JP2000273288A - Sealing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing resin composition equipped having a light shading property and an insulation property simultaneously and an optimal characteristic used for a semiconductor device. SOLUTION: This sealing resin composition contains carbon black of having physical properties of having 20-40 nm mean particle diameter and containing >=10 wt.% vaporizing amount, by 0.3-1.0 wt.% based on the total sealing resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing resin composition for a semiconductor chip having excellent insulating properties and light shielding properties.

[0002]

2. Description of the Related Art In recent years, semiconductor devices having a large number of electrode terminals have been developed as electronic circuits become more sophisticated. A typical example is flip-chip mounting.

FIG. 8 is a sectional view showing a conventional flip chip mounting. As shown in FIG. 8, the semiconductor chip 1
A connection electrode 3 formed on the substrate 5, a connection electrode 4 formed on the substrate 5, a connection material 3 such as a conductive adhesive or solder for connecting the connection electrode 4 and the protrusion electrode 2, a semiconductor chip 1 and the substrate 5, a structure having a sealing resin composition 6 therebetween.

The semiconductor chip 1 is an aggregate of diodes and transistors. When irradiated with light, light energy is converted to electric energy by a photoelectric effect, and the semiconductor chip cannot be driven normally. Therefore, carbon black is added to the sealing resin composition 6 as a coloring agent to provide light-shielding properties. However, since carbon black itself is conductive, increasing the amount of addition to enhance the light-shielding properties results in sealing. There is a possibility that the insulating property of the resin composition 6 may be reduced. When the insulating property of the sealing resin composition 6 decreases, it causes a leak current, consumes more power than originally used, and causes a malfunction of the semiconductor chip 1.

When a pigment such as phthalocyanine or quinacridone is used as a coloring agent other than carbon black, there are wavelengths of light to be absorbed and wavelengths of light reflected by the color of the pigment, and all wavelengths of light for generating a photoelectric effect are required. Cannot be shielded. Particularly at infrared wavelengths, the light-shielding properties are inferior to carbon black.

[0006]

In a conventional sealing resin composition, carbon black or a pigment is added as a colorant to shield light. However, when carbon black is used as a colorant, the light-shielding property is reduced. It was not possible to fully satisfy both the insulation properties and the insulation properties. In addition, when a pigment is used as a colorant, there is a problem that a light-shielding property for preventing malfunction of a semiconductor chip due to a photoelectric effect cannot be obtained.

An object of the present invention is to solve the above-mentioned problems and to provide a sealing resin composition having both light-shielding properties and insulating properties and having optimum characteristics for use in a semiconductor chip.

[0008]

Means for Solving the Problems To achieve the above object, the sealing resin composition of the present invention employs the following constitution.

The encapsulating resin composition of the present invention comprises a main component of an epoxy resin, a curing agent and a curing accelerator.
In 0% by weight, carbon black having an average particle diameter of 20 to 40 nm and heating at 950 ° C. for 7 minutes in a nitrogen atmosphere to obtain a carbon black having a weight change before and after heating, ie, a volatilization amount of 10% by weight or more. It is characterized by containing 3 to 1.0% by weight.

[0010] The sealing resin composition of the present invention comprises a main component of an epoxy resin, a curing agent and a curing accelerator.
0% by weight contains 0.3 to 1.0% by weight of carbon black having an average particle diameter of 20 to 40 nm and a volatilization amount of 10% by weight or more.
%, And is cured under a curing condition in which the insulation resistance value is 10 ¹⁵ Ω or more.

The encapsulating resin composition of the present invention comprises a main component of an epoxy resin, a hardening agent, and a hardening accelerator.
0% by weight contains 0.3 to 1.0% by weight of carbon black having an average particle diameter of 20 to 40 nm and a volatilization amount of 10% by weight or more.
It is characterized by curing in two stages of one hour.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, in order to obtain a sealing resin composition having both light-shielding properties and insulating properties and having optimum characteristics for a semiconductor chip, the average particle diameter of carbon black contained in the sealing resin is reduced. The optimum range and the dispersibility of carbon black were examined. Regarding the dispersibility of carbon black, attention was paid to the content of polar groups formed on the surface of carbon black by the oxidation treatment, and the relationship between the insulation resistance value and the light transmittance was examined. From these examination results, it became clear that the physical properties of carbon black affected the light-shielding properties and insulation properties of the sealing resin composition,
It has been found that in order to obtain a sealing resin composition having both good light-shielding properties and insulating properties, it is necessary to control the physical properties of carbon black within an optimum range.

