Wafer probe station z-axis precision lifting transmission mechanism

Abstract

The utility model relates to wafer probe station technical field especially relates to a wafer probe station Z axis precision lifting transmission mechanism, including mounting panel, and install the lifting seat of probe seat, two groups of lifting rods are fixedly installed on the lifting seat, left lifting seat and right lifting seat, the left lifting groove that is connected with two groups of lifting rods sliding is set up on the left lifting seat, the right lifting groove that is connected with two groups of lifting rods sliding is set up on the right lifting seat, the utility model is synchronous to the opposite movement of double lifting seat, and the symmetrical push structure of conical roller is combined with cross distribution lifting groove cooperation, multidimensional offset lateral component, realize Z axis pure vertical lifting, and prevent probe lateral deflection scratch wafer, and simultaneously utilize the self -adaptation compensation transmission wear gap of tension spring constant pre -tightening structure, eliminate vertical shake and height deviation, improve Z axis positioning accuracy and probe contact pressure stability, guarantee wafer test accuracy and yield.

Description

Technical Field

[0001] This utility model relates to the field of wafer probe station technology, and in particular to a precision lifting transmission mechanism for the Z-axis of a wafer probe station. Background Technology

[0002] Wafer probe stations are core precision equipment for semiconductor wafer-level electrical testing. Primarily used before wafer chip packaging, they rely on a precision stage for positioning and a lifting mechanism to control the probes to accurately press down and contact the wafer chip pads. This connects to external testing instruments to complete the electrical performance testing of the bare chip, screen for defective dies, and calculate wafer yield. At the same time, relying on vision alignment and a high-precision transmission structure, they ensure the stability of the probe position and contact pressure, achieving non-destructive and highly repeatable batch testing of wafers. They are key equipment connecting wafer manufacturing and packaging processes.

[0003] Currently, wafer probe stations generally use vertical ball screw drives for the Z-axis. This single-sided traction structure continuously generates lateral thrust during movement, causing the screw nut pair and guide rail to bear a single-sided radial load for a long time. The lifting slide is subjected to overturning moment, resulting in pitching and swaying phenomena. The resulting offset directly introduces Z-axis positioning error, which not only causes probe tilting and puncture, and deterioration of repeatability positioning accuracy, but also the lateral offset will accumulate and intensify with the running time, which can easily cause the probe to laterally move and scratch the wafer, reducing the test yield.

[0004] To address the aforementioned technical shortcomings, a solution is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a precision lifting transmission mechanism for the Z-axis of a wafer probe station to solve the aforementioned technical defects.

[0006] The following technical solution is used to achieve a precision lifting transmission mechanism for a wafer probe station Z-axis, including a mounting plate and a lifting seat on which probe holders are mounted, wherein two sets of lifting rods are fixedly mounted on the lifting seat. The left lifting seat and the right lifting seat are located on both sides of the lifting seat, and the left lifting seat and the right lifting seat move synchronously relative to each other or away from each other. The left lifting seat has a left lifting groove that is slidably connected to the two sets of lifting rods, and the right lifting seat has a right lifting groove that is slidably connected to the two sets of lifting rods. The left lifting groove and the right lifting groove are distributed in a cross pattern, which eliminates the lateral thrust while lifting the lifting rods. The gap compensation component, including a fixed frame and a tension spring, ensures that the lifting seat always has an upward force, eliminating vertical wear gaps.

[0007] Preferably, the fixed frame is fixedly connected to the top of the mounting plate and slidably connected to the lifting seat, and a tension spring is fixedly connected between the top of the lifting seat and the fixed frame.

[0008] Preferably, two sets of guide rods are fixedly connected to both the left and right lifting seats, and the guide rods are fixedly connected to the fixed frame.

[0009] Preferably, the cross-sections of the left lifting seat and the right lifting seat are both U-shaped and are slidably connected to each other. The lifting rod is rotatably connected to an outer roller that is rolledly connected to the left lifting groove and an inner roller that is rolledly connected to the right lifting groove.

