JPH0211631A - Resins for protecting semiconductors and semiconductors - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a protective resin for semiconductors with a high degree of integration, and more particularly to a buffer coat that relieves stress generated between a semiconductor element and a sealing material. α prevents malfunctions (soft errors) due to incidence of α rays from outside the film or semiconductor element
The present invention relates to a resin for protecting semiconductors such as a radiation shielding film, and a semiconductor protected by this resin or a resin obtained by imidizing this resin.

In semiconductor devices, there is a trend toward larger chips and finer wiring, and this is accompanied by curing shrinkage of the resin encapsulant, stress generation due to the difference in thermal expansion coefficient between the chip and the encapsulant, and the occurrence of stress in the encapsulant. Fillers and the like make electrode sliding, passivation cracks, etc. more likely to occur, causing a decrease in moisture resistance.

For this reason, efforts have been made to reduce the stress of the sealing material in order to reduce the defective rate caused by these factors, but on the other hand, a 2-5* polyimide film is formed on the inorganic passivation film, There are increasing attempts to reduce the stress applied to chips.

Generally, polyimide with excellent stress relaxation properties and a low elastic modulus is said to be effective for such purposes.

On the other hand, it has become clear that when α rays are incident on highly integrated semiconductor memory devices, they cause soft errors. Furthermore, in semiconductor memories, as the degree of integration increases, the cell area tends to decrease, and as a result, the rough 1 to error resistance inevitably decreases, and it is said that the formation of an α-ray shielding film becomes essential when the memory size exceeds 4 Mbits.

Various methods have been proposed for these purposes. For example, a method using a polyamic acid small aggregate with improved adhesion to semiconductor elements as a surface protective film (Japanese Patent Laid-Open No. 59-5
6.453@ and JP-A No. 61-84.025) or a method using highly heat-resistant polyamic acid as a surface protective film (JP-A-58-218.127 and JP-A-54-74.677) Publications) etc. are known. However, with these methods, both moisture resistance and stress relaxation properties are insufficient, and polyimide itself has a relatively high dielectric constant, so although it is sufficient as a protective resin for semiconductors. do not have.

In addition, a method is known in which diaminoborisloginane is used as a copolymerization component for the purpose of obtaining a polyimide with a low elastic modulus (JP-A-62-223.22S and JP-A-63
35.626), but in this method, the siloquinane block and the aromatic polyimide block formed an opaque film with macroscopic phase separation, and the electrical and mechanical properties were not sufficient.

[Problems to be Solved by the Invention] The present invention provides stress relaxation properties, moisture resistance, adhesion to the element surface,
It is possible to form a pinhole-free polyimide protective film with excellent electrical properties. Therefore, the workability for forming the protective film and the resistance to electrolytic corrosion at high temperatures or high humidity can be greatly improved, and this protective film also has excellent thermal shock resistance. Another object of the present invention is to provide a resin composition for protecting a semiconductor and a semiconductor that have an excellent function of preventing errors.

[Means for Solving the Problems] That is, the present invention provides the following - formation (1) 250 to 99 mol% and general formula (2) (in the formula, 1<4 and R5 represent a divalent organic group, R6 -R
9 represents a methyl group, an ethyl group, a phenyl group, or a substituted phenyl group, and ρ represents an integer of 1 to 50. The semiconductor is provided with a semiconductor protective resin made of a polyimide precursor obtained by wide condensation with an anhydride, and a protective film resin whose main component is this resin or a polyimide resin obtained by imidizing this resin.

The aromatic tetracarboxylic dianhydride used in this invention has the following -formation (3), R2 and R3 represent monovalent hydrocarbon groups, n and m represent integers of O to 4, and , X represents a divalent group)
It is a diether-based aromatic diamide represented by (wherein Ar represents a tetravalent R1 containing at least one aromatic ring). Specifically, 3.3', 4.4'-
Benzophenone tetracarboxylic dianhydride, 3,3°,
4,4°-Biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3°, 4.4°-diphenyl ethertetracarboxylic dianhydride, 2,3,3°,4
”-Biphenyltetracarboxylic dianhydride, 2,3,6
．． 7-naphthalenetetracarboxylic dianhydride, 1,2,
5.8-Naphthalenetetracarboxylic dianhydride, 282
-Bis(3,4-dicarboxyphenyl)propanihydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,4,9.10-perylenetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)propananhydride, -dicarboxyphenyl)ether dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propanihydride, 1,1-bis(2,3-
dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride,
Examples include 2,3,6.7-anthracenetetracarboxylic dianhydride and 1,2,7.8-phenanthrenetetracarboxylic dianhydride.

