TWI894560B - Detection jig and its pressing head for a fingerprint sensing chip - Google Patents

Abstract

The present invention relates to a detection jig for a fingerprint sensing chip. The detection jig has a pressing head and a base. The pressing head has a detection part corresponding to the position of the sensing array of the fingerprint sensing chip and a conductive part that does not overlap with the detection part. The detection part and the conductive part are made of conductive materials and form a common ground through the common ground leads of the base to generate capacitive sensing changes with the sensing array during the detection process. In the detection process, in addition to forming an electrical connection with the contacts on the active surface of the fingerprint sensing chip through the preset detection circuit of the base, the effect of detecting whether the internal integrated circuit of the fingerprint sensing chip is operating correctly is achieved. At the same time, through the capacitive sensing changes generated by the detection part and the sensing array, it is detected whether the sensing array is correctly set. In this way, the effect of completely detecting the fingerprint sensing chip can be achieved.

Description

Fingerprint sensor chip detection fixture and its pressing head

The present invention relates to a testing fixture, and more particularly to a testing fixture for testing fingerprint sensor chips.

Chips are commonly used in a wide variety of electronic products. They contain pre-configured integrated circuits (ICs). Typically, after production is complete, they undergo testing to confirm that the chip's circuitry is functioning correctly. Referring to Figure 8 , a conventional testing fixture 80 for testing a chip 70 comprises a base 81 and a press head 82 . The base 81 is mounted on a testing circuit board 90 and has test circuits 811 connected to the circuitry on the testing circuit board 90. During testing, a through hole 821 preset in the center of the pressing head 82 is connected to a vacuum suction mechanism, and vacuum suction is performed through the through hole 821 to grab the back side 701 of the chip 70 to be tested. After the chip 70 is placed on the base 81, the contacts on the active surface 702 of the chip 70 that are connected to the internal integrated circuit are electrically connected to the test circuit board 90 through the test line 811 of the base 81. Then, testing can be carried out to confirm whether the circuit on the chip 70 is operating normally.

However, in addition to the contacts on the active surface, the fingerprint sensor chip also has a fingerprint sensor array on the back surface. Therefore, if the conventional detection fixture 80 is used to detect the fingerprint sensor chip, it can only detect whether the internal integrated circuit of the fingerprint sensor chip can operate correctly, but cannot detect whether the fingerprint sensor array is normal.

In view of this, the present invention is based on the needs of fingerprint sensing chips and designs a detection fixture that can simultaneously detect internal integrated circuits and back-side fingerprint sensing arrays.

To achieve the aforementioned objectives, the present invention employs a technical means to provide a press head for a fingerprint sensor chip testing fixture, comprising: A body having a contact surface, a portion of which forms a detection portion formed of a conductive material; A conductive portion disposed at a location that does not overlap with the detection portion and is electrically connected to the detection portion; A through-hole extending through the contact surface of the body, with the opening of the through-hole in the contact surface not overlapping with the detection portion and the conductive portion.

Furthermore, the present invention also provides a testing fixture having the aforementioned ram, the testing fixture further comprising a base, comprising a base body, a plurality of testing circuits, a first common ground circuit, and a second common ground circuit; the base body having a testing groove for accommodating the main body of the ram, one end of the testing circuit being exposed on the surface of the testing groove; the first common ground circuit and the second common ground circuit being formed in the base body, one end of the first common ground circuit being exposed on the surface of the testing groove, and the other end being grounded or connected to a fixed potential; one end of the second common ground circuit being exposed on the surface of the base body and corresponding to the conductive portion of the ram.

The advantage of the present invention lies in that, when detecting a fingerprint sensor chip, the detection portion of the indenter contacts the sensor array on the back of the fingerprint sensor chip. By making the detection portion conductive and allowing the fingerprint sensor chip and the indenter to share a common ground, the indenter and the fingerprint sensor chip contact each other, causing the sensor array to generate a capacitive induction change. Then, by connecting the contacts provided on the front of the fingerprint sensor chip to the detection circuitry of the base, the internal integrated circuit of the fingerprint sensor chip and the sensor array on the back are fully detected. Furthermore, because the through-hole of the pressure head does not overlap with the detection portion or the conductive portion, when vacuum suction is applied to the back side of the wafer to be tested through the through-hole, the function of the inductive array in contact with the detection portion is not affected, and the inductive array can be accurately tested.

