Probe system and probe method

• US 5,640,101 A
• Filed: 04/18/1996
• Issued: 06/17/1997
• Est. Priority Date: 03/31/1994
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited, Tokyo Electron Yamanashi Ltd. (Tokyo Electron Limited)
• Inventors: Yoshioka, Haruhiko, Takahashi, Shigeaki, Kuji, Motohiro, Akaike, Shinji
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BOWSER, BARRY
• Application Number:
  US08/634,675
• Time in Patent Office: 425 Days
• Field of Search: 324/73.1, 324/754, 324/690, 324/458, 324/537, 358/101, 358/106, 358/107
• US Class Current: 324/756.03
• CPC Class Codes: G01R 1/07314 the body of the probe being perpendicular to test object, e.g. bed of nails or probe with bump contacts on a rigid support on an elastic support, e.g. a film, G01R1/0735
• CPC Class Codes: G01R 31/2887 involving moving the probe head or the IC under test; docking stations moving single probes G01R1/06705; moving individual probes in multiple probes G01R1/07392

Abstract

A probe system tests the electrical characteristics of chips arranged in a matrix on a semiconductor wafer. An XYZ stage movable in the directions of three-dimensional axes is disposed under a probe card having probes to be brought into contact with the electrode pads of the chips. A wafer table rotatable within a horizontal plane is disposed on the XYZ stage. A first image pickup means for picking up the probe images is mounted on the XYZ stage. A second image pickup means for picking up a wafer image is disposed above the table. The second image pickup means is movable horizontally to and from a use position under the probe card. A target is supported and moved by a driving member mounted on the XYZ stage, for aligning the focal points and optical axes of the first and second image pickup means. The target is moved between forward and retreat positions within and outside the field of view of the first image pickup means. At the forward position, the target provides a reference point aligned with the focal point of the first image pickup means. The table, the stage, and the image pickup means are connected to control and processing section which manages the position of the stage based on the three-dimensional coordinate system defined by the pulse count of encoders.

Claims

1. A method of detecting a coordinate point of a chip in a probe system for testing electrical characteristics of a plurality of chips arranged in a matrix on a substrate, said system comprising:

a probe card on which a plurality of probes are disposed to be brought into contact with the chips,

a tester for exchanging an electrical signal with the chips through said probes,

a stage arranged to oppose said probe card and movable in directions of two-dimensional axes,

a table which is supported on said stage to be rotatable within a horizontal plane, and adapted to place the substrate thereon,

image pickup means, disposed above said table such that a field of view thereof faces downward, for picking up an image of the substrate,

a target supported by said stage and having a reference point to be aligned with an optical axis of said image pickup means, and

a control and processing section connected to said table, said stage, and said image pickup means, so as to control operations thereof, and to process and store signals therefrom, said control and processing section serving to recognize a position of said stage in the directions of the two-dimensional axes based on a two-dimensional coordinate system defined by operation signals exchanged between said control and processing section and said stage, and

said method comprising;

a step of inputting a design map of the matrix of the chips in said control and processing section;

an aligning step of aligning the optical axis of said image pickup means with said reference point, and storing a position of said stage obtained at this time, as a reference coordinate point of the optical axis of said image pickup means in the two-dimensional coordinate system, in said control and processing section;

a substrate image pickup step of moving said stage by said control and processing section based on the design map, capturing respective specific portions of first, second and third chips selected from said plurality of chips within the field of view of said image pickup means, setting the specific portions to coincide with the optical axis of said image pickup means, and storing positions of said stage obtained at these time, as first, second and third coordinate points of the respective specific portions of the first, second and third chips in the two-dimensional coordinate system, in said control and processing section, where the first and second chips belong to the same row of the matrix while the first and third chips belong to the same column of the matrix, and the respective specific portions of the first, second and third chips have identical positional relationship with the first, second and third chips; and

a calculation step of calculating, by said control and processing section, coordinated points of chips located between the first and second chips, and between the first and third chips, in the two-dimensional coordinate system based on the first, second and third coordinate points in accordance with proportional distribution.

2. The method according to claim 1, wherein said specific portions of the first, second and third chips correspond to reference electrode pads of the first, second and third chips, respectively.

3. The method according to claim 1, wherein said image pickup means is located at a use position located under said probe card in the aligning step and in the substrate image pickup step, and said image pickup means is movable in the horizontal direction so as to move to and from said use position.

4. The method according to claim 1, wherein said substrate image pickup step further comprises a step of moving said stage by said control and processing section based on the design map, capturing respective specific portions of fourth and fifth chips within the field of view of said image pickup means, setting the specific portions to coincide with the optical axis of said image pickup means, and storing positions of said stage obtained at this time, as fourth and fifth coordinate points of the respective specific portions of the fourth and fifth chips in the two-dimensional coordinate system, in aid control and processing section, where the second and fourth chips belong to the same row of the matrix with the first chip interposed therebetween while the third and fifth chips belong to the same column of the matrix with the first chip interposed therebetween, and the respective specific portions of the first to fifth chips have identical positional relationship with the first to fifth chips, and

wherein said calculation step further comprises a step of calculating, by said control and processing section, coordinated points of chips located between the first and fourth chips, and between the first and fifth chips, in the two-dimensional coordinate system based on the first, fourth and fifth coordinate points in accordance with proportional distribution.

