GB2214513A - Semi-conductor packages - Google Patents

Semi-conductor packages Download PDF

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Publication number
GB2214513A
GB2214513A GB8906366A GB8906366A GB2214513A GB 2214513 A GB2214513 A GB 2214513A GB 8906366 A GB8906366 A GB 8906366A GB 8906366 A GB8906366 A GB 8906366A GB 2214513 A GB2214513 A GB 2214513A
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GB
United Kingdom
Prior art keywords
weight
paste
metallising
parts
semi
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8906366A
Other versions
GB2214513B (en
GB8906366D0 (en
Inventor
Michael Morris
John Vickers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oxley Developments Co Ltd
Original Assignee
Oxley Developments Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB858526397A external-priority patent/GB8526397D0/en
Application filed by Oxley Developments Co Ltd filed Critical Oxley Developments Co Ltd
Publication of GB8906366D0 publication Critical patent/GB8906366D0/en
Publication of GB2214513A publication Critical patent/GB2214513A/en
Application granted granted Critical
Publication of GB2214513B publication Critical patent/GB2214513B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/52—Electrically conductive inks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H01L21/486—Via connections through the substrate with or without pins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H01L21/4867—Applying pastes or inks, e.g. screen printing
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
    • H05K1/097—Inks comprising nanoparticles and specially adapted for being sintered at low temperature

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Conductive Materials (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)

