US4569814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preforming of preheated plastic pellets for use in transfer molding
Assignee: NXP USA Inc
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Filing: 1984-07-03
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Granted: 1986-02-11
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Expires: 2004-07-03
Abstract
Abstract Prior to supplying plastic encapsulant to the reservoir of a mold for the purpose of encapsulating semiconductor devices, pellets of the encapsulant are heated until they become soft. An operator then places the pellets into a preforming chamber where they are compressed to form a softened charge of encapsulant. This charge is then removed from the chamber and placed into the reservoir of the mold.
Inventors
- 👤 T. S. Chong
- 👤 F. C. Chong
- 👤 C. K. Ng
- 👤 T. T. Lim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:30
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/462; B29C45/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
135 words
A method for encapsulating objects, comprising: providing a mold having at least one mold cavity therein for receiving and containing said objects, said at least one cavity communicating with a reservoir of encapsulant; placing said objects in said at least one cavity; heating a plurality of pellets of encapsulant to soften said pellets; placing the softened pellets in a preforming chamber having dimensions for receiving said pellets, said chamber having first and second open ends; compressing the plurality of heated pellets of encapsulant from said first and second ends to form a charge of softened encapsulant while at the same time permitting air to escape from said chamber to avoid entrapping air in said charge; dropping said charge into said reservoir; and forcing the softened encapsulant from said reservoir to said at least one cavity.
Claim 2
Independent Claim
135 words
A method for encapsulating objects, comprising: providing a mold having at least one mold cavity therein for receiving and containing said objects, said at least one cavity communicating with a reservoir of encapsulant; placing said objects in said at least one cavity; heating a plurality of pellets of encapsulant to soften said pellets; placing the softened pellets in a preforming chamber having dimensions for receiving said pellets, said chamber having first and second open ends; compressing the plurality of heated pellets of encapsulant from said first and second ends to form a charge of softened encapsulant while at the same time permitting air to escape from said chamber to avoid entrapping air in said charge; dropping said charge into said reservoir; and forcing the softened encapsulant from said reservoir to said at least one cavity.
Claim 3
Dependent Claim
11 words
A method according to claim 1 wherein said encapsulant is plastic.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-10 | 1989-08-12 | 1990-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-10 | 1993-08-12 | 1994-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-10 | 1997-08-12 | 1998-02-11 | $7700.00 | Window Closed / Lapsed |