JPH06140384A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a resin precursor composition which can be adapted to a wet etching process by turning one part of aromatic series tetrabaseacid dianhydride into aromatic series tetrabaseacid diester and then using the cured object of a composition including polyimide resin precursor which is obtained by causing diamine compound to react with it. CONSTITUTION:70.9g N-methyl - 2 pyrrolidone with water content of 0.03wt.% and 32.21g 3,3',4,4',-benzophenonetetrocarbonaciddianhydride are stocked into a flask. After it is heated up to 80 deg.C, 2.3g ethanol is added. Further, it is allowed to react at 90 deg.C for two hours to form one part of the benzophenonetetracarbonaciddianhydride as diester. Then, metaphenylenediamine, 4,4'-diaminophenyeter, and 1,3-bistildisiloxane are stocked into a liquid solution and are allowed to react at 25 deg.C for five hours and at 40 deg.C for one hour. The resin content concentration of a composition including the obtained polyimide resin precursor is 40wt.% and 30 poise viscosity is indicated at 25 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a highly reliable multilayer wiring structure suitable for high integration.

[0002]

2. Description of the Related Art Conventionally, for manufacturing a multilayer wiring structure in a semiconductor integrated circuit or the like, SiO _{2 is} deposited on a substrate having a patterned wiring layer by a vapor deposition method such as vacuum deposition or CVD (chemical vapor deposition). , An interlayer insulating film made of SiN or the like is formed and through holes are formed,
A method of forming an upper wiring layer is used. But,
In the method of forming the interlayer insulating film by the vapor phase epitaxy method, the step of the lower wiring layer (4) has the interlayer insulating film (5) as shown in FIG.
There is a problem that the wiring layer is left as it is after the formation of the wiring layer, and when the upper wiring layer (8) is formed, the wiring layer becomes extremely thin at the step portion and the wiring is easily broken. In Figure 8 (1)
Is the substrate. Therefore, in order to improve this, as shown in FIG. 6, the formation of the interlayer insulating film (5 ′) is obtained by applying and curing a solution of polyamic acid obtained from aromatic diamine aromatic tetrabasic acid dianhydride. A method using a polyimide has been proposed and is now widely used (Japanese Patent Publication No. 51-44).
871).

However, the degree of integration in electronic components such as semiconductor integrated circuits has been remarkably improved, and the wiring structure has become more and more multilayered, and the need for flattening wiring steps has further increased. On the other hand, in the polyamic acid obtained from the aromatic diamine and the aromatic tetrabasic acid dianhydride, the solubility of the polyamic acid in the solvent is very low, and the solution cannot be made to have a high concentration. The flatness of the step was not sufficient, and it was difficult to manufacture a multilayer wiring structure having two or more layers. Further, there is a problem that the polyimide film is not sufficiently embedded in a very fine groove-shaped pattern, and a void is generated in the film in the groove. The higher the concentration of the polyamic acid solution applied on the substrate having the patterned insulating layer, the higher the flattening rate of the wiring step and the burying property of the groove-shaped pattern. The present inventors have clarified that it is effective to form a low molecular weight ester oligomer in order to increase the concentration (Japanese Patent Laid-Open No. 63-14452).

[0004]

On the other hand, it is necessary to form a via hole at a predetermined position after forming a film for a semiconductor interlayer insulating film and a surface protective film. In a polyimide film, a negative or positive type resist is generally used as a mask. As a method, a method of making holes by a wet etching process using hydrazine hydrate or tetramethylammonium hydroxide is used. However, for the polyamic acid solution obtained by the above-mentioned conventionally known low molecular weight ester oligomerization, the applicability to this wet etching process was evaluated, and as a result, an etching residue was generated in the via hole portion, and a crack was generated in the polyimide film during resist stripping It became clear that it could not be used practically due to problems such as the fact that it did. As a result of intensive studies in view of these drawbacks of the prior art, the present inventors have found that a resin precursor composition applicable to a wet etching process can be obtained under a specific condition and a specific composition. Has arrived at a semiconductor device having a highly reliable multilayer wiring structure using.

[0005]

According to the present invention, in a semiconductor device having a multilayer wiring structure using an organic resin as an insulating film material on a wiring conductor, 1 mol of an aromatic tetrabasic acid dianhydride is used as the organic resin. And 0.1 to 1 mol of a monohydric alcohol and / or alcohol derivative having 4 or less carbon atoms in a solvent having a water content of 0.1 wt% or less to form a part of an aromatic tetrabasic dianhydride. After the diester of aromatic tetrabasic acid,
A composition containing an aromatic diamine compound having an amino group at an asymmetric position with respect to a molecular long axis and a polyimide resin precursor obtained by reacting 0.8 to 1.2 mol of another diamine compound as necessary. The present invention relates to a semiconductor device using the cured product.