Description

DESCRIPTION METALLISING PASTE The invention relates to metallising pastes, and in particular, but not exclusively, to metallising pastes which may be fired at high1 temperatures.
The use of low-temperature-firing metallising pastes as intermediates in the electroplating of pre-sintered ceramics is widespread, for example, in the manufacture of ceramic packages for mounting a semiconductor device, wherein pastes are screenprinted onto ceramic components of the package. These form a metallic base onto which other metals may be electroplated to provide electrical and thermal contact with the semiconductor device within the package. Many metals may be used in the pastes, for example, silver, nickel and copper.
However, in some applications it would be advantageous if the paste could be deposited on a "green" (i.e. unsintered) ceramic and subsequently co-fired with the ceramic at temperatures up to 1,6000C. However, at such temperatures the known pastes described above do not provide acceptable results.
In accordance with the present invention, there is provided a metallising paste comprising tungsten and an organic vehicle system.
This provides a screen-printable refractory metal formulation which when co-fired with a ceramic (e.g.
alumina) or fired onto pre-sintered ceramic yields an adherent, electrically conductive metallised area, upon which a variety of metals may be electroplated.
Preferably, the paste further comprises frit material.
The tungsten may be in the form of a powder, advantageously comprising particles of approximately one micron in size.
The organic vehicle system preferably comprises a polymeric material, e.g. ethyl cellulose, and an appropriate solvent, e.g. terpineol, which are preferably mixed in the ratio 1 to 12 by weight.
The weight of the vehicle system is preferably from 20% to 50%, and more preferably 35%, of the weight of the paste.
The frit material preferably comprises one or more of alumina, cerium fluoride, bismuth oxide and silica, which preferably are present in equal proportions.
The ratio of tungsten to frit in the paste may be from 100 to 0 to 50 to 50 parts by weight. For example, the ratio may be 90 to 10, 60 to 40 or 99 to 1.
Other compositions could contain up to 20% by weight of manganese and/or 10% by weight of nickel, in addition to tungsten and the frit materials.
The advantages of such compositions are that the addition of manganese allows the percentage of non-conductive frit materials within the paste to be reduced since the manganese itself will bond chemically to the ceramic substrate.
The addition of small amounts of nickel is advantageous in that the presence of this metal facilitates the subsequent electrodeless nickel plating of the fired metallisation.
The invention also includes an article formed using a metallising paste in accordance with the invention.
By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings and examples, in which: Fig. 1 is a perspective view of an embodiment of a semiconductor device package formed using a metallising paste in accordance with the present invention; and Fig. 2 is a sectional view on the line II-II in Fig. 1.
Example 1 A mixture A according to the present invention comprises 90 parts by weight of high purity tungsten powder, the tungsten powder being 99.9% pure and having an average grain size of one micron. The tungsten powder is mixed with 10 parts by weight of frit material, comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight. The constituents of the frit material are passed through a 45 micron sieve so that the frit.
material does not contain particles of size greater than 45 microns. To the mixture of tungsten powder and frit material is added an organic vehicle solution comprising 9 parts by weight of terpineol (which acts as a solvent) and one part by weight of ethyl cellulose which is a polymeric binder material. The resultant mixture A is 70% by weight of tungsten and frit and 30% by weight of vehicle solution. The addition of the vehicle solution forms a metallising paste having viscosity suitable for screen-printing.
Examples 2 and 3 Mixtures B and C according to the present invention are similar to mixture A, except that mixture B has a minimal proportion of frit material content, in the present case 1 part to 99 parts by weight tungsten powder, and mixture C has a high proportion of frit material, i.e. 40 parts to 60 parts by weight of tungsten in the present case.
It should be appreciated that the amount of frit material in 100 parts by weight of a tungsten and frit mixture, which, with the vehicle system, forms a mixture according to the present invention may be as low as zero parts, as high as 50 parts, and may take any value in between. All such tungsten and frit mixtures as described in Examples 1 to 3, when mixed with vehicle solution, provide a paste which may be screen printed directly onto "green" (i.e. unsintered) alumina and co-fired, in a reducing atmosphere, at 1,5000C or above, or which may be applied to pre-sintered alumina and fired at temperatures as low as 1,2000C, in both cases to provide adherent, electrically conductive metallised areas upon which a variety of metals may be subsequently electroplated.
It should also be appreciated that the resultant tungsten/frit mixture may comprise from 50% to 80% by weight of the total mixture.
Referring to Figs. 1 and 2, a semiconductor package device is shown. This comprises a plurality of sheets (not individually visible in the drawings) of alumina, one 10 of which is screen-printed with mixture A to provide a rectangular die attachment area 12. Another sheet 14 of alumina is screen-printed with mixture A to form feedthroughs 16 and horizontal, corner metallisation areas 18.
The sheets of alumina are laminated and co-fired to yield a monolithic structure 20 about which are positioned adherent electrically conductive tungsten metallised areas.
After the structure 20 has been cut to size and suitably lapped, mixture B is introduced into via holes 22 which extend through the base 24 of the structure-20 to the die attachment area 12. When filled with mixture B, the resulting metal structures in the via holes provide good electrical and thermal conductivity between the die attachment area and the undersurface of the structure 20.
Mixture C is screen-printed on the upper surface of the structure 20 to provide a lid attachment area 26, and also on the sides to provide vertical , corner metallisation areas 28 and also on the undersurface 30 of the structure 20.
The whole structure is then re-fired at 1,2500C in a reducing atmosphere and the metallised areas which remain are finished conventionally, in gold over a nickel undercoat.

Claims (14)

