US5424261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature sintering route for aluminum nitride ceramics
Assignee: CMC INTERCONNECT TECHNOLOGIES Inc
•
Filing: 1993-12-22
•
Granted: 1995-06-13
•
Expires: 2013-12-22
Abstract
Abstract An aluminum nitride ceramic having desired properties suitable for electronic packaging applications can be prepared from a novel aluminum nitride powder/sintering aid mixture. The sintering aid comprises a glassy component formed from alumina, calcia and boria, and a non-vitreous component comprising an element or compound of a metal of Group IIa, IIIa, or the lanthanides, preferably crystalline oxides, reactible with the crystallized glass component and the alumina from the AlN grains. Alternatively, the sintering aid comprises a multi-component glass composition capable of forming the above components upon melting and thereafter crystallizing upon reaction.
Inventors
- 👤 Jonathan H. Harris
- 👤 Subhash L. Shinde
- 👤 Takeshi Takamori
- 👤 Robert A. Youngman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:28
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/581; Y; Y10; Y10S; Y10S428/00; Y10S428/901
Claims Analysis
Total Claims: 70
Claim 1
Independent Claim
70 words
A presintering aluminum nitride powder/sintering aid mixture wherein the aluminum nitride contains impurity alumina and wherein the sintering aid comprises a) an element or compound of a metal selected from the group consisting of Group IIa, IlIa, lanthanide metals and mixtures thereof, and b) a glassy component formed from alumina, calcia, and boria, said metal element or compound being reactible with the glassy component and the alumina from the AlN.
Claim 2
Dependent Claim
70 words
A presintering aluminum nitride powder/sintering aid mixture wherein the aluminum nitride contains impurity alumina and wherein the sintering aid comprises a) an element or compound of a metal selected from the group consisting of Group IIa, IlIa, lanthanide metals and mixtures thereof, and b) a glassy component formed from alumina, calcia, and boria, said metal element or compound being reactible with the glassy component and the alumina from the AlN.
Claim 3
Dependent Claim
25 words
The presintering mixture as in claim 1 wherein the glassy component is a glass formed by rapid quenching a melt of calcia, alumina and boria.
Claim 4
Dependent Claim
19 words
The presintering mixture as in claim 1 wherein the metal element or compound is yttrium or a yttrium compound.
Claim 5
Dependent Claim
13 words
The presintering mixture as in claim 3 wherein the yttrium compound is yttria.
Claim 6
Dependent Claim
53 words
The presintering mixture as in claim 1 wherein the glassy component comprises a vitreous composition formed from a mixture of calcia, alumina, and boria in a proportion of calcia between about 40 and 80 weight percent, alumina between about 10 and 50 weight percent, and boria between about 3 and 25 weight percent.
Claim 7
Dependent Claim
53 words
The presintering mixture as in claim 1 wherein the glassy component comprises a vitreous composition formed from a mixture of calcia, alumina, and boria in a proportion of calcia between about 45 and 65 weight percent, alumina between about 20 and 45 weight percent, and boria between about 5 and 20 weight percent.
Claim 8
Dependent Claim
53 words
The presintering mixture as in claim 1 wherein the glassy component comprises a vitreous composition formed from a mixture of calcia, alumina, and boria in a proportion of calcia between about 45 and 55 weight percent, alumina between about 30 and 40 weight percent, and boria between about 5 and 15 weight percent.
Claim 9
Dependent Claim
36 words
The presintering mixture as in claim 1 wherein the glassy component comprises a vitreous composition formed from a mixture of about 50 weight percent calcia, about 40 weight percent alumina, and about 10 weight percent boria.
Claim 10
Dependent Claim
28 words
The presintering mixture as in claim 1 wherein the sintering aid is present in the presintering mixture in a particle size of about 3 to about 5 microns.
Claim 11
Dependent Claim
25 words
The presintering mixture as in claim 1 wherein said Group IIa metals are selected from the group consisting of Ca, Sr, Ba and mixtures thereof.
Claim 12
Dependent Claim
38 words
The presintering mixture as in claim 1 wherein said Group IIIa and lanthanide metals are selected from the group consisting of Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof.
Claim 13
Dependent Claim
24 words
The presintering mixture of claim 1 wherein said compounds are selected from the group consisting of oxides, carbonates, nitrates, sulfates, fluorides and mixtures thereof.
