I 1111111111111111 11111 lllll lllll 111111111111111 11111 111111111111111 IIII IIII
`US007659739B2
`
`c12) United States Patent
`Kister
`
`(IO) Patent No.:
`(45) Date of Patent:
`
`US 7,659,739 B2
`Feb.9,2010
`
`(54) KNEE PROBE HAVING REDUCED
`THICKNESS SECTION FOR CONTROL OF
`SCRUB MOTION
`
`(75)
`
`Inventor: January Kister, Portola Valley, CA (US)
`
`(73) Assignee: Micro Porbe, Inc., Carlsbad, CA (US)
`
`4,706,019 A
`4,730,158 A
`4,747,698 A
`4,757,255 A
`4,772,846 A
`4,773,877 A
`
`11/1987 Richardson
`3/1988 Kasai et al.
`5/1988 Wickramasinghe et al.
`7/1988 Margozzi
`9/1988 Reeds
`9/1988 Kruger et al.
`
`(Continued)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by O days.
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`0764352
`
`5/2004
`
`(21) Appl. No.: 11/521,944
`
`(22) Filed:
`
`Sep.14,2006
`
`(65)
`
`Prior Publication Data
`
`US 2008/0068035 Al
`
`Mar. 20, 2008
`
`(51)
`
`Int. Cl.
`(2006.01)
`GOJR 31102
`(52) U.S. Cl. ....................................... 324/761; 324/754
`(58) Field of Classification Search ....................... None
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
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`
`(Continued)
`
`OTHER PUBLICATIONS
`
`Sporck, Nicholas, "A New Probe Card Technology Using Compliant
`Microsprings", Proceedings 1997 IEEE international Test Confer(cid:173)
`ence Nov. 1, 1997, pp. 527-532.
`
`Primary Examiner-Vinh P Nguyen
`(74) Attorney, Agent, or Firm-Samantha A. Updegraff;
`Deborah A. Oeacock; Robert Lodenkamper
`
`(57)
`
`ABSTRACT
`
`An improved knee probe for probing electrical devices and
`circuits is provided. The improved knee probe has a reduced
`thickness section to alter the mechanical behavior of the
`probe when contact is made. The reduced thickness section of
`the probe makes it easier to deflect the probe vertically when
`contact is made. This increased ease of vertical deflection
`tends to reduce the horizontal contact force component
`responsible for the scrub motion, thereby decreasing scrub
`length. Here "thickness" is the probe thickness in the deflec(cid:173)
`tion plane of the probe (i.e., the plane in which the probe knee
`lies). The reduced thickness probe section provides increased
`design flexibility for controlling scrub motion, especially in
`combination with other probe parameters affecting the scrub
`motion.
`
`42 Claims, 29 Drawing Sheets
`
`FF1020
`Formfactor v. Feinmetall
`Page 1 of 41
`
`

`

`US 7,659,739 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`4,807,159 A
`4,901,013 A
`4,967,148 A
`5,015,947 A
`5,026,291 A
`5,030,318 A
`5,145,384 A
`5,205,739 A
`5,207,585 A
`5,230,632 A
`5,354,205 A
`5,422,574 A
`5,430,614 A
`5,436,571 A
`5,531,022 A
`5,576,631 A
`5,632,631 A
`5,635,846 A
`5,644,249 A
`5,676,599 A
`5,720,098 A
`5,742,174 A
`5,751,157 A
`5,764,070 A
`5,764,072 A
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`5,767,691 A
`5,773,987 A
`5,802,699 A
`5,806,181 A
`5,832,601 A
`5,884,395 A
`5,892,539 A
`5,914,613 A
`5,917,707 A
`5,923,178 A *
`5,932,323 A
`5,934,914 A
`5,936,421 A
`5,945,836 A
`5,952,843 A
`5,970,167 A
`6,027,630 A
`6,064,215 A
`6,071,630 A
`6,086,386 A
`6,133,072 A
`6,204,674 Bl
`6,205,660 Bl
`6,218,203 Bl
`6,246,245 Bl
`6,247,228 Bl
`6,278,284 Bl
`6,292,003 Bl *
`6,344,753 Bl
`6,411,112 Bl
`6,419,500 Bl
`6,420,887 Bl
`6,424,164 Bl
`6,433,571 Bl
`6,441,315 Bl
`
`2/1989 Komatsu et al.
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`4/1998 Kister et al.
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`10/2000 Fjelstad
`3/2001 Dabrowiecki
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`8/2002 Montoya
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`
`........ 324/754
`
`6,443,784 Bl
`6,482,013 B2
`6,486,689 Bl
`6,525,552 B2
`6,529,021 Bl
`6,530,148 Bl
`6,570,396 Bl
`6,573,738 Bl
`6,575,767 B2 *
`6,576,485 B2
`6,633,176 B2
`6,677,245 B2
`6,707,311 B2
`6,727,719 B2
`6,731,123 B2
`6,765,228 B2
`6,842,023 B2
`6,847,221 B2
`6,853,208 B2
`6,890,185 Bl
`D507,198 S
`6,917,525 B2
`D510,043 S
`6,956,389 Bl
`6,965,245 B2
`6,970,005 B2
`7,015,707 B2
`7,046,021 B2
`7,059,865 B2
`7,064,564 B2
`D525,207 S
`7,078,921 B2
`7,091,729 B2
`7,109,731 B2
`7,148,709 B2
`7,150,658 Bl
`7,202,682 B2
`7,218,127 B2
`7,218,131 B2
`7,265,565 B2
`7,274,195 B2
`7,285,966 B2
`7,436,192 B2
`7,511,523 B2
`2002/0070743 Al
`2002/0153913 Al
`2004/0104737 Al
`2004/0119485 Al
`2004/0239352 Al
`2005/0179458 Al
`2005/0189955 Al
`2006/0073712 Al*
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`2006/0170440 Al
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`2007/0167022 Al
`
`9/2002 Kimoto
`11/2002 Eldridge et al.
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`3/2003 Yu
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`6/2003 Satoh et al. ................... 439/71
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`
`FOREIGN PATENT DOCUMENTS
`
`JP
`WO
`WO
`
`11241690
`WO 8704568
`WO 96/15458
`
`* cited by examiner
`
`9/1999
`7 /1987
`5/1996
`
`FF1020
`Formfactor v. Feinmetall
`Page 2 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 1 of 29
`
`US 7,659,739 B2
`
`2---.--
`
`.
`
`~-26
`
`Fig. 1
`
`FF1020
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`Page 3 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 2 of 29
`
`US 7,659,739 B2
`
`Fig. 2
`
`FF1020
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`

`

`U.S. Patent
`
`Feb. 9, 2010
`
`Sheet 3 of 29
`
`us 7,659,739 B2
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`
`FF1020
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`Page 5 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 4 of 29
`
`US 7,659,739 B2
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`FF1020
`Formfactor v. Feinmetall
`Page 6 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 5 of 29
`
`US 7,659,739 B2
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`
`FF1020
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`Page 7 of 41
`
`

`

`U.S. Patent
`
`Feb. 9, 2010
`
`Sheet 6 of 29
`
`US 7,659,739 B2
`
`fig. 6
`
`FF1020
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`Page 8 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 7 of 29
`
`US 7,659,739 B2
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`FF1020
`Formfactor v. Feinmetall
`Page 9 of 41
`
`

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`U.S. Patent
`
`Feb.9,2010
`
`Sheet 8 of 29
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`US 7,659,739 B2
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`Fig. 8
`
`FF1020
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`Page 10 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 9 of 29
`
`US 7,659,739 B2
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`
`FF1020
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`Page 11 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 10 of 29
`
`US 7,659,739 B2
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`
`FF1020
`Formfactor v. Feinmetall
`Page 12 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 11 of 29
`
`US 7,659,739 B2
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`
`FF1020
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`Page 13 of 41
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`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 12 of 29
`
`US 7,659,739 B2
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`FF1020
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`Page 14 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 13 of 29
`
`US 7,659,739 B2
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`
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`
`FF1020
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`Page 15 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 14 of 29
`
`US 7,659,739 B2
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`
`FF1020
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`Page 16 of 41
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`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 15 of 29
`
`US 7,659,739 B2
`
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`
`FF1020
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`Page 17 of 41
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`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 16 of 29
`
`US 7,659,739 B2
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`FF1020
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`Page 18 of 41
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`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 17 of 29
`
`US 7,659,739 B2
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`FF1020
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`Page 19 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 18 of 29
`
`US 7,659,739 B2
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`FF1020
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`Page 20 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 19 of 29
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`US 7,659,739 B2
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`FF1020
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`Page 21 of 41
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`

`U.S. Patent
`
`Feb.9,2010
`
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`FF1020
`Formfactor v. Feinmetall
`Page 22 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 21 of 29
`
`US 7,659,739 B2
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`Fig. 27a
`
`Fig. 27b
`
`FF1020
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`Page 23 of 41
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`U.S. Patent
`
`Feb.9,2010
`
`Sheet 22 of 29
`
`US 7,659,739 B2
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`
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`
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`
`FF1020
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`Page 24 of 41
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`U.S. Patent
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`Feb.9,2010
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`Sheet 23 of 29
`
`US 7,659,739 B2
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`FF1020
`Formfactor v. Feinmetall
`Page 25 of 41
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`U.S. Patent
`
`Feb.9,2010
`
`Sheet 24 of 29
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`US 7,659,739 B2
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`Formfactor v. Feinmetall
`Page 26 of 41
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`U.S. Patent
`
`Feb.9,2010
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`Sheet 25 of 29
`
`US 7,659,739 B2
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`FF1020
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`Page 27 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 26 of 29
`
`US 7,659,739 B2
`
`Fig. 33
`
`Fig. 34
`
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`Formfactor v. Feinmetall
`Page 28 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 27 of 29
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`US 7,659,739 B2
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`FF1020
`Formfactor v. Feinmetall
`Page 29 of 41
`
`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 28 of 29
`
`US 7,659,739 B2
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`FF1020
`Formfactor v. Feinmetall
`Page 30 of 41
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`

`

`U.S. Patent
`
`Feb.9,2010
`
`Sheet 29 of 29
`
`US 7,659,739 B2
`
`3008
`
`Fig. 37
`
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`Page 31 of 41
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`

`

`US 7,659,739 B2
`
`1
`KNEE PROBE HAVING REDUCED
`THICKNESS SECTION FOR CONTROL OF
`SCRUB MOTION
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims the benefit of U.S. patent applica(cid:173)
`tion Ser. No. 11/450,977, filed on Jun. 9, 2006, entitled "Knee
`Probe having Increased Scrub Motion". Application Ser. No.
`11/450,977 claims the benefit of U.S. patent application Ser.
`No. 10/850,921, filed on May 21, 2004, entitled "Freely
`Deflecting Knee Probe with Controlled Scrub Motion".
`
`FIELD OF THE INVENTION
`
`The present invention relates to probes for testing elec(cid:173)
`tronic circuitry. Particularly, the present invention relates to
`vertical probes having a rigid colunmar structure and a sus(cid:173)
`pension knee for controlled scrub motion.
`This invention relates to electrical probes for automated
`circuit and device testing.
`In the field of electronic circuitry testing, scrubbing and
`contact force is an important factor in establishing a low
`resistance electrical contact between a probe tip and the test 25
`contact. During scrubbing, an eventual insulating oxide layer
`is removed in the interface between the contact tip and the test
`contact. Scrubbing is a microscopic shear movement of the
`probe tip along the test contact surface while a certain pres(cid:173)
`sure is exerted from the probe tip onto the test contact. As size 30
`and pitch of test contacts decrease, it becomes increasingly
`difficult to tune the scrub motion irrespective offriction influ(cid:173)
`ences in the tip/contact interface. Also, as the IC manufactur-
`ers incorporate designs with I.C. pads and bumps placed over
`chip's active circuitry it becomes important that the scrub of 35
`the probe does not cause damage to the underlying circuitry.
`The size of the window of acceptable probe operation there(cid:173)
`fore, is restrained from one side by the contact resistance
`requirements calling for a sizable scrub, smaller scrub size
`required by smaller targets that need to be probed as pitches 40
`decrease, and smaller scrub (including depth) to avoid dam(cid:173)
`age to the underlying circuitry.
`The new generation of I.C. chips has pads that are placed
`over active circuitry in order to maximize use of the real
`estate. These types of chips are commonly referred in the 45
`industry as chips with "low-K dielectric". The low-K dielec(cid:173)
`tric refers to the fragile polymer-based insulator now placed
`between the pads and the underlying circuits for electrical
`purposes. It is not acceptable to damage the low-K dielectric
`during probing operations either.
`In the prior art, well known buckling beam probes have
`been utilized to provide a combined resilient deflection and
`scrubbing. In order for a buckling beam probe to operate
`properly with a well defined scrub motion it needs to be
`rigidly held on its peripheral shaft and additionally guided 55
`close to the contact tip. This makes the buckling beam probe's
`assembly increasingly challenging with ever decreasing
`scale. Therefore, there exists a need for a probe that may be
`easily assembled in large numbers and small scale while
`providing a well definable scrub motion. The present inven- 60
`tion addresses this need.
`The contact resistance issue has also been addressed by
`probes having separate parts for scrubbing and for making
`electrical contact. For example, US 2004/0239352 considers
`dual probes having a contact probe and a separate scrub
`probe, where the scrub probe moves in such a way as to clean
`the part of the contact pad that will end up under the contact
`
`2
`probe during test. In some cases (e.g., copper deposition
`manufacturing), circuit fabrication processes provide contact
`pads which are covered with a protective dielectric film ( e.g.,
`a silicon dioxide film). U.S. Pat. No. 6,727,719 considers a
`5 probe having an inner contact needle and an outer hard layer,
`where the hard outer layer is adapted for penetrating such a
`protective film.
`An important consequence of decreasing probe and contact
`pad dimensions is that the current density at the probe-pad
`10 contact increases. This increased current density also raises
`issues which have not come up before in connection with
`large probes on large pads. More specifically, the current
`density can be high enough to form micro-welds between the
`probe and the pad due to local heating. Breaking these micro-
`15 welds as the probe is removed from the contact pad can lead
`to degradation of the probe tip ( e.g., by accumulation of
`non-conductive material), thereby reducing probe reliability
`and/or lifetime.
`
`20
`
`BACKGROUND
`
`Testing of electrical devices and circuits has been an impor-
`tant component of electronic manufacturing processes for
`some time. Such testing typically entails probing a circuit
`with a fixture including multiple flexible probes, each probe
`making electrical contact to a contact pad on the circuit chip.
`Various practical issues that have arisen in this context have
`been addressed in the prior art, especially in connection with
`providing reliable, low-resistance electrical contact.
`It is well known that electrical contact between the probe
`and the contact pad can be hampered by the presence of
`non-conductive material on the pad and/or the probe ( e.g., a
`thin oxide film). Accordingly, considerable attention has been
`devoted to details of how the tip of the probe moves relative to
`the contact pad in order to improve the resulting electrical
`connection. This relative motion is usually referred to as a
`scrub motion. For example, U.S. Pat. No. 5,923,178 considers
`a probe having a shape which provides a scrub motion which
`is primarily a rocking motion without appreciable sliding.
`U.S. Pat. No. 5,952,843 considers a probe having a canted tip
`portion to facilitate penetration of the passivation layer. U.S.
`Pat. No. 6,529,021 considers a probe arrangement where the
`probe tip can be made to move in a reciprocating manner to
`reduce contact resistance.
`As circuit manufacturing technology continues to evolve to
`smaller critical dimensions, new practical issues relating to
`probing tend to arise which are not fully addressed by prior art
`approaches. For example, the decreasing size of contact pads
`as critical dimensions are reduced leads to increasingly
`50 demanding requirements on the ability to precisely control
`the probe scrub motion. Excessive scrub motion can cause
`loss of electrical contact, if the probe moves off the contact
`pad.
`Accordingly, it would be an advance in the art to provide
`greater control of probe scrub motion.
`
`SUMMARY
`
`A preferably vertically assembled probe features a sub(cid:173)
`stantially rigid colunmar structure and a connected suspen(cid:173)
`sion knee. The probe is held in assembly via its colunmar
`structure. The suspension knee has a base arm laterally con(cid:173)
`necting at and propagating away from a connect end of the
`colunmar structure. The base arm extends up to a lateral knee
`65 extension where a reverse arm continues from the base arm
`back in direction towards a central axis of the colunmar
`structure. The reverse arm terminates in a contact tip in a tip
`
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`Page 32 of 41
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`

`

`US 7,659,739 B2
`
`5
`
`4
`In particular, U.S. patent application Ser. No. 11/450,977 by
`the present inventor considers a knee probe where the knee
`curves away from the probe axis and then curves back to
`connect to the probe tip, crossing the probe axis on the way to
`the tip. This configuration can be described as having a nega(cid:173)
`tive tip offset, in contrast to probes having no tip offset (i.e.,
`the probe tip is aligned with the probe axis), or probes having
`a positive tip offset (i.e., the knee section does not cross the
`probe axis). Other parameters being comparable, probes hav-
`10 ing negative tip offset tend to provide longer scrub marks than
`probes having zero or positive tip offset. In some cases, it is
`desirable to decrease the scrub length provided by a probe
`having negative tip offset.
`Such reduction in scrub length can be provided according
`15 to the present invention by modifying the probe shape. More
`specifically, the probe knee section includes a reduced thick(cid:173)
`ness section to alter the mechanical behavior of the probe
`when contact is made. Providing a reduced thickness section
`of the probe makes it easier to deflect the probe vertically
`20 when contact is made. This increased ease of vertical deflec(cid:173)
`tion tends to reduce the horizontal contact force component
`responsible for the scrub motion, thereby decreasing scrub
`length. Here "thickness" is the probe thickness in the deflec(cid:173)
`tion plane of the probe (i.e., the plane in which the probe knee
`25 lies).
`The reduced thickness section of the probe can be
`described in terms of a probe thickness function h(z), where z
`is distance along the probe, having a local minimum. A probe
`having uniform thickness would have a constant h(z), and a
`30 tapered pro be would have a monotonically decreasing h( z). In
`either of these two conventional cases, h(z) would not have a
`local minimum.
`Although reduction of scrub length for negative tip offset
`probes is one application of the invention, the invention is also
`35 applicable to probes having no tip offset and to positive tip
`offset probes. In general, embodiments of the invention can
`provide improved control of scrub motion ( e.g., by varying
`details of the reduced thickness section such as location,
`amount of thickness reduction, etc.), especially in combina-
`40 tion with other probe parameters affecting scrub motion.
`
`3
`offset to the column axis that is smaller than the lateral knee
`extension. During application of a contacting force onto the
`contact tip, a first deflection of the base arm and a second
`deflection of the reverse arm counter act in conjunction with
`base and reverse arms structural configuration. As a result,
`scrub motion may be well defined in direction and magnitude
`without need for additional guidance of the deflecting probe
`structure.
`The entire probe is preferably symmetric with respect to a
`symmetry plane through the colunm axis and a tip axis, which
`is central with respect to a contacting face of the contact tip.
`The probe has preferably a continuous profile in direction
`normal to the symmetry plane fabricated for example by
`electroplating. Base and reverse arms are preferably linearly
`protruding with a knee bent in between, which results in
`combination with continuous probe profile in a scrub motion
`highly in plane with the symmetry plane.
`The probes may be arrayed with tight pitch that is less than
`the total width of the probe. Adjacent suspension knees may
`overlap while leaving sufficient clearance. The probes may be
`assembled via their colunmar structures for example in a
`sandwiching fixture and clamping plates that provide a shear(cid:173)
`ing clamping of the colunmar structures. The probes may be
`also simultaneously fabricated in a probe comb including a
`number of probes linearly arrayed with final assembly pitch
`and held together by a bridge connecting to each of the
`arrayed probes on the peripheral end of the colunmar struc(cid:173)
`ture. The bridge may be removed after a number of probe
`combs are stacked and fixed with respect to each other.
`Improved probing is provided using a knee probe where the
`knee curves away from the probe axis and then curves back to
`connect to the probe tip, crossing the probe axis on the way to
`the tip. The resulting lateral offset between the probe tip and
`the probe axis is a key geometrical parameter for predeter(cid:173)
`mining the scrub motion provided by the pro be in response to
`a predetermined contact force. The scrub motion preferably
`includes both a sliding motion and a rocking motion, where
`the sliding motion acts to clean the contact pad and the rock(cid:173)
`ing motion acts to bring a clean part of the probe tip into
`contact with the freshly cleaned part of the contact pad. In
`preferred embodiments, the probe tip can include one or more
`relatively narrow "skates" for making contact to the contact
`pad. A dual skate configuration is especially appropriate
`when small dimples are at the centers of the contact pads.
`Embodiments of the invention provide numerous advan- 45
`tages. The use of a probe having an "overshoot" knee as
`described above and in more detail below generally tends to
`increase the scrub motion compared to knee probes which do
`not "overshoot" the probe axis. In preferred embodiments, the
`invention makes use of multilayer probes, which facilitates 50
`the fabrication of probes having narrow "skates" on the probe
`tips. Such skates advantageously decouple the contact width
`(which should be small to increase contact for per unit area)
`from the probe width (which should be large enough to pre(cid:173)
`vent motion in directions other than in the intended deflection 55
`plane). Multi-layer probes also allow the skate layers to be
`made of a suitable tip contact material, while the remaining
`layers are not constrained to be suitable tip contact materials.
`Dual-skate probe tips can be employed to probe contact pads
`having dimples at their centers ( e.g., as provided by plating 60
`techniques for forming contact pads). In this case, the skates
`advantageously avoid the dimple, thereby avoiding issues
`relating
`to degraded electrical contact and increased
`mechanical stress on the probe tip that can arise when probing
`is performed directly at dimple locations.
`To better appreciate the present invention, it is helpful to
`consider some aspects of prior work by the present inventor.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a first perspective view of an exemplary probe in
`accordance with a preferred embodiment of the invention.
`FIG. 2 is the first perspective view of a number of probes of
`FIG. 1 in exemplary assembly array.
`FIG. 3 is a top view of the probe array of FIG. 2.
`FIG. 4 is the top view of the probe array of FIG. 2 together
`with sandwiched fixture and clamping plate in aligned cutout
`position for probe insertion.
`FIG. 5 is a second perspective view of the assembly ofFIG.
`
`4.
`
`FIG. 6 is the second perspective view of the assembly of
`FIG. 5 in shear clamp configuration.
`FIG. 7 is the second perspective view of the assembly of
`FIG. 6 with the top fixture plate being removed for illustration
`purpose.
`FIG. 8 is a third perspective view of an exemplary probe
`comb of a number of linearly arrayed probes combined by a
`bridge.
`FIG. 9 is a schematic front view of a suspension knee in
`deflected and non deflected condition.
`FIGS. 10, 12, 14, 16, 17, 19 are colored front views of
`spectral displacement plots of variously configured suspen(cid:173)
`sion knees.
`
`65
`
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`Page 33 of 41
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`

`

`US 7,659,739 B2
`
`5
`FIG.11 is a colored front view ofa spectral stress plot of the
`suspension knee of FIG. 10.
`FIG.13 is a colored front view ofa spectral stress plot of the
`suspension knee of FIG. 12.
`FIG.15 is a colored front view ofa spectral stress plot of the
`suspension knee of FIG. 14.
`FIG.18 is a colored front view ofa spectral stress plot of the
`suspension knee of FIG. 17.
`FIG. 20 is a front view of a multiradius contacting tip in
`initial contact with a test contact.
`FIG. 21 is the front view with themultiradius contacting tip
`of FIG. 20 in operational contact with the test contact of FIG.
`20.
`FIG. 22 is a fourth perspective view of a contacting tip with
`three tip segments.
`FIG. 23a shows a first contact probe configuration accord(cid:173)
`ing to an embodiment of the invention.
`FIG. 23b shows an operational probe configuration accord(cid:173)
`ing to an embodiment of the invention.
`FIG. 24 shows a close up view of a probe tip making
`contact to a contact pad according to an embodiment of the
`invention.
`FIG. 25 shows a close up view of a probe tip making
`contact to a contact pad according to another embodiment of
`the invention.
`FIG. 26 shows a close up view of a probe tip making
`contact to a contact pad according to yet another embodiment
`of the invention.
`FIG. 27a shows a photograph of a probe tip.
`FIG. 27b shows a photograph of the probe tip of FIG. 27a
`after 1,000,000 probing cycles according to an embodiment
`of the invention.
`FIGS. 28a-d are photographs of probe array configurations
`suitable for use with embodiments of the invention.
`FIG. 29 shows a depth profile for a scrub mark made in
`accordance with an embodiment of the invention.
`FIG. 30 shows a probe according to a first embodiment of
`the invention.
`FIGS. 31-32 show alternate embodiments of the invention
`having different tip offsets.
`FIGS. 33-34 show alternate embodiments of the invention
`having different upper knee section thickness profiles.
`FIG. 35 shows an embodiment of the invention having a
`tapered lower knee section.
`FIG. 36a shows an embodiment of the invention in an
`initial contact configuration.
`FIG. 36b shows an embodiment of the invention in an
`operating contact configuration.
`FIG. 3 7 shows a pro be according to another embodiment of
`the invention.
`
`DETAILED DESCRIPTION
`
`Referring to FIG. 1, a probe 1 in accordance with a pre(cid:173)
`ferred embodiment of the invention features a rigid columnar
`structure 2 having a peripheral end 21, a connect end 22, a
`knee opposing face 23, a connect face 24, a front face 25 and
`a back face 26. The colunmar structure 2 is preferably sym(cid:173)
`metric with respect to a central colunm axis CA. At the
`connect end 22, a suspension knee 3 is laterally connecting
`via its base arm 32, which propagates away from the column
`axis CA substantially up to a lateral knee extension PK. A
`reverse arm 34 continues from the base arm 32. The reverse
`arm 34 propagates away from the lateral knee extension PK in
`direction towards the colunm axis CA with a reverse length
`RL. At the end of the reverse arm 34 is a contacting tip 35. The
`contacting tip 35 has a contacting face 36 with a tip axis TA
`
`5
`
`10
`
`6
`central with respect to the contacting face 36. The tip axis TA
`is offset from the colunm axis CA in a tip offset TO. The tip
`offset TO is smaller than the lateral knee extension PK such
`that during application of a contacting force preferably along
`the tip axis TA a first deflection of the base arm 32 and a
`second deflection of the reverse arm 34 counteract, resulting
`in a predetermined scrub motion of the contacting tip 35, The
`suspension knee 3 is connected to the rigid columnar struc(cid:173)
`ture 2 via a suspension connect 31.
`The probe 1 is preferably symmetric with respect to a
`symmetry plane SP that coincides with the colunm axis CA
`and the tip axis TA. As a preferred result, the scrub motion is
`substantially in plane with the symmetry plane SP. The probe
`1 may have a continuous profile in direction perpendicular
`15 with respect to the symmetry plane SP such that the columnar
`structure 2 as well as the elements of the suspension knee 3
`hav