5. A probe method in a probe system for testing electrical characteristics of a plurality of chips arranged in a matrix on a substrate, said system comprising,

a probe card on which a plurality of probes are disposed to be brought into contact with the chips,

a tester for exchanging and electrical signal with the chips through said probes,

a stage arranged to oppose said probe card and movable in directions of three-dimensional axes,

a table which is supported on said stage to be rotatable within a horizontal plane, and adapted to place the substrate thereon,

first image pickup means, mounted on said stage such that a field of view thereof faces upward, for picking up an image of said probes,

second image pickup means, disposed above said table such that a field of view thereof faces downward, for picking up an image of the substrate,

a target supported by said stage and having a reference point used for aligning focal points and optical axes of said first and second image pickup means, and

a control and processing section connected to said table, said stage, and said first and second image pickup means, so as to control operations thereof, and to process and store signals therefrom, said control and processing section serving to recognize a position of said stage in the directions of the three-dimensional axes based on a three-dimensional coordinate system defined by operation signals exchanged between said control and processing section and said stage, and

said method comprising:

a step of inputting a design map of the matrix of the chips in said control and processing section;

a probe image pickup step of capturing a specific portion of said probes within the field of view of said first image pickup means and setting the specific portion to coincide with the focal point of said first image pickup means, and storing a position of said stage obtained at this time, as a probe coordinate point of the specific portion of said probes in the three-dimensional coordinate system, in said control and processing section;

an aligning step of causing the focal points and optical axes of said first and second image pickup means to coincide with each other through said reference point, and storing a position of said stage obtained at this time, as a reference coordinate point of the focal points of said first and second image pickup means in the three-dimensional coordinate system, in said control and processing section;

a substrate image pickup step of moving said stage by said control and processing section based on the design map, capturing respective specific portions of first, second and third chips selected from said plurality of chips within the field of view of said second image pickup means, setting the specific portions to coincide with the focal point of said second image pickup means, and storing positions of said stage obtained at this time, as first, second and third coordinate points of the respective specific portions of the first, second and third chips in the three-dimensional coordinate system, in said control and processing section, where the first and second chips belong to the same row of the matrix while the first and third chips belong to the same column of the matrix, and the respective specific portions of the first, second and third chips have identical positional relationships with the first, second and third chips;

a calculation step of calculating, by said control and processing section, coordinated points of chips located between the first and second chips, and between the first and third chips, in the three-dimensional coordinate system based on the first, second and third coordinate points in accordance with proportional distribution; and

a test step of calculating a necessary moving amount of said stage by said control and processing section from the probe coordinate point, the reference coordinate point, and the first to third coordinate points, and bridging the chips into contact with said probes by operating said stage based on the calculated moving amount, thereby testing electrical characteristics of the chips.

6. The method according to claim 5, wherein said specific portions of the first, second and third chips correspond to reference electrode pads of the first, second and third chips, respectively.

7. The method according to claim 5, wherein said second image pickup means is located at a use position located under said probe card in the aligning step and in the substrate image pickup step, and said second image pickup means is movable in the horizontal direction so as to move to and from said use position.

8. The method according to claim 5, wherein said substrate image pickup step further comprises a step of moving said stage by said control and processing section based on the design map, capturing respective specific portions of fourth and fifth chips within the field of view of said second image pickup means, setting the specific portions of coincide with the optical axis of said second image pickup means, and storing positions of said stage obtained at these time, as fourth and fifth coordinate points of the respective specific portions of the fourth and fifth chips in the three-dimensional coordinate system, in a said control and processing section, where the second and fourth chips belong to the same row of the matrix with the first chip interposed therebetween while the third and fifth chips belong to the same column of the matrix with the first chip interposed therebetween, and the respective specific portions of the first to fifth chips have identical positional relationship with the first to fifth chips, and

wherein said calculation step further comprises a step of calculating, by said control and processing section, coordinated points of chips located between the first and fourth chips, and between the first and fifth chips, in the three-dimensional coordinate system based on the first, fourth and fifth coordinate points in accordance with proportional distribution.

9. The method according to claim 7, wherein the probe image pickup step is executed first, said second image pickup means is forwarded to the use position, the aligning step and the substrate image pickup step are executed in that order, said second image pickup means is retreated from the use position, and thereafter the test step is executed.

10. The method according to claim 7, wherein the probe image pickup step is executed first, said second image pickup means is forwarded to the use position, the substrate image pickup step and the aligning step are executed in that order, said second image pickup means is retreated from the use position, and thereafter the test step is executed.

11. The method according to claim 7, wherein said second image pickup means is forwarded to the use position first, the aligning step and the substrate image pickup step are executed in that order, said second image pickup means is retreated from the use position, the probe image pickup step is executed, and thereafter the test step is executed.

12. The method according to claim 7, wherein said second image pickup means is forwarded to the use position first, the substrate image pickup step and the aligning step are executed in that order, said second image pickup means is retreated from the use position, the probe image pickup step is executed, and thereafter the test step is executed.