Wafer Test Cassette

Abstract

To provide a wafer test cassette configured so that a probe can apply different needle pressure to different wafers.SOLUTION: A wafer test cassette includes a first enclosure, a second enclosure and a wafer. The first enclosure includes a prove card. The probe card includes at least one probe. The at least one probe has paramagnetism. The second enclosure is joined to the first enclosure. A magnetic force generating assembly is provided in the second enclosure, which is arranged to correspond to at least one prove. The wafer is positioned in the second enclosure, and the at least one probe is electrically contacted to at least one solder pad of the wafer by predetermined contact force. When the magnetic force generating assembly generates first magnetic attractive force, and the at least one probe is attracted, the at least one probe is electrically contacted with the at least one solder pad by first contact force, where the first contact force is above the predetermined contact force.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer test cassette, and more particularly to a wafer test cassette having a magnetic structure for adjusting the needle pressure of a probe against an object under test. [Background technology]

[0002] When the design of an integrated circuit on a wafer is completed, the wafer must undergo a burn-in test and an electrical test. Traditionally, when wafers undergo burn-in and reliability tests, each wafer is tested individually using a test host and a probe card. Each wafer is placed on a carrier and electrically contacted with the probes of the probe card to complete the test. Therefore, the larger the quantity of wafers, the more test hosts and probe cards are required, which increases the time and equipment costs of the test process.

[0003] In order to improve the efficiency of burn-in tests, a multi-test unit system capable of simultaneously burn-in testing multiple wafers has been developed. The system has multiple test unit arrays at one test end, with each wafer individually placed in each test unit array, and each test unit has at least one tray to hold the wafers, and the wafers are subjected to burn-in tests or electrical tests via a test host.

[0004] Recently, a wafer test cassette has been developed in which the probe card and wafer are positioned in advance and placed inside the wafer test cassette, and the wafer test cassette is electrically connected directly to the test host and placed inside the test unit to perform burn-in tests or electrical tests. Existing wafer test cassettes require position adjustment between the probe card and the wafer due to the coupling method between the upper and lower housings.

[0005] Furthermore, due to manufacturing tolerances and the weight of the wafer itself, the wafer does not have a perfectly flat surface after fabrication. As a result, the solder pads on the chip may not be on a flat horizontal surface, which may result in uneven contact between the probes and the solder pads in a pre-positioned manner or insufficient contact force, further increasing the inaccuracy of the needle test results.

[0006] Furthermore, the existing wafer test cassette has a fixed probe pressure due to the method of pre-positioning the probe card and the wafer, and there is no way to adjust the probe pressure according to different measurement requirements. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, finding ways to improve structural design to overcome the above drawbacks has become one of the key challenges that the industry wants to solve. [Means for solving the problem]

[0008] The present invention provides a wafer test cassette that addresses the shortcomings of existing technologies. The wafer test cassette includes a first housing, a second housing, and a wafer. The first housing includes a probe card, and the probe card includes at least one paramagnetic probe. The second housing is coupled to the first housing, and a magnetic force generating assembly is provided in the second housing and arranged to correspond to the at least one probe. The wafer is positioned within the second housing, and the at least one probe electrically contacts at least one solder pad on the wafer with a predetermined contact force. When the magnetic force generating assembly generates a first magnetic attraction force, the at least one probe is attracted, and the at least one probe electrically contacts at least one solder pad with a first contact force, the first contact force being equal to or greater than the predetermined contact force. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a wafer test cassette according to a first embodiment of the present invention. [Figure 2] FIG. 2 is another schematic diagram of the embodiment shown in FIG. [Figure 3] 1. FIG. 4 is a schematic diagram showing a state in which the wafer test cassette of the second embodiment of the present invention shown in FIG. 1 is used. [Figure 4] 4 is a schematic diagram of another state of use of the embodiment shown in FIG. 3. FIG. [Figure 5] FIG. 10 is a schematic view showing a wafer test cassette according to a third embodiment of the present invention. [Figure 6] FIG. 10 is a schematic view showing a wafer test cassette according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 and 2 are schematic diagrams of a wafer test cassette 1A according to a first embodiment of the present invention. The wafer test cassette 1A includes a first housing 11, a second housing 12, and a wafer 13. The first housing 11 includes a probe card 112, which includes at least one probe 1121. The probe 1121 is paramagnetic and is made of, for example, metal nickel. The second housing 12 is coupled to the first housing 11, and a magnetic force generating assembly MG1 is provided in the second housing 12 and is positioned corresponding to the probe 1121. The wafer 13 is located within the second housing 12. When the first housing 11 and the second housing 12 are coupled, the probe 1121 electrically contacts a solder pad 131 of the wafer 13 with a predetermined contact force P1. Here, when the magnetic force generating assembly MG1 generates a first magnetic attraction force M1, it attracts the probe 1121, and the probe 1121 comes into electrical contact with the solder pad 131 with a first contact force F1. The first contact force F1 is equal to or greater than a predetermined contact force P1.

