TWI901161B - Test socket - Google Patents

Abstract

The present invention is a test socket that is suitable for being locked on a circuit board and can be used to test a device under test. The device under test has a degree of warpage to define a first surface topography. The test socket includes a base, a plurality of elastic metal parts provided in the base and a conductive elastic piece located above the base and capable of conforming to the first surface topography to electrically connect to the device under test. By allowing the conductive elastic piece to conform to the first surface topography and contact the elastic metal parts, the problem of poor contact between the device under test and the elastic metal parts can be solved.

Description

Test socket

This invention relates to semiconductor testing technology, particularly a test socket.

Semiconductor package testing often involves placing an object under test (DUT), such as a semiconductor package or chip, into a test socket equipped with multiple probes. After each probe contacts the DUT's electrical connection pads or solder balls, the test signal is transmitted through the probes to the DUT, achieving the test objective. However, direct contact between the probes and the DUT can easily cause wear between the probes and the electrical connection pads or solder balls, impacting their functionality.

Furthermore, as the design dimensions of DUTs increase, for example, to 65mm*65mm and above, the packaged DUT will experience increasing warpage. This means that the DUT surface is no longer flat. Furthermore, probes mounted in the base may have varying heights, resulting in the tips of the probes not being aligned. All of these issues can lead to poor contact between the probes and the DUT. Improving this poor contact between the DUT and the probes has become a pressing goal for researchers in this field.

To address the aforementioned problems of the prior art, the present invention discloses a test socket adapted to be fastened to a circuit board and used to test a device under test (DUT) having a degree of curvature defining a first surface topography. The test socket comprises: a base; a plurality of elastic metal members disposed within the base; and a conductive elastic sheet disposed above the base and conforming to the first surface topography to electrically connect to the DUT.

In one embodiment, the conductive elastic sheet is ductile and can be deformed to contact the top end of each elastic metal member.

In one embodiment, the plurality of elastic metal members include at least one first elastic metal member and at least one second elastic metal member. When the base is locked to the circuit board, the top of the at least one first elastic metal member and the top of the at least one second elastic metal member are located at different heights, thereby defining a second surface topography, and the conductive elastic sheet conforms to the second surface topography.

In another embodiment, the conductive elastic sheet includes a first substrate layer and a second substrate layer stacked together.

In another embodiment, the first substrate layer is a silicon (Si) gel, and the second substrate layer is a polymer material.

In another embodiment, the thickness ratio of the second substrate layer in the conductive elastic sheet is 25% to 75%.

In another embodiment, the first substrate layer includes a plurality of conductive elastic regions corresponding to each of the elastic metal parts and a plurality of conductive particles distributed in each of the conductive elastic regions.

In another embodiment, the second substrate layer is a frame-shaped structure, and each of the conductive elastic regions corresponds to a hollow area within the frame-shaped structure.

In another embodiment, the present invention further includes a plurality of guide pins, the conductive elastic sheet is placed on the guide pins to be spaced apart from the surface of the base, and the conductive elastic sheet is in a concave arc shape.

The present invention further discloses a test stand comprising: a base; a plurality of elastic metal parts disposed in the base; and a conductive elastic sheet positioned above the base and contacting the top of each of the elastic metal parts. The conductive elastic sheet has a tensile strength greater than 550 MPa%.

In one embodiment, the plurality of elastic metal members include at least one first elastic metal member and at least one second elastic metal member. When the base is locked to a circuit board, the top of the at least one first elastic metal member and the top of the at least one second elastic metal member are located at different heights, thereby defining a surface topography. The conductive elastic sheet conforms to the surface topography so that the conductive elastic sheet contacts the top of the at least one first elastic metal member and the top of the at least one second elastic metal member, respectively.

In another embodiment, the conductive elastic sheet is adapted to conform to an object to be tested.

In another embodiment, the conductive elastic sheet includes a first substrate layer and a second substrate layer stacked together.

In another embodiment, the first substrate layer is silicone, and the second substrate layer is a polymer material.

In another embodiment, the thickness ratio of the first substrate layer in the conductive elastic sheet is 25% to 75%.