Claim 14
Dependent Claim
18 words
The presintering mixture of claim 1 wherein the weight ratio of a):b) is about 1:1 to about 3.5:1.
Claim 15
Dependent Claim
18 words
The presintering mixture of claim 1 wherein the weight ratio of a):b) is about 2:1 to about 3:1.
Claim 16
Dependent Claim
17 words
The presintering mixture of claim 1 wherein the presintering mixture additionally comprises added alumina as metal oxide.
Claim 17
Dependent Claim
13 words
A shaped aluminum nitride green body comprising the presintering mixture of claim 1.
Claim 18
Dependent Claim
22 words
The shaped green body as in claim 16 comprising a laminate of at least one ceramic and at least one metal layer.
Claim 19
Dependent Claim
19 words
The shaped green body as in claim 17 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 20
Dependent Claim
123 words
A low temperature process for producing sintered aluminum nitride bodies comprising ramping the temperature of a presintering mixture as set forth in claim 1 in a sintering atmosphere to a sintering temperature between about 1550° C. to about 1700° C., maintaining boria vapor in the sintering atmosphere at temperatures greater than about 1200° C., forming a liquid at a temperature of about 1500° C. containing said metal element or compound and said glassy component, providing a partial pressure of the liquid in the sintering atmosphere at temperatures greater than about 1500° C., and holding said sintering temperature for an effective period of time to achieve aluminum nitride density of greater than about 95% of theoretical and thermal conductivity greater than about 120 W/m-K.
Claim 21
Dependent Claim
20 words
The process as in claim 19 wherein the sintering temperature is held between about 1550° C. to about 1650° C.
Claim 22
Dependent Claim
20 words
The process as in claim 19 wherein the sintering temperature is held between about 1550° C. to about 1600° C.
Claim 23
Dependent Claim
31 words
A sintered aluminum nitride body having a density of greater than about 95% of theoretical and a thermal conductivity greater than about 120 W/m-K prepared by the process of claim 19.
Claim 24
Dependent Claim
33 words
A co-sintered multilayer laminate comprising at least one ceramic layer and at least one metal layer wherein the at least one ceramic layer comprises the sintered aluminum nitride body as in claim 22.
Claim 25
Dependent Claim
19 words
The co-sintered multilayer laminate as in claim 23 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 26
Dependent Claim
15 words
A multilayer metal-ceramic electronic package containing the sintered aluminum nitride body as in claim 22.
Claim 27
Dependent Claim
52 words
A presintering aluminum nitride powder/sintering aid mixture wherein the aluminum nitride contains impurity alumina and wherein the sintering aid comprises a glassy component formed from a) an oxide of at least one metal selected from the group consisting of Group IIIa, lanthanide metals and mixtures thereof, and b) alumina, calcia, and boria.
Claim 28
Dependent Claim
52 words
A presintering aluminum nitride powder/sintering aid mixture wherein the aluminum nitride contains impurity alumina and wherein the sintering aid comprises a glassy component formed from a) an oxide of at least one metal selected from the group consisting of Group IIIa, lanthanide metals and mixtures thereof, and b) alumina, calcia, and boria.
Claim 29
Dependent Claim
19 words
The presintering mixture as in claim 26 wherein the glassy component is a glass having the constituent elements Ca-Al-B-Y-O.
Claim 30
Dependent Claim
26 words
The presintering mixture as in claim 27 wherein the glassy component is a glass formed by rapid quenching a melt of calcia, alumina, boria and yttria.
Claim 31
Dependent Claim
55 words
The presintering mixture as in claim 26 wherein the glassy component comprises a vitreous composition formed from a mixture of about 10 to greater than 20 weight percent yttria, about 5 to about 10 weight percent boria, and the remainder calcia and alumina in a weight ratio of about 40-60 calcia to about 60-40 alumina.
Claim 32
Dependent Claim
41 words
The presintering mixture as in claim 26 wherein the glassy component comprises a vitreous composition formed from a mixture of about 40 weight percent calcia, about 30-40 weight percent alumina, about 10-20 weight percent yttria and about 10 weight percent boria.