[0010] Preferably, both the outer roller and the inner roller have a conical structure, and the diameter of their opposite ends is larger than the diameter of their opposing ends. The cross-sections of the left lifting groove and the right lifting groove are isosceles trapezoidal structures.

[0011] Preferably, a bidirectional screw is rotatably connected to the top of the mounting plate, and the bidirectional screw is threadedly connected to the left lifting seat and the right lifting seat. A servo motor that drives the bidirectional screw to rotate is bolted to the top of the mounting plate.

[0012] Preferably, the lifting seat has an L-shaped structure, and the probe seat is bolted to the bottom of the lifting seat on one side of the mounting plate.

[0013] The beneficial effects of this utility model are as follows: This invention uses a bidirectional screw to drive the left and right lifting seats to move synchronously relative to each other or away from each other. It utilizes the cross-shaped inclined left and right lifting grooves in conjunction with the inner and outer rollers of the conical structure to roll. While pushing the lifting rod upward, the lateral forces in the left, right, front and back directions cancel each other out, outputting only pure vertical lifting power. This effectively eliminates lateral sway and lateral offset during the Z-axis lifting process and avoids the probe seat from laterally moving and scratching the wafer. At the same time, the tension spring continuously applies an upward pre-tightening force to the lifting seat, ensuring that the roller and the top of the lifting groove always maintain a tight fit. This automatically compensates for vertical wear gaps, solving the problems of vertical sway and height deviation caused by transmission wear, improving the lifting and positioning accuracy and contact pressure stability of the probe holder, and ensuring the accuracy consistency and yield of the wafer testing process. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of the lifting seat of this utility model; Figure 3 This is a schematic diagram showing the connection between the lifting seat and the fixed frame of this utility model; Figure 4 This is a schematic diagram showing the disassembly of the left lifting seat and the right lifting seat of this utility model; Figure 5 This is a schematic diagram showing the cooperation between the left lifting seat and the right lifting seat of this utility model.

[0015] Legend: 1. Mounting plate; 11. Lifting seat; 12. Lifting rod; 13. Outer roller; 14. Inner roller; 15. Double-acting screw; 2. Left lifting seat; 21. Left lifting slot; 3. Right lifting seat; 31. Right lifting slot; 4. Fixed frame base; 41. Tension spring. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example 1: Please refer to Figures 1-5 As shown, the problem that traditional traction structures continuously generate lateral thrust during movement, causing the screw nut pair and guide rail to bear unilateral radial load for a long time, and the lifting slide to pitch and sway under the action of overturning moment, can be solved by the following solution; This embodiment of a wafer probe station Z-axis precision lifting transmission mechanism includes a mounting plate 1 and a lifting seat 11 on which probe holders are mounted. Two sets of lifting rods 12 are fixedly mounted on the lifting seat 11. The mounting plate 1 is an existing structure on an existing wafer probe station. The lifting seat 11 is a carrier for mounting the probe holders. It drives the probe to complete the needle insertion and lifting avoidance actions by moving up and down as a whole. The two lifting rods 12 are located in the force transmission intermediate components, receiving the lifting driving force and synchronously driving the lifting seat 11 to move up and down as a whole.

[0018] The left lifting seat 2 and the right lifting seat 3 are located on both sides of the lifting seat 11, and the left lifting seat 2 and the right lifting seat 3 move synchronously relative to each other or away from each other. The left lifting seat 2 has a left lifting groove 21 that is slidably connected to the two sets of lifting rods 12, and the right lifting seat 3 has a right lifting groove 31 that is slidably connected to the two sets of lifting rods 12. The left lifting seat 2 and the right lifting seat 3 move towards each other synchronously, and the left lifting groove 21 and the right lifting groove 31 lift the lifting rods 12 synchronously to achieve the rise. If the two sets of lifting seats move away from each other in opposite directions, the lifting support is released, and the lifting seat 11 falls accordingly. The left lifting groove 21 and the right lifting groove 31 are distributed in a cross pattern, which lifts the lifting rods 12 while eliminating the lateral thrust. The two sets of cross grooves generate horizontal components in opposite directions, which cancel each other out the lateral thrust in the left and right directions, thus avoiding the lifting deviation caused by unilateral load from the root.

