US3821099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing encapsulated solid state electronic devices having a sealed lead- encapsulant interface
Assignee: Westinghouse Electric Corp
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Filing: 1972-04-19
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Granted: 1974-06-28
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Expires: 1992-04-19
Abstract
Abstract An encapsulated solid state electronic device, such as a semiconductor, with attached metallic connection leads is made moisture resistant by coating the leads with a smooth, flexible, pinhole free resinous barrier film, which intimately bonds to the leads and encapsulant, providing a void-free lead-encapsulant interface.
Inventors
- 👤 D Phillips
- 👤 J Szedon
- 👤 J Jackson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:47
CPC Classifications
H; H10; H10W; H10W72/00; C; C09; C09D; C09D5/00; C09D5/44; C09D5/4419; C09D5/4461; H10W70/00; H10W70/40; H10W70/456; H10W70/458; H10W70/464; H10W70/465; H10W72/20; H10W74/00; H10W74/10; H10W74/111; H10W74/121; H10W74/127; H10W74/40; H10W74/47; H10W74/473; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W90/00; H10W90/701; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
61 words
The method of claim 1 wherein the current density is between about 2 to 10 mA/sq. in. of negative electrode plus lead surface, the pH of the bath is between about 8-10, the solvent for the acid, non-solvent for the salt and basic nitrogen containing compound are non-electrolizable, and the coating is cured by passing the device through a heat source.
Claim 2
Dependent Claim
54 words
The method of claim 1 wherein the basic organic nitrogen containing compound is selected from the group consisting of amines and imidazoles, the non-solvent for the salt is a ketone and wherein the lead is connected to the positive terminal and the negative electrode is connected to the negative terminal of a power supply.
Claim 3
Dependent Claim
87 words
The method of claim 3 wherein the basic organic nitrogen containing compound is selected from the group consisting of trimethylamine, triethylamine, N, N-dimethylbenzylamine, tri-n-propylamine, tri-n-butylamine, N-ethylpiperidine, N-allylpiperidine, N-ethylmorpholine, N, N-diethyl-m-toluidine, N, N-diethyl-p-toluidine, N-allylmorpholine, N, N-diethylaniline pyridine, imidazole, 1-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-propylimidazole, 1, 2-dimethylimidazole, 1-ethyl-2-methylimidazole and 1-phenylimidazole and the non-solvent for the salt is selected from the group of ketones consisting of acetone, methyl isobutyl ketone, methyl ethyl ketone, methyl n-propyl ketone, dimethyl ketone, mesityloxide, cyclohexanone, methyl-n-butyl ketone, ethyl-n-butyl ketone, methyl-n-amylketone, acetophenone, methyl-n-hexyl ketone isophorone and di-isobutyl ketone.
Claim 4
Dependent Claim
20 words
The method of claim 2 wherein the polyamic acid is selected from the group of polyamic acids having the structure:
Claim 5
Dependent Claim
32 words
The method of claim 5 wherein the solvent for the acid is selected from the group consisting of N, N-dialkylcarboxylamides, dimethyl sulfoxide, pyridine and mixtures thereof, said device being a semiconductor device.
Claim 6
Independent Claim
182 words
A method of coating metallic connection leads attached to a solid state electronic device comprising the steps of: A. making a metallic connection lead attached to the solid state device an anode and placing the device near a negatively charged electrode in a bath of a conducting non-aqueous polyamic acid electrodeposition solution, said electrodeposition solution comprising acid salt within a solvent mixture, said acid salt being the reaction product of a polyamic acid and a basic organic nitrogen containing compound, said electrodeposition solution comprising about 1 part by weight polyamic acid, about 0.8 to about 1.5 parts by weight basic organic nitrogen containing compound, about 12.5 to about 15.5 parts by weight non-aqueous, organic solvent for the acid and about 7 to about 9 parts by weight non-aqueous, organic, non-solvent for the salt, so that the current density between the metallic connection lead and negative electrode is sufficient to electrodeposit and intimately bonded coating on the metallic connection leads, and B. curing the coating to form a smooth, void free polyimide film about 0.5 to about 5 mils thick on the leads.
Claim 7
Dependent Claim
61 words
The method of claim 7 wherein the current density is between about 2 to 10 mA/sq. in. of negative electrode plus lead surface, the pH of the bath is between about 8-10, the solvent for the acid, non-solvent for the salt and basic nitrogen containing compound are non-electrolizable, and the coating is cured by passing the device through a heat source.
Claim 8
Dependent Claim
20 words
The method of claim 8 wherein the polyamic acid is selected from the group of polyamic acids having the structure:
Claim 9
Dependent Claim
32 words
The method of claim 9 wherein the solvent for the acid is selected from the group consisting of N, N-dialkylcarboxylamides, dimethyl sulfoxide, pyridine and mixtures thereof, said device being a semiconductor device.
Claim 10
Dependent Claim
54 words
The method of claim 7 wherein the basic organic nitrogen containing compound is selected from the group consisting of amines and imidazoles, the non-solvent for the salt is a ketone and wherein the lead is connected to the positive terminal and the negative electrode is connected to the negative terminal of a power supply.
Claim 11
Dependent Claim
85 words
The method of claim 11 wherein the nitrogen containing base is selected from the group consisting of trimethylamine, triethylamine, N, N-dimethylbenzylamine, tri-n-propylamine, tri-n-butylamine, N-ethylpiperidine, N-allylpiperidine, N-ethylmorpholine, N, N-diethyl-m-toluidine, N, N-diethyl-p-toluidine, N-allylmorpholine, N, N-diethylaniline pyridine, imidazole, 1-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-propylimidazole, 1, 2-dimethylimidazole, 1-ethyl-2-methylimidazaole and 1-phenylimidazole and the non-solvent for the salt is selected from the group of ketones consisting of acetone, methyl isobutyl ketone, methyl ethyl ketone, methyl n-propyl ketone, dimethyl ketone, mesityloxide, cyclohexanone, methyl-n-butyl ketone, ethyl-n-butyl ketone, methyl-n-amylketone, acetophenone, methyl-n-hexyl ketone isophorone and di-isobutyl ketone.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |