JPS5835368B2 - Semiconductor device and its surface coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to materials having protective and encapsulating coating properties for semiconductor devices.

In the past, several prior art methods provide for coating at least preselected exposed surface areas of a semiconductor device with an electrically insulating oxide material.

Such coatings are thin, offer virtually no resistance to mechanical abrasion, and require relatively expensive processing equipment.

In almost all cases, a second, thicker coat of protective coating material is provided to protect the initial electrically insulating material.

Silicone greases, varnishes, rubbers and resins used as overcoatings for protective materials lack desirable physical properties.

No. 3,615,913, dated Oct. 26, 1971, Robert R. Shaw applies a cured protective coating selected from the group consisting of polyimide and polyamide-polyimide over the exposed end portion of at least one P-N junction. It is taught to place the coating side of the material.

Although these materials have shown good wear resistance properties, there is still room for improvement in the immobilization requirements of semiconductor devices.

In addition, Shaw has engineered the consistency of polymeric materials for application to selected surface areas using silicon oxide, fiberglass, boron nitride, aluminum oxide, quartz, mica, magnesium oxide, reactivated polytetrafluoroethylene, etc. I was in control.

Alizarin has also been incorporated into various coating materials to aid in a type of surface cleaning treatment for semiconductor materials.

Oxide/glass layers are currently widely used for immobilization and encapsulation of semiconductor devices where device stability and longevity are important considerations.

However, if a glassy layer must be applied after aluminum metallization (a widespread requirement), the selection of a suitable glass system is severely limited by the maximum allowable application temperature of approximately 577°C. .

This limit is determined by the aluminum-silicon eutectic point,
Care must be taken during all processing operations after aluminization of silicon.

Several glass coating methods are currently in use.

These include chemical vapor deposition (CVD), glass fit, and spin-on glass forming alcoholates.

Although this last method can only produce very thin glass layers on the order of zoooA, this glass tends to be more reactive than desired, which limits its use in packaging.

Glass coating method) Widely used for U packaging, but surface immobilization is difficult because the expansion matches well with silicon and at the same time it is a suitable immobilizing agent and makes it difficult to prepare chemically stable glass. Not normally used.

Although the CVD method allows sufficient thickness, wide composition selection, expansion matching, etc., it is difficult to control sodium contamination in the CVD reactor, so it can be tolerated by direct deposition on the base silicon. It was difficult to obtain the Urufudo layer.

Therefore, the use of this method H5i02 as an overcoating of metal layers is usually limited.

Given the current state of development, none of these methods is believed to be capable of providing a reliable immobile/encapsulation method for large thyristors and other power semiconductor devices.

Recently, immobile coating materials have been developed for coating electronic components.

This material is a copolymer that is the reaction product of a silicon-free organic cyanide, an organic tetracarboxylic dianhydride, and a polysiloxane.

This material is a significant improvement over prior art materials;
Exhibits better adhesion and corona bass than currently available polyimide and boria doid coatings.

This useful surface property makes it desirable to use these materials to coat high-voltage semiconductor devices, where the high electric field generated by the surface coating on the silicon surface can be absorbed into the surrounding air by surface breakdown or corona. It is desirable to reduce the value at a sufficiently low value such that no surface leakage occurs and surface leakage is not a big deal. Yes.

This is difficult to do with very thin layers of polymeric materials.

Forming thick layers of defect-free coatings is time consuming and expensive.

In accordance with the teachings of the present invention, a semiconductor device is provided that includes a body of semiconductor material having at least two regions of opposite conductivity type.

P-N between the abutting surfaces of each pair of regions of opposite conductivity type
A junction is formed.

An end portion of at least one P-N junction is exposed on the surface of the body.

A layer of organic material free of silicone material is disposed over selected surface areas of the semiconductor device as well as the end portions of at least one P-N junction exposed at the surface.

This layer of material is an immovable coating for the surface area covered thereby and 151 is an encapsulant.

This organic substance consists of (a) a reaction product of a silicon-free organic cyanide and an organic tetracarboxylic dianhydride, and a polymer having a repeating structural unit of the formula; A reaction product of an anhydride and an amino-terminated polysiloxane containing a repeating structural unit of the formula (1) and 15 to 45 moles of structural units of the formula condensed together; and 15 to 45 moles of polyide of formula (2).

