US5225023A
Expired / Lapsed
US
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High density interconnect thermoplastic die attach material and solvent die attach processing
Assignee: Lockheed Martin Corp
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Filing: 1991-08-05
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Granted: 1993-07-06
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Expires: 2011-08-05
Abstract
Abstract A mixture for affixing dice to a substrate includes a thermoplastic polyimide, a solvent for the polyimide, and a solvent which does not dissolve the polyimide but adds thixotropicity to the mixture. The mixture is applied to the substrate, the dice are placed thereon, and the solvents are evaporated to bond the dice to the substrate. The bond is radiation hard and exhibits high shear pull strength. A poor solvent for the polyimide, sprayed over the dice and exposed portions of die attach material, causes some polyimide to precipitate out of solution in the exposed portions of die attach material to form a grid that extends between the dice and prevents the dice from "swimming together" during high temperature processing. In a solvent die-attachment method, the substrate is first coated with a mixture of die attach material, and the mixture is dried. Spraying a solvent over the die attach material causes the material to soften so that the dice applied thereto may adhere. The die attach material is then dried to form the bond.
Inventors
- 👤 Robert J. Wojnarowski
- 👤 Charles W. Eichelberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:08
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/60; H10W70/611; H10W70/614; H10W70/67; H10W70/68; H10W70/682; H10W70/685; H10W72/00; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; H10W72/30; H10W72/351; H10W72/353; H10W72/354; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1089; Y10T156/109; Y10T156/1092; Y10T156/11; Y10T156/1111
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
143 words
A method of attaching a plurality of dice to a substrate, comprising the steps of: coating said substrate with a solution of thermoplastic polymer material to form a polymer solution layer on said substrate; immersing said dice in said polymer solution layer so as to displace a portion of said solution of thermoplastic polymer material beneath the dice such that the surface of said solution of thermoplastic polymer material rises up in the space between the dice; applying to said thermoplastic polymer material a poor solvent therefor to precipitate polymer material from the solution of thermoplastic polymer material between the dice to form a precipitate grid; and drying said polymer solution layer so as to attach said dice to said substrate and form a thicker deposit of polymer material alongside the dice compared to thickness of the thermoplastic polymer material beneath the disc.
Claim 2
Independent Claim
143 words
A method of attaching a plurality of dice to a substrate, comprising the steps of: coating said substrate with a solution of thermoplastic polymer material to form a polymer solution layer on said substrate; immersing said dice in said polymer solution layer so as to displace a portion of said solution of thermoplastic polymer material beneath the dice such that the surface of said solution of thermoplastic polymer material rises up in the space between the dice; applying to said thermoplastic polymer material a poor solvent therefor to precipitate polymer material from the solution of thermoplastic polymer material between the dice to form a precipitate grid; and drying said polymer solution layer so as to attach said dice to said substrate and form a thicker deposit of polymer material alongside the dice compared to thickness of the thermoplastic polymer material beneath the disc.
Claim 3
Dependent Claim
30 words
The method recited in claim 1 wherein said solution of thermoplastic polymer material is a polyetherimide comprised of bisphenol-A-dianhydride and pyromellitic dianhydride condensed with metaphenylene diamine dissolved in a solvent.
Claim 4
Dependent Claim
12 words
The method recited in claim 2 wherein said solvent comprises a cresol.
Claim 5
Dependent Claim
11 words
The method recited in claim 3 wherein said cresol comprises meta-cresol.
Claim 6
Dependent Claim
29 words
The method recited in claim 2 wherein said solvent comprises one of the group consisting of creosote, methylene chloride, tetrahydrafuran, tetra methyl urea, 1,1,2 trichloroethane, n-methyl pyrrolidone and anisole.
Claim 7
Dependent Claim
27 words
The method recited in claim 1 wherein said solution of thermoplastic polymer material is a polyetherimide comprised of bisphenol-A-dianhydride condensed with metaphenylene diamine dissolved in a solvent.
Claim 8
Dependent Claim
12 words
The method recited in claim 6 wherein said solvent comprises a cresol.
Claim 9
Dependent Claim
11 words
The method recited in claim 7 wherein said cresol comprises meta-cresol.
Claim 10
Dependent Claim
29 words
The method recited in claim 6 wherein said solvent comprises one of the group consisting of creosote, methylene chloride, tetrahydrafuran, tetra methyl urea, 1,1,2 trichloroethane, n-methyl pyrrolidone, and anisole.
Claim 11
Dependent Claim
19 words
The method recited in claim 1 wherein said solution of thermoplastic polymer material comprises a solution of thermoplastic polyimide.
Claim 12
Dependent Claim
24 words
The method recited in claim 1 wherein the drying step comprises a predetermined heat and time cycle dependent upon said solution of polymer material.