The following, in conjunction with drawings and embodiments of the present invention, further illustrates the technical means employed by the present invention to achieve the intended purpose of the invention. The drawings have been simplified for illustrative purposes only and illustrate the structure or method of the present invention by describing the relationships between the elements and assemblies of the present invention. Therefore, the elements shown in the drawings are not presented in actual numbers, actual shapes, actual sizes, or actual proportions. The sizes or dimensional proportions have been exaggerated or simplified to provide better illustration. The actual numbers, actual shapes, or actual dimensional proportions have been selectively designed and configured, and the detailed component layout may be more complex.

1 , the fingerprint sensor chip testing fixture of the present invention includes a pressing head 10 and a base 20.

The aforementioned press head 10 includes a body 11, a conductive portion 12, and a through-hole 13. The body 11 has a contact surface 111 for contacting the back side of the wafer under test. At least a portion of the contact surface 111 is a detection portion 112. The detection portion 112 is used to correspond to the sensor array of the wafer under test. The detection portion 112 is made of a conductive material. The conductive material refers to a conductor that generates a capacitance change upon contact with the sensor array. For example, conductive carbon fiber-added polyetheretherketone (PEEK), nickel, or copper are conductive materials. In one embodiment (as shown in FIG2 ), the detection portion 112 is a flat surface. In another embodiment (as shown in FIG3 ), the detection portion 112A is provided with a detection pattern composed of multiple concave and convex portions. The conductive portion 12 is disposed on the body 11 at a location that does not overlap the detection portion 112 and is electrically connected to the detection portion 112. The conductive portion 12 is also made of a conductive material. In one embodiment, the entirety of the ram 10 is made of a conductive material, so both the detection portion 112 and the conductive portion 12 are made of a conductive material. In another embodiment, the detection portion 112 and the conductive portion 12 are formed by coating with a conductive material. In one embodiment (as shown in FIG1 ), the body 11 is provided with extensions 113 on both sides, and the conductive portions 12 are disposed on the extensions 113 . In another embodiment (as shown in FIG4 ), the sidewalls of the body 11B serve as the conductive portions 12B, and the sidewalls are perpendicular to the contact surface 111B. The through-hole 13 is provided through the contact surface 111 of the body 11 , and the opening of the through-hole 13 on the contact surface 111 does not overlap with the detection portion 112 . The through-hole 13 may be a single annular through-hole located around the detection portion 112 , or may comprise two through-holes 13 located on opposite sides of the detection portion 112 .

In one embodiment, the body 11 includes a channel 114 and a through hole 115. The two ends of the channel 114 are respectively connected to the through holes 13. The channel 114 is arranged across the two through holes 13 and connects them. The through hole 115 is formed through the other surface of the body 11 and is connected to the channel 114.

The aforementioned base 20 includes a base 21, multiple detection circuits 22, a first common ground circuit 23, and a second common ground circuit 24. The base 21 has a detection slot 211 formed concavely therein. The body 11 of the ram 10 is accommodated in the detection slot 211. The detection circuit 22 is disposed within the base 21, with one end exposed on the surface of the detection slot 211. The first common ground circuit 23 and the second common ground circuit 24 are formed within the base 21. One end of the first common ground circuit 23 is exposed on the surface of the detection slot 211, and the other end is grounded or connected to a fixed potential. The second common ground circuit 24 has one end exposed on the surface of the base 21 and corresponds to the conductive portion 12 of the ram 10, and the other end is grounded or connected to a fixed potential. In one embodiment (as shown in FIG1 ), the second common ground line 24 corresponds to the conductive portion 12 disposed on the extension portion 113 , such that the conductive portion 12 is connected to the second common ground line 24 . In another embodiment (as shown in FIG4 ), the second common ground line 24B corresponds to the conductive portion 12B disposed on the sidewall of the main body 11B, such that the conductive portion 12B is connected to the second common ground line 24B. Referring to FIG5 , in one embodiment, the base 20 has a plurality of first common ground lines 23 and a plurality of second common ground lines 24 symmetrically distributed on both sides of the detection line 22 .