Here, lj is a divalent hydrocarbon group, R' is a hydrocarbon group with UI valence, R' is a tetravalent organic group, Q is a divalent silicon-free organic group of the residue of organic diamine, and X is zero. A larger integer is advantageously 1 to 8, but may be as large as 1oooo, and m and n are integers greater than 1, preferably 10 to 10,000 or more.

Each of these materials contains a mixture of one filler material selected from the group of rutile, lead zirconate, and barium titanate.

Filler materials enhance the electrical properties of the polymeric material by adjusting its dielectric constant and providing a high dielectric constant material.

FIG. 1 shows a semiconductor component 10 consisting of a body 12 of semiconductor material.

The body 12 is suitably prepared by polishing and lapping the two surfaces 14 and 16 until they are parallel.

Body 12 is made of a suitable semiconductor material, such as silicon, silicon carbide,
Comprises of germanium, compounds of Group (I) and Group (II) elements, and compounds of Group (II) and Group (II) elements.

In order to more fully describe the invention, body 12 will be described as being comprised of a silicon semiconductor material having five conductivity type regions and four P-N junctions.

The element 10 in this form functions as a thyristor.

Therefore, the main body 12 has P-type conductivity type regions 18 and 20, P
A region 19 of ten-type conductivity type and a region 22 of N-type conductivity type.
24 and 26.

The p-N junctions 28, 30, 32 and 34 are connected to each pair of regions 18 and 22, 22 and 20, 20 and 2 of opposite conductivity type.
4 and formed by the abutment surfaces of 20 and 26.

One means of controlling the surface electric field on such a controlled rectifier is to connect the body 12 partially treated with a layer 40 of a suitable resistive electrical conductor to large area contacts or supporting electrodes 38.
The side surface 36 is contoured after being fixed to the surface.

Electrical contacts 42 and 44 are secured to respective regions 24 and 26.

As shown, the contouring of surface 36 results in the well-known "double bevel" surface.

FIG. 2 shows a semiconductor device 50 having a double positive bevel configuration for controlling the surface electric field.

All items designated by the same reference numerals as items in element 10 of FIG. 1 are the same as the corresponding items in element 10 and function similarly.

For the shape shown, element 50 functions as a cycloster.

Regardless of the method used to control the surface electric field.

At least some selected end portions of the P-N junction are connected to the body 1
2 surface areas are exposed.

Therefore, it is necessary to apply a suitable material to protect this exposed end portion of the p-N junction.

A layer 46 of encapsulant or protective coating material is disposed over at least surface 36 and at least the exposed end portions of P-N junctions 28 and 30.

Preferably, the material of layer 46 adheres to the material of surface 36 as well as layer 44 and contact and support electrodes 38.

The material of layer 46 must have sufficient dielectric properties and must be able to withstand the high temperatures encountered during processing of device 10.

Additionally, the material of layer 46 must be capable of providing an adhesive bond to the selected surfaces of element 10 when cured, and must have good abrasion resistance as well as chemical reagents used in completing the fabrication of element 10. should show resistance to

Encapsulants that are also protective coating materials, such as poly-dosilicone copolymers, have been found to be such a desirable material when disposed over at least surface 36 and at least the exposed end portions of P-N junctions 28 and 30. Ta.

The encapsulating agent or protective coating material may be disposed on surface 36 as a polymeric precursor dissolved in a suitable solvent.

Upon heating and vaporizing the solvent, the protective coating material of layer 46 is polymerized in situ on surface 36 and the edge of the at least one P-N junction.

Preferably, the material of layer 46 is applied to preselected surface areas of surface 36 of body 12 as a solution of a soluble polymeric intermediate.

Application of the material to at least surface 36 of body 12 may include spraying,
By appropriate means such as turning, painting, etc.

Heating the coated body 12 with the protective coating material then converts the resinous soluble polymeric intermediate into a hardened solid selectively insoluble material.

