MEMS PROBE FABRICATION ON A REUSABLE SUBSTRATE FOR PROBE CARD APPLICATION

• US 20100033201A1
• Filed: 08/05/2008
• Published: 02/11/2010
• Est. Priority Date: 08/05/2008
• Status: Active Grant

• Current Assignee: Winmems Technologies Co., Ltd.
• Original Assignee: Winmems Technologies Co., Ltd.
• Inventors: Lam, Cao Ngoc, Hsu, Tseng-Yang
• Granted Patent: US 8,089,294 B2
• Time in Patent Office: Days
• US Class Current: 324/755.50
• CPC Class Codes: G01R 1/06716 Elastic
• CPC Class Codes: G01R 1/06727 Cantilever beams
• CPC Class Codes: G01R 1/06744 Microprobes, i.e. having dimensions as IC details
• CPC Class Codes: G01R 1/07342 the body of the probe being at an angle other than perpendicular to test object, e.g. probe card
• 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: Y10T 29/49204 Contact or terminal manufacturing

Abstract

A Micro-Electro-Mechanical-Systems (MEMS) probe is fabricated on a substrate for use in a probe card. The probe has a bonding surface to be attached to an application platform of the probe card. The bonding surface is formed on a plane perpendicular to a surface of the substrate. An undercut is formed beneath the probe for detachment of the probe from the substrate.

Claims

1. A method comprising:

forming a probe on a substrate using Micro-Electro-Mechanical Systems (MEMS) processing techniques, the probe having a bonding surface to be attached to an application platform of a probe card, the bonding surface formed on a plane perpendicular to a surface of the substrate; and

forming an undercut beneath the probe for detachment of the probe from the substrate.

2. The method of claim 1, further comprising:

detaching the probe from the substrate by breaking a joint located between a base portion of probe and an anchoring structure on the substrate.

3. The method of claim 2, wherein detaching the probe from the substrate further comprises:

forming a sacrificial layer on the substrate;

forming the probe and the anchoring structure on the sacrificial layer; and

removing the sacrificial layer beneath the probe without completely removing the sacrificial layer beneath the anchoring structure.

4. The method of claim 2, wherein detaching the probe from the substrate further comprises:

forming a conductive layer on the substrate;

forming a sacrificial layer on the conductive layer, the sacrificial layer having an opening to expose the conductive layer;

forming the probe and the anchoring structure on the sacrificial layer, the anchoring structure having contact to the conductive layer through the opening; and

removing the sacrificial layer beneath the probe.

5. The method of claim 1, wherein forming a probe on a substrate further comprises:

forming a tip base for a contact tip of the probe in a first lithographic operation;

forming a contact tip on the tip base in a second lithographic operation; and

forming a remaining portion of the probe on the substrate in a third lithographic operation.

6. The method of claim 1, wherein the anchoring structure has a surface area greater than that of the probe.

7. The method of claim 1, wherein the anchoring structure has a substantially round shape and the probe has a substantially long and narrow shape.

8. A Micro-Electro-Mechanical Systems (MEMS) probe comprising:

a contact tip to form a contact with a device-under-test, the contact tip sandwiched between two conductive layers of the MEMS probe;

a probe body, which comprises;

a tip portion to support the contact tip;

a spring portion; and

a base portion to support the tip portion and the spring portion, the base portion having an exposed broken surface that is formed by detaching the MEMS probe with force from a substrate on which the MEMS probe was fabricated.

9. The MEMS probe of claim 8, wherein the probe body has thickness variations in its cross sections, the thickness measured in a direction perpendicular to a surface of the substrate.

10. The MEMS probe of claim 8, wherein the spring portion has one or more curved shapes and a width that varies along a length of the spring portion, with a first end of the spring portion extending to the tip portion and a second end connecting to the base portion.

11. The MEMS probe of claim 8, wherein the spring portion includes more than one curved springs connected in parallel.

12. The MEMS probe of claim 8, wherein the spring portion provides a buckling force that has two stages with a stop between the two stages.

13. The MEMS probe of claim 8, wherein the base portion is corrugated.

14. A Micro-Electro-Mechanical Systems (MEMS) probe on a substrate, the MEMS probe comprising:

a contact tip to form a contact with a device-under-test, the contact tip sandwiched between two conduct layers of the MEMS probe;

a probe body, which comprises;

a tip portion to support the contact tip;

a spring portion; and

a base portion to support the tip portion and the spring portion, the base portion having a bonding surface to be attached to an application platform of a probe card, the bonding surface formed on a plane perpendicular to a surface of the substrate.

15. The MEMS probe of claim 14, wherein the base portion is connected though a joint to an anchoring structure on the substrate, the joint having a thin and narrow cross section compared to that of the base portion and the anchoring structure.

16. The MEMS probe of claim 14, wherein the probe body has thickness variations in its cross sections, the thickness measured in a direction perpendicular to a surface of the substrate.

17. The MEMS probe of claim 14, wherein the substrate is reusable for fabricating a next batch of probes.

18. A method for fabricating a Micro-Electro-Mechanical Systems (MEMS) probe, the method comprising:

forming a sacrificial layer on a substrate;

forming a first conductive pattern on the sacrificial layer, the first conductive pattern having a shape of a tip base of the MEMS probe;

forming a second conductive pattern on the first conductive pattern, the second conductive pattern having a shape of a contact tip of the MEMS probe; and

forming a third conductive pattern on the second conductive pattern and the sacrificial layer, the third conductive pattern having a shape of a probe body and an anchoring structure for the MEMS probe.

19. The method of claim 18, wherein the anchoring structure is anchored on the sacrificial layer, the method further comprising:

removing the sacrificial layer beneath the MEMS probe without completely removing the sacrificial layer beneath the anchoring structure.

20. The method of claim 18, wherein the anchoring structure is anchored on a metal layer beneath the sacrificial layer, the method further comprising:

removing the sacrificial layer beneath the MEMS probe, leaving the anchoring structure anchored on the metal layer.