JP2574403B2 - Organosilicon polymer, method for producing the same, and semiconductor device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] With respect to an organosilicon polymer, an object of the present invention is to provide a novel organosilicon polymer useful in the field of semiconductor devices and the like, and has the following general formula (I): [R ₁ SiO _2/2 (R ₂ ) _1/2 ] _n (1) (in the above formula, R ₁ represents hydrogen, a hydroxyl group, a lower alkyl group or a lower alkoxy group, R ₂ represents an alkylene group, And n represents an integer of 10 to 50,000)
And comprising an organosilicon polymer having a weight average molecular weight of 5,000 to 5,000,000.

[Industrial applications]

The present invention relates to a novel organosilicon polymer, a method for producing the organosilicon polymer, and a semiconductor device using the organosilicon polymer as an interlayer insulating film. The organosilicon polymer of the present invention can be advantageously used in a multilayer wiring forming step in the production of semiconductor devices such as various integrated circuits. That is, the organosilicon polymer of the present invention forms a film having excellent insulating properties while flattening the underlying steps when forming a multilayer wiring of a semiconductor device having a high integration density such as IC and LSI. Reliability can be improved.

[Conventional technology]

2. Description of the Related Art In a semiconductor integrated circuit, a three-dimensional wiring has been required to improve the degree of integration and to facilitate the wiring and to improve the operation speed. Therefore, a multilayer wiring structure has been developed. In the case of forming a multi-layer wiring, it has been general that a first-layer wiring is provided, a second-layer wiring is provided via an insulating film, and this process is sequentially repeated. Here, as a material used as an interlayer insulating film, conventionally, an SiOx-based material formed by CVD of an inorganic film such as silicon dioxide, silicon nitride, and phosphorus glass (PSG) using a silane-based gas,
Alternatively, a polymer insulating material such as polyimide or silicone resin, or a laminate of these materials is used. However, as the wiring pattern becomes finer, a material having better characteristics in terms of reliability has been required.

When considering multilayer wiring, the semiconductor substrate on which the first wiring is provided has irregularities due to the wiring, so if this is used as a base and an inorganic film is formed thereon, the surface of the interlayer insulating film will reproduce the irregularities of the base as it is . This causes disconnection of the upper wiring formed thereon, insulation failure, and the like. Therefore, development of an interlayer insulating material capable of flattening the substrate surface when applied on a base having irregularities has been desired.

Therefore, a method of obtaining a flat surface from an insulating film manufacturing process such as an etch-back method and a bias sputtering method, and a method of obtaining a flat insulating film by forming a resin by spin coating have been studied. Among these methods, a resin application method that is simple in terms of process requires a heating effect after applying the resin, but conventionally used polyimide,
A polymer material such as a silicone resin has a defect that cracks due to film distortion are observed due to oxidation or thermal decomposition at a temperature of about 400 ° C. Therefore, development of a heat resistant resin which is not damaged in the curing step has been desired.

The present inventors have previously described the following general formula: [R ₁ SiO _2/2 (R ₂ ) _1/2 ] _n (wherein R ₁ is hydrogen, a hydroxyl group, a lower alkyl group or a lower alkoxy group) R ₂ represents an arylene group and n represents an integer from 10 to 50,000)
And obtained a patent application by obtaining a finding that an organosilicon polymer having a weight average molecular weight of 10,000 to 5,000,000 is useful as an interlayer insulating film in a semiconductor device having a multilayer structure. The organosilicon polymer can effectively flatten a high step generated in a multilayer wiring process, and does not have a crack at a high temperature conventionally observed in a silicone resin.

[Problems to be solved by the invention]

A first object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to be equal to or more than the organosilicon polymer previously applied for a patent, which is useful in the field of semiconductor devices and the like. To provide a novel organosilicon polymer.

A second object of the present invention is to provide a method for producing such a novel organosilicon polymer.

A third object of the present invention is to provide a semiconductor device using such a novel organosilicon polymer.

[Means for Solving the Problems] According to the present invention, the above first problem is solved by the following general formula (1): [R ₁ SiO _2/2 (R ₂ ) _1/2 ] _n. 1) (In the above formula, R ₁ is hydrogen, a hydroxyl group, for example, a lower alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or a methoxy group, an ethoxy group, an n-propoxy group, represents a lower alkoxy group such as an i-propoxy group, R ₂ represents an alkylene group such as a methylene group or an ethylene group, and n represents an integer of 10 to 50,000), and a weight of 5,000 to 5,000,000. The problem can be solved by an organosilicon polymer having an average molecular weight. R ₁ and R ₂ in the formula may be optionally substituted. In the formula, O _2/2 and (R ₂ ) _1/2
Respectively constitute the center of the organosilicon polymer.
When looking at one Si atom, for that Si atom,
It means that _two O _1/2 and one (R ₂ ) _1/2 are bonded.