A suitable material for layer 46 that satisfies the above requirements ν is (1)
(2) which, when cured with the reaction product of a silicon-free organic cyanide and an organic tetracarboxylic dianhydride in a suitable organic solvent, yields a polymer having repeating structural units of the formula; (2) a suitable organic solvent; When cured with the reaction product of a silicon-free organic diamine, an organic tetracarboxylic dianhydride, and a polysiloxane diamine, the repeating structural units of formula (1) and structural units of formula (15 to 45, preferably 25 to 35 moles) and (3) the polyimide compound of formula I, and 15 to 45 moles, preferably 2
5 to 35 moles of polyimide of formula (1), where Ri divalent hydrocarbon group, R'ff monovalent hydrocarbon group, R'U tetravalent organic group, QU organic diamine. a divalent silicon-free radical which is the residue of
, advantageously an integer from 1 to 8, as high as 1 to 10,000 or more, m and nH the same or different, greater than 1,
It is an integer of 10 to 10,000 or more.

The above-mentioned block or random copolymer can be prepared by reacting a component mixture containing a general tetracarboxylic dianhydride in an appropriate molar ratio, R, R'.

R'', Q and xn have the above meanings.

Alternatively, as mentioned above, based on the total molar concentration of the units of formula ■ and the units of formula
A polysiloxanimide combination is prepared by combining a polyimide of formula (1) with a polyimide consisting exclusively of repeating structural units of formula (2), preferably in a molar proportion such that it is in the range of 25 to 35 molar proportions. may be used with comparable effectiveness in a suitable solvent.

The formulation of this material is applied to a suitable surface area and the solvent is allowed to evaporate in situ.

As will be appreciated, the final polyimidosiloxane compositions used in the practice of this invention will consist essentially of the i-do structure of Formula I and Formula II.

However, the actual precursor materials resulting from the various reactions of diaminosiloxanes, silicon-free organic diamines, and tetracarboxylic dianhydrides are in the form of polyamic acid structures comprising one or more structural units of the original formula.

Diaminosiloxanes of formula (1) that may be used in the practice of the present invention include compounds of the following formula.

etc.

The diamines of the formula (2) are materials which are commercially available in large quantities with gp as described in the prior art.

Typical diamines prepared from prepolymers include the following:

m-phenylenecyamine, p-phenylenecyamine, 4
．． 4-cyanodiphenylpropane, 4.4-diaminodiphenylmethane, 4.4' methylene dianiline, benzidine, 4.4-diaminodiphenyl sulfide, 4
．． 4-diaminodiphenylsulfone, 4.4-diaminodiphenyl ether, 1,5-diaminophthalene, 3
, 3-dimethylbenzidine, 3.3′-dimethoxybenzidine, 2.4-bis(β-amino-t-7′-thyl)toluene, bis(p-β-a,□not-7′-tylphenyl)ether, Bis(p-β-methyl-〇-aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene, 1,2-bis(3-aminopropoxy)ethane, m-xylylenediamine, p-xylylenediamine , bis(4-aminocyclohexyl)methane, decamethylenediamine, 3-methylhebutamethylenecyan, 4
, 4-dimethylhexamethylene diamine, 2,11-dodecanediamine, 2,2-dimethylpropylene diamine, octamethylene diamine, 3-methoxyhexamethylene cyan, 2,5-dimethylhexamethylene cyan, 2.5-dimethylhebutamethylene diamine, 3-methylhebutamethylene cyanine, 5-methylnonamethylene cyanine, 1,4-cyclohexanediamine, ■, 12-
Octadecanediamine, bis(3-aminopropyl) sulfide, N-methyl-bis(3-aminopropyl)amine, hexamethylenediamine, heptamethylenediamine, nonamethylenediamine, and mixtures thereof.

These cyan colors are included for illustrative purposes only;
It is unlikely that this includes everything.

Accordingly, other unlisted diamines will be readily apparent to those skilled in the art.

Tetracarboxylic dianhydride of formula V is further defined as R
' is a tetravalent group, for example a group derived from or containing an aromatic group containing at least 6 carbon atoms characterized by benzenoid unsaturation;
Each of the four carbonyl groups of the dianhydride is bonded to a separate carbon atom of the tetravalent group, and the carbonyl groups form pairs, with the groups in each pair bonded to the R' group zero instantaneous carbon atom. or Uf is bonded to two carbon atoms in the R'' group separated by at most one carbon atom to provide the following 5- or 6-membered ring.

