JPS6228511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a method for manufacturing a bubble memory device in which a silicone resin solution is applied and cured as an interlayer insulation material and/or a protective film.

(2) Background of the technology Bubble memory devices require a high degree of reliability over a long period of time, but if a small amount of electrolyte is present in the insulating material or protective film used in the device, defects due to electrolytic corrosion may occur and the service life may be shortened. shorten.

(3) Prior art and problems As an insulating material or protective film for bubble memory devices, a solution of PDAS, which is a hydrolyzed polycondensate of tetraalkoxysilane, is applied and heated to form an SiO ₂ film. It is.

Tetraalkoxysilane Si(OR) ₄ (in the formula, R
(CnH _2o+1 , such as methyl, ethyl, propyl, butyl, etc.) undergoes hydrolysis and polycondensation in the presence of a reaction promoter acid as shown in the following equation.

Si(OR) ₄ +2H ₂ O→Si(OR) ₂ (OH) ₂ +2ROH ……(1) nSi(OR) ₂ (OH) ₂ →HO[−Si(OR) ₂ O]− _o H+(n− 1) H ₂ O ……(2) In addition to the reaction of formula (2), dealcoholization is performed and ≡Si
It easily undergoes a reaction where it changes into (OH) group and gels.

To prevent gelation, PDAS is always dissolved in an organic solvent during reaction or storage.

The reaction accelerator acid is hydrochloric acid, and 0.05 to 0.5% hydrogen chloride is often added to the weight of the monomer. This is to take advantage of the fact that hydrogen chloride can be removed by volatilization during heat curing of the coating film. However, in long-term bias tests, the aluminum wiring and permalloy film appear to be electrolytically corroded, resulting in defects. This is thought to be due to a trace amount of hydrogen chloride remaining.

Removal of hydrogen chloride is generally possible by washing with water. However, in PDAS, the ≡Si(OR) group is ≡Si
It easily converts into (OH) groups, and if there are too many of them, it will gel or PDAS will be distributed in the washing water phase. If alcohol is used as a solvent, it will be lost in the washing aqueous phase, so alcohol cannot be used to remove hydrogen chloride.

Volatile hydrogen chloride can be separated by distillation, but this is not possible because PDAS will gel if the distillation temperature is increased.

As the coating liquid for the surface protection material, not only PDAS alone but also a mixed solution with other silicone resins can be used. The silicone resin to be mixed is, for example, a hydrolysis product of alkyltrialkoxysilane (JP-A-48-81928 and JP-A-Sho.
48-26822) and polysilsesquioxane prepolymer (see JP-A-54-171005), and the present inventors have disclosed that the latter is used to protect bubble memories or insulate between wiring layers. There is. Furthermore, as the organic solvent used in this mixed solution, butyl cellosolve acetate, ethyl cellosolve acetate, methyl cellosolve acetate, and n-butyl alcohol (see JP-A-55-158114) can be used to obtain a uniform coating film. The present inventors have disclosed that.

(4) Object of the Invention An object of the invention is to provide a bubble memory device that forms a protective agent and/or a wiring interlayer insulating material that does not cause electrolytic corrosion defects over a long period of time, and a method for manufacturing the same.

(5) Structure of the Invention The above object of the present invention is to provide a magnetic substrate capable of holding a magnetic bubble memory, a conductive pattern formed on the substrate, a soft magnetic material pattern, and a silicone resin conductive pattern. Or, in the bubble memory device having the wiring interlayer insulating material of the soft magnetic material pattern and/or the protective film of silicone resin, the silicone resin wiring interlayer insulating material and/or the protective film is polydialkoxysilane alone or polydialkoxysilane alone. A bubble memory device characterized by being a cured product of a mixture of polysilsesquioxane and polysilsesquioxane, and a method for producing a bubble memory device using a silicone resin as an interlayer insulation material and/or a protective film, the method comprising: Polydialkoxysilane prepolymer (PDAS) is produced by hydrolyzing and polycondensing silane in the presence of hydrogen chloride.
Dissolve this PDAS in an organic solvent with a boiling point of 110°C or higher, and heat the resulting solution at a temperature of 40°C or lower and a pressure of 5 mm.
Hydrogen chloride is removed by reducing the pressure below Hg and obtained
The PDAS solution alone or a solution containing polysilsesquioxane prepolymer mixed with this solution is applied to the metal film on the garnet substrate and cured to form a silicone resin insulating material and/or protective film. This can be achieved by a bubble memory device manufacturing method.

PDAS dissolved in this organic solvent is 0.5-3.0mmHg
It is advantageous to drive off the hydrogen chloride under reduced pressure.
At this time, it is preferable to drive out hydrogen chloride at a temperature of 5 to 28°C.

As the organic solvent used, it is convenient to use methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, n-butyl alcohol, or a mixed organic solvent containing any of them.