The organosilicon polymer according to the present invention is preferably a polymer of the following structural formula (I) or (II) or a mixture of these polymers.

(Wherein R ₁ and R ₂ may be the same or different and are as defined above, and n is as defined above).

Further, according to the present invention, the second object described above is represented by the general formula (1), and is 5,000 to 5,000,000.
In producing an organosilicon polymer having a weight average molecular weight of the following, an organosilicon compound of the following formula (2): (Wherein R ₁ may be the same or different and are as defined above, R ₂ is as defined above, and R ₃ may be the same or different, such as chlorine (Representing a halogen or a lower alkoxy group) with water to hydrolyze, followed by dehydration-condensation polymerization of the resulting reaction product to produce the organosilicon polymer of the general formula (1). The problem can be solved by a method for producing an organosilicon polymer.

In the practice of the method of the present invention, the hydrolysis of the compound of the general formula (2) is preferably carried out at a low temperature in order to suppress the occurrence of a sudden reaction. Further, after the polymer of the general formula (1) is obtained by dehydration-condensation polymerization, it is further polymerized to have a weight average molecular weight of 5,000 to 5,000,000, but if necessary, water is condensed between hydroxyl groups from the reaction system. May be removed to increase the molecular weight.

The hydrolysis and dehydration polycondensation of the process of the present invention proceed, for example, according to the following reaction formula: And / or (Wherein R ₁ and R ₂ may be the same or different, are as defined above, and n is as defined above). As will be appreciated from the above, the polymers of general formulas (I) and (II) may each be formed alone, as a mixture, or as a conjugate not shown here. .

The organosilicon compound used as a starting material in the method of the present invention has a structural formula (2): In the formula, R ₁ represents a C _{1 to} C ₃ monovalent alkyl group or the like as described above, and may be the same or different. R ₂ may be any alkylene group, preferably a C _{1 to} C ₅ lower alkylene group,
In _{particular, -CH 2, -C 2 H 4} - is practical. R ₃ preferably represents chlorine or a group selected from C _{1 to} C ₃ monovalent alkoxy groups. Specifically, the following are useful starting materials.

Bis (methyldichlorosilyl) methane Bis (methyldimethoxysilyl) methane 1,2-bis (methyldichlorosilyl) ethane 1,2-bis (methyldichlorosilyl) ethane 1,1-bis (methyldichlorosilyl) ethane 1,1-bis (methyldimethoxysilyl) ethane In order to produce an organosilicon polymer by the method of the present invention, first, at least one of the organosilicon compounds is
Dissolve in an organic solvent, and then slowly drop the solution of the organosilicon compound into water or a mixed system of water and one or more organic solvents under an air atmosphere or an inert atmosphere such as nitrogen or argon. , Hydrolyze.
Alternatively, into the solution of the organosilicon compound, water, or a mixed system of water and at least one organic solvent is gradually dropped,
Let it hydrolyze. At this time, since dehydration condensation continues to occur, the temperature during dropping must be optimized according to the properties of the organic compound in order to prevent gelation due to irregular three-dimensional condensation and obtain an appropriate low molecular weight polymer, , When R ₃ is chlorine, it is preferable to perform the reaction at a low temperature of −70 to 10 ° C. for controlling a rapid three-dimensional reaction, and more preferably −
It is good to carry out at a low temperature of 70 to -50 ° C. When R ₃ is an alkoxy group, hydrolysis is not efficiently performed under the above-mentioned conditions, but rather it is preferably performed at a high temperature of 50 ° C. or higher. In the hydrolysis process, an organic amine such as pyridine or triethylamine or a hydrochloride thereof, or an acid such as hydrochloric acid, sulfuric acid or acetic acid can be used as a catalyst.
Next, the mixture containing the low molecular weight polymer obtained by the above reaction is further subjected to dehydration condensation to obtain a high molecular weight polymer.
At this time, in an atmosphere of air or an atmosphere of an inert gas such as nitrogen or argon, a temperature of 80 to 100 ° C. is usually used.
By allowing the reaction to proceed for 0.5 to 6 hours, the molecular weight can be efficiently increased, and a polymer having a weight average molecular weight of 5,000 to 5,000,000 can be obtained. Note that it is preferable to use a hydrochloride of an organic amine such as pyridine or triethylamine as the catalyst.

Still further, according to the present invention, the third object described above is represented by the general formula (1), and is 5,000 to 5,0.
The problem can be solved by a semiconductor device having a multilayer wiring structure, comprising an interlayer insulating film made of an organosilicon polymer having a weight average molecular weight of 00,000.