Examples of the aromatic tetrabasic dianhydride used for producing the polyimide resin precursor used in the present invention include pyromellitic dianhydride, 3,3 ', 4.
4'-benzophenone tetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3', 4,4'-biphenyl tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 4,4'-sulfonyldiphthalic dianhydride, 3,6- Dimethyl-1,2,4,5-benzenetetracarboxylic dianhydride, 3-trifluoromethyl-
1,2,4,5-benzenetetracarboxylic dianhydride,
There are acid dianhydrides such as 3-methyl-1,2,4,5-benzenetetracarboxylic acid dianhydride and substitution products thereof, and one or more of these are used. Of these, 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride is preferable.

The alcohol and alcohol derivative used in the present invention have 4 or less carbon atoms, and for example, one or more of methanol, ethanol, propanol, butanol and the like are used. When the number of carbon atoms is 5 or more, the ester portion is not detached during heat curing, dehydration ring closure does not proceed completely, and a polyimide resin film having good properties cannot be obtained.

As the solvent used in the present invention, a solvent having no group capable of reacting with a carboxylic acid of a tetrabasic acid dianhydride or a polyamic acid, such as an alcoholic hydroxyl group, an amino group or a phenol group, is used. Methyl-2
-Pyrrolidone, N, N-dimethylacetamide, N, N
An amide solvent such as dimethylformamide and dimethyl sulfoxide, an ether glycol solvent such as butyl cellosolve, and the like are preferable. Regardless of which solvent is used, it is necessary that the water content is strictly dehydrated and the water content is 0.1% by weight or less. When the water content exceeds 0.1% by weight, the ring opening reaction of the acid anhydride proceeds in parallel with the esterification reaction, so that the viscosity of the resin composition containing the polyimide resin precursor finally obtained Variation, deterioration of film forming property, and the like.

The aromatic tetrabasic acid dianhydride and alcohol and / or alcohol derivative are added to the above solvent and heated to partially diesterify the aromatic tetrabasic acid.
The amount of alcohol and / or alcohol derivative used is in the range of 0.1 to 1 mol with respect to 1 mol of the aromatic tetrabasic dianhydride. If it is less than 0.1 mol, it is difficult to lower the viscosity when the concentration is high, and if it exceeds 1 mol, cracks are formed in the film when the resist is peeled off after etching the cured film of the obtained resin composition. It is easy to occur. The reaction temperature for esterification varies depending on the solvent used, but
The temperature is in the range of 0 to 150 ° C., and is preferably 8 from the viewpoint of the viscosity uniformity of the obtained resin composition and the hue of the resin composition.
The temperature is from 0 to 150 ° C.

The aromatic diamine compound having an amino group at an asymmetric position with respect to the molecular long axis used in the present invention includes metaphenylenediamine, 3,4-diaminodiphenyl ether and 3,3'-diaminodiphenyl sulfone. , 3,3′-diaminodiphenyl sulfide and the like, and one or more of these are used. Further, other diamine compounds used as necessary include, for example, paraphenylenediamine, 4,4′-
Diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3,
3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 2,2'-bis (4-aminophenyl) propane, 4,4'-methylenedianiline, 4,
Aromatic diamines such as 4′-diaminodiphenyl ether-3-carbonamide, siloxane-based diamines such as 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, and the like, and the like. One or more of these may be used.

The amount of the aromatic diamine compound having an amino group at the asymmetric position with respect to the long axis of the molecule and the other diamine compound used as necessary is such that the cured product of the resin composition finally obtained. From the viewpoint of heat resistance, the amount is 0.8 to 1.2 mol with respect to 1 mol of the aromatic tetrabasic acid dianhydride. The amount of the diamine compound other than the aromatic diamine used is preferably within 50 mol% of the total diamine compounds.

The reaction temperature between the diamine compound and the partially diesterified aromatic tetrabasic dianhydride is preferably 90 ° C. or lower. If the reaction temperature is too high, the polyimide-based resin precursor produced may be imidized to lower the solubility and be precipitated. In these reactions, if necessary, a solvent used in the above esterification reaction, a hydrocarbon solvent such as xylene and toluene, an acetate solvent such as ethyl cellosolve acetate and butyl cellosolve acetate can be used.

It is preferable to manufacture a semiconductor device having a multilayer wiring structure in the following manner by using the composition containing the above polyimide resin precursor. First, a wiring conductor layer made of aluminum is formed on a substrate on which a semiconductor integrated circuit is formed by a well-known method such as sputtering, and an unnecessary portion of aluminum is removed by etching using a normal photolithography process to form a lower layer. Wiring layer. Next, a composition containing a polyimide-based resin precursor is applied onto the wiring layer on which the above pattern is formed by using a spinner or the like, and preferably dried at a temperature of 80 ° C. to 150 ° C., and then the ordinary photolithography is performed. According to the process, a positive resist is applied and exposed, and a dry film of a polyimide resin precursor and the resist are simultaneously etched with an alkaline developer to form a pattern (via hole). At this time, an ordinary phenol novolac-based resist is used as the positive type resist, and the film thickness thereof is preferably between 2 and 5 μm.
If the thickness is less than 2 μm, the resist is likely to be cracked or cracked during development, and if it exceeds 5 μm, the resolution tends to be lowered. If the drying temperature of the resist is less than 100 ° C., cracks and cracks are likely to occur as described above, and if it exceeds 120 ° C., pattern deformation tends to occur.
The temperature is preferably 120 ° C. The exposure of the resist is not particularly limited as long as it is an exposure device that covers the photosensitive wavelength range of the resist used. The development is preferably carried out using a 1.6 to 3.2 wt% aqueous solution of tetramethylammonium hydroxide, and if the time is less than 50 seconds, it is difficult to control the development end point.
If it exceeds 150 seconds, chipping and cracking of the resist are likely to occur, so the time is preferably 50 to 150 seconds. Next, after peeling off the resist film with a solvent such as n-butyl acetate or ethyl cellosolve, preferably from 200 ° C. to 4 ° C.
It is cured at a temperature of 00 ° C. and dehydrated and ring-closed to obtain an interlayer insulating film in which a via hole made of a polyimide resin is formed. In the dehydration ring-closing reaction, acetic anhydride, phosphoric acid or the like may be used as a dehydrating agent. Then, an upper wiring layer is formed on the interlayer insulating film in which the via hole is formed by using a method such as sputtering as described above, and after patterning, the wiring layer and the insulating layer are multilayered by repeating the above steps. A semiconductor device having a multilayer wiring structure is obtained. When forming the interlayer insulating film of the polyimide resin, an adhesion aid such as aminosilane or epoxysilane may be added to the resin composition, if necessary, for the purpose of enhancing the adhesion to the substrate surface.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 a. Method for producing a composition containing a polyimide resin precursor A 0.2 liter flask equipped with a stirrer, a thermometer, a nitrogen introduction tube, and a Dimroth cooling tube was placed in a dry box after being sufficiently dried, and dry nitrogen was added to the composition. It was run for 1 hour. N-methyl-2-pyrrolidone 7 having a water content of 0.03% by weight
0.6 g and 32.21 g of 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride were placed in a flask, heated to 80 ° C, and added with 2.3 g of ethanol.
Further, the mixture was reacted at 90 ° C. for 2 hours to partially convert benzophenonetetracarboxylic dianhydride into a diester. Next, to this solution, 4.86 g of metaphenylenediamine, 4,4'-
Charge 9.01 g of diaminodiphenyl ether and 2.49 g of 1,3-bis (3-aminopropyl) -1,1,3,3, -tetramethyldisiloxane and charge at 25 ° C. for 5 hours and 40 ° C. for 1 hour. It was made to react. The resin component concentration of the composition containing the obtained polyimide resin precursor is 40% by weight,
It showed a viscosity of 30 poise at 25 ° C.