In another embodiment, the present invention further includes a plurality of guide pins, the conductive elastic sheet is placed on the guide pins to be spaced apart from the surface of the base, and the conductive elastic sheet is in a concave arc shape.

In another embodiment, the first substrate layer includes a plurality of conductive elastic regions corresponding to each of the elastic metal parts and a plurality of conductive particles distributed in each of the conductive elastic regions.

In another embodiment, the second substrate layer is a frame-shaped structure, and each of the conductive elastic regions corresponds to a hollow area within the frame-shaped structure.

In another embodiment, the second substrate layer forms a plurality of hollow portions corresponding to each of the conductive elastic regions.

In another embodiment, each of the conductive elastic regions of the first substrate layer extends into each of the corresponding hollow portions.

As can be seen from the above, the test socket of the present invention, through the conductive elastic sheet, can adapt to the degree of curvature of the object under test or the different heights of multiple elastic metal parts, maintaining contact with each elastic metal part, thereby achieving the goal of providing good contact between the object under test and the elastic metal parts.

1: Test socket

11: Base

111: First Surface

112: Second Surface

113: Through hole

12: Elastic metal parts

120: Top

121: First elastic metal parts

122: Second elastic metal part

13, 13': Conductive elastic sheet

131, 131': First substrate layer

1311: Conductive elastic area

1312:Conductive particles

132,132’: Second substrate layer

1321: Hollow Section

1322: Hollow Area

133: Frame

14: Guide pin

8: Object under test

81: Conductor

9: Circuit board

a: First thickness

b: Second thickness

D: separation distance

H1: First Height

H2: Second Height

S: Area

S1: First surface morphology

S2: Second surface morphology

Figure 1 is an exploded view of the test socket of the present invention.

Figure 2 is a three-dimensional structural diagram of the test base of the present invention carrying the object to be tested.

Figure 3 is a cross-sectional view taken along line A-A in Figure 2.

Figure 4 is a partial enlarged view of area S in Figure 3.

Figure 5 is a schematic diagram of the structure of the test base of the present invention when the base is warped.

Figure 6 is a schematic diagram showing the drooping state of the conductive elastic sheet in the test socket of the present invention.

Figure 7 is a schematic diagram of the structure of the conductive elastic sheet of the first embodiment of the present invention.

Figure 8 is a schematic diagram of the structure of the conductive elastic sheet of the second embodiment of the present invention.

The following describes the technical content of the present invention using a specific embodiment. Those skilled in the art can easily understand the advantages and effects of the present invention from the content disclosed in this specification. However, the present invention can also be implemented or applied through other different specific embodiments.

Figure 1 is an exploded view of the test socket of the present invention, Figure 2 is a three-dimensional view of the test socket of the present invention supporting an object under test, and Figure 3 is a cross-sectional view taken along line A-A of Figure 2, both for reference. As shown in the figures, the test socket 1 of the present invention is adapted to be fastened to a circuit board 9 and used to test an object under test 8. The object under test 8 defines a first surface topography S1 based on its degree of warp. Specifically, the object under test 8 may warp during the packaging process, and the uneven surface resulting from this warp (i.e., the surface of the object under test 8 that is in electrical contact with the test socket 1 and on which the conductive member 81, such as a solder ball, or electrical contact pads, is formed) defines the first surface topography S1. The present invention enables the object under test 8 to be smoothly placed on the test base 1. The test base 1 of the present invention includes a base 11, a plurality of elastic metal parts 12, a conductive elastic sheet 13, and a plurality of guide pins 14. A detailed description of the test base 1 of the present invention is provided below.

The base 11 includes a first surface 111 and a second surface 112 that face each other, and a through hole 113 connecting the first surface 111 and the second surface 112. The base 11 is positioned on the circuit board 9 with the second surface 112 and can be fastened to the circuit board 9 using fasteners such as screws or bolts. Other fastening methods may also be used to connect the base 11 to the circuit board 9.

Each of the elastic metal parts 12 is disposed in the base 11. Specifically, each of the elastic metal parts 12 can be, for example, a spring probe, and is respectively placed in each of the corresponding through holes 113.