[0011] In one embodiment, the first magnetic attraction force M1 directs the probe 1121 toward the second housing 12, making electrical contact with the solder pad 131 of the wafer 13 more stable, but does not increase the predetermined contact force P1 by the probe 1121 to the solder pad 131 of the wafer 13.

[0012] In one embodiment, due to issues such as unevenness of the wafer 13 or tolerances of the solder pads 131, the predetermined contact force P1 of the probes 1121 is insufficient to make sufficient electrical contact with the solder pads 131 of the wafer 13. The first magnetic attraction force M1 attracts the probes 1121, directing the probes 1121 toward the second housing 12, and provides a first contact force F1 that exceeds the predetermined contact force P1 so that each probe 1121 makes sufficient electrical contact with the solder pads 131 of the wafer 13. In this embodiment, the probes 1121 return to making electrical contact with the solder pads 131 at the predetermined contact force P1, for example, when the magnetic force generating assembly MG1 releases the first magnetic attraction force M1 or when the probes 1121 complete the test process.

[0013] 1 and 2, the magnetic force generating assembly MG1 is a non-permanent magnet, such as an electromagnet, and is connected to a switch S and a power source P. The magnetic force generating assembly MG1 generates and releases a first magnetic attraction force M1 by opening and closing the switch S. However, the present invention is not limited to this.

[0014] Please refer to Figures 3 and 4, which are schematic diagrams showing the use state of a wafer testing cassette 1B according to a second embodiment of the present invention. According to this embodiment, the wafer testing cassette 1B also includes a shielding member 2. The magnetic force generating assembly MG1 is a permanent magnet, and the shielding member 2 is used to shield the magnetic force generating assembly MG1 and block the first magnetic attractive force M1 between the magnetic force generating assembly MG1 and the probe 1121. At this time, the probe 1121 electrically contacts the solder pad 131 of the wafer 13 with a predetermined contact force P1. When the probe 1121 performs a test process, the shielding member 2 moves from the position shielding the magnetic force generating assembly MG1, causing the magnetic force generating assembly MG1 to generate the first magnetic attractive force M1 on the probe 1121. The probe 1121 is attracted and electrically contacts the solder pad 131 with a first contact force F1, thereby performing the test process. After the probe 1121 completes the test process, the shielding member 2 returns to the original shielding position as shown in FIG. 3, interrupting the first magnetic attraction force M1. At this time, the probe 1121 again makes electrical contact with the solder pad 131 with a predetermined contact force P1. In some embodiments, even though the shielding member 2 is in the shielding position, the magnetic force generating assembly MG1 still generates a third magnetic attraction force (not shown, smaller than the first magnetic attraction force M1) on the probe 1121. The predetermined contact force P1 at this time includes the third magnetic attraction force as well as a force generated when the first housing 11 and the second housing 12 are coupled together.

[0015] Please refer to FIG. 5, which is a schematic diagram of a wafer test cassette 1C according to a third embodiment of the present invention. In this embodiment, the magnetic force generating assembly MG1 can also generate a second magnetic attraction force M2, and the probe 1121 electrically contacts the solder pad 131 with a second contact force F2, which is greater than the first contact force F1. For example, the magnetic force generating assembly MG1 is connected to a control circuit CRT, which controls whether the magnetic force generating assembly MG1 generates a magnetic attraction force and controls the magnitude of the magnetic attraction force (e.g., whether the first magnetic attraction force M1 or the second magnetic attraction force M2 is generated). For example, the control circuit CRT adjusts the current or power of the power supply P according to the control signal, thereby influencing the magnetic attraction force of the magnetic force generating assembly MG1 to be the first magnetic attraction force M1 or the second magnetic attraction force M2. This allows the probes to apply different needle pressures to the wafers 13 (solder pads 131) according to the test requirements of different wafers 13, and the needle pressure can be adjusted to adjust for wafer or chip tolerances, ensuring that each probe makes contact with the solder pads. After the probes perform the test process, the control circuit CRT controls the magnetic force generating assembly MG1 to stop the magnetic attraction force (first magnetic attraction force M1 or second magnetic attraction force M2), and the contact force between the probes 1121 and the wafer 13 returns to the predetermined contact force P1. For example, the control circuit CRT controls the power supply P to stop outputting current using a control signal, or the control circuit CRT opens the switch S, thereby controlling the magnetic force generating assembly MG1 to stop the magnetic attraction force.

[0016] In some embodiments, unlike the embodiment shown in FIG. 5, the control circuit CRT can be installed inside the wafer test cassette 1C, but the present invention is not limited to this.

[0017] 1 and 3 again. In the embodiment shown in FIGS. 1 and 3, the first housing 11 has a first magnetic member 111, and the second housing 12 has a second magnetic member 121. The second magnetic member 121 is disposed corresponding to the first magnetic member 111, and the first housing 11 and the second housing 12 are tightly coupled by a magnetic attractive force MF generated between the first magnetic member 111 and the second magnetic member 121. Here, when the magnetic attractive force MF is not generated (for example, when the magnetic force shielding member 14 has moved to a position where it shields the second magnetic member 121), the probe and the solder pad 131 are in electrical contact with each other by a third contact force. On the other hand, when a magnetic attraction force is generated between the first housing 11 and the second housing 12 (for example, when the magnetic force shielding member 14 is moved away from the position where it shields the second magnetic member 121), the magnetic attraction force MF provides an additional fourth contact force for electrical contact between the probes and the solder pads 131. The aforementioned predetermined contact force P1 is equal to the sum of the third contact force and the fourth contact force. In other words, the third contact force and the additional fourth contact force generated during the process of joining the first housing 11 and the second housing 12 correspond to a predetermined needle pressure applied by the probes 1121 to the wafer 13, and the probes 1121 do not break or damage the wafer 13. In other words, when the magnetic attraction force is generated, the magnetic attraction force MF contributes to electrical contact between at least one of the probes 1121 and at least one of the solder pads 131 on the wafer 13 with the predetermined contact force P1.

[0018] Please refer to FIG. 6, which is a schematic diagram showing a wafer test cassette 1D according to a fourth embodiment of the present invention. In addition to the first housing 11 and the second housing 12 being tightly coupled by magnetic attraction as described above, in the embodiment shown in FIG. 6, the first housing 11 has a first engaging member 115, and the second housing 12 has a second engaging member 116. The second engaging member 116 is disposed corresponding to the first engaging member 115, and the first housing 11 and the second housing 12 are tightly coupled by the engaging force of the first engaging member 115 and the second engaging member 116. When no engaging force is generated (i.e., when the first housing 11 and the second housing 12 are not yet tightly coupled), the probes and the solder pads 131 are in electrical contact with each other by a fifth contact force. When the engagement force is generated (when the first housing 11 and the second housing 12 are tightly coupled), the engagement force provides an additional sixth contact force for electrical contact between the probes and the solder pads 131. Here, the predetermined contact force P1 is equal to the sum of the fifth contact force and the sixth contact force. In other words, the fifth contact force and the additional sixth contact force generated in the process of the first housing 11 and the second housing 12 being tightly coupled by the engagement force correspond to the predetermined needle pressure (predetermined contact force P1) applied by the probes 1121 to the wafer 13, and the probes 1121 do not break or damage the wafer 13. In other words, when the engagement force is generated, the engagement force contributes to at least one probe 1121 making electrical contact with at least one solder pad 131 of the wafer 13 with the predetermined contact force P1.

[0019] In some embodiments, the first housing 11 and the second housing 12 are tightly coupled by a vacuum pumping method. When no vacuum pumping is performed, the probes 1121 and the solder pads 131 make electrical contact with each other with a seventh contact force. When a vacuum pumping is performed, an additional eighth contact force is applied to the electrical contact between the probes 1121 and the solder pads 131. Here, the predetermined contact force P1 is equal to the sum of the seventh and eighth contact forces. In other words, the seventh and eighth contact forces generated during the process of tightly coupling the first housing 11 and the second housing 12 by a vacuum pumping method correspond to a predetermined needle pressure (predetermined contact force P1) applied by the probes 1121 to the wafer 13, and the probes do not break or damage the wafer. In other words, when a vacuum pumping is performed, at least one probe 1121 makes electrical contact with at least one solder pad 131 of the wafer 13 with a predetermined contact force P1.

[0020] One beneficial effect of the present invention is that the wafer test cassette provided by the present invention utilizes magnetic attraction to enable accurate electrical contact between the probes of the probe card and the wafer. The magnetic attraction allows the probes to apply different needle pressures to different wafers. Furthermore, the magnetic attraction prevents the positional relationship between the probes and the wafer from being affected, for example, misalignment, and maintains stable electrical contact when the wafer test cassette is subjected to external forces (e.g., vibrations). [Explanation of symbols]

[0021] 1A, 1B, 1C, 1D Wafer Test Cassettes 2. Shielding material 11 First enclosure 111 first magnetic member 112 Probe Card 115 first engaging member 116 second engaging member 1121 Probe 12 Second enclosure 121 second magnetic member 13 wafers 131 solder pad 14 Magnetic shielding material CRT control circuit F1 First contact force F2 Second contact force M1 First magnetic attraction force M2 Second magnetic attraction force MG1 Magnetic force generation assembly P1 Predetermined contact force

Claims

1. a first housing including a probe card including at least one probe having paramagnetic properties; a second housing coupled to the first housing; a magnetic force generating assembly installed in the second housing and arranged corresponding to the at least one probe; a wafer located within the second enclosure, the at least one probe making electrical contact with at least one solder pad of the wafer with a predetermined contact force; the magnetic force generating assembly attracts the at least one probe when generating a first magnetic attractive force; the at least one probe makes electrical contact with the at least one solder pad with a first contact force; the first contact force is equal to or greater than the predetermined contact force, the at least one probe returns to electrical contact with the at least one solder pad with the predetermined contact force when the first contact force exceeds the predetermined contact force and the magnetic force generating assembly releases the first magnetic attractive force. Wafer test cassette.

2. the magnetic force generating assembly is further capable of generating a second magnetic attractive force; the at least one probe makes electrical contact with the at least one solder pad with a second contact force; the second contact force exceeds the first contact force; 2. The wafer test cassette according to claim 1.

3. the magnetic force generating assembly is a non-permanent magnet; 2. The wafer test cassette according to claim 1.

4. the magnetic force generating assembly is connected to a control circuit; the control circuit controls generation of the first magnetic attraction force.

4. The wafer test cassette according to claim 3.

5. the control circuit is installed in the wafer test cassette; 5. The wafer test cassette according to claim 4.

6. the control circuit controls the magnetic force generating assembly to discontinue the first magnetic attraction force after the at least one probe performs a test process; 5. The wafer test cassette according to claim 4.

7. the first housing includes a first magnetic member, the second housing has a second magnetic member, the second magnetic member is disposed corresponding to the first magnetic member, the first housing and the second housing are tightly coupled by a magnetic attraction force generated between the first magnetic member and the second magnetic member, the magnetic attraction force causes the at least one probe to electrically contact with at least one solder pad of the wafer with the predetermined contact force while the magnetic attraction force is being generated; 2. The wafer test cassette according to claim 1.

8. the first housing includes a first engagement member; the second housing has a second engaging member; the second engaging member is disposed corresponding to the first engaging member, the first housing and the second housing are tightly coupled by an engagement force between the first engaging member and the second engaging member, the engagement force causes the at least one probe to make electrical contact with at least one solder pad of the wafer with the predetermined contact force while the engagement force is being generated; 2. The wafer test cassette according to claim 1.

9. the first housing and the second housing are tightly coupled by a vacuum method; the at least one probe electrically contacts with at least one solder pad of the wafer with the predetermined contact force in the vacuum state; 2. The wafer test cassette according to claim 1.

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