JPS62224646A - Composite material and its production - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION This application describes the application of Varnish, Etch, Butt (S, H, Butt).
), U.S. Pat. No. 4,569.692, entitled "Low Thermal Expansion and High Thermal Conductivity Substrate."

Although the invention has a wide range of applications, it is particularly suitable for use as a substrate for microelectronics. The present invention is primarily aimed at combining materials with different coefficients of thermal expansion and thermal conductivity to create bonded composites with improved stiffness and thermal properties.

Low coefficient of expansion materials are widely used in the microelectronics industry for semiconductor packaging.
, multi-device hybrid
ce hybrid) is used as a base material for circuit packages, chip supports, and printed wiring boards. The latter application is particularly useful when the coefficient of thermal expansion of the substrate is important, such as when attaching silicon chips or low coefficient of expansion chip supports directly to the substrate.

In many cases, it is known in the art that low coefficient of expansion ceramic or metal substrates can be substituted with relatively high coefficient of thermal expansion metals. Generally, high coefficient of expansion metallic materials are utilized in combination with appropriately selected high coefficient of expansion glasses or organic bonding agents. The thermal expansion mismatch between this combined material and the low coefficient of thermal expansion (CTE) silicon-based microelectronic components creates unacceptably high thermal stresses in typically fragile and fragile semiconductor components. Compatibility is achieved by installing a system such as an adhesive or solder that prevents this from happening. However, it is not possible to create a component assembly system that can accommodate the potential thermal stresses resulting from the large mismatch between a high coefficient of thermal expansion metal substrate and a low coefficient of thermal expansion semiconductor chip. In order to better understand the effectiveness of the eye-catching materials according to the present invention, the limitations of conventional substrates are listed in the following text.

Alumina ceramics are currently the most widely used substrate. There is a moderate mismatch between the coefficients of thermal expansion of alumina and semiconductors. This unbalance generally causes a chip assembled on an alumina substrate to undergo thermal cycling.
It does not create unacceptably high stresses. Unbalance is generally tolerable even when the chip size is fairly large or when the chip is tightly adhered to the substrate. Alumina ceramics are particularly attractive because they are less expensive than many other low coefficient of expansion substrates. However, alumina has a number of drawbacks, such as difficulty in tolerance control and poor thermal conductivity, ranging from about 10 to about 20 watts per meter absolute (W/m-'K).

Additionally, manufacturing capacity constraints limit the alumina substrate area to less than about 50 square inches.

Beryllia ceramic possesses a relatively high thermal conductivity of approximately 190 W/m-0 and may be substituted for alumina ceramic in special applications. Due to the inherently high price of beryllium,
These substrates would be very expensive. A further disadvantage of beryllia substrates is that they are toxic and require careful handling and very careful dust control. However, despite the problems of high material costs, high processing costs, and toxic substance control, beryllia substrates have often been utilized when high thermal conductivity is required.

A thin metal plate of molybdenum has a thermal conductivity of approximately 142w/@
-'x, and is sometimes used as a substrate, especially in hybrid circuit packages. Although expensive and difficult to process, molybdenum has a low coefficient of thermal expansion, approximately 49X.
10-7in/in 10Cs'k, combined with high thermal conductivity coefficient. A major disadvantage in the use of molybdenum parts is the inherent difficulty in processing them due to their poor resistance to oxidation.

For laminated metals with low expansion coefficient substrates, generally
There are high conductivity and high thermal expansion coefficient copper or copper alloy clad 9 laminates with a very low coefficient of thermal expansion nickel-iron alloy (eg INVAR) core. The resulting composite is made of alumina and PeIJ.
It possesses a coefficient of thermal expansion comparable to that of rear ceramics. The purpose of laminating with copper or copper alloys is to completely improve the relatively poor thermal conductivity of nickel-iron alloys.

However, the thermal conductivity is improved primarily in the longitudinal and widthwise surfaces of the substrate. At the same time, the through-thickness thermal conductivity of the composite material, consisting mainly of six plates of nickel-iron alloy, remains relatively low.

The cost of nickel-iron alloys and the relatively expensive processes involved in producing the laminate metal result in these substrate substrates being relatively expensive, although cheaper than comparable beryllia or molybdenum substrates. As the terminology indicates,
It is a mixture of metal and ceramic. of this material,
The advantage over metal substrates of comparable dimensions is increased stiffness and reduced weight. Compared to ceramic substrates, it possesses a very high coefficient of thermal expansion and thermal conductivity, and is an electrical conductor. Additionally, cermets are produced at temperatures much lower than those required for sintering ceramics, ie, about 1600'C, and processing costs are typically lower.

