Apparatus and method for packaging eprom integrated circuits

• US 4,644,384 A
• Filed: 02/02/1984
• Issued: 02/17/1987
• Est. Priority Date: 02/02/1984
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Charoensakvirochana, Chamras, Boey, Wing K.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US06/576,300
• Time in Patent Office: 1,111 Days
• Field of Search: 357/74, 357/80, 357/84
• US Class Current: 438/116
• CPC Class Codes: B29C 45/14655 connected to or mounted on a carrier, e.g. lead frame
• CPC Class Codes: G11C 16/18 Circuits for erasing optically
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: Y10T 29/49121 Beam lead frame or beam lead device

Abstract

An apparatus and a method for forming a protective package for an EPROM circuit are disclosed. The protective package includes a two piece inner ceramic package and a molded outer plastic package. The inner ceramic package includes a base member upon which the chip is mounted for wiring to a lead frame, and also includes a protective cover with a radiation transparent window that covers and protects the chip and wires. The base member and the protective cover are bonded together to hermetically seal the chip. The molded outer plastic package is formed in a mold that includes an elastomeric plug that contacts the top of the window to isolate it from the mold cavity. The plug prevents plastic from covering the top of the window during molding.

Claims

1. An apparatus for molding a protective package around a subassembly, wherein the subassembly includes an integrated circuit chip and a protective cover disposed over the chip, and wherein the cover has a radiation transparent window positioned proximate the chip, said apparatus comprising:

a mold defining a cavity, said cavity is operable for receiving said subassembly and for defining the outer shape of said protective package upon the injection of a moldable material into said cavity; and

a silicone rubber plug having a hardness approximately equal to a durometer number of eighty disposed within said cavity and positioned adjacent to and contacting the window of said subassembly, said plug being compressed against said window by the closure of said mold for sealing off the outer surface of the window from said cavity to provide an opening in said protective package.

2. A method for packaging a radiation sensitive integrated circuit chip, said method comprising the steps of:

attaching a base member to one side of a lead frame;

attaching said chip to said base member, and wiring said chip to said lead frame;

positioning a protective cap over said chip and attaching it to the other side of said lead frame to form a subassembly, said protective cap having a radiation transparent window positioned proximate said chip;

placing said subassembly into a cavity of a mold, said mold including a silicon rubber plug having a hardness substantially equal to a durometer number of eighty disposed adjacent to said window;

closing said mold to compress and seal said plug against the outer surface of said window; and

introducing moldable material into the cavity of the mold to encapsulate said subassembly, with said plug acting to prevent said moldable material from covering said window.