The conductive elastic sheet 13 is positioned above the base 11 and conforms to the first surface topography S1 to electrically connect to the object under test 8. Specifically, the conductive elastic sheet 13 is positioned above the first surface 111 of the base 11. In this embodiment, the conductive elastic sheet 13 is ductile and can be deformed to form a curved shape conforming to the first surface topography S1, thereby contacting the top ends of the elastic metal members 12.

Each guide pin 14 is used to position the conductive elastic sheet 13 on the base 11, wherein the conductive elastic sheet 13 is adapted to move up and down relative to the base 11 along each guide pin 14. Specifically, the guide pin 14 may have a top end and a bottom end, and the conductive elastic sheet 13 may have a through-hole corresponding to each guide pin 14. The bottom end may be fixed to the first surface 111 of the base 11. The conductive elastic sheet 13 is inserted into the corresponding guide pin 14 through each through-hole, so as to be adapted to move up and down relative to the base 11 along each guide pin 14. In this embodiment, the number of guide pins 14 may be four, symmetrically disposed at opposite corners of the conductive elastic sheet 13. This allows the conductive elastic sheet 13 to be securely fixed to the base 11 via the guide pins 14. In other embodiments, the conductive elastic sheet 13 may be fixed without the guide pins 14. For example, the conductive elastic sheet 13 may be directly attached to the base 11. This is not a limitation.

When not under test, the central region of the conductive elastic sheet 13 sags toward the base 11 to form a concave arc. During actual testing, the DUT 8 is placed on the conductive elastic sheet 13 and pressed against the sheet 13 toward the base 11, causing the sheet 13 to move along the guide pins 14 onto the base 11 and contact the elastic metal parts 12. At this point, the circuit board 9 provides a test signal, which is input into the DUT 8 via the elastic metal parts 12, the conductive elastic sheet 13, and the conductors 81 to test whether the DUT 8 is functioning properly.

In this embodiment, as shown in Figures 1 to 3, the object under test 8 exhibits a crying face warp (as shown in the figure, the notch is curled downward), that is, the first surface morphology S1 is a curved surface with the notch downward. When the test is performed, the object under test 8 is placed on the test seat 1, and the object under test 8 is pressed toward the test seat 1 (for example, by providing pressure through a press joint). Since the conductive elastic sheet 13 of the test seat 1 of the present invention can adapt to the first surface morphology S1 of the warped object under test 8, and each of the elastic metal parts 12 has elasticity, the test seat 1 can exhibit different degrees of pressure. There are different travel states. For example, as shown in Figure 3, the portions on both sides of the conductive elastic sheet 13 extend downward to a greater extent following the first surface topography S1, while the central portion of the conductive elastic sheet 13 extends upward to a greater extent following the first surface topography S1. This ensures close contact between the conductive elastic sheet 13 and the respective conductors 81 of the object under test 8 without creating any gaps where they are not in contact. As a result, the conductive elastic sheet 13 and the object under test 8 have good contact, thereby achieving good test performance of the object under test 8 during the test process.

Figure 4 is a partial enlarged view of area S in Figure 3. As shown, during the test process, the top end 120 of each elastic metal member 12 can be immersed or even inserted into the conductive elastic sheet 13, thereby contacting the conductive particles within the conductive elastic sheet 13. This increases the contact area and thus improves electrical transmission. Furthermore, the conductive body 81 of the object under test 8 can also be immersed in the conductive elastic sheet 13, achieving better contact. Thus, by allowing both the top end 120 of the elastic metal member 12 and the conductive body 81 of the object under test 8 to be immersed in the conductive elastic sheet 13, the contact resistance is reduced.