B. Manufacture of Semiconductor Device Having Multi-Layered Wiring Structure The semiconductor device of the present invention was manufactured as follows. As shown in FIG. 1, first, a CVD method (chemical vapor deposition method) is performed on the surface of a semiconductor substrate (1) on which a semiconductor element including a collector region C, a base region B and an emitter region E is formed.
Thus, for example, a silicon dioxide film (2) was formed.
Then, a predetermined portion to be an electrode lead-out portion was removed by etching by a normal photolithography process, and a via hole (window) (3) was provided in the silicon dioxide film to expose a part of the emitter region and the base region. Further, an aluminum wiring layer was formed on the via hole by a sputtering method, and a photolithography process was performed to form a lower wiring layer (4). This wiring layer is 1
It had a thickness of μm and a width of 0.5-5 μm. Next, the composition containing the polyimide resin precursor of a was applied onto the lower wiring layer using a spinner coater (FIG. 2). After that, using a hot plate, 90 ℃
/ 60 seconds, 140 ° C./60 seconds, and then positive type resist 6 (OFPR-5000, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied by spinner and dried at 110 ° C./60 seconds. Exposure (exposure amount 300 mj / cm
² ) (Fig. 3). Then, a 2.38 wt% aqueous solution of tetramethylammonium hydroxide was used to simultaneously etch the resist and the polyimide resin dry film by the paddle method, and a good pattern was obtained with an etching time of 100 seconds (FIG. 4). Next, the resist is stripped by a spray method using n-butyl acetate, and then 2 in a convection oven.
It was cured at 00 ° C./1 hour and then at 350 ° C./1 hour to obtain a polyimide resin interlayer insulating film (5 ′) having a thickness of 2 μm (FIG. 5). Then, an aluminum upper wiring layer (8) was formed by a sputtering method to obtain a semiconductor device having a two-layer wiring structure as shown in FIG.

C. Evaluation of burying property of flattening rate The flattening rate of the lower layer wiring step obtained in the above-described multilayer wiring structure is calculated from the values of a and b shown in FIG.

[Equation 1] It was about 90% as determined by (in the figure, 1, 2, 3, 4 are the same as in FIG. 1). Further, when the semiconductor device was cut and the cross-sectional shape was observed with a scanning electron microscope, it was found that any inter-wiring space was sufficiently filled with an interlayer insulating film of a polyimide resin.

Example 2 In the same manner as in Example 1, N-containing water containing 0.03% by weight.
Methyl-2-pyrrolidone 63.6 g and 3,3 ', 4
4'-biphenyl ether tetracarboxylic dianhydride 3
1.01 g was charged into a flask, heated to 80 ° C., 3.2 g of ethanol was added, and the mixture was further reacted at 90 ° C. for 2 hours to partially convert biphenyl ether tetracarboxylic dianhydride into a diester. Next, 17.38 g of 3,3'-diaminodiphenyl sulfone, 5.01 g of 4,4'-diaminodiphenyl ether and 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyl were added to this solution. Charge 1.24 g of disiloxane, 5 hours at 25 ℃,
The reaction was carried out at 40 ° C for 1.5 hours. The resin component concentration of the composition containing the obtained polyimide resin precursor is 45% by weight,
It showed a viscosity of 50 poise at 25 ° C. Thereafter, in the same manner as in Example 1, a semiconductor device having a two-layer wiring structure having an interlayer insulating film with a thickness of 2 μm was manufactured, and the flattening rate thereof was evaluated, and it was about 95%. The burying property of the interspace, the wet processability, and the film state after the resist was peeled off were all good.

Comparative Example 1 In the same manner as in Example 1, 63.6 g of N-methyl-2-pyrrolidone having a water content of 0.3% by weight and 3,3 ', 4,4'.
-Biphenyl ether tetracarboxylic dianhydride 31.
After charging 01 g into a flask and heating to 80 ° C., 3.2 g of ethanol was added, and the mixture was further reacted at 90 ° C. for 2 hours to partially convert biphenyl ether tetracarboxylic dianhydride into a diester. Next, 17.38 g of 3,3'-diaminodiphenyl sulfone, 5.01 g of 4,4'-diaminodiphenyl ether and 1,3-bis (3
-Aminopropyl) -1,1,3,3-tetramethyldisiloxane (1.24 g) was added, and the mixture was allowed to stand at 25 ° C for 5 hours for 40 hours.
The reaction was carried out at ℃ for 1.5 hours. The composition of the obtained polyimide-based resin precursor has a resin concentration of 45% by weight,
It showed a viscosity of 20 poise at ° C. Thereafter, in the same manner as in Example 1, a semiconductor element having a two-layer wiring structure having an interlayer insulating film with a thickness of 2 μm was manufactured, and the flattening rate was evaluated. The flattening rate was 90%. Some turbidity and foreign matter adhered to the polyimide interlayer insulating film. Therefore, when the resin composition containing the polyimide-based resin precursor was observed in detail, the presence of an insoluble substance presumed to be a ring-opening acid was recognized.

