistance can be manufactured.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. Note that the present invention is not limited to the following examples. Table 1 below shows an epoxy resin, a thermosetting agent, silica fine particles of an inorganic filler, a silane coupling agent, a curing accelerator (catalyst), a release agent, a thermoplastic organic material,
The composition examples of the thermosetting resin compositions (Examples 1 to 8 and Comparative Examples 1 to 4) containing a coloring agent (carbon black) and, if necessary, a modifier and a flame retardant are shown below. The content of silica fine particles in the resin composition is 90% by weight.
It is.

[0028]

[Table 1]

The unit of the compounding amount in the table is part by weight. Table 2 below summarizes the types and characteristics of the thermoplastic organic materials blended in the resin compositions of Examples and Comparative Examples.

[0030]

[Table 2]

The examples (1 to 1) prepared as described above
8) and the resin compositions of Comparative Examples (1 to 4) were evaluated for adhesion as follows. 8.5mm x 29m
Using a strip-shaped frame having a thickness of m, resins having different thicknesses (0.5 mm and 2 mm) were molded on one side to prepare samples, and peeling evaluation was performed on each sample by ultrasonic flaw detection. In Table 3 below, a resin composition containing a biphenyl-based epoxy resin as an epoxy resin (Examples 5 to 8,
The numbers of peelings for Comparative Examples 1, 3, and 4) are shown together.

[0032]

[Table 3]

As shown in Table 3, resin compositions of the present invention containing specific thermoplastic organic materials (Examples 5 to 8)
Is extremely excellent in adhesiveness and is not affected at all by the resin film thickness. On the other hand, in the resin composition of the comparative example, peeling was observed, and particularly when the resin film thickness was 0.5%.
This is remarkable when the area is as thin as mm and the frame surface is 42 alloy.

Table 4 below shows resin compositions containing bisphenol F as an epoxy resin (Examples 1 to 3).
4, Comparative Example 2) are shown together with the results of evaluation in the same manner as described above.

[0035]

[Table 4]

From the results shown in Table 4, the resin compositions of the present invention (Examples 1 to 4) containing a specific thermoplastic organic material are extremely excellent in adhesiveness and are not affected by the resin film thickness at all. You can see that. On the other hand, in the conventional example, peeling was observed, and contrary to the result in Table 3 above, the resin film thickness was 2.
It appears when the area is as thick as 0 mm and the frame surface is made of 42 alloy and polyimide.

Next, using the resin composition according to the present invention,
A resin-encapsulated semiconductor device was manufactured, and its reliability was evaluated by appearance inspection and electrical characteristic inspection. In manufacturing the resin-encapsulated semiconductor device, first, the resin tablets of this example and the comparative example were left at room temperature for 24 hours. on the other hand,
QFP (Quad Flat Package) 184
An 18 mm square test semiconductor chip was assembled on a pin frame. Then, these are Q
Using a mold exclusively for FP184pin, molding was performed with a transfer molding apparatus to obtain a sample of a resin-sealed semiconductor device. Note that the resin sealing condition is 185
° C and 60 seconds.

Each sample was inspected for initial resin peeling by an ultrasonic flaw detector before the reliability test, and the sample in which peeling occurred was not subjected to the reliability test. The QFP (Quad Flat Package) manufactured here
FIG. 1 is a perspective view schematically showing e), and FIG. 2 is a sectional view thereof. The QFP 10 is, as shown in FIG.
A semiconductor chip 12 is mounted on 1, and the semiconductor chip 12 is electrically connected to a lead frame 13 by a bonding wire 14. These are sealed by the resin layer 15 obtained by curing the resin composition of the present invention.

Package visual inspection and TCT of a sample sealed with a resin composition using bisphenol F as an epoxy resin (Examples 1 to 4, Comparative Examples 1 and 4)
The results of the test are summarized in Table 5 below, and the results of the PCT test on similar samples are summarized in Table 6 below.

The TCT test was performed at -60 ° C (30 minutes).
→ A room temperature (5 minutes) → 150 ° C. (30 minutes) → Room temperature (5 minutes) cycle is performed by a cooling and heating cycle, and the PCT test is performed under the condition of a saturated steam pressure of 127 ° C. (2.5 atm). Was.

[0041]

[Table 5]

[0042]

[Table 6]

A resin composition using a biphenyl-based epoxy as an epoxy resin (Examples 5 to 8, Comparative Example 2)
Package external inspection for the sample sealed with
The results of the TCT test are summarized in Table 7 below, and the results of the PCT test on similar samples are summarized in Table 8 below.

[0044]

[Table 7]

[0045]

[Table 8]

From the results shown in these tables, the resin-encapsulated semiconductor device sealed with the resin composition of the present invention containing a specific thermoplastic organic material shows almost no defects in any of the tests. It can be seen that the semiconductor device has better reliability than the semiconductor device sealed with the resin composition of the comparative example.

The resin composition of the present invention was prepared using bisphenol S type, diphenyl ether type, naphthalene type, trifunctional type, etc. as an epoxy resin, and was evaluated in the same manner as described above. However, in each case, an effect equivalent to that of the bisphenol F type was obtained.

[0048]

As described in detail above, according to the present invention,
A resin composition having a low viscosity at the time of resin injection, a low coefficient of thermal expansion after molding, and a high adhesive strength to a frame and a chip surface is provided. By using this resin composition, it is possible to manufacture a resin-encapsulated semiconductor device having excellent reliability, especially excellent reflow resistance,
Its industrial value is immense.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of a resin-sealed semiconductor device of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a resin-sealed semiconductor device of the present invention.

[Explanation of symbols]

 Reference Signs List 10 QFP (Quad Flat Package) 11 Substrate 12 Semiconductor chip element 13 Lead frame 14 Bonding wire 15 Resin layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuo Okuyama 1 Toshiba-cho, Komukai Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa Inside the R & D Center of Toshiba Corporation

Claims (4)

[Claims] 1. An epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a release agent containing an aliphatic component as a main component, and a thermoplastic organic material, wherein the thermoplastic organic material is And a low molecular weight organic material having a steroid structure. 2. An epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and a release agent containing aliphatic as a main component.
A resin composition comprising a thermoplastic organic material, wherein the thermoplastic organic material has at least an alicyclic structure having 6 or more carbon atoms and a methylene chain having 12 or more carbon atoms. 3. The resin composition according to claim 2, wherein the alicyclic structure having 6 or more carbon atoms is selected from a steroid structure, an adamantane structure, and a norbornene structure. 4. A semiconductor device comprising: a semiconductor element; and a resin layer for encapsulating the semiconductor element, wherein the resin layer comprises
A resin-encapsulated semiconductor device, comprising using a cured product of the resin composition according to any one of the above.