Moreover, in this invention, the diamines shown in the above-mentioned -formation (1) and -formation (2) are used as the diamine component.

In general formula (1), R1 is a wing, (wing) or 0-X-
0, where X is -o-1-s-1-s
o2--co-1-CO2--CONH-1-CH2-
1-C(CH3)2-1-C(CF3)2- can be mentioned as preferred.

- Specific examples of the diether aromatic diamine represented by formation (1) include (c)
Examples include, but are not limited to, H2(t)''2 NGOGOGOGNH2 and alkyl substituted products thereof such as methyl and ethyl substituted products.

Specific examples of diaminosiloxanes represented by -formation (2) include the following.The average value of 1 for these diaminosiloxanes is usually 1 to 50, but preferably 10 to 30.
It is. If the average value of 1 is less than 10, the effect of lowering the elastic modulus is small, and if the average value of 9 is 50 or more, the reactivity with tetracarboxylic dianhydride decreases and siloxane block bonds are formed. The resulting polyimide has the disadvantage of poor adhesion to the substrate.

The polyimide precursor solution of the present invention is obtained by reacting the above-mentioned diether-based aromatic diamine and siloxane-based diamine in substantially equimolar amounts with an aromatic tetracarboxylic dianhydride. In addition, in order to suppress the decrease in heat resistance and increase in the coefficient of thermal expansion of the polyimide film, which is a cured product of the polyimide precursor, diether-based aromatic diamine is added to 50 to 9
It is preferable that the amount of siloxane diamine be 9 mol % and 1 to 50 mol % of the siloxane diamine.

Further, as the solvent used in producing the resin solution of the present invention, it is preferable to use a reaction solvent having an ether bond such as tetrahydrofuran, diethyl glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether. It is preferable to use these ether solvents in an amount of 30% by weight or more based on the total amount of solvents. Use of these ether solvents increases the uniformity and storage stability of the polyimide precursor solution, and also enables low-temperature heat treatment during conversion into a polyimide film.

Furthermore, as part of the diamine component, a diaminodisiloxane compound of ρ-1 among the diaminosiloxane compounds represented by -formation (2) can also be used in combination for the purpose of improving adhesive strength. Specific examples of such diaminodisiloxane compounds include the following. The content of these is preferably 0.1 to 10 in the total cyamine component.
It is mol%, more preferably 0.1 to 5 mol%. Such a disiloxane compound is known to be effective in improving adhesive strength, but if it is less than 0.1 mol%, it has no significant effect, and if it is more than 10 mol%, it greatly reduces heat resistance. In addition, small amounts of other diamine components or tetracarboxylic acid components may be used for the purpose of improving the physical properties of the resin.

The method for producing the resin composition of the present invention includes: (1) dissolving the entire amount of the diamine component in a mixed solvent, and then gradually adding tetracarboxylic dianhydride and polymerizing it; A method in which the diamine component is sequentially added after being dispersed or dissolved in a polymerization solvent and polymerized; ■ A method in which the tetracarboxylic dianhydride and the diamine component are charged into a reactor and then a polymerization solvent is added; etc., and either method can be adopted, but ■
The polymerization method is more preferred.

That is, after dispersing or dissolving the entire amount of tetracarboxylic dianhydride in a polymerization solvent, adding the siloxane diamine shown in -formation (2) to form a siloxane block, and then -forming (1). ) is required by adding a diether aromatic diamine to complete the polymerization.

By such a method, a transparent resin in which siloxane blocks are microdispersed can be obtained.

