Utilize ultrasonic energy to reduce the initial contact forces in known-good-die or permanent contact systems

• US 6,296,171 B1
• Filed: 10/12/1999
• Issued: 10/02/2001
• Est. Priority Date: 02/23/1998
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farnworth, Warren M., Hembree, David R., Wood, Alan G., Hess, Michael E., Jacobson, John O.
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US09/416,248
• Time in Patent Office: 721 Days
• Field of Search: 228/1.1, 228/110.1, 228/173.3, 156/73.1, 156/73.2
• US Class Current: 228/110.1
• CPC Class Codes: B23K 20/10 making use of vibrations, e.g. ultrasonic welding
• CPC Class Codes: B23K 2101/38 Conductors

Abstract

A machine and method for bonding puncture-type conductive contact members of an interconnect to the bond pads of a bare semiconductor die includes the use of one or two ultrasonic vibrators mounted to vibrate one or both of the die and interconnect. A short axial linear burst of ultrasonic energy enables the contact members to pierce hard oxide layers on the surfaces of the bond pads at a much lower compressive force and rapidly achieve full penetration depth.

Claims

1. A method of simultaneously forming bonds between a semiconductor die having at least one bond pad on a first surface thereof and an interconnect having at least one contact member on a connection surface thereof, said at least one contact member configured to penetrate a layer of hard material on an outer surface of said at least one bond pad, thereby connecting said at least one contact member to said at least one bond pad of said semiconductor die, said method comprising:

aligning said semiconductor die and said interconnect;

bringing together the first surface of the semiconductor die and the connection surface of the interconnect having said at least one contact member aligned proximate said at least one bond pad on said first surface of said semiconductor die;

engaging said semiconductor die and said interconnect using an increasing force; and

substantially ultrasonically vibrating one of said semiconductor die and said interconnect using vibrational energy having said at least one contact member of said nterconnect penetrating a portion of said at least one bond pad of said semiconductor die forming an electrical connection.

2. The method of claim 1, wherein said ultrasonic vibration is conducted to achieve a vibrational amplitude of about 5 to about 30 percent of the predetermined depth.

3. The method of claim 1, wherein said ultrasonic vibration is conducted for about 5 to about 200 milliseconds.

4. The method of claim 1, wherein said method forms a non-permanent electrical connection between said at least one bond pad and said at least one contact member.

5. The method of claim 1, wherein said method forms a permanent electrical connection bond between said at least one bond pad and said at least one contact member.

6. The method of claim 1, further comprising:

retracting said semiconductor die and said interconnect from each other while applying linear axial ultrasonic vibrational force to one of said semiconductor die and said interconnect, said retraction disconnecting said semiconductor die from said interconnect.

7. The method of claim 1, whereby said engaging and said ultrasonic vibration are continued having said at least one contact member penetrating said portion of said at least one bond pad to a predetermined depth.

8. The method of claim 7, wherein said predetermined depth comprises about 0.3-0.8 of the thickness of said at least one bond pad.

9. The method of claim 7, further comprising:

detecting penetration of said at least one bond pad to the predetermined depth by detection/feedback apparatus.

10. The method of claim 9, further comprising:

detecting the penetration of said at least one bond pad on said first surface of said semiconductor die upon detecting the penetration of said at least one bond pad to

the predetermined depth by said detection/feedback apparatus.