Figure 5 is a schematic diagram of the test base of the present invention when warping occurs. When each elastic metal member 12 is installed in the base 11, it is typically preloaded by the base 11. Consequently, each elastic metal member 12 exerts a counteracting force on the base 11. However, as the size of the test object increases, the size of the base 11 and the number of elastic metal members 12 in the test base 1 must also increase. Consequently, the elastic force on the base 11 increases, causing the base 11 to warp, resulting in the tops of the elastic metal members 12 located at different heights. In detail, the plurality of elastic metal parts 12 of the present invention may include at least one first elastic metal part 121 and at least one second elastic metal part 122. When the base 11 is locked to the circuit board 9, the elastic metal part 12 causes the base 11 to warp. Accordingly, the top of the at least one first elastic metal part 121 and the top of the at least one second elastic metal part 122 are located at different heights. In this embodiment, the middle portion of the warped base 11 is higher than the two side portions. Therefore, the first end of the first elastic metal part 121 located in the middle is higher than the second end. Height H1 is higher than the second height H2 of the second elastic metal parts 122 on either side. The different heights of the top ends of the first elastic metal part 121 and the second elastic metal part 122 define a second surface topography S2, allowing the conductive elastic sheet 13 to conform to this second surface topography S2. Because the conductive elastic sheet 13 in this embodiment is ductile, it can conform to this second surface topography S2 and contact the top ends of the first elastic metal part 121 and the second elastic metal part 122, thereby achieving good contact.

Figure 6 is a schematic diagram of the conductive elastic sheet in the test socket of the present invention in a drooping state. As shown, when the conductive elastic sheet 13 of the present invention is positioned above the base 11 through guide pins 14 (e.g., the aforementioned threading method), before the test socket 1 is locked to the circuit board, the portion where the conductive elastic sheet 13 connects to the guide pins 14 is spaced a distance D from the first surface 111 of the base 11. Because the conductive elastic sheet 13 is relatively soft, its center portion droops toward the base 11 in a concave arc. In other words, the distance between the conductive elastic sheet 13 and the first surface 111 is less than the distance D, allowing it to contact the elastic metal members 12.

Figure 7 is a schematic diagram of the conductive elastic sheet of the present invention in a first embodiment. As shown, the conductive elastic sheet 13 comprises a stacked first substrate layer 131 and a second substrate layer 132. Specifically, the first substrate layer 131 is a relatively soft silicone (Si) gel, while the second substrate layer 132 is a relatively hard polymer material, such as polyimide. This ensures good bonding between the first substrate layer 131 and the second substrate layer 132.

Furthermore, the thickness ratio of the second substrate layer 132 to the conductive elastic sheet 13 is 25% to 75%. That is, as shown in the figure, the percentage of the first thickness a of the second substrate layer 132 to the second thickness b of the conductive elastic sheet 13 is 25% to 75%. Consequently, the conductive elastic sheet 13 of the present invention has excellent ductility.

In one specific embodiment, the ultimate ductility value of the ductile conductive elastic sheet 13 is greater than 550 MPa%. The ultimate ductility is defined as the product of tensile strength (MPa) and elongation (%). The tensile strength and elongation are measured according to the American Society for Testing and Materials (ASTM) tensile testing standard. Ultimate strength refers to the maximum stress a material can withstand before tensile fracture, and elongation refers to the maximum deformation a material can achieve before tensile fracture. In one embodiment of the present invention, the ultimate strength is, for example, 280 MPa and the elongation is 2%, or the ultimate strength is, for example, 150 MPa and the elongation is 15%. Therefore, the conductive elastic sheet 13 of the present invention is suitable for conforming to the object under test due to its ductility.

In this embodiment, the ductility of the first substrate layer 131 is greater than that of the second substrate layer 132. By combining the two according to the aforementioned thickness ratio, a conductive elastic sheet 13 with a high ductility greater than 550 MPa% is obtained.

In another embodiment, the first substrate layer 131 includes a plurality of conductive elastic regions 1311 corresponding to the respective elastic metal parts, and a plurality of conductive particles 1312 distributed within each conductive elastic region. When the object under test is pressed against the base, the corresponding conductor and the elastic metal part clamp the conductive elastic region 1311, shortening the distance between the conductive particles 1312 within the conductive elastic region 1311 so that they come into contact with each other, thereby providing an electrical connection between the corresponding conductor and the elastic metal part.