Comparative Example 2 N-containing water of 0.03% by weight in the same manner as in Example 1.
Methyl-2-pyrrolidone 63.7 g and 3,3 ', 4
4'-benzophenone tetracarboxylic dianhydride 32.
After charging 21 g into a flask and heating to 80 ° C., 9.2 g of ethanol was added, and the mixture was further reacted at 90 ° C. for 2 hours to convert all of benzophenonetetracarboxylic dianhydride into a diester. Next, 4.86 g of metaphenylenediamine, 9.01 g of 4,4'-diaminodiphenyl ether and 1,3-bis (3-aminopropyl)-were added to this solution.
1.49 g of 1,1,3,3-tetramethyldisiloxane
Was charged and reacted at 25 ° C. for 5 hours and at 40 ° C. for 1 hour. The composition containing the obtained polyimide resin precursor had a resin content of 40% by weight and a viscosity of 2 poise at 25 ° C. Hereinafter, in the same manner as in Example 1, an attempt was made to manufacture a semiconductor element having a two-layer wiring structure having an interlayer insulating film having a thickness of 2 μm. However, after etching, an etching residue was left in the opening of the polyimide film and the resist was peeled. After that, a crack was generated in the polyimide film. The crack after the resist was peeled off could be eliminated by setting the drying temperature of the polyimide precursor composition to 150 ° C. or higher, but in that state, it was hardly dissolved in the etching solution and could not be processed.

Comparative Example 3 In the same manner as in Example 1, N-containing water containing 0.03% by weight.
Methyl-2-pyrrolidone 76.8 g and 3,3 ', 4
4'-benzophenone tetracarboxylic dianhydride 32.
21 g was placed in a flask, heated to 80 ° C., added with 2.3 g of ethanol, and further reacted at 90 ° C. for 2 hours to partially convert benzophenonetetracarboxylic dianhydride into a diester. Next, to this solution 18.02 g of 4,4'-diaminodiphenyl ether and 1,3-bis (3-
Aminopropyl) -1,1,3,3-tetramethyldisiloxane (2.49 g) was added, and the mixture was heated at 25 ° C. for 5 hours at 40 ° C.
And reacted for 1 hour. The resin component concentration of the composition containing the obtained polyimide resin precursor is 40% by weight and is 5 at 25 ° C.
It showed a viscosity of 0 poise. Hereinafter, in the same manner as in Example 1, an attempt was made to manufacture a semiconductor device having a two-layer wiring structure having an interlayer insulating film with a thickness of 2 μm. After etching, the opening of the polyimide film was etched in the same manner as in Comparative Example 2. The remainder was generated and a good pattern could not be obtained.

[0021]

According to the semiconductor device of the present invention, since the step of the lower wiring layer can be almost completely flattened by the interlayer insulating film by using a simple wet etching process, there is almost no step due to the multi-layer wiring. A highly integrated semiconductor device that can be manufactured at a low cost and has a multi-layered wiring structure with dramatically improved wiring reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device having a lower wiring layer.

FIG. 2 is a diagram showing a state in which a polyimide insulating film is applied on a semiconductor device having a lower wiring layer.

FIG. 3 is a diagram showing a state in which a resist layer is formed on a polyimide film and exposed through a photomask.

FIG. 4 shows etching of a resist and a polyimide film,
The figure which shows the state which opened the via hole.

FIG. 5 is a view showing a state in which the resist has been peeled off and the polyimide insulating layer forming step has been completed.

FIG. 6 is a cross-sectional view of a semiconductor device having a two-layer wiring structure planarized using polyimide.

FIG. 7 is a diagram showing a method of evaluating a flattening rate.

FIG. 8 is an example of a cross-sectional view of a multilayer wiring structure according to a conventional method in which a SiO ₂ film formed by a vapor phase growth method is used as an interlayer insulating film.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Silicon Dioxide Film 3 Via Hole (Window) 4 Lower Wiring Layer 5, 5'Interlayer Insulating Film 6 Photoresist 7 Photomask 8 Upper Wiring Layer

Claims (2)

[Claims] 1. A semiconductor device having a multilayer wiring structure using an organic resin as an insulating film material on a wiring conductor, wherein 1 mol of aromatic tetrabasic dianhydride and 4 carbon atoms are used as the organic resin.
0.1 to 1 mol of the following monohydric alcohol and / or alcohol derivative is heated in a solvent having a water content of 0.1% by weight or less, and a part of the aromatic tetrabasic acid dianhydride is converted into aromatic tetrahydrate. A polyimide obtained by reacting a diester of a basic acid with an aromatic diamine compound having an amino group at an asymmetric position with respect to the molecular long axis and, if necessary, 0.8 to 1.2 mol of another diamine compound. A semiconductor device using a cured product of a composition containing a resin precursor. 2. The aromatic tetrabasic dianhydride is 3,3'4.
The semiconductor device according to claim 1, which is 4'-benzophenone tetracarboxylic dianhydride.