Organosilicon polymer used for forming the interlayer insulating film,
Preferably, R _{1 is represented} by the general formula (1),
_{There, H, CH 3, C 2} H 5, n-C 3 H 7, i-C 3 H 7, OH, OCH 3, OC 2 H 5, O-n
—C ₃ H ₇ , OiC ₃ H _7, etc., wherein R ₂ is an alkylene group and n is an integer of 10 to 50,000. Further, the alkylene group is not particularly limited, but is preferably -CH ₂
−, −C ₂ H ₄ − is practical. Further, the ratio of the polyorganosylalkyleneloxane structural unit in the molecular chain may be any, but is preferably 25% by weight or more from the viewpoint of heat resistance. The above resin may form an interlayer insulating film alone, or may form an interlayer insulating film in combination with an inorganic film such as silicon dioxide, silicon nitride, and phosphor glass (PSG).

(Operation)

The polyorganosylalkylenesiloxane resin according to the present invention is soluble in many organic solvents and can be formed into a film by a conventional spin coating method. Therefore, the surface of the semiconductor substrate having the uneven surface can be easily flattened.

In addition, this polyorganosylalkylenesiloxane resin is flexible and can be damaged only up to 2-3 μm even when heated up to 480 ° C., and can maintain its film quality. Therefore, sufficient insulation can be expected, and it is suitable for use as an interlayer insulating film of a semiconductor integrated circuit.

〔Example〕

Subsequently, the present invention will be specifically described with reference to some examples.

Example 1 (Preparation Example) 5 g of 1,2-bis (methyldichlorosilyl) ethane was dissolved in 50 cc of tetrahydrofuran, and the obtained solution was 100 cc of methyl isobutyl ketone and 50 c of methyl cellosolve acetate.
c, 15 cc of triethylamine and 30 cc of ion-exchanged water were added dropwise, and the mixture was stirred at 75 ° for 3 hours. After cooling, the mixture was allowed to stand to remove an aqueous layer, and further washed sufficiently with water. The obtained reaction solution was dried, and the remaining resin was redissolved in 1,4-dioxane and freeze-dried. 2.8 g of polydimethylsilethylenedisiloxane powder could be recovered.

Example 2 (Preparation Example) 5 g of bis (methyldichlorosilyl) methane was dissolved in 50 cc of tetrahydrofuran, and the resulting solution was dropped into a mixed system of 100 cc of methyl isobutyl ketone, 50 cc of methyl cellosolve acetate, 15 cc of triethylamine and 30 cc of ion-exchanged water. Stir at 75 ° C. for 3 hours. After cooling, the mixture was allowed to stand to remove an aqueous layer, and further sufficiently washed with water. The obtained reaction solution was dried, and the remaining resin was redissolved in 1,4-dioxane and freeze-dried. 2.8 g of polydimethylsilmethylenedisiloxane powder could be recovered.

Example 3 (Preparation Example) 100 ml of methyl isobutyl ketone was placed in a 300 cc four-necked flask.
Then, 50 cc of methylcellosolve acetate and 30 cc of water were charged, 30 cc of hydrochloric acid was added as a catalyst, and the mixture was heated, stirred and refluxed. 10 g of 1,2-bis (methyldimethoxysilyl) ethane was dissolved in 50 cc of tetrahydrofuran and added dropwise to the flask over 30 minutes. After dropping, reflux was maintained for 2 hours. After cooling, the system was transferred to a 500 cc separatory funnel, to which 100 cc of water and 100 cc of methyl isobutyl ketone were added and stirred. After standing, the lower aqueous layer was removed. The organic layer was thoroughly washed with water, returned to the flask, heated and stirred, and the remaining water was completely removed by azeotropic distillation. The obtained reaction solution was dried, and the remaining resin was redissolved in 1,4-dioxane and freeze-dried. 3.0 g of polydimethylsilethylenedisiloxane powder could be recovered.

Example 4 The powder obtained according to Example 1 was dissolved in isoamyl acetate,
A semiconductor element was formed and a first layer aluminum wiring was applied on a silicon substrate (aluminum thickness 1 μm, minimum line width 1 μm, minimum line interval 1.5 μm) by spin coating to a thickness of 1.5 μm. After coating, solvent drying at 80 ° C for 20 minutes, followed by nitrogen at 420 ° C,
Heat treatment was performed for 1 hour. The step on the substrate surface after the heat treatment was about 0.2 μm, and the step caused by the aluminum wiring was flattened. Subsequently, a through hole was formed, a second layer of aluminum wiring was formed, a 1.2 μm SiO ₂ film was formed as a protective layer, and a window for taking out an electrode was opened to obtain a semiconductor device. This device did not show any defect even after a heating test at 450 ° C. for 1 hour in the atmosphere and 10 thermal shock tests from −65 ° C. to 150 ° C.