Examples of dianhydrides suitable for use in the present invention (abbreviations shown in parentheses) include:

Pyromellitic dianhydride (PMDA), 2.3.6.7-
Naphthalenetetracarboxylic dianhydride, 3,3,4.4
-diphenyltetracarboxylic dianhydride, 1.2.5.
6. - naphthalenetetracarboxylic dianhydride, 2.2.
3.3-diphenyltetracarboxylic dianhydride, 2,2
-bis(3,4-dicarboxyphenyl)sulfonic anhydride, bis(3,4-dicarboxyphenyl)sulfonic anhydride, 2,2-bis[:4-(3,4-dicarboxyphenoxy)phenyl]propanni Anhydride (BPA dianhydride), 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propanihydride, benzophenonetetracarboxylic dianhydride B PD A, perylene-1,2,7 , 8-tetracarboxylic dianhydride, bis(
3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, and aliphatic anhydrides such as cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, Butanetetracarboxylic dianhydride, etc.

By mixing other dianhydrides such as trimellidic anhydride,
The creation of doimidosiloxane polymers is also prohibited.

The novel composition of matter of the present invention additionally includes one selected from the group consisting of rutile, lead zirconate and barium titanate.
Stir in seed filler material.

The filler material fltrs, encapsulation or passive material may help to control the dielectric properties and/or interact with the surface effects of the applied electronic component to improve its electrical properties.

One option is to apply the material of coating 46 to surface 36 as a precursor.

The precursor or formulation solution may be prepared in a suitable solvent (e.g., N-methylpyrrolidone,
(N,N-dimethylacetamide, N,N-dimethylformamide, etc.) alone or in combination with a non-solvent containing a resinous substance.

Precursor or formulation solutions containing 10-40% solids by weight are suitable for semiconductor work.

Preferably, the precursor or formulation solution contains 20 to 40 polysolids resinous material.

Sufficient material is applied to surface 36 to provide layer 46 with a thickness of 1 to 100 microns.

Application of the substrate material to the surface 36 may be by conventional means such as, for example, dipping, spraying, painting, swirling, and the like.

Block or random copolymers or polymer blends may be dried by an initial heating step, often under vacuum at a temperature of about 75 DEG to 125 DEG C. for a sufficient period of time.

The polyamic acid of the precursor solution is then converted to the corresponding polyimide-siloxane by heating to a temperature of about 150 DEG to 300 DEG C. for a sufficient period of time to achieve the desired conversion to the polyimide structure and final curing.

Preferred curing cycles for materials of the above general formula are as follows.

(a) 15-30 at 135-150°C in dry N2
Minutes.

('b) 15-60 minutes at about 185±10°C in dry N2.

(e) Vacuum width at about 225°C for 1 to 3 hours.

Alternatively, the coating material can be formed in other atmospheres, such as air, to facilitate commercial application of the invention.

A suitable polymer precursor solution containing the filler material of choice is prepared by reacting benzophenonetetracarboxylic dianhydride with methylene dianiline and bis(gamma-aminopropyl)tetramethyldisiloxane, forming a compound of the form e. .

The two diamine materials are present in a molar ratio of 85:15 to 55:45.

Preferably, the desired molar ratio of the two diamine materials ranges from 75:25 to 65:35.

A good polymer precursor material has a molar ratio of 70:30.

The reaction of these chemical components is carried out at 50°C using appropriately purified and dried materials to favor polymers with large molecular weight.
carried out at temperatures below.

The polymer precursor solution is in the form of polyamic acid dissolved in UN-methyl-2-pyrrolidone and has a solids content of 10 to 40 parts by weight.

Preferably, the solution contains about 25 weight solids in the form of polyamic acid.

To this solution is added a material selected to enhance the electrical properties of both the coating material and the selected surface area of the electronic component to which it is applied.

The dielectric constant of the cured polymer is on the order of about 3.7.

When an unfilled polymeric material is applied to a selected surface area of silicon with a dielectric constant of 12, the electric field strength is 1 to 1 at reverse breakdown.
This is almost three times the electric field strength in silicon, which can reach levels of 2×10′ volts/crr1.

Therefore, the poly□do-silicone copolymer is approximately 6×10
It must be possible to maintain a maximum electric field of the order of 5 (3×2×10 5 ) volts/cm.

Increasing the dielectric constant of a film of polyimide silicone copolymer material by introducing selected filler materials reduces the electric field that the material must withstand.

For example, a material filled with rutile (dielectric constant 90) and having an average dielectric constant of about 12 has an electric field for this cured film of approximately 2 x 10' volts/cm when the filler material is present up to 10 volumes of the cured mixture. Become.

