Process for forming a raised portion on a projecting contact for electrical testing of a semiconductor

• US 5,585,282 A
• Filed: 03/20/1995
• Issued: 12/17/1996
• Est. Priority Date: 06/04/1991
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farnworth, Warren M., Doan, Trung T., Wood, Alan G., Corbett, Tim J.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Graybill, David E.
• Application Number:
  US08/406,637
• Time in Patent Office: 638 Days
• Field of Search: 437/8, 437/183, 437/216, 437/222, 437/977, 257/739, 257/785, 228/180.22
• US Class Current: 438/613
• CPC Class Codes: G01R 1/0466 concerning contact pieces or mechanical details, e.g. hinges or cams; Shielding
• CPC Class Codes: G01R 3/00 Apparatus or processes specially adapted for the manufacture or maintenance of measuring instruments , e.g. of probe tips
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/056 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 2224/13012 in top view
• CPC Class Codes: H01L 2224/13019 at the bonding interface of the bump connector, i.e. on the surface of the bump connector
• CPC Class Codes: H01L 2224/16014 the bump connector being smaller than the bonding area, e.g. bond pad
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/81192 wherein the bump connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81345 Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/81375 having an external coating, e.g. protective bond-through coating
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83851 being an anisotropic conductive adhesive
• CPC Class Codes: H01L 2225/06562 at least one device in the stack being rotated or offset
• CPC Class Codes: H01L 23/13 characterised by the shape
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 23/49838 Geometry or layout
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/16 : of an individual bump connector
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15151 : the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections
• CPC Class Codes: H01L 2924/15174 : in different layers of the multilayer substrate
• CPC Class Codes: H05K 2201/0133 : Elastomeric or compliant polymer elastomeric conductor H05K2201/0314
• CPC Class Codes: H05K 2201/0347 : Overplating, e.g. for reinforcing conductors or bumps; Plating over filled vias reinforcing the conductive pattern H05K3/24
• CPC Class Codes: H05K 2201/0367 : Metallic bump or raised conductor not used as solder bump solder materials or compositions and methods of application thereof H05K3/3457
• CPC Class Codes: H05K 2201/0394 : Conductor crossing over a hole in the substrate or a gap between two separate substrate parts
• CPC Class Codes: H05K 2201/09481 : Via in pad; Pad over filled via if used for surface mounting H05K1/113
• CPC Class Codes: H05K 2201/09563 : Metal filled via plated through-hole filled with insulating material H05K2201/0959
• CPC Class Codes: H05K 2203/0307 : Providing micro- or nanometer scale roughness on a metal surface, e.g. by plating of nodules or dendrites
• CPC Class Codes: H05K 2203/0723 : Electroplating, e.g. finish plating
• CPC Class Codes: H05K 3/0058 : Laminating printed circuit boards onto other substrates, e.g. metallic substrates H05K1/0281 takes precedence
• CPC Class Codes: H05K 3/0067 : onto an inorganic, non-metallic substrate
• CPC Class Codes: H05K 3/4007 : Surface contacts, e.g. bumps H05K3/4092 takes precedence; deposition of finish layers on pads H05K3/24; forming solder bumps H05K3/3457
• CPC Class Codes: H05K 3/423 : characterised by electroplating method

Abstract

A process for forming die contacting substrate for establishing ohmic contact with the die is formed with raised portions on contact members. The raised portions are dimensioned so that a compression force applied to the die against the substrate results in a limited penetration of the contact member into the bondpads. In the preferred embodiment, the substrate is formed of semiconductor material, with the raised portions being formed by etching. The arrangement may be used for establishing temporary electrical contact with a burn-in oven and with a discrete die tester. This permits the die to be characterized prior to assembly, so that the die may then be transferred in an unpackaged form. A Z-axis anisotropic conductive interconnect material may be interposed between the die attachment surface and the die.