0.2% HCl, 15% PDAS in ethyl alcohol
Three types of solutions in which 100 parts by weight of methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate were mixed at 150, 130, and 100 parts by weight, respectively, were distilled under reduced pressure at a pressure of 3.0 mmHg and a temperature of 25°C to obtain a solution in which chloride ions could not be detected with silver nitrate. And so. The amounts of cellosolve acetate remaining were 48%, 76%, and 98% of the amounts originally added, respectively.
The boiling points of these cellosolve acetates are
144.5-145.1°C, 156.3°C, and 191.5°C, and is a conventionally known PDAS solvent. The boiling point is 117.7℃
When using n-butyl alcohol as a solvent, the remaining amount after vacuum distillation with silver nitrate until chloride ions can no longer be detected is 45%, which can be used in the present invention. However, the remaining amount of isobutyl alcohol with a boiling point of 107.9℃ is
This is not appropriate as it decreases to 25%.

As organic solvents with a boiling point of 110° C. or higher, in addition to the above-mentioned alcohol-based and cellosolve acetate-based solvents, cellosolve-based and ketone-based solvents dissolve PDAS. When mixed with the polysilsesquioxane prepolymer, since ketone solvents have a problem in compatibility with the primer, it is preferable to use cellosolve solvents in addition to the above. Note that in the case of PDAS treatment alone, aromatic hydrocarbons mixed with ketones and alcohols can be used.

In the present invention, there are no particular limitations on the polysesquioxane prepolymer that can be used in combination with PDAS. This prepolymer is prepared by dissolving R′SiCl ₃ in, for example, methyl isobutyl ketone, adding a hydrochloric acid acceptor such as triethylamine, and then adding water.
R′Si(OH) ₃ is obtained. R′Si(OH) ₃ is polycondensed by heating, washed with water, concentrated, and a precipitant such as methyl alcohol is added to form white powder HO(−R′SiO ₁ . ₅
)-H is obtained. Polycondensation of R′Si(OR) ₃ is promoted by adding hydrochloric acid, but when starting from R′SiCl ₃ , HCl
There is no need to do so since it includes

The molecular structure of polysilsesquioxane prepolymer starts from R′SiCl ₃ and has a relatively complete ladder structure as shown in formula (3) (see JP-A-53-88099), and R′Si( OR) Starting from ₃ , it has a partial ladder structure as shown in formula (4) (Shiro Takeda et al., Proceedings of the 44th Autumn Annual Meeting of the Chemical Society of Japan, p. 582, 1982)
Year).

In the formula, R is a lower alkyl group or a partially hydrogen group, and R' is a lower alkyl group or a phenyl group. m, n are positive integers, m is 10 including 0
It is often less than or equal to

In the present invention, these polysilsesquioxane prepolymers can be mixed with PDAS, and the mixing ratio is not limited. In any case
PDAS contains hydrogen chloride. Therefore, in order to use it as a protective film for a bubble memory device or as an interlayer insulation material for wiring, it is necessary to drive out hydrogen chloride during polycondensation. Note that it is desirable to use it in combination with an inorganic oxide film formed by other vapor phase growth methods. For example, the resin layer of the present invention may be formed on the aluminum wiring, and a vapor-phase grown oxide film may be formed thereon, or vice versa. Alternatively, the resin layer of the present invention may be formed on a vapor-phase growth film formed between wiring layers by a lift-off method.

(6) Examples and Comparative Examples The weight average molecular weight (referred to as below the value converted to standard polystyrene by gel permeation chromatography) is 5400, and the functional groups are ethoxy groups and hydroxyl groups, and the molar ratio is approximately 1:1. is
100 g of a mixed solution of ethyl alcohol and isopropyl alcohol in a weight ratio of approximately 3:2 (hereinafter referred to as PDAS solution) containing 15.5% by weight of PDAS and 0.2% by weight of HCl was placed in a 500ml eggplant-shaped flask, and 84.5% of butyl cellosolve acetate was added. g was added. The flask was set at an angle of 45°, connected to a rotary evaporator, and rotated at 60 rpm. Next, put the flask in a water bath with a bath temperature of 25℃, and use a vacuum pump to
The pressure was reduced to mmHg and the pressure was treated under reduced pressure for 4 hours. Solvent 86.1 for dry ice/ethyl alcohol traps
g was collected and the residual solution was 98.4 g, to which 1.6 g of n-butyl cellosolve acetate was added.
A PDAS solution was obtained.

Take 1 g of this PDAS solution in a test tube and
When 2 g of a wt % silver nitrate aqueous solution was added and the mixture was shaken, a white gelled substance eventually adhered to the tube wall of the organic phase, and the aqueous phase became silvery brown, but no white precipitate was formed. Further, the remaining PDAS solution was extracted and washed with water, burned in a flask, and an attempt was made to detect chlorine using the mercuric thiocyanate method, but the detection limit was 10 ppm or less.

On the other hand, take 1 g of PDAS solution in a test tube and add 0.1
When one drop of weight percent silver nitrate was added and shaken, the mixture became cloudy. Furthermore, when 3 g each of water and n-butyl cellosolve acetate were added, most of the white turbidity was transferred to the aqueous phase, and the PDAS gelled product was transferred to the organic phase.