For filled polymers and filled polyide silicone materials, the maximum filler content of the cured resin is on the order of about 50 vol., thus achieving a maximum dielectric constant of about 47 when used as a rutile filler. becomes possible.

The maximum weight ratio of filler material added and mixed into the precursor solution depends on particle size, shape, and density and polymer solution solids content.

Assuming a void-free composite in which the spherical particles of rutile form a cubic array after curing, the maximum weight of solids that can be effectively added to the precursor solution is:

where W is the weight of the solid filler and %8 is the weight of the polymer solution (
WFP is the weight percentage of the polymer in the precursor solution.

For example, some typical values for precursor solutions containing rutile as filler are listed in the table below.

High values of W8/WPs do not result in void-free composites after curing.

The surface charge at the interface between the cured film of the coating material and the silicon element is in some cases due to the effect of charge distribution in the coating material.

In such cases, a high dielectric constant has the added benefit of lowering the effective surface charge value.

This is especially true in the case of semiconductor P-N junctions with lightly doped n and p regions, where minimizing the surface charge rate maximizes breakdown and minimizes reverse leakage.

The dielectric material that is an excellent filler is rutile, the tetragonal or most stable form of titanium dioxide.

It has the highly desirable property of a high dielectric constant of around 90 rutile.

This value for the dielectric constant is 12 for silicon and 8 for General Electric Company proprietary composition 351 glass.
6 and 3.8 for silicon dioxide.

= In general, leakage and avalanche amplification of dielectric materials depend on electric field strength.

The electric field strength is inversely proportional to the dielectric constant of the material.

The higher the dielectric constant, the more effective it is to lower the electric field in the dielectric for a given applied voltage.

Therefore, the novel immobile or encapsulating material of the present invention with rutile blends can withstand higher applied voltages than unfilled copolymer materials.

Other suitable filler materials, barium titanate and lead zirconate, work similarly to rutile.

The range of addition of these fillers to the resin solids in the precursor solution varies somewhat from the values listed in the table due to density differences, but can be similarly calculated.

The addition of filler materials also enhances the laser scribability of silicon sea urchins coated with the polymeric materials described herein.

This provides a secondary benefit to using the desired filler material.

[Brief explanation of the drawing]

1 and 2 are cross-sectional side elevational views of semiconductor devices using the novel polymeric materials of the present invention. 10... Semiconductor element, 12... Main body,
14. 16... surface, 28, 30, 32 and 34...
...P-N junction, 36...Side, 46...
...Protective coating material layer.

Claims (1)