Claims

1. A method for forming a contact member for establishing electrical contact with a contact location on a discrete, unpackaged semiconductor die, said contact location formed as a metal pad, said method comprising:

forming a substrate;

forming a contact on the substrate, said contact projecting from a surface of the substrate by a distance of from 20 μ

m to 75 μ

m to provide a clearance between the die and substrate;

forming a raised portion on the contact, said raised portion shaped as an elongated ridge projecting from a surface of the contact with a height of from 2 Å

to 1.5 μ

m, for penetrating the contact location to a penetration depth that is less than a thickness of the contact location while the surface of the contact limits the penetration depth into the contact location; and

forming a conductive trace on the substrate for transmitting signals to and from said contact to the contact location.

2. The method as claimed in claim 1 and wherein a plurality of raised portions shaped as elongated ridges are formed on the contact.

3. The method as claimed in claim 2 and wherein the elongated ridges are formed in a concentric pattern.

4. The method as claimed in claim 1 and wherein said raised portion is formed by etching the substrate.

5. The method as claimed in claim 4 and wherein said contact is formed as a plateau by etching the substrate around the raised portion.

6. The method as claimed in claim 5 and wherein said contact is formed by forming a mask on the substrate, etching the substrate around the raised portion to form the plateau and then removing the mask.

7. The method as claimed in claim 6 and wherein the raised portion is etched at an etch angle of approximately 55°

.

8. The method as claimed in claim 7 and wherein the raised portion is formed by wet etching.

9. The method as claimed in claim 1 and wherein the substrate is formed of a material selected from the group consisting of silicon, germanium and silicon on sapphire.

10. The method as claimed in claim 1 and wherein the raised portion is formed as a pointed elongated ridge.

11. A method for forming a contact member for establishing electrical contact with a pattern of contact locations on a discrete, unpackaged semiconductor die, said contact location formed as a metal pad, said method comprising:

forming a substrate;

forming a first mask on the substrate;

etching the substrate around the mask to form a plurality of elongated ridges with each ridge projecting from the substrate with a height of from 2 Å

to 1.5 μ

m for penetrating the contact location to a penetration depth that is less than a thickness of the contact locations;

forming a second mask on the substrate;

etching the substrate around each ridge to form a plurality of raised contacts in a pattern matching the pattern of contact locations, each contact projecting from a surface of the substrate by a distance of from 20 μ

m to 75 μ

m to provide a clearance between the die and substrate; and

forming a conductive trace on the substrate for transmitting signals to and from said contact to the contact location.

12. The method as claimed in claim 11 and wherein each elongated ridge includes sloped sidewalls.

13. The method as claimed in claim 12 and wherein each contact includes a plurality of elongated ridges arranged in a concentric pattern.

14. The method as claimed in claim 13 and wherein the ridges are etched at an angle of approximately 55°

using an isotropic wet etch process.

15. The method as claimed in claim 14 and wherein each contact is formed as a raised plateau with the ridges formed on a flat top surface of the plateau.

16. The method as claimed in claim 15 and wherein the conductive traces are formed using a metallization process.

17. The method as claimed in claim 16 and wherein the conductive traces are formed using a conductive doping process.

18. A method for forming a contact member for establishing electrical contact with a contact location on a discrete, unpackaged semiconductor die, said contact location formed as a metal pad, said method comprising:

forming a substrate;

forming a raised contact on the substrate for contacting the contact location, said raised contact formed with a height to provide a clearance between the substrate and the contact location of at least 20 μ

m;

forming a conductive trace on the substrate for transmitting signals to and from said contact to the contact location; and

forming a raised portion on the contact, said raised portion shaped as an elongated ridge projecting from a surface of the contact with a height of from 2 Å

to 1.5 μ

m, for penetrating the contact location to a penetration depth that is less than a thickness of the contact location while the surface of the contact limits the penetration depth into the contact location.

19. The method as claimed in claim 18 and wherein said raised portion is formed by etching the substrate.

20. The method as claimed in claim 19 and wherein said contact is formed as a plateau with a flat top surface by etching the substrate around the raised portion.