Referring to Figure 1 , before testing, the ram 10 is secured to a carrier 30 . The carrier 30 is equipped with a vacuum suction line 31 , which communicates with the through-hole 13 of the ram 10 via a channel 114 and a through-hole 115 in the body 11 . The base 20 is secured to a test circuit board 40 , which includes a test circuit for connecting the test line 22 . Furthermore, the test circuit board 40 includes a grounding line or a fixed potential line for connecting the first common ground line 23 and the second common ground line 24 .

As shown in FIG6 , during testing, the vacuum suction line 31 of the carrier 30 begins vacuum suction, sucking the wafer 50 under test through the through-hole 13 of the press head 10 . The sensor array 51 of the wafer 50 under test corresponds to the detection portion 112 of the press head 10 . Because the opening of the through-hole 13 does not overlap with the detection portion 112 , the sensor array 51 of the wafer 50 under test is not affected by the through-hole 13 . As shown in FIG7 , after the wafer 50 is sucked up, the press head 10 draws the wafer 50 into the detection groove 211 of the base 20 , so that the active surface 52 of the wafer 50 contacts the detection circuit 22 of the base 20 . At this time, the sensor array 51 of the wafer 50 also contacts the detection portion 112 of the press head 10 . When testing begins, the detection circuit 22 of the base 20 transmits a detection signal. The integrated circuit within the chip under test 50 transmits a feedback signal to the detection circuit board 40 via the contacts on the active surface 52 through the detection circuit 22 of the base 20, thereby confirming whether the integrated circuit in the chip under test 50 is operating correctly. At the same time, through the contact between the sensor array 51 of the chip under test 50 and the detection portion 112 of the press head 10, the conductive portion 12 and the detection portion 112 are connected to the ground terminal of the detection circuit board 40 via the first and second common ground lines 23 and 24, thereby forming a common ground. Changes in capacitance induction between the detection portion 112 and the sensor array 51 can be detected. The integrated circuit within the chip under test 50 converts the aforementioned capacitance induction changes into capacitance sensing signals and transmits them to the capacitance sensing change detection circuit board 40. Since the detection portion 112 is pre-configured, whether it is a flat surface or has a detection pattern, the normal pattern or form of capacitance sensing changes is known in advance. Therefore, the capacitance sensing signals received by the detection circuit board 40 can be used to confirm whether the capacitance sensing changes generated by the sensor array 51 are correct.

Therefore, through the configuration of the detection portion 112 and the conductive portion 12 of the press head 10 of the present invention, the detection fixture of the present invention can not only detect whether the internal integrated circuit of the chip under test 50 is correctly configured, but also detect the fingerprint sensing capability of the sensor array 51 to meet the requirements of detecting fingerprint sensing chips.

The above description is merely an embodiment of the present invention and does not constitute any form of limitation on the present invention. Although the present invention has been disclosed as above through the embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make slight changes or modifications to the technical contents disclosed above to obtain equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

10: Crimping head 11, 11B: Main body 111, 111B: Contact surface 112, 112A: Detection section 113: Extension section 114: Channel 115: Through hole 12, 12B: Conductive section 13: Through hole 20: Base 21: Base 211: Detection slot 22: Detection circuitry 23: First common ground line 24, 24B: Second common ground line 30: Carrier 31: Vacuum suction line 40: Detection circuit board 50: Wafer under test 51: Sensor array 52: Active surface 70: Wafer 701: Back surface 702: Active surface 80: Detection fixture 81: Base 811: Test circuit 82: Press head 821: Through hole 90: Circuit board

Figure 1 is a schematic side cross-sectional view of the first embodiment of the test fixture of the present invention combined with a carrier and a test circuit board; Figure 2 is a perspective view of the press head of the present invention combined with a carrier; Figure 3 is a perspective view of another embodiment of the press head of the present invention combined with a carrier; Figure 4 is a schematic side cross-sectional view of the second embodiment of the test fixture of the present invention combined with a carrier and a test circuit board; Figure 5 is a top view of the base of the present invention; Figures 6 and 7 are schematic diagrams of the test fixture of the present invention in operation when testing a wafer under test; Figure 8 is a schematic side cross-sectional view of a conventional test fixture.