Further, the relationship between the curing conditions of the sealing resin composition and the light transmittance was examined, and it was found that the curing conditions affected the insulation resistance value and the light transmittance of the cured product. .
By optimizing the curing conditions, a sealing resin composition having both light-shielding properties and insulating properties was obtained. By combining the optimum physical properties of the carbon black and the curing conditions, it has become possible to obtain a sealing resin composition having more excellent light shielding properties and insulating properties.

[0014]

EXAMPLES The encapsulating resin composition of the present invention will be specifically described below. In order to investigate the optimal physical properties of carbon black contained in the sealing resin for semiconductor chips, first, the particle diameter of carbon black, the insulation resistance value when carbon black is contained in the sealing resin, and the light transmittance When the relationship was examined, the result shown in FIG. 1 was obtained.

The sealing resin used at this time was bisphenol F type epoxy which is a liquid epoxy resin as a main ingredient, methylnadic anhydride (hereinafter referred to as MNA) as a curing agent, and 2-phenyl-epoxy as a curing accelerator. 4-methyl-5-hydroxymethylimidazole (hereinafter referred to as 2P4
MHZ) and containing 50% by weight of a SiO ₂ filler. The amount of the MNA as a curing agent was determined by using the value of the molecular weight of the acid anhydride / epoxy equivalent to 105 parts by weight of the MNA with respect to 100 parts by weight of the bisphenol F type epoxy as the main agent.
The addition amount of MHZ was blended so as to be 1 part by weight with respect to 100 parts by weight of the main agent.

The average particle size of the carbon black is 13,
17, 20, 25, 29, 34, 38, 45, 60 nm
The weight of carbon black is 0.3 with respect to the total encapsulating resin composition obtained by mixing the epoxy resin main agent, curing agent, curing accelerator, filler, and carbon black.
The insulation resistance value and the light transmittance of the sealing resin composition contained at a concentration of 130 wt% and cured at 130 ° C. for 2 hours were measured.

The insulation resistance value was obtained by reading the current value when a voltage of 100 V was applied between the protruding electrodes 2 for 1 minute in the flip-chip mounting shown in FIG. 2 and calculated according to Ohm's law. Further, as shown in FIG. 3, the light transmittance was about 100 μm
After the sealing resin composition was poured into the one in which the gap b was formed and cured by heating, the light transmittance was measured in a wavelength range of 300 to 1000 nm including the visible light wavelength and the near infrared wavelength, and the wavelength was measured. Regardless, the maximum value was used.

As shown in FIG. 1, the relationship between the average particle size of carbon black and the light transmittance is such that the larger the average particle size, the easier it is to transmit light, and the relationship between the average particle size of carbon black and the insulation resistance value is as follows. It was found that the smaller the average particle diameter, the higher the conductivity. The light transmittance is 0.5% or less when the average particle size of carbon black is less than 40 nm, but the transmittance increases when the average particle size is 40 nm or more, and the insulation resistance value is the average particle size of carbon black. Is greater than or equal to 20 nm, the value is on the order of 10 ¹³ Ω, but if it is less than 20 nm, the insulation resistance value decreases. From the above, it was found that the average particle diameter of carbon black having both insulating properties and light-shielding properties and optimal for a sealing resin composition for a semiconductor chip was 20 to 40 nm.

Next, the relationship between the volatilization amount of carbon black and the insulation resistance when carbon black was contained in the sealing resin composition was examined. The result is shown in FIG. The sealing resin used at this time was made of the same material as the above-mentioned sealing resin.

The amount of volatilization of carbon black means that carbon black is heated at 950 ° C. for 7 minutes in a nitrogen atmosphere,
The change in weight of the carbon black itself before and after heating was taken. In order to improve the dispersibility of carbon black itself, a dispersant such as an organic compound is mixed. When a large amount of a dispersant is contained, the number of polar groups formed on the surface of carbon black increases, and the amount of volatilization increases by heating. That is, when the weight change before and after heating is large, it means that the carbon black particles have many polar groups, and it is presumed that the carbon black particles before heating form small aggregates. You.