Further, the thermal expansion coefficient and thermal conductivity of the cermet can be selected from a relatively wide range of values. The problem is that, to this day, these materials cannot easily be joined together to form the rigid bodies required for electronic industry applications.

A method for producing an aluminum-alumina composite is described by B, F, Quigley et al.
et.), the American Society for Metals and the American Society for Metals
orMetals And The Metalur
5ociety of AIME),
Metaradical Transaction A (Meta
Illurgical Transactions A
), Volume 13A, January 1982 issue, in an article entitled "Method for producing aluminum-alumina composites". This article presents a method for bonding alumina fibers into an AJ-Mg matrix to achieve complete wetting and bond formation. This manufacturing method uses ceramic fJ
2mt - Adopt the casting technique of mixing in molten AI-Mg. About 50 to about 70% of the aluminum is squeezed out of the mixture through a ceramic filter. The remaining mixture contains up to about 23 volumes of alumina particles in an Al-Mg matrix. Further, the article stated that substantial fiber breakage occurs when the fibers of the starting material are at a level of about 10-20 vol. Therefore, the corruption is
By compressing the composite material containing fibers in the range of 5 to 10 bodies, it was possible to keep it to a minimum.

This article describes a manufacturing method that is completely different from the manufacturing method of the present invention. First of all, the present invention utilizes powder metallurgy techniques, thereby allowing the inclusion of a substantially higher percentage of ceramic particles in the alloy material IJ socks. This high volume is very useful in controlling the coefficient of thermal expansion of the mixture and making it similar to that of copper alloy materials typically used in leadframe construction for semiconductor packaging applications.
Jk is essential.

The amount of alloy particles added to the aluminum is limited within a predetermined range to increase the thermal conductivity of the finished composite. The size of the ceramic particles is kept very small so that the resulting composite has a smooth finish and is suitable for electronic industrial applications.

The problem leading to the present invention is to produce a rigid cermet that has both a relatively high coefficient of thermal expansion and a relatively high thermal conductivity.

An advantage of the present invention is to produce composites that eliminate one or more of the limitations and disadvantages of the conventional methods described above.

It is also another object of the present invention to provide a composite body having a coefficient of thermal expansion that closely matches that of a metal lead frame, and a method for making the entire composite body.

It is a further advantage of the present invention to provide a composite and a method of making the composite that can be applied as a substrate that is rigid and resistant to thermal shock.

It is also another advantage of the present invention to provide a highly thermally conductive composite and a method of making the composite.

Another advantage of the present invention is to provide a composite that can be manufactured relatively cheaply and a method for producing the composite.

A cermet material suitable for use as a semiconductor substrate was thus produced. Cermets are composites that are preferably made using powder technology procedures. The complex consists essentially of about 25 to about 80 units, preferably about 40 to about 6 units.
0 body M% metal or alloy, effective amount ~ about 10 bodies 8 tons
% of a binder that strengthens the bond between the metal or alloy and the ceramic particles, and the remainder of the mixture of particles that are essentially ceramic. Composite materials have a matrix of metal or alloy with binder and ceramic particles dispersed therein. In a second embodiment, the composite has glass-coated ceramic particles dispersed therein in a matrix of metals or alloys.

The drawing shows a semiconductor package consisting of a cermet bottom and a cover according to the invention.

The present invention is particularly aimed at cermets with a relatively high coefficient of thermal expansion and a relatively high thermal conductivity. This cermet is manufactured from relatively inexpensive materials using powder metallurgy techniques. The resulting cermet is suitable for use in a number of industrial ceramic applications, such as substrates for semiconductor devices, hybrid packages or rigid printed wiring boards. The basic concept is that ceramic particles are mixed with metal or alloy particles, such as aluminum or aluminum alloy particles, and the mixture is thermally treated.
The resulting cermet has ceramic particles dispersed in an aluminum matrix. Ceramic materials have a low coefficient of thermal expansion, a high modulus of elasticity, and generally have poor thermal conductivity. In contrast, aluminum is a highly thermally conductive and high coefficient of thermal expansion material. The production of this cermet is very limited due to the inability of liquid aluminum to wet the ceramic particles.

