Lead-on-chip integrated circuit apparatus

• US 5,448,450 A
• Filed: 10/28/1991
• Issued: 09/05/1995
• Est. Priority Date: 08/15/1991
• Status: Expired due to Term

• Current Assignee: OVID Data Company LLC (Intellectual Ventures LLC)
• Original Assignee: Staktek Corporation (Entorian Technologies)
• Inventors: Burns, Carmen D.
• Primary Examiner(s): Thompson, Gregory D.
• Application Number:
  US07/783,737
• Time in Patent Office: 1,408 Days
• Field of Search: 174/52.4, 257/668, 257/676, 257/675, 257/684, 257/796, 361/705, 361/708, 361/712-713, 361/723, 437/813, 437/209, 437/217, 437/219
• US Class Current: 361/713
• CPC Class Codes: H01L 2221/68363 used in a transfer process involving transfer directly from an origin substrate to a target substrate without use of an intermediate handle substrate
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/451 with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/4826 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/75315 Elastomer inlay
• CPC Class Codes: H01L 2224/75822 Rotational mechanism
• CPC Class Codes: H01L 2224/83101 as prepeg comprising a layer connector, e.g. provided in an insulating plate member
• CPC Class Codes: H01L 2224/83191 wherein the layer connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 23/4951 Chip-on-leads or leads-on-chip techniques, i.e. inner lead fingers being used as die pad
• CPC Class Codes: H01L 23/49513 having bonding material between chip and die pad
• CPC Class Codes: H01L 24/27 Manufacturing methods
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/31 Structure, shape, material or disposition of the layer connectors after the connecting process
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/75 Apparatus for connecting with bump connectors or layer connectors
• 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 2924/00014 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: H01L 2924/00015 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed as prior art
• 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 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/30105 : Capacitance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3512 : Cracking
• CPC Class Codes: Y10T 428/2835 : including moisture or waterproof component

Abstract

A lead-on-chip integrated circuit package comprising at least one extremely thin adhesive layer transferred from a carrier onto the face of integrated circuit chips, and a lead frame laminated to the last adhesive layer, with cured adhesive acting as an insulator, integrated circuit chip connection pads bonded to and encapsulating the chip and lead frame. Thermally conductive and electrically insulating filling may be included with the adhesive to improve heat conduction from the IC. Compliant adhesive reduces thermally induced stresses between the lead frame and IC chip. Both the improved thermal performance and reduced moisture absorption of the encapsulated package improves the reliability of the integrated circuit package.

Claims

1. A lead-on-chip integrated circuit package having good thermal conductivity for efficient transfer of heat contained therein comprising:

an integrated circuit chip having a face with circuit connection pads thereon;

a first layer of adhesive on said face of said integrated circuit chip wherein said circuit connection pads are exposed;

said first layer of adhesive cured to form an insulator on the face of said integrated circuit;

a second layer of adhesive on said cured first layer of adhesive wherein said circuit connection pads are exposed;

a lead frame having tips and a plurality of electrical conductors, wherein a substantial portion of said lead frame is laminated to said second layer of adhesive and fixedly aligned with said integrated circuit connection pads for connection thereto; and

an encapsulating case surrounding said integrated circuit chip and lead frame.

2. The integrated circuit of claim 1, wherein said second layer of adhesive is from 0.25 mils to 2 mils in thickness.

3. The integrated circuit of claim 1, wherein said second layer of adhesive is compliant.

4. The integrated circuit of claim 3, wherein said compliant adhesive is phenolic butyryl epoxy.

5. The integrated circuit of claim 1, wherein said second layer of adhesive is B-staged.

6. The integrated circuit of claim 1, wherein said second layer of adhesive is a low moisture absorption adhesive.

7. The integrated circuit of claim 1, wherein said lead frame tips are selectively etched in order to reduce the space required for connection of said tips to said connection pads, thus reducing the overall package thickness.

8. The integrated circuit of claim 7, wherein said lead frame tips are bent slightly away from the face of said integrated circuit chip to prevent shorting thereto.

9. A lead-on-chip integrated circuit package having good thermal conductivity for efficient transfer of heat contained therein comprising:

an integrated circuit chip having a face with circuit connection pads thereon;

at least two layers of adhesive on said face of said integrated circuit chip wherein said circuit connection pads are exposed;

at least one layer of adhesive cured to form an insulator on said face of said integrated circuit; and

a lead frame having a plurality of electrical conductors, a substantial portion of said lead frame being laminated to a last layer of adhesive and fixedly aligned with said integrated circuit connection pads for connection thereto, wherein said insulator prevents said lead frame from shorting to said integrated circuit chip; and

an encapsulating case surrounding said integrated circuit chip and lead frame.