Test sockets, test systems, and methods for testing microfeature devices
Test sockets, test systems, and methods for testing microfeature devices with a substrate and a plurality of conductive interconnect elements projecting from the substrate. In one embodiment, a test socket includes a support surface and a plurality of apertures in the support surface corresponding to at least some of the interconnect elements of the microfeature device. The individual apertures extend through the test socket and are sized to receive a portion of one of the interconnect elements so that the substrate is spaced apart from the support surface when the microfeature device is received in the test socket. In one aspect of this embodiment, the individual apertures have a cross-sectional dimension less than a cross-sectional dimension of the interconnect elements so that the apertures receive only a portion of the corresponding interconnect element.
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The present invention is related to test sockets, test systems, and methods for testing microfeature devices.
BACKGROUNDConventional microelectronic devices are manufactured for specific performance characteristics required for use in a wide range of electronic equipment. A microelectronic bare die, for example, includes an integrated circuit and a plurality of bond-pads and/or redistribution layer (RDL) pads electrically coupled to the integrated circuit. The bond-pads can be arranged in an array, and a plurality of solder balls can be attached to corresponding bond-pads to construct a “ball-grid array.” Conventional bare dies with ball-grid arrays generally have solder balls arranged, for example, in 6×9, 6×10, 6×12, 6×15, 6×16, 8×12, 8×14, or 8×16 patterns, but other patterns are also used. Many bare dies with different circuitry can have the same ball-grid array but different outer profiles.
Bare dies are generally tested in a post-production batch process to determine which dies are defective. In one conventional test process, several bare dies are placed in corresponding test sockets of a test tray.
One problem with conventional test sockets is that debris can accumulate within the sockets, which damages and contaminates the bare dies. More specifically, particles and contaminants from other processes, such as chemical-mechanical planarization, vapor deposition, etc., may be carried to the test socket 20 on the bare dies. This debris can accumulate in the test socket and eventually scratch, impinge, pierce, contaminate and/or otherwise damage subsequent bare dies. For example, during processing, the test socket 20 illustrated in
Another problem with conventional test sockets is that the solder balls may not be aligned with the test contacts. More specifically, if the profile of a bare die is slightly out of tolerance, the solder balls on the die may not align with the test contacts. In the test socket 20 of
Another drawback of conventional test sockets is that the sockets limit the space available on bare dies for ball-grid arrays. For example, because the shelf 34 of the test socket 20 of
A. Overview
The present invention is directed toward test sockets, test systems, and methods for testing microfeature devices. The term “microfeature device” is used throughout to include microelectronic devices, micromechanical devices, data storage elements, read/write components, and other articles of manufacture. For example, microfeature devices include SIMM, DRAM, Flash-Memory, ASICS, processors, flip chips, ball-grid array chips, and other types of microelectronic devices or components. Several specific details of the invention are set forth in the following description and in
Several aspects of the invention are directed to test sockets for receiving a microfeature device having a substrate and a plurality of conductive interconnect elements projecting from the substrate. The interconnect elements, for example, can be solder balls or other types of conductive balls. In one embodiment, a test socket includes a support surface and a plurality of apertures in the support surface corresponding to at least some of the interconnect elements on the microfeature device. The apertures extend through the test socket and are sized to receive a portion of one of the interconnect elements so that the substrate is spaced apart from the support surface when the microfeature device is received in the test socket. In one aspect of this embodiment, the apertures have a cross-sectional dimension less than the cross-sectional dimension of the interconnect elements so that the apertures receive only a portion of corresponding interconnect elements.
The apertures in the support surface can have numerous configurations. For example, the apertures can be arranged in rows and columns corresponding to an array of conductive balls on the microfeature device. Alternatively, the support surface can include an opening, and the apertures can be arranged around the perimeter of the opening. In this arrangement, when the microfeature device is received in the test socket, the apertures receive corresponding interconnect elements and the other interconnect elements are positioned at the opening. In any of these arrangements, the individual apertures can include a first beveled portion proximate to the support surface and/or a second beveled portion proximate to an exterior surface of the test socket.
Another aspect of the invention is directed to systems for testing microfeature devices. In one embodiment, a system includes a test tray having a plurality of test sockets to support a plurality of microfeature devices and a tester interface movable relative to the test tray to test the microfeature devices. The individual test sockets include a support surface and an array of apertures in the support surface arranged to receive corresponding interconnect elements of the microfeature device. The individual apertures extend through the test socket and have a cross-sectional dimension less than a cross-sectional dimension of the corresponding interconnect element so that the substrate is spaced apart from the support surface when the microfeature device is received in the test socket. The tester interface includes a plurality of test contact arrays, and the individual test contact arrays are aligned to selectively contact a corresponding interconnect element array.
Another aspect of the invention is directed to methods of testing a microfeature device. In one embodiment, a method includes positioning several of the interconnect elements on the microfeature device partially within corresponding apertures in a support surface of a test socket so that the substrate is spaced apart from the support surface. The method further includes contacting the interconnect elements with corresponding test contacts to test the microfeature device while the microfeature device is received within the test socket.
B. Embodiments of Systems for Testing Microfeature Devices
The illustrated system 100 includes a test tray 110 and a plurality of test sockets 120 carried by the test tray 110, which in turn carry corresponding microfeature devices 160. The individual test sockets 120 include an array of apertures 130 corresponding to the array of solder balls 168 on the microfeature device 160, as described in greater detail below. The illustrated system further includes a tester interface 190 having a plurality of test contacts 192 arranged in arrays corresponding to the arrays of solder balls 168 on the respective microfeature devices 160 in the test tray 110. The test tray 110 is movable relative to the tester interface 190 to insert the test contacts 192 into corresponding apertures 130 so that the test contacts 192 can apply electrical signals to respective solder balls 168 and test the microfeature devices 160. The system 100 also includes a computer 195 operatively coupled to the tester interface 190. The computer 195 sends/receives signals from the microfeature devices 160 via the tester interface 190.
C. Embodiments of Test Sockets for Carrying Microfeature Devices
Referring to
Referring only to
For purposes of illustration, in one embodiment, the second diameter D2 of the apertures 130 can be from approximately 70 percent to approximately 80 percent of the diameter D4 of the solder balls 168. In one aspect of this embodiment in which the solder balls 168 have a diameter D4 of approximately 0.45 mm, the second diameter D2 of the apertures 130 can be approximately 0.35 mm or approximately 78 percent of the diameter D4 of the solder balls 168. In other embodiments, the second diameter D2 of the apertures 130 can be greater than 80 percent or less than 70 percent of the diameter D4 of the solder balls 168. In additional embodiments, such as those described below with reference to
One feature of the test socket 120 shown in
Another feature of the illustrated test socket 120 is that the microfeature device 160 is aligned with the tester interface 190 by placing the solder balls 168 partially within the corresponding apertures 130. An advantage of this feature is that the microfeature device 160 is properly aligned with the tester interface 190 even if the profile of the substrate 162 is out of specification because the alignment of the device 160 is based on the solder balls 168 instead of the profile of the substrate 162. In contrast, the prior art device 60 illustrated in
Another feature of the illustrated test socket 120 is that the space on the microfeature device 160 available for solder balls 168 is not limited by the socket 120. Because the substrate 162 is spaced apart from the support surface 128, the solder balls 168 can be attached to the substrate 162 proximate to the ends 165 of the device 160. An advantage of this feature is that the profile of the substrate 162 can be reduced and/or the solder ball count or size can be increased. In contrast, the prior art test socket 20 illustrated in
Another feature of the illustrated test socket 120 is that the support surface 128 and the exterior surface 129 are generally flat and the apertures 130 include beveled portions 131 and 133. An advantage of this feature is that the flat surfaces 128 and 129 allow misaligned solder balls 168 and test contacts 192 to slide laterally along the surfaces 128 and 129, and the beveled portions 131 and 133 automatically receive and center the solder balls 168 relative to the test contacts 192. Moreover, this feature aligns and corrects test contacts 192 that are angled or otherwise inclined such that the contacts 192 are not perpendicular to the substrate 162. Another advantage of the beveled portions 131 and 133 of the individual apertures 130 is that the lack of sharp edges reduces the likelihood that the solder balls 168 will be damaged, deformed, or detached from the substrate 162.
D. Additional Embodiments of Test Sockets
The illustrated ball support member 240 further includes a support surface 228, an exterior surface 229 opposite the support surface 228, and a plurality of apertures 230 extending through the support member 240 from the support surface 228 to the exterior surface 229. The apertures 230 are generally similar to the apertures 130 described above with reference to
One feature of the illustrated test socket 220 is that the ball support member 240 can be retrofit onto existing test sockets, such as the socket 20 illustrated in
An advantage of the test socket 620 illustrated in
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. For example, many of the elements of one embodiment can be combined with the other embodiments in addition to or in lieu of the elements of the other embodiments. Accordingly, the invention is not limited except as by the appended claims.
Claims
1-51. (canceled)
52. A method of manufacturing a test socket for receiving a microfeature device having a substrate and a plurality of interconnect elements projecting from the substrate, the method comprising:
- providing a test socket body including a recess and a shelf in the recess; and
- placing a support member in the recess so that the support member is carried by the shelf, the support member having a plurality of apertures positioned to receive corresponding interconnect elements of the microfeature device, the individual apertures being sized to receive a portion of the corresponding interconnect elements so that the substrate is spaced apart from the support member when the microfeature device is received in the recess.
53. The method of claim 52, further comprising constructing the support member by forming the plurality of apertures in rows and columns corresponding to an array of interconnect elements on the microfeature device.
54. The method of claim 52, further comprising constructing the support member by forming an opening in the support member and the apertures around a perimeter of the opening.
55. The method of claim 52, further comprising constructing the support member by forming the apertures such that the individual apertures have a cross-sectional dimension less than a cross-sectional dimension of the corresponding interconnect elements.
56. The method of claim 52, further comprising constructing the support member by forming the apertures such that the individual apertures have a first portion with a first diameter and a second portion with a second diameter greater than the first diameter.
57. The method of claim 52, further comprising constructing the support member by forming the apertures such that the individual apertures have a beveled portion.
58. A method of manufacturing a test socket for receiving a microfeature device having a substrate and a plurality of conductive balls on the substrate, the method comprising forming a test socket including a support surface and a plurality of apertures in the support surface corresponding to at least some of the conductive balls of the microfeature device, the individual apertures being sized to receive a portion of the corresponding conductive ball so that the substrate is spaced apart from the support surface when the microfeature device is received in the test socket.
59. The method of claim 58 wherein forming the test socket comprises:
- forming a ball support member having the support surface and the apertures in the support surface; and
- placing the ball support member in a recess of the test socket.
60. The method of claim 58 wherein forming the test socket comprises forming the apertures in the support surface in rows and columns corresponding to an array of conductive balls on the microfeature device.
61. The method of claim 58 wherein forming the test socket comprises forming an opening in the support surface and the apertures around a perimeter of the opening.
62. The method of claim 58 wherein forming the test socket comprises forming the apertures in the support surface such that the individual apertures have a diameter less than a diameter of the corresponding conductive ball.
63. The method of claim 58 wherein forming the test socket comprises forming the apertures in the support surface such that the individual apertures have a first portion with a first diameter and a second portion with a second diameter greater than the first diameter.
Type: Application
Filed: May 1, 2006
Publication Date: Sep 7, 2006
Applicant: Micron Technology, Inc. (Boise, ID)
Inventors: John Caldwell (Meridian, ID), Mark Tverdy (Boise, ID), Michael Slaughter (Boise, ID)
Application Number: 11/415,335
International Classification: G01R 31/02 (20060101);