The present invention is directed to a method of manufacturing an aluminum or aluminum alloy ceramic composite comprising adding a binder to the aluminum or aluminum alloy matrix to strengthen the bond between the aluminum or aluminum alloy particles and the ceramic particles. There is. The binder forms a binder-ceramic link at the interface between the matrix and the ceramic particles, chemically bonding the ceramic particles within the aluminum alloy matrix.

The ceramic particles are preferably aluminum oxide (A
1203), but for example AJN.

Any other ceramic particles may be used, such as Si3N4 and mixtures thereof. A1203 (alumina) particles are particularly desirable because they are readily available, inexpensive, and have coefficients of thermal expansion and compressive modulus numbers in desirable ranges. The ceramic particles have a particle size of about 10 to about 400 microns, preferably about 15 to about 25 microns. The upper limit for ceramic particles is set by the need for finished products to have a relatively smooth finish 9 and to meet electronic industry packaging standards. If used in applications other than composite t-electronic packaging, the ceramic particle size may be any size greater than about 10 microns. After setting the body of ceramic particles 8%, the body of aluminum and binder #t%,
The final composite is determined to contain up to essentially about 10 volumes of binder. Typically 1t of ceramic
is selected to adjust the composite to the desired coefficient of thermal expansion. As the amount of ceramic decreases, the coefficient of thermal expansion of the composite increases.

The composite material also contains about 30 to about 65 volumes of metal or alloy particles, preferably consisting essentially of aluminum and aluminum alloys.

Preferably, the aluminum or aluminum alloy comprises about 40 to about 60 branches of the composite material.

By choosing this volume percent, the finished composite will have approximately 1
4DX10-7~about 170X10-7in/in/'
Q1 preferably about 150X10-7 to M+5X10-7
Possesses a relatively high coefficient of thermal expansion of in/in/°C. This high volumetric strength of aluminum or aluminum alloys makes the finished composite electrically conductive. This constitutes an EMI shield and is effective in preventing electrostatic shock.

The aluminum or aluminum alloy particles are about 3 to about 25
The dimensions shall be between microns. Preferably, the aluminum or aluminum alloy particles are about 5 to about 10 microns in size. The lower limit size of the aluminum or aluminum alloy particles is set to keep oxide contamination to a low level.

Very small particles, such as about 5 microns or less, oxidize easily and the oxygen content in the mixture becomes undesirably high. At the same time, it is preferred to use relatively small aluminum or aluminum alloy particles to achieve a relatively high final density of the composite, such as about 96% or more of the theoretical density. This is important for applications requiring tight parts that cannot tolerate significant porosity. Aluminum itself U
, a coefficient of thermal expansion of about 230x10-7 in/in/°C;
It has a thermal conductivity of approximately 270 W/m-'.

The aluminum or aluminum alloy particles are selected to be smaller than the ceramic particles because ceramic is relatively difficult to deform, whereas aluminum is easily deformed. this is,
This can be understood from the following explanation.

Assuming that a powder mixture is molded into spherical particles of the same size, the gap or space between adjacent spherical particles can be made up to 65% of the theoretical packing value without any deformation. If a mixture of two different powders is packed together and one of the materials consists of larger or coarser particles than the other, the finer particles can get into the spaces between the larger particles. In this example, the larger particles are preferably ceramic, less deformable particles. The smaller aluminum or aluminum alloy particles are more deformable and can be packed into the interstices for maximum densification.

Composites of aluminum or aluminum alloy matrix containing high strength ceramic particles are ideal for profiteering applications. However, the production of this composite is very limited due to the inability of liquid aluminum to wet the ceramic #a fibers. The lack of adhesion in this type of system was demonstrated by the following experiment. Aluminum powder with a size of 5 microns is mixed with β-A1 with a size of about 30 microns.
20° and thoroughly mixed. The aluminum powder makes up about 40 parts of the mixture; the rest of the heel is β-A12o3.

The powder was then compacted into cylinders using about 15 to about 25 tons of pressure. The unfired density of the molded body was about 88%. The compact was then degassed at about 400°C and sintered at about 600°C for 24 hours. The density of the molded body after sintering was about 92%. The compressive modulus of the sintered compact was approximately 7X 10' psi. As a result of the fracture surface test, IUI-AA! It was found that there was no close contact of 203. The inability of liquid metal to wet alumina particles has already been discussed in the article by Quigley et al., discussed in the background of the present invention.

The present invention is to add an effective amount of binder, about 10% by weight, to strengthen the bond between the aluminum alloy matrix and the ceramic particles. The binder is approximately 3
It can be added in particulate form with a size between ~25 microns. Preferably, the binder particles are 85 to about 10 microns in size. The binder is preferably Mg, Li,
Cr, Ca, Be.

selected from the group consisting of MgO and mixtures thereof;

An effective weight range is believed to be from about 0.5 to about 10 degrees of Mg, preferably from 2 to 6 degrees of Mg. The effective range of other ingredients is about 1 to about 5
Body 1% Li, cauterization 0.05~6 Body 1% Cr, approx. 0-05~? fg1 body Ca, about 0.05 to about 0
．． 5 volumes of Be, and about 1 to about 5 volumes of MgO
It is.

Magnesium is considered a preferred additive to aluminum because it does not react with aluminum and is relatively inexpensive. Magnesium diffuses into the aluminum shell and significantly reduces its thermal conductivity.For example, as shown in Table 1, when 8% magnesium is added to aluminum, when 1 Ja of total magnesium is added to aluminum, Thermal conductivity is significantly reduced compared to

1st material Thermal conductivity (W/m -0K)
Aluminum 270 Ceramic
10~20fI11
380 copper alloy (CDA 72400)
45 Aluminum + 1-Mg 22
The amount of Mg added to the D Aluminum + 8% Mg 140 mixture is preferably kept low to increase the thermal conductivity of the cermet material.

The final thermal conductivity of the cermet material is approximately 40-120
It is between W/m-'. Preferably about 50 to about 1
0 Q W/m-' K, and most preferably from about 60 to about f3 Q W/m-' K.

Another important property of cermet materials is that approximately 140
×10-7~about 170X10-7in/in/'
in the range of Q, preferably about 140XI D-F to 1
70X 10= in /in/-Cノ1tXaKJ'
+ Le, the best 4 likes tL<ha! IJ 1 50x1 0-7
It has a high coefficient of thermal expansion in the range of ~165 x 10-1 in/in/°C. By selecting a value within this range, the Leadframe
Hand-drawn alloys with large coefficients of thermal expansion can be eliminated with copper alloy materials, which are the preferred materials for the application. For example, 0DA
The coefficient of thermal expansion of 72400 is approximately 170X10-7in/
in/'Q.

The binder forms a chemical bond at the interface between the particulate ceramic and the aluminum alloy during solid or liquid phase sintering. The bond is by a spinel such as MgO-At2C)3.

Due to the strong bond with alumina S and aluminum-magnesium alloy formed by spinel bonding, the composite material fully embodies the law of mixed properties, being able to withstand both mechanical and thermal loads.

The finished cermet or composite has certain characteristics such as crystalline compressive modulus, high thermal conductivity and still thermal tensile modulus, % for coating for conductors.
Vh indicates a combination of particularly important characteristics. An important property of cermets is a high compressive modulus. The final molded body has an Ff: elastic modulus of at least about 20 x 10'psi. This high compressive modulus of elasticity allows the material to be applied directly to the finished cermet as shown in the example shown.
172 physical integrity and rigidity of the semiconductor package.

The method of making the inventive cermet 1 preferably applies all powder metallurgy techniques. Particle size from about 3 to about 100
Prepare a mixture containing about 25 to about 80 microns of aluminum or aluminum alloy particles by volume. Next, up to about 10 volumes of particulate binder with a grain size of about 3 to 25 microns is effectively added to strengthen the bond between the aluminum or aluminum alloy particles and the ceramic particles. . The binder is Mg, Li, Cr
, Ca.

Selected from the group consisting of Be, MgO and mixtures thereof. Add the rest of the mixture to the whole? 100
The volume is assumed to be 1. The remainder are ceramic particles having dimensions of about 10 to about 100 microns. Ceramic particles are
Selected from the group consisting of AIM, Si3N4, Al2O3N and mixtures thereof. Mix the mixture thoroughly;
The molded body is then molded using a pressure of between about 15 x 10 and about 100 x 10'' psi, preferably between about 40 x 10 and 60 x 10' psi. degassing at a temperature of about 1 hour. This step typically heat-treats the aluminum powder in a manner that vaporizes and removes the lubricant, such as stearic acid, with which it is usually coated from the compact. Sintering It may be carried out in the solid state at temperatures below about 660°C, and in the semi-solid state at temperatures above about 660°C, in each case within 24 hours.
Preferably, it is carried out in an inert or cyclic atmosphere such as nitrogen, nitrogen-4% hydrogen or albino. When sintering is carried out in a semi-solid state, MgO can be added as a binder.

As an example of a method for making cermets, β-At203 powder with a size of 30-100 microns is mixed with magnesium powder with a size of 5 microns. Next, 6 micron size aluminum powder was mixed into the mixture. The volume ratio of the aluminum powder was about 35%, the volume ratio of the magnesium powder was about 6%, and the remainder was Az2O3. The mixture was molded at a pressure of F130,000 bond. Next, the molded body was degassed and sintered at about 600° C. for 24 hours.

When the compressive elastic modulus was measured, it was approximately 24X106 to approximately 2
It was between 7 X 10' psi. Further treatments, such as hot compression molding or hot forging, can be used to increase densification and improve properties.

In the figure, a semiconductor casing (casing) 10'l
show.

Cover 12 and bottom 14 were made from cermet according to the invention. The recesses 16N and 18 can have any desired shape in the bottom and cover to match the semiconductor device [20]. leadfra A
me) 22 is preferably a copper alloy and is located between the bottom and the cover. Glass 24 having a high coefficient of thermal expansion is preferably utilized as a seal to seal casing 10. A suitable glass is a lead borate type sealing glass which is fully doped with calcium fluoride or barium fluoride so that the coefficient of thermal expansion is the same as that of the copper alloy lead frame. Furthermore, it is also preferable to add a small amount of copper oxide to the glass to strengthen the bond with the copper alloy lead frame. The lead frame can be made of a copper-based alloy, such as ODA 72400, which provides a strong bond with the sealing glass and has good resistance to softening when exposed to high temperatures. O.D.
Can be sealed with glass such as A 63800.
It is also within the scope of this invention to use other alloys. Both these alloys and glasses possess coefficients of thermal expansion in the range of about 160 x 10 = to about 170 x 10 -' in /in/'Q. This is comparable to the coefficient of thermal expansion of cermets made by the method of the invention.

The second embodiment is a bonded glass (5old glass).
) The aim is to create a cermet e that uses a binder to form a strong bond between aluminum and ceramic particles. This binder is different from the metal binders previously described herein. Glass is particularly effective because it does not alloy with the aluminum matrix and thus does not reduce the thermal conductivity of the aluminum matrix. Additionally, the choice of glass allows for the creation of finished composite materials with a wide range of coefficients of thermal expansion.

The glass used as a binder is preferably silicon #I salt, lead borate, borosilicate fl! salts, phosphates, zinc borosilicate, soda lime - silica, lead silicate, and lead -
It is a zinc-borate glass. Preferably, the selected glass has the general composition MO-B2O3-5io2 (in the composition MO=At203, BaO, CaO
, ZrO2.

Na2O, SrO, K2O and mixtures thereof) are borosilicate bonded glasses. The glass is not limited to this group, but can be any glass that can chemically react with ceramic particles and metal particles. Glass may be vitrified or devitrified and has a diameter of about 50
°C to about 1200 °C, preferably about 350 °C to F1650 °C
It may have a softening stage between. The glass is selected to be from about 60X10-7 to about 170X10" inch, preferably from about 100X10-7 to about 150X10" inch
/°C.

Typically, a glass is selected whose coefficient of thermal expansion is closer to that of aluminum or an aluminum alloy than that of a cermet. The glass is preferably made into particles having dimensions between about 3 and about 25 microns, preferably between about 5 and about 10 microns. However, it is within the scope of the invention to use glass particles of any size since the glass is heated to a liquid state during the bonding of the ceramic and glass particles. The glass reacts chemically with aluminum and ceramic to form a strong 'zlFi bond, making it capable of withstanding loads under mechanical and thermal stress. The bonds of the present invention are formed because the aluminum reacts with the oxides in the glass, creating an exothermic reaction. Additionally, the glass possesses oxides that dissolve throughout the ceramic and form excellent bonds.

The aluminum or aluminum alloy used in the cermet of the second embodiment is particulate and essentially:
It is the same as the aluminum or aluminum alloy described in relation to the first embodiment earlier in this specification. The aluminum or aluminum alloy particles have a size of about 3 to about 100 microns, preferably about 3 to about 25 microns. The volume of the aluminum particles is about 25 to about 80 volume, preferably about 40 to about 60 volume. It is also within the scope of this invention to substitute any desired metal particles on the aluminum or aluminum alloy that will chemically react with the selected glass to form a strong bond. Metal particles include At, Cu, N'i, TLCr, Fe
, Ag, Au and alloys thereof. The present invention is not limited to these metals and alloys, but can include any metal or alloy particles that chemically bond with the selected glass.

The ceramic particles are also the same as described earlier herein in connection with the first embodiment.

However, misfires are not limited to these ceramics,
At203 * SiC, BeO, TiO2# ZrO
2. MgO1A/! , N, 813N4, BN-
j+? and mixtures thereof. Additionally, the present invention can be blended onto any desired ceramic or mixture of ceramics. Preferably,
The ceramic particles are about 10 to about 100 microns, preferably about 10 to about 40 microns, most preferably about 15 to about 40 microns.
It measures approximately 25 microns. The ceramic particles are selected to have larger dimensions than the metal particles, such as aluminum or aluminum alloy particles.

A preferred method of making the composite material is from about 25 to about 80 bodies.
iJ% of any desired metal particles, essentially consisting of aluminum or aluminum alloys, or Cu, Ni, Ti, Cr, Fe, Ag1Au and alloys thereof; Effective amount ~ about 10
a binder in the form of any glass particles, such as a bonded glass, which strengthens the bond between the aluminum or aluminum alloy or metal particles and the ceramic particles, and the remainder particles which are ceramic in nature; First, make a mixture consisting of. More preferably, the binder in the form of glass particles comprises from about 1% to about 9% total of the mixture.

Bonding glass binder particles are mixed with ceramic particles and the ceramic particles are coated with glass particles. The glass-coated ceramic particles are then heated to a temperature at which the glass becomes a liquid. The heated glass-coated ceramic particles are then cooled to melt the glass into all-ceramic particles.

The resulting mixture is ground to create glass-coated ceramic particles. Next, the glass-coated ceramic particles are
Mixes thoroughly with metal particles such as aluminum particles.

Mix @ fully molded. Finally, the shaped mixture is heated to a predetermined temperature to sinter or melt the metal particles to form a matrix of coalescence or alloy, such as aluminum or aluminum alloy, in which glass-coated ceramic particles are dispersed. do.

The finished sir, met, or composite possesses an effective combination of high compressive modulus, high thermal conductivity, and high coefficient of thermal expansion, which is particularly important in semiconductor applications. Preferably, the coefficient of thermal expansion is at least about 80X10-7 in/in/'Q, preferably 11g80X10-γ to about 190X10'''' fi
n/in/'Q, most preferably about 140X10-
1 to about 170X10''''in/in/'Q. The thermal conductivity is at least about 5 D W/m −'K.

An important property of Muscermet is a high compressive modulus, preferably between about 50 and about 150 W/m-'.

The finished molded body has a compressive modulus of at least about 20 x 10' psi. This high compressive modulus of elasticity provides excellent physical integrity of the finished cermet and stiffness of the conductor package when the material is used as in the example shown in the figure. A feature of the exemplary method of making is the use of powder metallurgy techniques. about 6
Aluminum or aluminum alloy powder having a size of ~100 microns forms a mixture of about 25 to about 80 microns. It is preferably added to strengthen the bond between the aluminum or aluminum alloy particles and the ceramic particles.

The glass is preferably selected from the group consisting of silicic, borosilicate, phosphate and borosilicate bonded glasses. The remainder of the mixture is then made up to 100 volumes by adding ceramic particles having a size of about 10 to about 100 microns. Ceramic particles are Azgo31 AtN, S
iC2* BeO, TiO2, ZrO□, Mg0゜1
3N, Si3N, and mixtures thereof.

In carrying out the present manufacturing method, glass and ceramic particles are first mixed in some manner, such as in a v-type mixer, to encapsulate the glass particles containing the ceramic particles. The glass-encased ceramic particles are then heated to a total softening temperature, ie, from about 350° to about 650°C, to melt the glass and chemically react with the ceramic. Next, the glass-coated ceramic particles are cooled. The resulting mass of glass-covered ceramic particles is ground to a size between about 10 and about 100 microns, preferably between 10 and about 40 microns. Next, the glass-coated ceramic particles are mixed with aluminum or aluminum alloy particles. This mixture is molded at a dark pressure of about 15 x 10'3 to about 100 x ID' psi, preferably about 40 x 103 to about 60 x 103 psi.

Before the latter mixing step, the aluminum powder was
It may be degassed for about 1 hour at a temperature of 0.degree. C. to about 650.degree. This step is necessary because the aluminum powder is typically coated with a lubricant, usually stearic acid, which must be vaporized and removed from the compact.