Example 5 A resin layer was formed up to a thickness of 1.0 μm on a silicon substrate in the same manner as in Example 4, and then an SiO ₂ film was further formed to a thickness of 0.3 μm.
m formed by a known method. This film has an underlying step of 0.3μ.
m. Thereafter, when a semiconductor device was manufactured and tested in the same manner as in Example 4, no defect was found.

Example 6 The powder obtained according to Example 2 was dissolved in isoamyl acetate,
A semiconductor element was formed and spin-coated to a thickness of 1.5 μm on a silicon substrate on which a first layer aluminum wiring was formed (the thickness of amino was 1 μm, the minimum line width was 1 μm, and the minimum line interval was 1.50 μm).
After coating, solvent drying at 80 ° C for 20 minutes, followed by 420
C., heat treatment was performed for 1 hour. The step on the substrate surface after the heat treatment was about 0.2 μm, and the step caused by the aluminum wiring was flattened. Subsequently, a through-hole was formed, a second layer of aluminum wiring was formed, and 1.2 μm SiO ₂ was used as a protective layer.
After forming the film, a window for taking out an electrode was opened to obtain a semiconductor device. This device did not show any defect even after a heating test at 450 ° C. for 1 hour in the atmosphere and 10 thermal shock tests from −65 ° C. to 150 ° C.

Example 7 A resin layer was formed up to a thickness of 1.0 μm on a silicon substrate in the same manner as in Example 6, and then an SiO ₂ film was further formed to a thickness of 0.3 μm.
m formed by a known method. This film has an underlying step of 0.3μ.
m. Thereafter, when a semiconductor device was manufactured and tested in the same manner as in Example 6, no defect was found.

Example 8 The powder obtained according to Example 3 was dissolved in isoamyl acetate,
A semiconductor element was formed and a first layer aluminum wiring was applied on a silicon substrate (aluminum thickness 1 μm, minimum line width 1 μm, minimum line interval 1.5 μm) by spin coating to a thickness of 1.5 μm. After coating, solvent drying at 80 ° C for 20 minutes, followed by nitrogen at 420 ° C,
Heat treatment was performed for 1 hour. The step on the substrate surface after the heat treatment was about 0.2 μm, and the step caused by the aluminum wiring was flattened. Subsequently, a through hole was formed, a second layer of aluminum wiring was formed, a 1.2 μm SiO ₂ film was formed as a protective layer, and a window for taking out an electrode was opened to obtain a semiconductor device. This device did not show any defect even after a heating test at 450 ° C. for 1 hour in the atmosphere and 10 thermal shock tests from −65 ° C. to 150 ° C.

Example 9 A resin layer was formed in the same manner as in Example 8 (applied to a thickness of 1.0 μm on a silicon substrate), and then a SiO ₂ film was formed to a thickness of 0.3 μm
m formed by a known method. This film has an underlying step of 0.3μ.
m. Thereafter, when a semiconductor device was manufactured and tested in the same manner as in Example 8, no defect was found.

〔The invention's effect〕

According to the present invention, not only can a new and useful organosilicon polymer be obtained, but also the production of the polymer can be efficiently performed by a simple method. Further, according to the present invention, it is possible to obtain a semiconductor device having a highly reliable interlayer insulating film which has a flattening function and does not damage the film even when used at high temperatures.

Claims (3)

(57) [Claims] 1. The following structural formulas (I) and / or (II): (Wherein R ₁ and R ₂ may be the same or different, R ₁ represents hydrogen, a hydroxyl group, a lower alkyl group or a lower alkoxy group, R ₂ represents an alkylene group, and n represents 10 An organosilicon polymer having a weight average molecular weight of 5,000 to 5,000,000. 2. The following structural formulas (I) and / or (II): (Wherein R ₁ and R ₂ may be the same or different, R ₁ represents hydrogen, a hydroxyl group, a lower alkyl group or a lower alkoxy group, R ₂ represents an alkylene group, and n represents 10 In preparing an organosilicon polymer having a weight average molecular weight of 5,000 to 5,000,000, represented by the following formula: (Wherein R ₁ may be the same or different and are as defined above, R ₂ is as defined above, and R ₃ may be the same or different and represent halogen Or represents a lower alkoxy group)
Is reacted with water to hydrolyze, and subsequently, the obtained reaction product is subjected to dehydration-condensation polymerization to produce an organosilicon polymer of the above structural formula, which is characterized in that: 3. The following structural formulas (I) and / or (II): (Wherein R ₁ and R ₂ may be the same or different, R ₁ represents hydrogen, a hydroxyl group, a lower alkyl group or a lower alkoxy group, R ₂ represents an alkylene group, and n represents 10 A semiconductor device having a multi-layer wiring structure, characterized by having an interlayer insulating film made of an organosilicon polymer having a weight average molecular weight of 5,000 to 5,000,000.