In this embodiment, the second substrate layer 132 may have a grid-like structure. Specifically, the second substrate layer 132 may have a plurality of cutouts 1321 corresponding to the conductive elastic regions 1311. Portions of the first substrate layer 131 located in the conductive elastic regions 1311 may extend into the cutouts 1321. In another embodiment, the first substrate layer 131 may not extend into the cutouts 1321, but the top of the elastic metal member may enter the cutouts 1321 and contact the first substrate layer 131.

In another embodiment, the conductive elastic sheet 13 may further include a frame 133 disposed between the first substrate layer 131 and the second substrate layer 132 to provide good support for the conductive elastic sheet 13 and allow the conductive elastic sheet 13 to be removed from the frame 133 for easy installation or removal.

Figure 8 is a schematic diagram of the conductive elastic sheet according to the second embodiment of the present invention. In this embodiment, the structure of the conductive elastic sheet 13' is substantially the same as that of the previous embodiment. The difference lies in that the second substrate layer 132' of this embodiment is a frame-shaped structure, and each conductive elastic region 1311 corresponds to a hollow region 1322 within the frame structure. In other words, each conductive elastic region 1311 is located within the area surrounded by the hollow region 1322, and the portion of the first substrate layer 131' corresponding to the hollow region 1322 extends into the hollow region 1322. In this embodiment, the present invention can increase the ductility of the conductive elastic sheet 13' by reducing the area ratio of the second substrate layer 132' superimposed on the first substrate layer 131'.

In summary, the test stand of the present invention, through the conductive elastic sheet, can conform to the first surface topography of a warped object under test or the second surface topography corresponding to each elastic metal component in the warped base, thereby achieving the goal of providing good contact between the object under test and each elastic metal component.

The above embodiments are provided for illustrative purposes only and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection for the present invention is defined by the patent application accompanying this invention. Any invention that does not affect the effectiveness and purpose of the present invention shall be covered by this disclosure.

1: Test socket

11: Base

12: Elastic metal parts

13: Conductive elastic sheet

14: Guide pin

8: Object under test

9: Circuit board

S1: First surface morphology

Claims (10)

A test base is suitable for being fastened to a circuit board and used to test an object under test. The object under test has a degree of warp that defines a first surface topography. The test base comprises: a base; a plurality of elastic metal members disposed within the base; and a conductive elastic sheet positioned above the base and conforming to the first surface topography to electrically connect to the object under test. The first surface topography is non-planar based on the degree of warp. The test socket as described in claim 1, wherein the conductive elastic sheet is ductile and can be deformed to contact the top end of each elastic metal member. The test base as described in claim 1, wherein the plurality of elastic metal parts include at least one first elastic metal part and at least one second elastic metal part. When the base is locked to the circuit board, the top of the at least one first elastic metal part and the top of the at least one second elastic metal part are located at different heights, thereby defining a second surface topography, and the conductive elastic sheet conforms to the second surface topography. The test socket as described in any one of claims 1 to 3, wherein the conductive elastic sheet includes a first substrate layer and a second substrate layer stacked together. The test socket as described in claim 4, wherein the first substrate layer is a silicon (Si) gel, and the second substrate layer is a polymer material. The test socket as described in claim 4, wherein the thickness ratio of the second substrate layer in the conductive elastic sheet is 25% to 75%. The test socket as described in claim 4, wherein the first substrate layer includes a plurality of conductive elastic regions corresponding to each of the elastic metal parts and a plurality of conductive particles distributed in each of the conductive elastic regions. The test socket as described in claim 7, wherein the second substrate layer is a frame-shaped structure, and each of the conductive elastic regions corresponds to a hollow area within the frame-shaped structure. The test socket as described in claim 1 further includes a plurality of guide pins, the conductive elastic sheet is placed on the guide pins to be spaced apart from the surface of the base, and the conductive elastic sheet is in a concave arc shape. The test socket as described in claim 1, wherein the conductive elastic sheet contacts the top of each elastic metal member, and the conductive elastic sheet has a tensile strength greater than 550 million Pascals (MPa)%.