[0019] The gap compensation component, including the fixed frame 4 and the tension spring 41, ensures that the lifting seat 11 always has an upward force, thereby eliminating vertical wear gaps.

[0020] The fixed frame 4 is fixedly connected to the top of the mounting plate 1 and slidably connected to the lifting seat 11. A tension spring 41 is fixedly connected between the top of the lifting seat 11 and the fixed frame 4. The fixed frame 4 restricts the lifting seat 11 to slide vertically, limiting the degree of freedom of offset, and at the same time provides a mounting fulcrum for the tension spring 41. The tension spring 41 continuously pulls the lifting seat 11 upward, so that the roller always presses against the upper wall of the lifting groove, preventing vertical swaying and inaccurate height caused by the fit gap.

[0021] Two sets of guide rods are fixedly connected to both the left lifting seat 2 and the right lifting seat 3, and the guide rods are fixedly connected to the fixed frame seat 4. The guide rods limit the left lifting seat 2 and the right lifting seat 3 in a straight line, ensuring that they can only move horizontally and will not deflect or jam, ensuring that the left and right displacements are completely equal, and ensuring that the lateral force cancellation effect is stable and reliable.

[0022] The cross-sections of the left lifting seat 2 and the right lifting seat 3 are both U-shaped, and they are slidably connected to each other. The lifting rod 12 is rotatably connected to an outer roller 13 that is rolledly connected to the left lifting groove 21, and an inner roller 14 that is rolledly connected to the right lifting groove 31. The rolling friction of the outer roller 13 and the inner roller 14 is used to replace the sliding friction, thereby reducing motion resistance, reducing wear, and improving the smoothness of lifting and the service life.

[0023] Both the outer roller 13 and the inner roller 14 have a conical structure, and the diameter of their opposite ends is larger than the diameter of their opposite ends. The cross-sections of the left lifting groove 21 and the right lifting groove 31 are isosceles trapezoidal structures. The conical rollers matched with the trapezoidal lifting groove surfaces can achieve front-to-back positioning and centering. When the rollers roll in the grooves, they generate a pair of opposing front-to-back components that cancel each other out in the front-to-back lateral thrust, preventing the lifting seat 11 from swinging back and forth and further ensuring the lifting centering posture.

[0024] The top of the mounting plate 1 is rotatably connected to a bidirectional screw 15, which is threadedly connected to the left lifting seat 2 and the right lifting seat 3. The top of the mounting plate 1 is bolted with a servo motor that drives the bidirectional screw 15 to rotate. The servo motor serves as the power source for the entire mechanism. The bidirectional screw 15 is equipped with positive and negative threads. The forward and reverse rotation of the bidirectional screw 15 can synchronously drive the two lifting seats to move towards or away from each other. Natural synchronization is achieved by relying on the mechanical structure, without the need for electrical control synchronization debugging, resulting in high displacement consistency.

[0025] The lifting seat 11 has an L-shaped structure. The probe holder is installed on the bottom of the lifting seat 11 on one side of the mounting plate 1 by bolts. The L-shaped layout of the lifting seat 11 reasonably avoids the surrounding structural space, which facilitates the disassembly and debugging of the probe holder. At the same time, it ensures that the probe installation position extends above the corresponding wafer stage, accurately aligning with the wafer to complete the pressure test operation.