A 1000 Å SiO ₂ layer was formed on a garnet substrate with an epitaxial layer formed on it, and a 4000 Å aluminum wiring layer was further formed on the wafer.
Rotate the PDAS solution at 2000 rpm for 30 seconds,
Heat treatment was performed at 300°C for 60 minutes in nitrogen. Then 800Å
Sputtering SiO ₂ layer and further 4000Å
A permalloy film was formed and patterned, and a PDAS solution was again spin-coated on top of this, and a 10,000 Å SiO ₂ layer was sputtered.
A bubble memory device was obtained by opening a window for taking out the electrodes. This device underwent a bias test with a voltage of 24V applied for 1000 hours at a temperature of 80°C and a relative humidity of 95%, but no malfunction occurred.

Comparative Example 1 Using PDAS solution instead of PDAS solution
A bubble memory device was obtained in the same manner as in Example 1, except that spin coating was performed at 3000 rpm for 30 seconds.

When this bubble memory device was subjected to a bias test in the same manner as in Example 1, malfunction occurred, which was thought to be caused by deterioration of the permalloy. In addition, a bubble memory device in which a PDAS solution was applied and heat treated only between wiring layers malfunctioned after 500 hours of a similar bias test.

Example 2 is 3100, 11.4% by weight of PDAS whose functional groups are methyl group and hydroxyl group in a molar ratio of about 2:1,
20 g of n-butyl cellosolve acetate and 6 g of n-butyl alcohol were added to 100 g of PDAS solution, which is a mixed solution of methyl ethyl ketone and methyl alcohol at a weight ratio of about 7:3, containing 0.05% by weight of HCl, and the same procedure as in Example 1 was carried out. A PDAS solution was obtained by distillation under reduced pressure.

In this solution, expressed by the formula (4) of 10600,
11.4 g of polysesquioxane prepolymer in which R' is a methyl group, R is an ethyl group and a hydroxyl group, the molar ratio is about 1:1, and the average value of m is 2.1, and 5.8 g of n-butyl alcohol are added. The mixture was dissolved to obtain a mixed silicone solution. No chloride ions were detected in this solution when tested using the same mercuric thiocyanate method as in Example 1.

Using this mixed silicone solution,
A bubble memory device was obtained in the same manner as in Example 1, except that spin coating was performed at 6000 rpm for 90 seconds.
No defects occurred even after 1000 hours of bias testing.

Comparative Example 2 A mixed silicone solution mixed with a polysesquioxane prepolymer was used in the same manner as in Example 2, except that the PDAS solution was used instead of the PDAS solution. Although no chloride ions could be detected in this solution when tested using the mercuric thiocyanate method, a bubble memory device similar to that of Example 2 was manufactured and the bias test of Example 1 was conducted, and after 120 hours, Electrolytic corrosion failure occurred.

Claims (1)

[Claims] 1. A magnetic substrate capable of holding a magnetic bubble memory;
A bubble having a conductor pattern formed on the substrate, a soft magnetic material pattern, a wiring interlayer insulating material of the conductive material pattern or the soft magnetic material pattern made of silicone resin, and/or a protective film of silicone resin. A bubble memory device characterized in that the silicone resin interlayer insulating material and/or the protective film is a cured product of polydialkoxysilane alone or a mixture of polydialkoxysilane and polysilsesquioxane. 2. At least one of the conductive wiring layer or the soft magnetic wiring layer and the silicone resin wiring interlayer insulating material and/or protective film,
The bubble memory device according to claim 1, characterized in that an inorganic insulating layer is interposed. 3. The bubble memory device according to claim 1, wherein the magnetic substrate is a garnet substrate on which an inorganic insulating layer is formed. 4 Silicone resin is used as wiring interlayer insulation material and/or
Or, a method for producing a bubble memory device as a protective film, in which tetraalkoxysilane is hydrolyzed and polycondensed in the presence of hydrogen chloride to form a polydialkoxysilane prepolymer (hereinafter referred to as PDAS), and this PDAS has a boiling point of 110°C or higher. dissolved in an organic solvent of
The obtained solution is depressurized to a temperature of 40°C or less and a pressure of 5 mmHg or less to remove hydrogen chloride, and the obtained PDAS solution alone or a mixture of this solution and a polysilsesquioxane prepolymer is applied to the metal film on the garnet substrate. 1. A method for manufacturing a bubble memory device, comprising: curing the silicone resin to form an insulating material and/or a protective film of silicone resin. 5 0.5 to 3.0 mm of PDAS dissolved in the organic solvent
The manufacturing method according to claim 4, wherein hydrogen chloride is expelled under reduced pressure of Hg. 6. The manufacturing method according to claim 4 or FIG. 5, in which hydrogen chloride is expelled at a temperature of 5 to 28°C. 7 The organic solvent is methyl cellosolve acetate,
The manufacturing method according to any one of claims 4 to 6, which is ethyl cellosolve acetate, n-butyl cellosolve acetate, methyl cellosolve, ethyl cellosolve, or n-butyl alcohol.