However, it is noted that aluminum particles that do not require the removal of any impurities are readily available; in this case, substantially pure aluminum or aluminum alloys do not require degassing. Finally, the molded body is processed by a method such as sintering, hot compression molding, or forging to about 6[]0°C to about 7°C.
Heat treatment at 50° C. for about 8 to about 100 hours. Sintering can be performed in a solid state, i.e., solid state sintering at temperatures below about 660°C, and in a semi-solid state, i.e., liquid state sintering at temperatures above about 660"C.
It can be done with In either case, preferably 24
within an inert or reducing atmosphere such as nitrogen, 4% hydrogen or aldene.

An example of a method for making cermets is to mix β-human z2o3 powder with dimensions of about 30 to about 100 microns with #5 micron PbO glass (#ing temperature about 400° C.) in a V-type mixer. The generated alumina particles coated with glass are
It was then mixed with 6 micron aluminum powder. The final volume proportions were approximately 32% aluminum, 80% glass, and 60% Az2o3. Mixture about 10
~15 ksi and hot compression molded at about 600° C. and about 1 Q ksi. The finished density of the composite was about 94 inches and the t0 compressive modulus was measured to be about 25 x 106 to about 30 x 10' psi.

A second method of manufacturing the cermet of the second embodiment consists essentially of the method described herein, ceramic particles encapsulating metal particles, such as aluminum or aluminum alloy, in glass, and heating. Essentially the same, except mixed before. In this method, particles of glass binder t are first mixed with ceramic particles and the ceramic particles are coated with glass particles. The glass-coated ceramic particles are then mixed with metal particles, such as aluminum or aluminum alloy particles. This mixture is mixed and molded within the above-mentioned range.Finally, the molded body containing aluminum or aluminum alloy is heat treated at a temperature of about 600 to about 700°C for about 8 to 100 hours. Heat treatment is approximately 66
It is carried out in a solid state below 0°C or in a solid state above about 660°C. In either case, preferably for no longer than 24 hours, nitrogen.

Crab - Carry out in an inert or reducing gas such as 4% hydrogen or argon.

Cermets produced from any of the methods of the second embodiment described above can be used to make the cover 12 and bottom 14 of the semiconductor casing 10 shown in the figures. The lead frame 22 is placed between the bottom and the cover and sealed with a glass 24 whose coefficient of thermal expansion is preferably high and relatively close to that of the lead frame material. The seal glass is made of calcium fluoride or paricum fluoride.
Contains a chemical agent to increase the coefficient of thermal expansion! + [11, to match the coefficient of thermal expansion of the lead frame 22, preferably made of copper alloy material.

The cermets of the present invention can also be used in desired applications such as engineered ceramics, ioceramics and electroceramics.

According to the present invention, a cermet containing a glass adhesive component that satisfies the above-mentioned objects, methods, and effects has been produced. Although the invention has been described in conjunction with this embodiment, numerous alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. It is obvious that he is deaf. It is therefore the full intention to embrace all such alternatives, modifications and variations within the spirit and scope of the appended claims.

[Brief explanation of drawings]

The drawing shows a semiconductor package consisting of a cermet bottom and cover according to the invention.

Claims (21)

