METHOD FOR OBTAINING BEAM LEAD CONNECTIONS FOR INTEGRATED CIRCUITS

• US 3,795,043 A
• Filed: 11/02/1971
• Issued: 03/05/1974
• Est. Priority Date: 11/05/1970
• Status: Expired due to Term

• Current Assignee: Franco Forlani
• Original Assignee: Franco Forlani
• Inventors: Forlani, Franco
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Tupman, W. C.
• Application Number:
  US05/196,442
• Time in Patent Office: 854 Days
• Field of Search: 29/574,578,576S,589,577
• US Class Current: 29/593
• CPC Class Codes: H01L 23/49572 consisting of thin flexible metallic tape with or without a film carrier H01L23/49503 - H01L23/49568 and H01L23/49575 - H01L23/49579 take precedence
• CPC Class Codes: H01L 23/49861 Lead-frames fixed on or encapsulated in insulating substrates H01L23/4985, H01L23/49805 take precedence
• CPC Class Codes: H01L 24/50 Tape automated bonding [TAB] connectors, i.e. film carriers; Manufacturing methods related thereto thin flexible metallic tape with or without a film carrier H01L23/49572, flexible insulating substrates H01L23/4985, H01L23/5387
• CPC Class Codes: H01L 24/86 using tape automated bonding [TAB]
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/01074 Tungsten [W]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/01327 Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/15787 Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: Y10T 29/49004 : including measuring or testing of device or component part
• CPC Class Codes: Y10T 29/49121 : Beam lead frame or beam lead device
• CPC Class Codes: Y10T 29/49135 : and shaping, e.g., cutting or bending, etc.
• CPC Class Codes: Y10T 29/49144 : by metal fusion

Abstract

A process for obtaining beam leads for connecting integrated circuit chips to an external circuit substrate, wherein aluminum beam leads are formed and directly and simultaneously bonded to aluminum pads on the chips while continuously being supported.

Claims

1. A continuous process for obtaining beam leads for a plurality of integrated circuits, comprising the following steps:

applying a photosensitive plastic film on one surface of a metallic ribbon to thereby form a photosensitive plastic film substrate for the metallic ribbon;

applying a layer of photoresist on the other surface of said metallic ribbon to provide an elongated sandwich ribbon;

moving the sandwich ribbon to an exposure station;

exposing said photoresist at said exposure station to radiation through a first mask;

exposing said photosensitive plastic film substrate at said exposure station to radiation through a second mask;

moving the exposed sandwich ribbon to a first tank for developing said photoresist layer and developing said layer in said first tank to obtain protected regions which represent the pattern of said beam leads;

etching said sandwich ribbon to remove the unprotected regions of said metallic ribbon so as to provide said pattern of beam leads;

moving said sandwich ribbon to a second tank for developing said photosensitive plastic film substrate and developing said film substrate in said second tank to obtain openings in said film substrate which extend through said plastic film substrate to said pattern to beam leads;

moving said sandwich ribbon to a bonding station and bonding said beam leads to integrated circuit semiconductor chips positioned within said openings at said bonding station;

moving said sandwich ribbon to a test station for testing the integrated circuits on said chips; and

moving said sandwich ribbon to a selecting station and selecting the integrated circuits from said sandwich ribbon.

2. A process for providing integrated circuit chips with individual beam leads comprising the following steps:

applying a photosensitive plastic film on one surface of a metallic sheet to thereby form a photosensitive plastic film substrate;

applying a layer of photoresist on the other surface of said metallic sheet;

exposing said photoresist layer to radiation through a suitable masking means;

developing the exposed photoresist layer to obtain protected regions of said metallic sheet which represent the pattern of said beam leads;

chemically etching said metallic sheet to remove the unprotected regions thereof so as to provide said beam leads;

exposing said photosensitive plastic film substrate to radiation through a suitable mask;

developing and etching the exposed plastic film substrate to thereby obtain a plastic frame substrate with an opening therein which extends through said plastic film substrate to said pattern of beam leads;

positioning a semiconductor chip provided with integrated circuits in said opening of the plastic frame substrate so as to correspond with said beam leads; and

bonding said beam leads to appropriate locations on the integrated circuit provided on said semiconductor chip.

3. The process of claim 2, comprising the following additional step:

electrically testing the integrity of the bonds and the operating quality of said integrated circuit.

4. A process for providing integrated circuit chips with individual beam leads employing a laminated structure comprising a substrate layer of photosensitive plastic and a metallic sheet, comprising the steps of:

applying a layer of photoresist material to the external surface of said metallic sheet;

exposing said photoresist layer to a radiation image of said beam leads;

developing the exposed photoresist layer to obtain protective regions with the pattern of said beam leads;

etching away those portions of said metallic sheet which are not protected by said protective regions so as to obtain said beam leads;

exposing said photosensitive plastic substrate layer to a radiation image of an area into which said beam leads extend;

developing and etching the exposed plastic substrate layer to provide an opening which extends through said plastic layer substrate in said area into which the ends of said beam leads project;

positioning an integrated circuit chip within said opening which extends through said plastic layer substrate with connection so as to register connection pads on said chip with ends of said beam leads which extend into said opening; and

bonding said pads to the corresponding beam leads.

5. The process of claim 2 further comprising the step of:

separating said beam leads from said plastic frame substrates so as to thereby obtain a semiconductor chip with accurately positioned and bonded beam leads.

6. The process of claim 4 further comprising the step of:

separating said beam leads which have been bonded to the conection pads on said chip from said plastic substrate layer so as to thereby obtain a semiconductor chip having beam leads which are accurately bonded to the connection pads of said chip.

7. The process of claim 4, wherein said metallic sheet and said connection pads are of aluminum.