Conversely, when the volatilization amount, that is, the change in weight is small, the number of polar groups formed on the surface of the carbon black is small, and aggregation or bonding of carbon black particles tends to occur. Are presumed to form large aggregates.

The average particle size of the carbon black is 25 nm.
And the volatilization amount is 1, 2, 5, 9, 10, 15, 20% by weight.
0.3% by weight in the sealing resin composition
And cured at 130 ° C. for 2 hours, but the insulation resistance was measured. The insulation resistance was measured by the method described above.

As shown in FIG. 4, when a carbon black having a volatilization amount of 10% by weight or more is used, the insulation resistance value is on the order of 10 ¹³ Ω, but a carbon black having a volatilization amount of less than 10% by weight is used. It was found that the insulation resistance value was reduced when was used. According to these results, the use of a material having a small volatilization amount of carbon black, that is, a material having large aggregates of carbon black particles, reduces the insulating property of the sealing resin composition and has a large volatilization amount, that is, carbon When using black particles that are small aggregates,
It was found that the insulating properties tended to be high. From the above, it has been determined that it is optimal to use the carbon black which is optimal for the sealing resin composition for a semiconductor chip under the above-mentioned heating conditions and which exhibits a volatilization amount of 10% by weight or more, and of course, is unheated. Was.

The relationship between the content of carbon black and the insulation resistance and light transmittance when carbon black was contained in the sealing resin composition was examined.
The result shown in FIG. As the sealing resin composition used at this time, the same sealing resin composition as described above was used. Carbon black having an average particle diameter of 25 nm and a volatilization amount of 10% by weight is used, and 0, 0.2, 0.3, 0.5, 1.0, 1.1 is contained in the sealing resin composition. 1.
The content was set to 2, 1.5% by weight, and the insulation resistance and light transmittance were measured. The insulation resistance value and light transmittance were measured by the methods described above.

As shown in FIG. 5, the relationship between the carbon black content and the light transmittance is such that the lower the content, the easier the light is to transmit, and the relationship between the carbon black content and the insulation resistance is the content. It has been found that the conductivity tends to increase as the number increases. The light transmittance was 0.5% or less when the content of carbon black was 0.3% by weight or more, but increased when the content was less than 0.3% by weight. The insulation resistance value is 1 when the carbon black content is 1% by weight or less.
It shows a level of 0 ¹³ Ω, but when it exceeds 1% by weight, the insulation resistance value decreases. From the above, it was found that the optimal content of carbon black in the encapsulating resin composition for semiconductor chips having both insulating properties and light shielding properties is optimally 0.3 to 1.0% by weight.

Although the above-mentioned experiment was able to elucidate the optimum physical properties of carbon black contained in the sealing resin composition, it was confirmed that the light transmittance was 0.5% and the carbon black was sealed. Since the insulation resistance when not contained in the resin composition is on the order of 10 ¹⁵ Ω, there is still room for improvement.

As a result of examining the relationship between the curing conditions of the sealing resin composition containing carbon black, the insulation resistance value and the light transmittance, the results shown in FIG. 6 were obtained. The same sealing resin composition as that described above was used for the sealing resin composition. Carbon black contained in the sealing resin composition has an average particle diameter of 25 nm and a volatilization amount of 10
% By weight of the total sealing resin composition. The curing condition of the sealing resin composition is DS
Estimated from Method C, 80 ° C for 20 hours, 90 ° C for 12 hours, 1
Curing was performed at 00 ° C for 5 hours, 130 ° C for 2 hours, and 150 ° C for 1 hour. The insulation resistance value and light transmittance were measured by the methods described above.

As shown in FIG. 6, the insulation resistance is 150 ° C.
The resin cured in one hour shows the lowest value, on the order of 10 ¹⁰ Ω. The lower the curing temperature, the higher the insulation resistance tends to be. The one cured at 80 ° C. for 20 hours shows the value on the order of 10 ¹⁵ Ω. I understand. Under the curing condition of 150 ° C. for 1 hour, the curing temperature and the heat generated during the curing reaction volatilize the curing agent and the curing accelerator, and the carbon black concentration in the sealing resin composition increases. This is because the volume shrinkage due to volatilization promotes the aggregation of carbon blacks. The light transmittance was 0% when cured at 80 ° C. for 20 hours, but it was found that light was transmitted under other conditions.