10: Pressing head

11: Body

111: Contact surface

112: Testing Department

113: Extension

114: Channel

115: Perforation

12: Conductive part

13: Perforation

20: Base

21: Seat

211: Test Tank

22: Detection circuit

23: First common ground line

24: Second common ground line

30: Vehicles

31: Vacuum suction line

40: Detection circuit board

Claims (12)

A pressing head for a fingerprint sensor chip testing fixture comprises: A body having a contact surface, a portion of which serves as a detection portion formed of a conductive material; A conductive portion disposed so as not to overlap with the detection portion and electrically connected to the detection portion; and A through-hole extending through the contact surface of the body, with the opening of the through-hole in the contact surface not overlapping with the detection portion and the conductive portion, and configured to facilitate vacuum suction. As described in claim 1, the pressing head of the fingerprint sensor chip detection fixture has an extension portion formed on both sides of the main body, and the conductive portion is arranged on the extension portion. The pressing head of the fingerprint sensing chip detection fixture as described in claim 2, wherein the surface of the extension portion and the detection portion facing the same side is made of a conductive material to form the conductive portion. A pressing head of a fingerprint sensing chip detection fixture as described in any one of claims 1 to 3, wherein the pressing head is made of a conductive material. A pressure head of a fingerprint sensing chip detection fixture as described in any one of claims 1 to 3, wherein a detection pattern is provided on the detection portion, and the detection pattern includes multiple concave portions and multiple convex portions. A pressure head of a fingerprint sensing chip detection fixture as described in any one of claims 1 to 3, wherein the body has a channel and a through hole, the channel is respectively connected to the through hole, and the through hole is connected to the channel and penetrates one of the surfaces of the body other than the contact surface. A fingerprint sensor chip testing fixture comprises: A pressing head comprising a body, a conductive portion, and two through-holes; the body having a contact surface, a portion of which serves as a detection portion formed of a conductive material; the conductive portion being disposed so as not to overlap with the detection portion and electrically connected to the detection portion; the two through-holes extending through the contact surface of the body, with the openings of the through-holes on the contact surface not overlapping with the detection portion; A base having a base body, a plurality of detection circuits, a first common ground circuit, and a second common ground circuit; the base body has a detection slot for accommodating the body of the pressure head; the detection circuit is disposed in the base body with one end exposed on the surface of the detection slot; the first common ground circuit and the second common ground circuit are formed in the base body; one end of the first common ground circuit is exposed on the surface of the detection slot, and the other end is grounded or connected to a fixed potential; one end of the second common ground circuit is exposed on the surface of the base body and corresponds to the conductive portion of the pressure head, and the other end is grounded or connected to a fixed potential. As described in claim 7, the fingerprint sensor chip detection fixture has an extension portion formed on both sides of the main body of the pressing head, and the conductive portion is arranged on the extension portion. The fingerprint sensing chip detection fixture as described in claim 8, wherein the surface of the extension portion and the detection portion facing the same side is made of a conductive material to form the conductive portion. A fingerprint sensing chip detection fixture as described in any one of claims 7 to 9, wherein the pressure head is made of a conductive material. A fingerprint sensing chip detection fixture as described in any one of claims 7 to 9, wherein a detection pattern is provided on the detection portion of the pressure head, and the detection pattern includes multiple concave portions and multiple convex portions. A fingerprint sensing chip detection fixture as described in any one of claims 7 to 9, wherein the main body of the pressure head has a back surface, a channel and a through hole, the back surface is different from the contact surface, the channel spans and connects to the through hole, and the through hole is connected to the channel and penetrates the back surface of the main body.