[0026] The working process and principle of this utility model are as follows: After the wafer is placed on the wafer carrier, the servo motor drives the bidirectional screw 15 to rotate. The bidirectional screw 15, together with the guide rod, guides the lifting seat and drives the left lifting seat 2 and the right lifting seat 3 to move synchronously relative to each other. While the left lifting groove 21 on the left lifting seat 2 pushes the lifting rod 12 upward, it also generates a tilted upper right thrust. While the right lifting groove 31 on the right lifting seat 3 pushes the lifting rod 12 upward, it also generates a tilted upper left thrust. Through the cooperation of the left lifting seat 2 and the right lifting seat 3, the thrusts on the left and right sides are offset. The outer rollers 13 of the conical structure on both sides of the lifting seat 11 roll in the inclined left lifting groove 21 on both sides of the top and bottom, generating a front-to-back inward thrust on the lifting seat 11. The inner rollers 14 of the conical structure on both sides of the lifting seat 11 roll in the inclined right lifting groove 31 on both sides of the top and bottom, generating a front-to-back outward thrust on the lifting seat 11. Thus, the lifting seat 11 is lifted in the center while the lateral thrust on the front and back sides is eliminated. Through the bidirectional symmetrical lifting seat opposing layout, combined with the cancellation of multi-directional lateral forces, the horizontal component force is effectively eliminated. The Z-axis lifting only outputs pure vertical force and does not generate lateral sway, thus avoiding slight lateral displacement of the probe seat and scratching of the wafer. During the lifting process of the lifting seat 11, the vertical upward pulling force generated by the tension spring 41 causes the roller to continuously and effectively contact the top of the lifting groove to avoid wear gaps between them. This prevents the probe seat from shifting and swaying in the vertical direction. Combined with the weight of the probe seat, after the probe seat descends and contacts the wafer, its height cannot be effectively controlled, resulting in difficulty in controlling the contact force between the two.

[0027] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A precision lifting transmission mechanism for the Z-axis of a wafer probe stage, characterized in that, It includes a mounting plate (1) and a lifting seat (11) on which a probe holder is mounted, and two sets of lifting rods (12) are fixedly mounted on the lifting seat (11). The left lifting seat (2) and the right lifting seat (3) are located on both sides of the lifting seat (11), and the left lifting seat (2) and the right lifting seat (3) move synchronously relative to each other or away from each other. The left lifting seat (2) is provided with a left lifting groove (21) that is slidably connected to the two sets of lifting rods (12), and the right lifting seat (3) is provided with a right lifting groove (31) that is slidably connected to the two sets of lifting rods (12). The left lifting groove (21) and the right lifting groove (31) are distributed in a cross pattern, which lifts the lifting rods (12) while eliminating the lateral thrust. The gap compensation component, including the fixed frame (4) and the tension spring (41), ensures that the lifting seat (11) always has an upward force, thereby eliminating vertical wear gaps.

2. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 1, characterized in that, The fixed frame (4) is fixedly connected to the top of the mounting plate (1) and slidably connected to the lifting seat (11). A tension spring (41) is fixedly connected between the top of the lifting seat (11) and the fixed frame (4).

3. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 1, characterized in that, Two sets of guide rods are fixedly connected to both the left lifting seat (2) and the right lifting seat (3), and the guide rods are fixedly connected to the fixed frame seat (4).

4. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 1, characterized in that, The cross-sections of the left lifting seat (2) and the right lifting seat (3) are both U-shaped and are slidably connected to each other. The lifting rod (12) is rotatably connected to an outer roller (13) that is rolled to the left lifting groove (21) and an inner roller (14) that is rolled to the right lifting groove (31).

5. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 4, characterized in that, The outer roller (13) and the inner roller (14) are both conical structures, and the diameter of their opposite ends is larger than the diameter of their opposite ends. The cross-sections of the left lifting groove (21) and the right lifting groove (31) are isosceles trapezoidal structures.

6. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 1, characterized in that, The top of the mounting plate (1) is rotatably connected to a bidirectional screw (15), and the bidirectional screw (15) is threadedly connected to the left lifting seat (2) and the right lifting seat (3). The top of the mounting plate (1) is bolted with a servo motor that drives the bidirectional screw (15) to rotate.

7. The wafer probe station Z-axis precision lifting transmission mechanism according to claim 1, characterized in that, The lifting seat (11) has an L-shaped structure, and the probe seat is installed on the bottom of the lifting seat (11) on one side of the mounting plate (1) by bolts.

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