Claim 33
Dependent Claim
28 words
The presintering mixture as in claim 26 wherein the sintering aid is present in the presintering mixture in a particle size of about 3 to about 5 microns.
Claim 34
Dependent Claim
40 words
The presintering mixture as in claim 26 wherein the sintering aid contains an additional non-vitreous component comprising at least one element or compound of a metal selected from the group consisting of Group IIa, IIIa, lanthanide metals and mixtures thereof.
Claim 35
Dependent Claim
57 words
The presintering mixture as in claim 32 wherein said Group IIa metals are selected from the group consisting of Ca, Sr, Ba and mixtures thereof, and wherein said Group IIIa and lanthanide metals are selected from the group consisting of Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof.
Claim 36
Dependent Claim
24 words
The presintering mixture of claim 32 wherein said compound is selected from the group consisting of oxides, carbonates, nitrates, sulfates, fluorides and mixtures thereof.
Claim 37
Dependent Claim
24 words
The presintering mixture of claim 32 wherein the weight ratio of the additional component to the glassy component is about 1:1 to about 3.5:1.
Claim 38
Dependent Claim
24 words
The presintering mixture of claim 32 wherein the weight ratio of the additional component to the glassy component is about 2:1 to about 3:1.
Claim 39
Dependent Claim
17 words
The presintering mixture of claim 32 wherein the presintering mixture additionally comprises added alumina as metal oxide.
Claim 40
Dependent Claim
13 words
A shaped aluminum nitride green body comprising the presintering mixture of claim 32.
Claim 41
Dependent Claim
22 words
The shaped green body as in claim 38 comprising a laminate of at least one ceramic and at least one metal layer.
Claim 42
Dependent Claim
19 words
The shaped green body as in claim 39 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 43
Dependent Claim
125 words
A low temperature process for producing sintered aluminum nitride bodies comprising ramping the temperature of a presintering mixture as set forth in claim 32 in a sintering atmosphere to a sintering temperature between about 1550° C. to about 1700° C., maintaining boria vapor in the sintering atomsphere at temperatures greater than about 1200° C., forming a liquid at a temperature of about 1500° C. containing said at least one element or compound and said glassy component, providing a partial pressure of the liquid in the sintering atmosphere at temperatures greater than about 1500° C., and holding said sintering temperature for an effective period of time to achieve aluminum nitride density of greater than about 95% of theoretical and thermal conductivity greater than about 120 W/m-K.
Claim 44
Dependent Claim
20 words
The process as in claim 41 wherein the sintering temperature is held between about 1550° C. to about 1650° C.
Claim 45
Dependent Claim
31 words
A sintered aluminum nitride body having a density of greater than about 95% of theoretical and a thermal conductivity greater than about 120 W/m-K prepared by the process of claim 42.
Claim 46
Dependent Claim
33 words
A co-sintered multilayer laminate comprising at least one ceramic layer and at least one metal layer wherein the at least one ceramic layer comprises the sintered aluminum nitride body as in claim 43.
Claim 47
Dependent Claim
19 words
The co-sintered multilayer laminate as in claim 44 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 48
Dependent Claim
15 words
A multilayer metal-ceramic electronic package containing the sintered aluminum nitride body as in claim 43.
Claim 49
Dependent Claim
38 words
The presintering mixture as in claim 26 wherein said Group IIIa and lanthanide metals are selected from the group consisting of Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof.
Claim 50
Dependent Claim
17 words
The presintering mixture of claim 26 wherein the presintering mixture additionally comprises added alumina as metal oxide.
Claim 51
Dependent Claim
13 words
A shaped aluminum nitride green body comprising the presintering mixture of claim 26.
Claim 52
Dependent Claim
22 words
The shaped green body as in claim 49 comprising a laminate of at least one ceramic and at least one metal layer.
Claim 53
Dependent Claim
19 words
The shaped green body as in claim 50 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 54
Dependent Claim
117 words
A low temperature process for producing sintered aluminum nitride bodies comprising ramping the temperature of a presintering mixture as set forth in claim 26 in a sintering atmosphere to a sintering temperature between about 1550° C. to about 1700° C., maintaining boria vapor in the sintering atmosphere at temperatures greater than about 1200° C., forming a liquid at a temperature of about 1500° C. containing said glassy component, providing a partial pressure of the liquid in the sintering atmosphere at temperatures greater than about 1500° C., and holding said sintering temperature for an effective period of time to achieve aluminum nitride density of greater than about 95% of theoretical and thermal conductivity greater than about 120 W/m-K.