However, it takes too much time under the curing condition of 80 ° C. for 20 hours, which is a problem in workability. Then, when the two-stage curing in which the carbon black is gelled or semi-cured to such an extent that it does not flow, and then cured at a high temperature was examined, the result shown in FIG. 7 was obtained. As the sealing resin composition used at this time, the same sealing resin composition as described above was used. The curing conditions of the sealing resin composition are as follows: 80 ° C. for 1 hour + 150 ° C. for 1 hour, 80 ° C. for 1.5 hours + 150 ° C. for
80 ° C 2 hours + 150 ° C 1 hour, 80 ° C 3 hours + 150
Cured for 1 hour at ℃. The insulation resistance value and light transmittance were measured by the methods described above.

As shown in FIG. 7, the first of the sealing resin composition
If the curing condition of the above is less than 2 hours at 80 ° C., it is insufficient for gelling or semi-curing the sealing resin composition, and the insulation resistance value is lowered. At 80 ° C. for 2 hours or more, the insulation resistance value was on the order of 10 ¹⁵ Ω, indicating that the resin composition had sufficient insulation properties as a semiconductor chip sealing resin composition. In addition, the light transmittance was 0% when the first curing condition of the sealing resin composition was 80 ° C. for 2 hours or more, but it was found that light was transmitted when the first curing condition was less than 80 ° C.

The same effect was obtained when liquid acid anhydrides such as methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and tetrapropenylsuccinic anhydride, which do not have a very high boiling point, were used as the curing agent. In addition, it has been found that similar effects can be obtained even when a liquid amine or the like is used as a curing agent.

[0032]

As is apparent from the above description, the physical properties of the carbon black contained in the sealing resin composition are as follows: the average particle diameter is 20 to 40 nm, and the volatilization amount is 10% by weight.
As described above, the content of carbon black contained in the sealing resin composition is 0.3 to 1.0% by weight based on the entire sealing resin composition.
By doing so, a sealing resin composition having both insulating properties and light shielding properties can be obtained.

When a curing agent having a very low boiling point is used, the curing condition of the sealing resin composition is 80 ° C. for 2 hours + 1.
By setting the temperature at 50 ° C. for 1 hour, a sealing resin composition having both insulating properties and light shielding properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship among an average particle diameter of carbon black, an insulation resistance value, and light transmittance in an example of the present invention.

FIG. 2 is a cross-sectional view showing a position where an insulation resistance value is measured in the example of the present invention.

FIG. 3 is a cross-sectional view showing a sample for measuring light transmittance in an example of the present invention.

FIG. 4 is a graph showing a relationship between a volatilization amount of carbon black and an insulation resistance value in Examples of the present invention.

FIG. 5 is a graph showing the relationship among the carbon black content in the sealing resin composition, the insulation resistance value, and the light transmittance in Examples of the present invention.

FIG. 6 is a graph showing the relationship between the curing conditions of the sealing resin composition, the insulation resistance value, and the light transmittance in Examples of the present invention.

FIG. 7 is a graph showing the relationship between the curing conditions of the sealing resin composition, the insulation resistance value, and the light transmittance in Examples of the present invention.

FIG. 8 is a cross-sectional view showing a structure of flip chip mounting in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Protrusion electrode 3 Connection material 4 Connection electrode 5 Substrate 6 Sealing resin composition 7 Glass plate 8 Double-sided tape

Claims (3)

[Claims] An average particle size of the epoxy resin as a main component, a curing agent and a curing accelerator is 20 to
40 nm, heated at 950 ° C. for 7 minutes in a nitrogen atmosphere, and carbon black having a weight change of 10% by weight or more before and after heating is added to 0.3% by weight in 100% by weight of the sealing resin composition.
An encapsulating resin composition characterized in that the content of the encapsulating resin is from 1.0 to 1.0% by weight. 2. The curing condition according to claim 1, wherein the light transmittance after curing of the sealing resin composition is substantially 0% and the insulation resistance value is 10 ¹⁵ Ω or more. A sealing resin composition characterized by being cured by: 3. The encapsulating resin composition according to claim 1, wherein the encapsulating resin composition is cured in two stages: 80 ° C. for 2 hours or more and 150 ° C. for 1 hour or more.