The polyimide precursor obtained in this way has spin-coating properties even at high resin concentrations, and after coating by this method, adhesion can be achieved by heat treatment at a low temperature and short time that can remove the organic solvent. Since it is possible to form a polyimide having a pinhole-free phase-separated structure with excellent properties, mechanical properties, and electrical properties, it is possible to significantly suppress the occurrence of semiconductor defects under high temperature and high humidity conditions. Furthermore, since this resin composition contains almost no uranium or thorium,
When various types of stabilization materials such as epoxy resin are further applied on this protective film, the α-ray shielding effect is sufficiently exhibited, greatly contributing to improving the reliability of the memory element.

In addition, this resin has a phase content of uranium and thorium of 0.2
It does not exceed ppb and has favorable performance as a surface protective film for semiconductor devices. Moreover, a microphase-separated structure can be formed between the siloxane block and the aromatic block in the cured film, resulting in excellent moisture resistance, stress affinity, and electrical properties.

The sealing layer of a semiconductor device using the resin of the present invention or a protective film material composition containing this resin as a main component is composed of a ceramic package, a metal package such as a metal can, a resin package such as an epoxy resin mold, etc. be done.

Further, the protective resin of the present invention or the resin composition containing this resin as a main component can obtain particularly favorable results when resin sealing is used as a sealing layer, and furthermore, it can be used in highly integrated semiconductor devices. Shows more effective action. Specifically, it is effective for semiconductor devices having an integration degree of 1 bit or more in the case of a bipolar type, and 16 bits or more in the case of a MOS type.

Examples of methods for forming coatings on these devices include spin coating, screen printing, and dispensing.

Imidization occurs by applying a resin or resin composition made of the polyimide precursor of the present invention to a semiconductor and heat-treating it at about 250°C, resulting in a semiconductor provided with a polyimide resin or a protective film containing the polyimide resin as a main component. is obtained.

[Example 1] The present invention will be specifically described below based on Examples and Comparative Examples.

The abbreviations of aromatic tetracarboxylic dianhydride, diether aromatic diamine, and siloxane diamine used in the following Examples and Comparative Examples are as follows.

[Aromatic tetracarboxylic dianhydride 1 8 DA: 3.3', 4,4°~benzophenonetetracarboxylic dianhydride BPDA: 3.3°, 4.4'-biphenyltetracarboxylic dianhydride PMOA : Pyromellitic dianhydride [diether aromatic diamine] ODA: 4,4°-oxydianiline BAPP:
2,2-bisE4-(aminophenoxy)phenyl]
Propane (structural formula (2)) p-BAPS: bis[4-(4-aminophenoxy)
phenyl]sulfone [structural formula (iii)] m-BAPS: bis(4-(3-aminophenoxy)phenyl]sulfone [structural formula (iii)] BAPF: 2.2-bis(4-(4-aminophenoxy) phenyl]hexafluoropropane [structural formula [siloxane diamine] GAP[): γ-aminopropyl-1.1,3.3-
Tetramethyldisiloxane (Structural Formula (A)) Compound of Structural Formula (a) (a-1): Average molecular weight 1,300, average number of units 15 (a-2): Average molecular weight 12,560, average number of units 33 (a-3): average molecule 11,000, average. ], Ninira 1 number 12 (a-4): average molecular weight 4,500, average unit number 58 Example 1 500 cc separable flask equipped with thermometer, stirring), calcium chloride tube, dropping funnel, and nitrogen introduction tube After charging and dispersing 32.2 g (0.1 mol) of 8-cho DA and 465 g of diethylene glycol dimethyl ether (diglyme), siloxane diamine (a-1) 1 3 'j ( 0.01
After reacting for 30 minutes, the diether aromatic diamine (8APP) represented by the structural formula (2) is added dropwise.
3 6. 9 9 (0.09 mol) was added and reacted with stirring for 5 hours to obtain a yellow transparent resin solution.

In this way, a polyimide precursor solution having a resin content of 15% by weight and a viscosity of 40 poise was obtained. The content of uranium and thorium in this solution was analyzed by spectrofluorophotometry and found to be O.
It was below ipb.

Next, apply this solution to a human MO3 type RAM with an integration degree of 16.
2 hours at 100'C and 1 hour at 250'C.
Heat treatment was performed for each time to form a silicone polyimide protective film having a thickness of about 40 cm.

