# US 11,029,334 B2 · Low force wafer test probe

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- Number: US 11,029,334 B2
- Document ID: US11029334B2
- Status: Granted
- Kind: B2
- Application number: 16/536,620
- Filed: 2019-08-09
- Published: 2019-11-28
- Granted: 2021-06-08
- Earliest claimed: 2016-07-12
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: David M. Audette; Dennis R. Conti; Marc D. Knox; Grant W. Wagner
- Web page: https://patentgrep.com/patent/US11029334B2

## CPC

- G01R 1/06711: {Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins}
- G01R 1/06733: {Geometry aspects (G01R1/06727 takes precedence)}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A probe includes a pedestal and at least one feature extending from the pedestal to engage a surface of a corresponding contact at a position offset from a central longitudinal axis of the contact. The pedestal includes a cavity and the feature can include one or more blades that extend from a periphery of the cavity to a central longitudinal axis of the pedestal. The three blades are configured to engage the surface of the contact. The three blades can be positioned within the cavity to provide a 120-degree rotational symmetry about the central longitudinal axis of the pedestal.

## Claims

### Claim 1

A method for manufacturing a wafer test probe, the method comprising:
forming a pedestal having a first end and a second end, the pedestal comprising a cavity that extends from a first planar surface of the first end towards the second end; and
forming three blades extending from a periphery of the cavity to a central longitudinal axis of the pedestal, the three blades configured to engage a surface of a contact at a position offset from a central longitudinal axis of the contact, each of the three blades comprising a first surface coplanar to the first planar surface and a second surface parallel to the central longitudinal axis of the pedestal;
wherein the three blades are positioned within the cavity such that the three blades and the cavity provide a 120-degree rotational symmetry about the central longitudinal axis of the pedestal.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the three blades are formed within an interior of the cavity.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the three blades are substantially identical.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the three blades are equidistantly spaced about the periphery of the cavity.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the three blades are configured to shear a surface of the contact to maximize displacement of an oxide layer formed at the surface of the contact.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the three blades are configured to minimize stress within the wafer test probe that occurs during engagement with the contact.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the three blades are configured to minimize deformation at an area of engagement between the three blades and a surface of the contact, thereby reducing a contact force applied to the contact.

### Claim 8

A method for conducting a low force wafer test, the method comprising:
providing a wafer test probe configured to minimize stress that occurs during engagement with a contact of a wafer, the wafer test probe comprising:
a pedestal having a first end and a second end, the pedestal comprising a cavity that extends from a first planar surface of the first end towards the second end; and
three blades extending from a periphery of the cavity to a central longitudinal axis of the pedestal, the three blades configured to engage a surface of a contact at a position offset from a central longitudinal axis of the contact, each of the three blades comprising a first surface coplanar to the first planar surface and a second surface parallel to the central longitudinal axis of the pedestal, wherein the three blades are positioned within the cavity such that the three blades and the cavity provide a 120-degree rotational symmetry about the central longitudinal axis of the pedestal; and
engaging the wafer test probe with a surface of the contact such that a portion of the contact is received within the cavity.

### Claim 9 (depends on 8)

The method according to claim 8, wherein a total surface area of the three blades comprises less than 10% of a total surface area of the contact.

### Claim 10 (depends on 8)

The method according to claim 8, wherein a radial thickness of each of the three blades comprises between 5% and 20% an outer diameter of the contact.