[Scope of Claims] 1(a) A reaction product of a silicon-free organic diamine and an organic tetracarboxylic dianhydride which, when cured, becomes a polymer having a repeating structural unit of the formula; (b)
Curing with the reaction product of a silicon-free organic diamine, an organic tetracarboxylic dianhydride, and an amino-terminated polysiloxane mutually combines 55-85% of the repeating structural units of formula (1) with 15-45 moles of repeating structural units of the formula. A copolymer containing 55 to 85 mol of polyimide of formula (1) and 15 to 85 mole of polyimide of formula (1) after acclimatization to (c)
A blend of the reaction product of a silicon-free diamine with an organic tetracarboxylic dianhydride and the reaction product of an organic tetracarboxylic dianhydride with an amino-terminated polysiloxane ( However, R is a divalent hydrocarbon group, R' is a monovalent hydrocarbon group, R'U is a tetravalent organic group,
A divalent silicon-free organogroup that is a residue of a Qpoorganodiamine,
X is an integer greater than zero, and m and n are integers greater than 1 and may be equal to each other), and the solution is applied to the surface of the semiconductor device. A semiconductor device comprising at least one high dielectric constant filler material selected from the group consisting of rutile, barium titanate, and lead zirconate mixed into and distributed throughout the precursor solution prior to coating. A filled polymer composition for use as a surface coating to prevent surface breakdown. 2. The filled polymer composition according to claim 1, wherein the precursor is the reaction product, and the molar ratio of the structural units of formula (1) is 25 to 35, and the remainder are structural units of formula (1). thing. 3. A filled polymer composition according to claim 1 or 2, wherein the molar coefficient of structural units of formula (1) is about 30, the remainder being structural units of formula I. 4. The reaction product is derived by reacting benzophenone tetracarboxylic dianhydride with methylene dianiline and bis(γ-a□nobrovir)tetramethyldisiloxane,
The molar ratio of methylene dianiline and bis(γ-aminopropyl)tetramethyldisiloxane is 80:20 to 65.
:35. 5. The filled polymer composition of claim 4, wherein the molar ratio of methylene dianiline to bis(γ-aminopropyl)tetramethyldisiloxane is 70:30. 6. The filled polymeric composition of claim 4, wherein the filler material is barium titanate. 7. The filled polymeric composition of claim 4, wherein the filler material is lead zirconate. 8. The filled polymeric composition of claim 4, wherein the filler material is rutile. 9 The maximum weight of rutile solids in a polymer composition filled with a filler in a cured, void-free polymer is expressed by the formula (where W8 is the weight of the solid filler and WF2 is the weight of the polymer solution (precursor)). 9. A filled polymer composition according to claim 8, expressed in weight and WF'P is the weight percentage of the polymer in the precursor solution. 10 at least two regions of opposite conductivity type are formed, the abutment surfaces of each pair of regions of opposite conductivity type forming a P-N junction therebetween;
In semiconductor devices that include a body of semiconductor material in which the ends of the N-junction are exposed at the surface, the filled polymer composition can be used as a surface coating to prevent surface failure of the device. at least one end of the P-N junction is disposed on the exposed surface, and the filled polymer composition is further characterized in that the filled polymer composition is composed of a silicon-free organic cyanide and an organic tetracarboxylic dianhydride. A reaction product which, when cured, results in a polymer having repeating structural units of formula I; b. a reaction product of a silicon-free organic diamine, an organic tetracarboxylic dianhydride, and an amino-terminated polysiloxine; when cured, a repeat of formula I; A copolymer containing 55 to 85 moles of structural units and 15 to 45 moles of repeating structural units of the formula is condensed with each other, and when cured, poly 42155 to 85 of formula I and formula Bolii □do 15-45
Blends of reaction products of silicon-free organic cyanide with organic tetracarboxylic dianhydride and of reaction products of organic tetracarboxylic dianhydride and amino-terminated polysiloxine to give blends with molar factors ( However, R is a divalent hydrocarbon group, R' is a monovalent hydrocarbon group, R' is a tetravalent organic group, Q
is a divalent silicon-free residue that is a residue of an organic diamine,
is an integer greater than zero, and m and n may be equal in number to each other), and the solution is used as a surface of a semiconductor device. and at least one high dielectric constant filler material selected from the group consisting of rutile, barium titanate and lead zirconate mixed into this precursor solution prior to application to the mouth and distributed throughout the solution. A semiconductor device characterized by: 11. The semiconductor device according to claim 10, wherein the precursor is the reaction product, and the molar preponderance of the structural unit of formula (1) is 25 to 35, with the remainder being the structural unit of formula (2). 12. The semiconductor device according to claim 10, wherein the molar coefficient of the structural unit of formula 12 is about 30, and the remainder is the structural unit of formula 1. 13 The reaction product is derived by reacting benzophenone tetracarboxylic dianhydride with methylene dianiline and bis(γ-aminopropyl)tetramethyldisiloxane, and is derived from methylene dianiline and bis(r-aminopropyl)tetramethyldisiloxane. The molar ratio of siloxane is 80:20 to 65:3
11. The semiconductor device according to claim 10, wherein: 14. The semiconductor device according to claim 13, wherein the molar ratio of methylene dianiline and bis(γ-anoprobyl)tetramethyldisiloxane is 70:30. 15. The semiconductor device of claim 13, wherein the filler material is barium titanate. 16. The semiconductor device of claim 13, wherein the filler material is lead zirconate. 17. The semiconductor device of claim 13, wherein the filler material is rutile. 18 The maximum weight of rutile solids in a polymer composition filled with a filler in a cured void-free polymer is expressed by the formula (where W8
18. The semiconductor device according to claim 17, wherein WFP is the weight of the solid filler, wP8rrs is the weight of the polymer solution (precursor), and WFP is the weight percentage of the polymer in the precursor solution. 19. The semiconductor device according to any one of claims 10 to 18, wherein the semiconductor material is silicon.