Claim 13
Dependent Claim
22 words
The method recited in claim 1 wherein the drying step comprises a predetermined heat and time cycle dependent upon said polymer solution.
Claim 14
Dependent Claim
23 words
The method recited in claim 2 wherein said solvent comprises one of the group consisting of meta-cresol, n-methyl pyrrolidone, anisole, and blends thereof.
Claim 15
Dependent Claim
23 words
The method recited in claim 6 wherein said solvent comprises one of the group consisting of meta-cresol, n-methyl pyrrolidone, anisole, and blends thereof.
Claim 16
Dependent Claim
29 words
The method of attaching a plurality of dice to a substrate of claim 1 wherein said poor solvent comprises one of the group consisting of methanol, acetone and water.
Claim 17
Independent Claim
146 words
A method of attaching a plurality of dice to a substrate comprising the steps of: coating said substrate with a solution of polymer material to a thickness in the range of 3 to 5 microns to form a polymer solution layer on said substrate; immersing said dice in said polymer solution layer so as to displace a portion of said solution of polymer material such that said solution of polymer material rises up in the regions between adjacent dice; applying to said solution of polymer material a poor solvent therefor to precipitate polymer material from the solution of polymer material in the regions between the dice to form a precipitate grid; and drying said polymer solution layer so as to attach said dice to said substrate and form a thicker deposit of polymer material alongside the dice compared to thickness of polymer material beneath the dice.
Claim 18
Independent Claim
146 words
A method of attaching a plurality of dice to a substrate comprising the steps of: coating said substrate with a solution of polymer material to a thickness in the range of 3 to 5 microns to form a polymer solution layer on said substrate; immersing said dice in said polymer solution layer so as to displace a portion of said solution of polymer material such that said solution of polymer material rises up in the regions between adjacent dice; applying to said solution of polymer material a poor solvent therefor to precipitate polymer material from the solution of polymer material in the regions between the dice to form a precipitate grid; and drying said polymer solution layer so as to attach said dice to said substrate and form a thicker deposit of polymer material alongside the dice compared to thickness of polymer material beneath the dice.
Claim 19
Dependent Claim
29 words
The method recited in claim 16 wherein said solution of polymer material is a polyetherimide comprised of bisphenol-A-dianhydride and pyromellitic dianhydride condensed with metaphenylene diamine dissolved in a solvent.
Claim 20
Dependent Claim
11 words
The method recited in claim 17 wherein said solvent comprises cresol.
Claim 21
Dependent Claim
11 words
The method recited in claim 18 wherein said cresol comprises meta-cresol.
Claim 22
Dependent Claim
29 words
The method recited in claim 17 wherein said solvent comprises one of the group consisting of creosote, methylene chloride, tetrahydrafuran, tetra methyl urea, 1,1,2 trichloroethane, n-methyl pyrolidone, and anisole.
Claim 23
Dependent Claim
23 words
The method recited in claim 17 wherein said solvent comprises one of the group consisting of meta-cresol, n-methyl pyrrolidone, anisole, and blends thereof.
Claim 24
Dependent Claim
25 words
The method recited in claim 16 wherein said dissolved polymer material is a polyetherimide comprised of bisphenol-A-dianhydride condensed with metaphenylene diamine solvented in a solvent.
Claim 25
Dependent Claim
12 words
The method recited in claim 22 wherein said solvent comprises a cresol.
Claim 26
Dependent Claim
11 words
The method recited in claim 23 wherein said cresol comprises meta-cresol.
Claim 27
Dependent Claim
29 words
The method recited in claim 22 wherein said solvent comprises one of the group consisting of creosote, methylene chloride, tetrahydrafuran, tetra methyl urea, 1,1,2 trichloroethane, n-methyl pyrrolidone, and anisole.
Claim 28
Dependent Claim
23 words
The method recited in claim 22 wherein said solvent comprises one of the group consisting of meta-cresol, n-methyl pyrolidone, anisole, and blends thereof.
Claim 29
Dependent Claim
18 words
The method recited in claim 16 wherein said solution of polymer material comprises a solution of thermoplastic polyimide.
Claim 30
Dependent Claim
23 words
The method recited in claim 16 wherein the drying step comprises a predetermined heat and time cycle dependent upon said polymer solution layer.
Claim 31
Dependent Claim
21 words
The method recited in claim 16 wherein the step comprises a predetermined heat and time cycle dependent upon said polymer solution.
Claim 32
Dependent Claim
29 words
The method of attaching a plurality of dice to a substrate of claim 16 wherein said poor solvent comprises one of the group consisting of methanol, acetone and water.
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| 3.5 Years (Year 4) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |