Linear vertical probe card

Abstract

The invention discloses a linear vertical probe card, and belongs to the technical field of semiconductor chip testing. The linear vertical probe card comprises N layers of upper guide plates, M layers of lower guide plates and a plurality of probes, N is greater than or equal to 2, and M is greater than or equal to 1; the N layers of upper guide plates and the M layers of lower guide plates are arranged in a staggered mode in the vertical direction and staggered in the same horizontal direction from top to bottom. A plurality of probe holes are formed in the upper guide plates and the lower guide plates; and the probes are arranged in the corresponding probe holes in the N-layer upper guide plates and the M-layer lower guide plates in a penetrating manner. According to the structure, the bending consistency of the probe can be controlled, the working stability of the probe is improved, the oxide at the test point can be automatically removed when the wafer is tested, and the contact performance of the probe is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor chip testing, and more particularly, relates to a linear vertical probe card. Background Art

[0002] A probe card is an interface instrument used to test chips. The core component of a probe card is the probe head. Common linear vertical probe cards are manufactured by machining pinholes on both the upper and lower guide plates, into which tens of thousands of probes are inserted. The upper and lower guide plates are separated by a distance, allowing the probes to bend within this space.

[0003] The tail end of the linear vertical probe is against the conductive contact of the circuit board, and the tip of the needle touches the test point of the wafer. In the pin insertion state, the pin holes of the upper and lower guide plates are aligned, and the linear probe is assembled into the hole. In the working state, the upper and lower guide plates are staggered by a certain distance, and the probe becomes curved, so that the probe has an elastic buffer function to avoid damage to the wafer or probe during testing. However, when the upper and lower guide plates are staggered, the tail end of the needle will press against one side of the upper edge of the upper guide plate and the other side of the lower edge of the upper guide plate. Figure 1 The force exerted by the upper guide plate on the needle tail end and the torque M1 equivalent to this force are plotted; similarly, a similar force will act between the needle tip and the lower guide plate, such as Figure 1 As shown, the torque equivalent to this force is M2.

[0004] Considering the force on the needle tail and needle tip, when the needle tip contacts the test point of the wafer, the probe will produce S-shaped deformation, such as Figure 1 However, the S-shaped deformation is a high-order deformation form, which is difficult to maintain balance. Slight manufacturing deviations will cause the increase or decrease of the torque M1 and M2, which will eventually stabilize the bending shape of the probe. Figure 1 The state of the middle right picture and the middle picture. This bending uncertainty has a very adverse effect on the stable operation of the probe.

[0005] In addition, the interaction between the probe tip and the wafer test point is also a key factor affecting contact performance. As we all know, a layer of oxide inevitably forms on the surface of the wafer test point, affecting the conductivity between the probe and the wafer. If the probe card can automatically remove the oxide from the test point while testing the wafer, the probe contact performance will be greatly improved.

[0006] Therefore, it is of great research significance to simultaneously solve the problem of low probe working stability caused by the uncertainty of bending of the probe in the working state in the existing technology, and the problem of low probe contact performance caused by oxides on the surface of the wafer test point. Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a linear vertical probe card, which aims to solve the problem in the existing technology that the bending of the probe in the working state is uncertain, thereby affecting the working stability of the probe. At the same time, it can automatically remove the oxide at the test point and solve the problem of low probe contact performance caused by oxide on the surface of the wafer test point.

[0008] To achieve the aforementioned object of the invention, the present invention provides a linear vertical probe card, comprising: N layers of upper guide plates, M layers of lower guide plates, and a plurality of probes, N ≥ 2, M ≥ 1; the N layers of upper guide plates and the M layers of lower guide plates are staggered with each other in the vertical direction, and staggered from top to bottom along the same horizontal direction; a plurality of probe holes are provided in both the upper guide plate and the lower guide plate, and the probes are passed through the probe holes corresponding to each other in the N layers of upper guide plates and the M layers of lower guide plates.

[0009] Preferably, the needle tail end of the probe is located above the upper guide plate of the top layer, and the needle tip is located below the lower guide plate of the bottom layer.

[0010] Preferably, in the working state, the upper guide plate of the middle layer is used to push the probe to deform in the first direction, so that the probe is pre-bent along the first direction, and the lower guide plate of the middle layer is used to push the probe to deform in the second direction, so that the probe is pre-bent along the second direction; the first direction is the offset direction of the lower guide plate relative to the upper guide plate in the horizontal direction, and the second direction is opposite to the first direction.

[0011] Preferably, when the linear vertical probe card switches from a non-working state to a working state, the swing generated by the needle tip automatically removes oxides from the test point.

[0012] Preferably, the swing distance of the needle tip is:

[0013] Among them, L is the swing distance of the needle tip, H is the distance between the bottom of the lower guide plate located at the bottom layer and the wafer to be measured, D is the diameter of the probe hole, T is the width of the probe, and B is the thickness of the lower guide plate located at the bottom layer.

[0014] Preferably, the range of M is 2≤M≤3, and / or the range of N is 1≤N≤4.

[0015] Preferably, the distance between two adjacent layers of upper guide plates is 3% to 10% of the total length of the probe, and / or the distance between two adjacent layers of lower guide plates is 3% to 7% of the total length of the probe.

[0016] Preferably, the distance between two adjacent upper guide plates and lower guide plates is 50% to 80% of the total length of the probe.

[0017] Preferably, the distance between the bottom of the lower guide plate at the bottom layer and the wafer to be tested is 180 μm-650 μm, and / or the thickness of the lower guide plate at the bottom layer is 8% to 15% of the total length of the probe.

[0018] Preferably, the diameter of the probe hole is 1.05T-1.35T, where T is the width of the probe.

[0019] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects: a linear vertical probe card is provided, comprising two or more upper guide plates, one or more lower guide plates, and a plurality of probes, wherein the upper guide plates and the lower guide plates are staggered with each other in the vertical direction and staggered from top to bottom in the same horizontal direction, and the probes are passed through the corresponding probe holes in the upper guide plates and the lower guide plates. Through this structure, the probes can be pre-bent. Through the effect of pre-bending, when the needle tip contacts the test point of the wafer, all the probes can be bent and deformed in the same direction in a consistent manner, thereby improving the working stability of the probe. Under this structure, the needle tip will swing in the corresponding direction after contacting the wafer. This swing can push away the oxide at the test point of the wafer and improve the contact performance of the probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the bending state of the probe in the working state in the prior art; Figure 2 A schematic structural diagram of a linear vertical probe card provided by an embodiment of the present invention; Figure 3 for Figure 2 A schematic diagram of the upper guide plate of the middle layer pushing the probe to pre-bend in the working state of the structure shown; Figure 4 for Figure 2 Schematic diagram of bending performance of the structure shown in the working state; Figure 5 for Figure 2 Schematic diagram of the needle tip swinging in the working state of the structure shown; Figure 6 This is a needle mark that does not adopt the structure of the embodiment of the present invention; Figure 7 for Figure 2 The needle mark of the needle tip swinging in the working state of the structure shown; Figure 8 for Figure 2 Schematic diagram of needle tip swing parameters under the working state of the shown structure.

[0021] Explanation of the reference numerals: 1 is an upper guide plate unit, 11 is a first-layer upper guide plate, 12 is a second-layer upper guide plate, 2 is a lower guide plate unit, 3 is a probe, 4 is a needle tail end, and 5 is a needle tip end. DETAILED DESCRIPTION

[0022] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The following will further explain this technical solution, its implementation process and principles.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0024] In addition, in the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "horizontal", "vertical", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] Throughout this specification, references to "one embodiment," "an embodiment," "the embodiment," and the like indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Throughout this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0026] The present invention provides a linear vertical probe card comprising: N layers of upper guide plates, M layers of lower guide plates, and a plurality of probes, where N ≥ 2 and M ≥ 1. The N layers of upper guide plates and the M layers of lower guide plates are vertically staggered and offset from top to bottom along the same horizontal direction. Multiple probe holes are provided in each of the upper and lower guide plates, and the probes are inserted into corresponding probe holes in the N layers of upper guide plates and the M layers of lower guide plates.

[0027] A linear vertical probe card consists of at least two layers of upper guide plates, at least one layer of lower guide plates, and a large number of probes. In the vertical plane, from top to bottom, there are the 1st to Nth layers of upper guide plates, followed by the 1st to Mth layers of lower guide plates. In the horizontal plane, from right to left or left to right, there are the 1st to Nth layers of upper guide plates, followed by the 1st to Mth layers of lower guide plates. Each layer of guide plates has multiple probe holes, and the probe holes in each layer correspond to each other. The probes penetrate the corresponding probe holes in the N layers of upper guide plates and the M layers of lower guide plates.

[0028] Preferably, the needle tail end of the probe is located above the upper guide plate of the top layer, and the needle tip is located below the lower guide plate of the bottom layer.

[0029] Preferably, in the working state, the upper guide plate of the middle layer is used to push the probe to deform in the first direction, so that the probe is pre-bent along the first direction, and the lower guide plate of the middle layer is used to push the probe to deform in the second direction, so that the probe is pre-bent along the second direction; the first direction is the horizontal offset direction of the lower guide plate relative to the upper guide plate, and the second direction is opposite to the first direction.

[0030] From right to left, the horizontal plane shows the upper guide plates for layers 1 to N, and the lower guide plates for layers 1 to M. For this type of linear vertical probe card, during operation, the upper guide plates in the middle layer are used to pre-bend the probes to the left, while the lower guide plates in the middle layer are used to pre-bend the probes to the right. From left to right, the horizontal plane shows the upper guide plates for layers 1 to N, and the lower guide plates for layers 1 to M. For this type of linear vertical probe card, during operation, the upper guide plates in the middle layer are used to pre-bend the probes to the right, while the lower guide plates in the middle layer are used to pre-bend the probes to the left.

[0031] Preferably, when the linear vertical probe card switches from a non-operating state to an operating state, the swinging of the needle tip automatically removes oxides from the test point.

[0032] Preferably, the swing distance of the needle tip is:

[0033] Wherein, L is the swing distance of the needle tip, H is the distance between the bottom of the lower guide plate located at the bottom layer and the wafer to be measured, D is the diameter of the probe hole, T is the width of the probe, and B is the thickness of the lower guide plate located at the bottom layer.

[0034] Preferably, M is in the range of 2 ≤ M ≤ 3, and / or N is in the range of 1 ≤ N ≤ 4. Further preferably, M = 2, and N = 1 or 2. For example, the number of upper guide plates is 2, and the number of lower guide plates is 2. The greater the number of guide plates, the thinner the thickness of the single-layer guide plates can be, which facilitates the machining of the guide plate pinholes. However, the greater the number of guide plates, the greater the difficulty of assembly. Therefore, M = 2 and N = 1 or 2 are ideal parameter choices.

[0035] Preferably, the distance between two adjacent layers of upper guide plates is 3% to 10% of the total length of the probe, and the distance between two adjacent layers of lower guide plates is 3% to 7% of the total length of the probe. Further preferably, the distance between two adjacent layers of upper guide plates is 5% to 8% of the total length of the probe, and the distance between two adjacent layers of lower guide plates is 4% to 5% of the total length of the probe. The distance between two adjacent layers of upper guide plates can be, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8% of the total length of the probe. The distance between two adjacent layers of lower guide plates can be, for example, 4%, 4.5%, or 5% of the total length of the probe. Generally speaking, the greater the distance between the upper guide plates, the thinner the upper guide plates, and the lower the strength of the upper guide plates. Therefore, the distance between the upper guide plates cannot be too large. The distance between the upper guide plates cannot be too small either, otherwise, due to positional deviations during processing or assembly, the probe holes of the guide plates will generate shear forces on the probes, affecting the normal operation of the probes. The same principle applies to the distance requirements between the lower guide plates.

[0036] Preferably, the distance between two adjacent upper and lower guide plates is 50% to 80% of the total probe length, more preferably 55% to 65%, for example 60%. The distance between adjacent upper and lower guide plates corresponds to the probe's bending section during operation. Lengthening the bending section can reduce probe stress and extend its service life, but an excessively long bending section can reduce probe stability. A distance of 55% to 65% of the probe's total length is optimal.

[0037] Preferably, the distance between the bottom of the lower guide plate on the bottom layer and the wafer to be measured is 180 μm-650 μm, more preferably 250 μm-450 μm. The thickness of the lower guide plate on the bottom layer is 8% to 15% of the total probe length, more preferably 8% to 10% of the total probe length. The distance between the bottom of the lower guide plate on the bottom layer and the wafer to be measured is a dynamic parameter that gradually decreases with probe wear. The thickness of the lower guide plate on the bottom layer is, for example, 8%, 9%, or 10%.

[0038] Preferably, the diameter D of the probe hole is 1.05T-1.35T, more preferably 1.1T-1.2T, where T is the width of the probe. For probe widths T ≤ 45 μm, 1.15T ≤ D ≤ 1.2T is more recommended. For probe widths 45 μm < T ≤ 75 μm, 1.1T ≤ D ≤ 1.15T is more recommended. For probe widths T > 75 μm, D = 1.1T is more recommended.

[0039] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The test methods in the following examples where specific conditions are not specified are generally based on conventional conditions.

[0040] Taking N=2 and M=1 as an example, the linear vertical probe card in the embodiment of the present invention is described.

[0041] See Figure 2 The linear vertical probe card includes an upper guide plate unit 1, a lower guide plate unit 2, and probes 3. The upper guide plate unit 1 comprises, from top to bottom, a first upper guide plate 11 and a second upper guide plate 12. The lower guide plate unit 2 comprises a lower guide plate. The probes 3 have a tip 4 on the outside of the first upper guide plate 11 that contacts the conductive contacts of the circuit board. The probes 3 have a tip 5 on the outside of the lower guide plate unit 2 that contacts the test points on the wafer.

[0042] See Figure 3 The second upper guide plate 12 moves rightward relative to the first upper guide plate 11. The second upper guide plate 12 pushes the probe 3 to deform rightward, causing the probe 3 to pre-bend rightward (outline shown by the dotted line). Through the pre-bending effect, when the needle tip contacts the test point of the wafer, all the probes 3 can be bent and deformed to the right in unison, as shown in the figure. Figure 4 shown.

[0043] See Figure 5 , the shapes of the probe in the free state and the contact state are drawn together to facilitate the description of the position change of the needle tip. It can be seen that the needle tip 5 will swing in the clockwise direction after contacting the wafer. This swing can push away the oxide at the wafer test point and improve the contact performance. Figure 6 The figure shows the needle marks of the linear vertical probe card in the prior art in the working state. Figure 7 The needle mark of the linear vertical probe card in the working state is shown in FIG. Figure 6 and Figure 7 , it can be seen that the needle mark range of the linear vertical probe card in the embodiment of the present invention is wider, which can push away the oxide of the wafer test point and improve the contact performance.

[0044] The swing amplitude of the needle tip can be achieved by controlling the size of the probe and the hole of the lower guide plate, e.g. Figure 8 As shown, the following geometric relationships exist:

[0045] The needle tip swing distance is:

[0046] Therefore, the needle tip swing distance can be precisely designed according to actual needs.

[0047] The linear vertical probe card provided by an embodiment of the present invention includes at least two layers of upper guide plates and at least one layer of lower guide plates. The pre-bending of the probe is achieved by the misalignment between the guide plates. The removal of oxides from the wafer test points is achieved by changing the angle of the needle tip when the probe is bent under force, which can improve the working stability and contact performance of the probe. Furthermore, by designing parameters such as B, H, D, and T, the precise control of the needle tip swing distance can be achieved, so that the probe has optimal contact performance.

[0048] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A linear vertical probe card, characterized in that: include: N layers of upper guide plates, M layers of lower guide plates and multiple probes, N ≥ 2, M ≥ 1; The N-layer upper guide plates and the M-layer lower guide plates are staggered with each other in the vertical direction and staggered in the same horizontal direction from top to bottom; A plurality of probe holes are provided in the upper guide plate and the lower guide plate, and the probes are provided through the probe holes corresponding to each other in the N-layer upper guide plate and the M-layer lower guide plate.

2. The linear vertical probe card according to claim 1, wherein: The needle tail end of the probe is located above the upper guide plate of the top layer, and the needle tip is located below the lower guide plate of the bottom layer.

3. The linear vertical probe card according to claim 2, wherein: In the working state, the upper guide plate of the middle layer is used to push the probe to deform in the first direction, so that the probe is pre-bent along the first direction, and the lower guide plate of the middle layer is used to push the probe to deform in the second direction, so that the probe is pre-bent along the second direction; the first direction is the horizontal offset direction of the lower guide plate relative to the upper guide plate, and the second direction is opposite to the first direction.

4. The linear vertical probe card according to claim 2, wherein: When the linear vertical probe card switches from a non-working state to a working state, the swinging of the needle tip automatically removes oxides from the test point.

5. The linear vertical probe card according to claim 4, wherein: The swing distance of the needle tip is: Among them, L is the swing distance of the needle tip, H is the distance between the bottom of the lower guide plate located at the bottom layer and the wafer to be measured, D is the diameter of the probe hole, T is the width of the probe, and B is the thickness of the lower guide plate located at the bottom layer.

6. The linear vertical probe card according to claim 1, wherein: The range of M is 2≤M≤3, and / or the range of N is 1≤N≤4.

7. The linear vertical probe card according to claim 1, wherein: The distance between two adjacent layers of upper guide plates is 3% to 10% of the total length of the probe, and / or the distance between two adjacent layers of lower guide plates is 3% to 7% of the total length of the probe.

8. The linear vertical probe card according to claim 1, wherein: The distance between the two adjacent upper guide plates and the lower guide plates is 50% to 80% of the total length of the probe.

9. The linear vertical probe card according to claim 1, wherein: The distance between the bottom of the lower guide plate located at the bottom layer and the wafer to be measured is 180 μm-650 μm, and / or the thickness of the lower guide plate located at the bottom layer is 8% to 15% of the total length of the probe.

10. The linear vertical probe card according to claim 1, wherein: The diameter of the probe hole is 1.05T-1.35T, where T is the width of the probe.

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