Claim 55
Dependent Claim
20 words
The process as in claim 52 wherein the sintering temperature is held between about 1550° C. to about 1650° C.
Claim 56
Dependent Claim
31 words
A sintered aluminum nitride body having a density of greater than about 95% of theoretical and a thermal conductivity greater than about 120 W/m-K prepared by the process of claim 53.
Claim 57
Dependent Claim
33 words
A co-sintered multilayer laminate comprising at least one ceramic layer and at least one metal layer wherein the at least one ceramic layer comprises the sintered aluminum nitride body as in claim 54.
Claim 58
Dependent Claim
19 words
The co-sintered multilayer laminate as in claim 55 wherein said metal comprises at least one of tungsten and molybdenum.
Claim 59
Dependent Claim
15 words
A multilayer metal-ceramic electronic package containing the sintered aluminum nitride body as in claim 54.
Claim 60
Dependent Claim
52 words
A sintered aluminum nitride body having low camber, high dimensional stability, at least 95% theoretical density and a thermal conductivity of at least 120 W/m-K comprising aluminum nitride and a second phase containing a ternary metal oxide CaYAl 3 O 7 having substitutional boron contained within the second phase ternary metal oxide.
Claim 61
Dependent Claim
52 words
A sintered aluminum nitride body having low camber, high dimensional stability, at least 95% theoretical density and a thermal conductivity of at least 120 W/m-K comprising aluminum nitride and a second phase containing a ternary metal oxide CaYAl 3 O 7 having substitutional boron contained within the second phase ternary metal oxide.
Claim 62
Dependent Claim
17 words
The sintered aluminum nitride body as in claim 58 wherein said second phase contains YAlO 3 .
Claim 63
Dependent Claim
19 words
The sintered aluminum nitride body as in claim 58 wherein said second phase contains at least one calcia borate.
Claim 64
Dependent Claim
16 words
A multilayer metal ceramic electronic package containing the sintered aluminum nitride body as in claim 58.
Claim 65
Dependent Claim
12 words
The process as in claim 19 wherein the sintering atmosphere contains nitrogen.
Claim 66
Dependent Claim
14 words
The process as in claim 62, wherein the sintering atmosphere contains nitrogen and hydrogen.
Claim 67
Dependent Claim
12 words
The process as in claim 46 wherein the sintering atmosphere contains nitrogen.
Claim 68
Dependent Claim
14 words
The process as in claim 64 wherein the sintering atmosphere contains nitrogen and hydrogen.
Claim 69
Dependent Claim
12 words
The process as in claim 52 wherein the sintering atmosphere contains nitrogen.
Claim 70
Dependent Claim
14 words
The process as in claim 66 wherein the sintering atmosphere contains nitrogen and hydrogen.
References Cited (Backward Citations)
US4540673A
Cited
US4720362A
Cited
US4520116A
Cited
US4618592A
Cited
US4569922A
Cited
US4591537A
Cited
US4478785A
Cited
US4533645A
Cited
US4627815A
Cited
US4547471A
Cited
US4766097A
Cited
US4659611A
Cited
US4642298A
Cited
US4615863A
Cited
US5165983A
Cited
US4578234A
Cited
US4672046A
Cited
US4578233A
Cited
US4746637A
Cited
US4578365A
Cited
US4578364A
Cited
US4578232A
Cited
US4877760A
Cited
US4883780A
Cited
US5063183A
Cited
US4786448A
Cited
US5154863A
Cited
US4678683A
Cited
US4897372A
Cited
JPS62176961A
Cited
US4764321A
Cited
US4818455A
Cited
US4843042A
Cited
US4950435A
Cited
US4810679A
Cited
US5077245A
Cited
US4960734A
Cited
US5073526A
Cited
US5250478A
Cited
JPH02275769A
Cited
JPH03218977A
Cited
US5147832A
Cited
US5214005A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-06-12 | 1998-12-12 | 1999-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-12 | 2002-12-12 | 2003-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-12 | 2006-12-12 | 2007-06-13 | $7700.00 | Window Closed / Lapsed |