[Claims] (1) A method of making a composite material comprising: from about 25 to about 80 volume percent of a particulate metallic material; from an effective amount to about 10 volume percent of a glass particulate binder; and an essentially ceramic material. providing a mixture comprising the remainder being particles, mixing the glass particles with the ceramic particles to coat the ceramic particles with glass particles, mixing the glass coated ceramic particles with metal particles;
A method of manufacture, characterized in that the mixture is compression molded and the molded mixture is heat treated to produce a matrix of metallic material in which the ceramic particles coated with glass are dispersed. (2) selecting metal particles having a size of about 3 to about 100 microns; selecting said glass particles having a size of about 3 to about 25 microns; selecting said glass particles having a size of about 10 to about 100 microns; 2. The method of claim 1, further comprising selecting the ceramic particles to have larger dimensions than the metal particles. Claim (2) characterized in that it includes a step of selecting the metal particles from the group consisting of aluminum, copper, nickel, titanium, chromium, iron, silver, gold, and alloys thereof. The method described in section. (4) The ceramic material is Al_2O_3, AlN,
SiC, BeO, TiO_2, ZrO_2, MgO, B
A method according to claim 3, further characterized by the step of selecting from the group consisting of N, Si_3N_4 and mixtures thereof. (5) The glass can be used as silicate glass, borosilicate glass, lead borate glass, phosphate glass, lead-silicate glass, sodium-lime-silica glass, lead-zinc-borate glass, 4. The method of claim 4, further characterized by selecting from the group consisting of: and zinc borosilicate glass. 6. The method of claim 5, further comprising the step of: (6) selecting the glass bonding agent having a softening temperature within the range of about 350<0>C to about 1200<0>C. (7) Thermal expansion coefficient is about 60 x 10^-^7 to about 17
0 x 10^-^7 in/in/°C,
The method described in section 6). (8) The molded mixture is heated to about 600°C to about 750°C.
8. The method of claim 7, further comprising the step of holding at a temperature of 0.degree. C. for a period of about 8 to about 100 hours. (9) A method of making a composite material comprising: from about 25 to about 80 volume percent of a particulate metallic material; from an effective amount to 10 volume percent of a glass particulate binder; and essentially ceramic particles. mixing the glass particles with the ceramic particles, coating the ceramic particles with the glass particles, heating the glass-coated ceramic particles to soften the glass;
melting the glass into ceramic particles by cooling the heated glass-coated ceramic particles; grinding the molten glass-coated ceramic into particles; mixing the glass-coated ceramic particles with metal particles; 1. A method of manufacturing comprising the steps of compression molding a mixture and heat treating the molded mixture to form a matrix of metal particles in which the ceramic particles coated with glass are dispersed. (10) selecting metal particles with a size of about 3 to about 100 microns; selecting glass particles with a size of about 3 to about 25 microns; selecting ceramic particles with a size of about 10 to about 100 microns; , selecting the ceramic particles of larger size than the metal particles. (11) The metal particles include aluminum, copper, nickel,
11. A method according to claim 10, further characterized by the step of selecting from the group consisting of titanium, chromium, iron, silver, gold and alloys thereof. (12) The ceramic material is Al_2O_3, AlN
, SiC, BeO, TiO_2, ZrO_2, MgO,
A method according to claim 11, further characterized by the step of selecting from the group consisting of BN, Si_3N_4 and mixtures thereof. (13) The glass can be used as silicate glass, borosilicate glass, lead borate glass, phosphate glass, sodium-
Lime - silica glass, lead - silicate glass, lead - zinc -
13. The method of claim 12, further characterized by the step of selecting from the group consisting of borate glasses and zinc borosilicate glasses. (14) Thermal expansion coefficient is about 60 x 10^-^7 to about 1
Claim No. (13) further characterized by the step of selecting said glass with a
). (15) The molded mixture is heated to about 600°C to about 75°C.
15. The method of claim 14, further comprising the step of heat treating at a temperature of 0<0>C for a period of from about 8 to about 100 hours. (16) consisting of about 25 to about 80 volume percent metal particles, an effective amount to about 10 volume percent glass, and the remainder being essentially ceramic particles, and the glass is combined with the metal and the ceramic particles; said metal material having glass-coated ceramic particles dispersed therein;
A composite material characterized by having a matrix consisting of. (17)) The ceramic particles are made of Al_2O_3, Al
N_2, SiC, BeO, TiO_2, ZrO_2, M
Composite material according to claim 16, further characterized in that it is selected from the group consisting of gO, BN, Si_3N_4 and mixtures thereof. (18) Claim 1, wherein the ceramic has a size of about 10 to about 100 microns.
Composite material described in section 7). (19) The glass coating may be a silicate glass, a borosilicate glass, a lead borate glass, a phosphate glass, a sodium-lime-silica glass, a lead-silicate glass, a lead-zinc-borate glass. and zinc borosilicate glass. (20) wherein the matrix having glass-coated ceramic particles dispersed therein has a coefficient of thermal expansion of from about 140 x 10^-^7 to about 170 x 10^-^7 in/in/°C, at least about Claim 19, characterized in that it has a thermal conductivity of 50 W/m^-°K and a compressive modulus of elasticity of at least about 20 x 10^6 psi.
Composite materials as described in Section. (21) A base (14) and a cover made of the composite material, a metal lead frame (22), and a glass (24) that connects the cover and the base with the lead frame inserted therebetween. Claim No. (20) further characterized in that the method is used for forming a casing (10) and incorporating a semiconductor device (20) therein.
Composite materials listed in section ).