1. A metallising paste comprising tungsten powder and an organic vehicle system in a mixture of viscosity suitable for screen printing applications.
2. A metallising paste as claimed in claim 1, further comprising frit material.
3. A metallising paste as claimed in claim 2, wherein the frit material comprises one or more of alumina, cerium fluoride, bismuth oxide and silica.
4. A metallising paste as claimed in claim 2, wherein the frit material comprises alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight.
5. A metallising paste as claimed in claim 2, 3 or 4, wherein the ratio of tungsten to frit in the paste is from 50 to 100 parts tungsten powder to 50 to O parts of frit material.
6. A metallising paste as claimed in any of claims 1 to 5, wherein the particles of tungsten powder are of approximately one micron in size.
7. A metallising paste as claimed in any of claims 1 to 6, wherein the organic vehicle system comprises a polymeric material and a solvent.
8. A metallising paste as claimed in claim 7, wherein said polymeric material is ethyl cellulose.
9. A metallising paste as claimed in claim 7 or 8, wherein said solvent is terpineol.
10. A metallising paste as claimed in claim 7, wherein said polymeric material is ethyl cellulose and said solvent is terpineol, the ethyl cellulose and terpineol being mixed in the ratio 1 to 12 by weight.
11. A metallising paste as claimed in any of claims 1 to 10, wherein the weight of the organic vehicle system is from 20% to 50% of the weight of the paste.
12. A metallising paste as claimed in any of claims 1 to 11, further including up to 20% by weight of manganese.
13. A metallising paste as claimed in any of claims 1 to 11, further including up to 105 by weight of nickel.
14. A semi-conductor package substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
14. A met & lising paste as claimed in any of claims 1 to 11, further including up to 205 by weight of manganese and 10% by weight of nickel.
15. An article formed using a metallising paste as claimed in any of claims 1 to 14.
16. An article as claimed in claim 15 in the form of a package for a semi-conductor.
17. A semi-conductor package as claimed in claim 16, comprising a laminated stack of sheets of alumina on which there is screen printed, with a metallising paste as claimed in any of claims 1 to 14, firstly a rectangular attachment area for receiving a semi conductor device and secondly a plurality of feedthrough paths for enabling external electrical communication with said semi-conductor device.
18. A semi-conductor package as claimed in claim 17, wherein a plurality of vias are formed through said stack of alumina sheets and filled with metallising paste, as claimed in any of claims 1 to 14, for electrically connecting said conductive rectangular attachment area with another conductive layer disposed on an exterior surface of the package and formed by a further screen-printed layer of said metallising paste.
19. A semi-conductor package as claimed in claim 18, wherein the metallisation paste used to form said attachment area comprises a mixture of approximately 90 parts by weight of tungsten powder and approximately 10 parts by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
20. A semi-conductor package as claimed in claim 18 or 19, wherein the metallisation paste used to form said vias comprises a mixture of approximately 99 parts by weight of tungsten powder and 1 part by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
21. A semi-conductor package as claimed in claim 18, 19 or 20, wherein the metallisation paste used to form said conductive layer disposed on the exterior surface of the package comprises a mixture of 50 to 60 parts by weight of tungsten powder and 50 to 40 parts by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
22. A metallising paste substantially as hereinbefore described with reference to any of the aforegoing examples.
23. A semi-conductor package substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Amendments to the claims have been filed as follows
1. A semi-conductor package comprising a laminated stack of sheets of alumina on which there is screen printed with a metallising paste firstly a rectangular attachment area for receiving a semi-conductor device and secondly a plurality of feed-through paths for enabling external electrical communication with said semi-conductor device, the metallising paste comprising tungsten powder and an organic vehicle system in a mixture of viscosity suitable for screen printing.
2, A semi-conductor package as claimed in claim 1, wherein the metallising paste includes a frit material comprising one or more of alumina, cerium fluoride, bismuth oxide and silica.
3. A semi-conductor package as claimed in claim 1, wherein the metallising paste includes a frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight.
4. A metallising paste as claimed in claim 1, 2, or 3, wherein the particles of tungsten powder are of approximately one micron in size.
5. A metallising paste as claimed in claim 1, 2, 3 or 4, wherein the organic vehicle system comprises a polymeric material and a solvent.
6. A metallising paste as claimed in claim 5, wherein said polymeric material is ethyl cellulose.
7. A metallising paste as claimed in claim 5 or 6, wherein said solvent is terpineol.
8. A semi-conductor package as claimed in claim 1, wherein the metallising paste comprises in combination: (a) tungsten powder; (b) frit material consisting of alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight; and (c) an organic vehicle system; wherein (1) the tungsten plus frit in the paste lies in an amount between 50-80% by weight of the paste; (2) the organic vehicle system in the paste lies in an amount between 20-50% by weight of the paste, and (3) the ratio of tungsten to frit in the paste lies in an amount between 50 to 99 parts tungsten powder to 50 to 1 parts of frit material.
9. A metallising paste as claimed in claim 8, wherein the organic vehicle system comprises terpineol and ethyl cellulose, the ratio of terpineol to ethyl cellulose being in an amount between 9 parts terpineol to 1 part ethyl cellulose and 12 parts terpineol to 1 part ethyl cellulose.
10. A semi-conductor package as claimed in any of -claims 1 to 9, wherein a plurality of vias are formed through said stack of alumina sheets and filled with said metallising paste, for electrically connecting said conductive rectangular attachment area with another conductive layer disposed on an exterior surface of the package and formed by a further screen-printed layer of said metallising paste.
11. A semi-conductor package as claimed in claim 10, wherein the metallisation paste used to form said attachment area comprises a mixture of approximately 90 parts by weight of tungsten powder and approximately 10 parts by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
12. A semi-conductor package as claimed in claim 10 or 11, wherein the metallisation paste used to form said vias comprises a mixture--of approximately 99 parts by weight of tungsten powder and 1 part by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
13. A semi-conductor package as claimed in claim 10, 11 or 12, wherein the metallisation paste used to form said conductive layer disposed on the exterior surface of the package comprises.a mixture of 50 to 60 parts by weight of tungsten powder and 50 to 40 parts by weight of frit material, the frit material comprising alumina, cerium fluoride, bismuth oxide and silica in equal proportions by weight, together with an organic vehicle system comprising approximately 9 parts by weight of terpineol and one part by weight of ethyl cellulose.
GB8906366A 1985-10-25 1989-03-20 Semi-conductor package Expired - Fee Related GB2214513B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858526397A GB8526397D0 (en) 1985-10-25 1985-10-25 Metallising paste
GB8625066A GB2182045B (en) 1985-10-25 1986-10-20 Metallising paste

Publications (3)

Publication Number Publication Date
GB8906366D0 GB8906366D0 (en) 1989-05-04
GB2214513A true GB2214513A (en) 1989-09-06
GB2214513B GB2214513B (en) 1990-02-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6471554B2 (en) 2000-04-27 2002-10-29 Oxley Developments Company Limited Multi-way electrical connection device having a compliant connector

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115073148B (en) * 2022-07-21 2023-08-08 瓷金科技(河南)有限公司 Ceramic packaging base and preparation method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB901261A (en) * 1960-07-14 1962-07-18 Purolator Products Inc Sintered porous metal filter
GB1339674A (en) * 1971-03-11 1973-12-05 Bendix Corp Coating for protecting a carbon substrate and method for applying said coating
GB1465908A (en) * 1972-12-14 1977-03-02 Dow Chemical Co Preparation and use of particulate metal
EP0165427A2 (en) * 1984-05-21 1985-12-27 International Business Machines Corporation Semiconductor package substrate and manufacturing process
GB2163168A (en) * 1984-08-16 1986-02-19 Shinetsu Polymer Co Electroconductive adhesive
GB2173199A (en) * 1985-04-02 1986-10-08 G C Dental Ind Corp Dental composite resin composition

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB901261A (en) * 1960-07-14 1962-07-18 Purolator Products Inc Sintered porous metal filter
GB1339674A (en) * 1971-03-11 1973-12-05 Bendix Corp Coating for protecting a carbon substrate and method for applying said coating
GB1465908A (en) * 1972-12-14 1977-03-02 Dow Chemical Co Preparation and use of particulate metal
EP0165427A2 (en) * 1984-05-21 1985-12-27 International Business Machines Corporation Semiconductor package substrate and manufacturing process
GB2163168A (en) * 1984-08-16 1986-02-19 Shinetsu Polymer Co Electroconductive adhesive
GB2173199A (en) * 1985-04-02 1986-10-08 G C Dental Ind Corp Dental composite resin composition

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6471554B2 (en) 2000-04-27 2002-10-29 Oxley Developments Company Limited Multi-way electrical connection device having a compliant connector

Also Published As

Publication number Publication date
GB2214513B (en) 1990-02-28
GB8906366D0 (en) 1989-05-04

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19951020