Next, this device was left in water vapor at 120° C. and 2.2 atm for 24 hours, and then a cellophane tape peeling test was performed, but no peeling between the protective film layer and the semiconductor device was observed, indicating that a high degree of adhesion was maintained. It turned out that

Briefly, a polyimide film was produced from this resin solution, and the tensile modulus (ASTHD-882-64T) and tensile strength (AS
THD-882-6dT), elongation (ASTM D-8
82-64T), thermal expansion coefficient (heating rate in nitrogen gas 10
TMA measurement under conditions of ℃/min), dielectric constant (measurement conditions: 20℃, 60%RH, I HI3), dielectric loss (measurement conditions: 20℃, 60%RH, I HHz), transparency (
○: transparent, , 73
%, after 24 hours of treatment) were measured. The results are shown in Table 2.

Examples 2 to 10 The same reaction apparatus as in Example 1 was used, and the aromatic tetracarboxylic dianhydride, diether aromatic diamine, and siloxane diamine shown in Table 1 were added in the proportions shown in Table 1. A polyimide precursor was prepared using the same reaction method as in Example 1.

In addition, a polyimide film was made from this resin solution,
Similar to Example 1, various physical properties were measured and the results are shown in Table 2.

Comparative Example 1 Using the same equipment as in Example 1, BTDA32.2! ? (
0.1 mol) and 4,4°-oxydianiline (008)
18.0 g (0.09 mol) of siloxane diamine (a-4) represented by structural formula (a) was reacted in 2505 g of N-methyl-2-pyrrolid to obtain an opaque solution with a viscosity of 55 voids. .

This resin solution was spin-coded onto a silicon wafer, and 1
00'C for 2 hours, 250'C for 1 hour, 3OO'C for 1 hour
Heat treatment was performed for each time to form a polyimide film having a thickness of about 451U. Next, this was heated to 120'C.
After being left in water vapor at 12.2 atm for 24 hours, a cellophane tape peeling test was performed, and the film showed no adhesion to the silicon wafer at all.

In addition, a polyimide film was made from this resin solution,
Similar to Example 1, various physical properties were measured and the results are shown in Table 2.

Comparative Examples 2 to 3 Polyimide precursors were produced in the same manner as in Comparative Example 1 according to Table 1.

In addition, a polyimide film was made from this resin solution,
Similar to Example 1, various physical properties were measured and the results are shown in Table 2.

[Effects of the Invention] The semiconductor protection resin of the present invention, the resin obtained by imidizing the same, or the resin composition containing these resins as a main component have a low elastic modulus, low moisture absorption, low dielectric constant, and low thermal expansion. It exhibits high adhesion to silicon wafers, and has a uranium and thorium content of 0. '＋pp
Since it is less than b, it exhibits good effects when used as a buffer coat film, an α-ray shielding film, or a passivation film in a semiconductor device. Further, the semiconductor of the present invention has excellent thermal shock resistance and soft error prevention function.

Patent applicant: Nippon Steel Chemical Co., Ltd.

Claims (5)

[Claims] (1) The following general formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (In the formula, R1 indicates ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R2 and R3 are monovalent hydrocarbon groups. , n and m represent integers of 0 to 4, and X represents a divalent group)
50 to 99 mol% of diether-based aromatic diamine represented by the general formula (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) (In the formula, R4 and R5 represent divalent organic groups, and R6 to R9
represents a methyl group, ethyl group, phenyl group, or substituted phenyl group, and l represents an integer of 1 to 50), and a diamine component consisting of 1 to 50 mol% of a siloxane diamine; A semiconductor protection resin made of a polyimide precursor obtained by polycondensation with an anhydride. (2) A semiconductor provided with a protective film containing the polyimide precursor according to claim 1 or a polyimide resin obtained by imidizing the polyimide precursor as a main component. (3) Claim 1 containing a siloxane diamine in which l in general formula (2) is 10 to 30 as a diamine component
The semiconductor protection resin described above. (4) The semiconductor-protecting resin according to claim 1, which contains 0.1 to 5 mol% of a siloxane diamine in which l in general formula (2) is 1 as a diamine component. (5) The polyimide precursor according to claim 1 or 2, which has a microphase separation structure.