Wafer coplanar testing device

Abstract

The utility model discloses a wafer coplanar testing device, including base, is equipped with load positioning mechanism, removes material rotary mechanism and coplanar testing mechanism on the base, and load positioning mechanism is by lift cylinder and the bearing platform of two with vacuum negative pressure hole, realizes the positioning of wafer front surface downward, and removes material rotary mechanism contains material removal module and the material grabbing rotary module, and completes the accurate transfer and rotation alignment of wafer, and coplanar testing mechanism is through the probe of two with double mercury electrode groove, vacuum adsorption groove and supplies mercury recovery from below, and the drive of cooperation cylinder realizes testing. The device can safely test PN junction / insulation substrate wafer lightly doped epitaxial layer carrier concentration, and positioning is accurate, and testing is efficient, is applicable to batch wafer testing.

Description

Technical Field

[0001] This utility model relates to wafer testing technology, and in particular to a wafer coplanar testing device, which is especially suitable for carrier concentration testing scenarios of wafers with PN junction structure or insulating substrate. Background Technology

[0002] In semiconductor manufacturing processes, the carrier concentration of lightly doped epitaxial layers is a key parameter for evaluating wafer performance. Conventional testing methods mainly adopt a "top-bottom structure": that is, a test circuit is formed by contacting the front side of the wafer with a small mercury electrode and the back side of the wafer with the stage. After applying a reverse bias voltage to the front mercury electrode, the capacitance of the depletion region on the wafer surface is measured, and then the carrier concentration is calculated.

[0003] However, this "top-bottom structure" testing scheme has significant limitations: when the wafer uses a PN junction structure or an insulating substrate, an effective conductive loop cannot be formed on the back side of the wafer, causing the test to fail. To solve this problem, the industry has gradually adopted a "coplanar structure" testing scheme—using two mercury electrodes on the front side of the wafer (the smaller electrode applies a reverse bias voltage to form a depletion region, and the larger electrode forms a loop) to achieve testing. However, existing coplanar structure testing devices still have the following technical defects: High mercury safety risks: In existing coplanar testing, wafers are mostly placed face up, and mercury electrodes supply mercury from above. Large-sized mercury electrodes are prone to mercury leakage, resulting in poor safety. Insufficient positioning and rotation accuracy: After the wafer is loaded, it is difficult to accurately adjust it to the test coordinate point, and the rotation angle of the stage is limited, making it impossible to achieve continuous positioning of multiple test points, resulting in low test efficiency; Therefore, there is an urgent need to design a wafer coplanar testing device that balances safety, accuracy, and efficiency to address the shortcomings of the existing technologies. Utility Model Content

[0004] To address the problems of high mercury safety risks, insufficient positioning and rotation accuracy, and low testing efficiency in existing wafer coplanar testing devices, this invention provides a wafer coplanar testing device aimed at achieving safe, accurate, and efficient testing of PN junction / insulating substrate wafers.

[0005] To achieve the above and other related objectives, the technical solution provided by this utility model is: a wafer coplanar testing device, including a base, on which a material positioning mechanism, a material transfer and rotation mechanism, and a coplanar testing mechanism are provided. The material positioning mechanism is used to position the wafer, keeping it in a testing posture with the lightly doped epitaxial layer facing down. The material transfer and rotation mechanism is used to pick up the wafer from the material positioning mechanism and send it to the coplanar testing mechanism, and to control the wafer to rotate in a testing posture to a position where the testing coordinate point corresponds to the testing end of the coplanar testing mechanism. The coplanar testing mechanism is used to test the carrier concentration of the lightly doped epitaxial layer of the wafer.

[0006] The preferred technical solution is as follows: the material transfer and rotation mechanism consists of a material transfer module and a material gripping and rotation module. The material transfer module is disposed on the base and is used to drive the material gripping and rotation module to move between the loading / unloading station and the inspection station. The material gripping and rotation module is used to grip or release the wafer and control the wafer rotation.

[0007] The preferred technical solution is as follows: the material transfer module consists of a motor, a lead screw, a lead screw nut, a guide rail assembly, and a slide block. The motor is fixed on the base and drives the lead screw to rotate. The guide rail assembly is fixed on the base and arranged parallel to the lead screw. The slide block slides on the guide rail assembly. The lead screw nut is screwed onto the lead screw and fixedly connected to the slide block. The motor drives the lead screw to rotate and causes the slide block to slide back and forth on the guide rail assembly, realizing the switching of the slide block between the loading / unloading station and the inspection station.

[0008] The preferred technical solution is as follows: the material gripping and rotating module consists of a second motor, a worm gear, a worm wheel, a rotating shaft, a bracket, a bearing seat, and a suction cup. The bracket is fixed on the slide, the bearing seat is fixed on the top of the bracket, the rotating shaft is vertically arranged and its top end is rotatably connected to the bearing seat through a bearing, the suction cup is coaxially fixed on the bottom end of the rotating shaft, the bottom of the suction cup is provided with multiple sets of vacuum negative pressure holes, all of which are connected to an external vacuum negative pressure system, the worm wheel is coaxially fixed on the outer periphery of the rotating shaft, the second motor is fixed on the slide and used to drive the worm gear to rotate, and the worm gear is meshed with the worm wheel.

[0009] The preferred technical solution is as follows: the material positioning mechanism is located at the loading and unloading station. The material positioning mechanism consists of a lifting cylinder and a support platform. The lifting cylinder is fixed on the base and is used to drive the support platform to lift. The top of the support platform is provided with a stepped groove. The stepped surface of the stepped groove is used to support the edge of the wafer. Multiple sets of vacuum negative pressure holes are provided on the stepped surface. All sets of vacuum negative pressure holes are connected to an external vacuum negative pressure system.

[0010] The preferred technical solution is as follows: the coplanar testing mechanism is located at the testing station. The coplanar testing mechanism consists of a substrate, a cylinder mounting plate, a cylinder, a connecting plate, connecting rod one, connecting rod two, a connecting flange, and a probe. The substrate is fixed on the base. The substrate has multiple sets of vacuum negative pressure holes three, all of which are connected to an external vacuum negative pressure system. The substrate also has through holes. The probe is configured to move up and down in the through holes. The cylinder mounting plate is located on the bottom side of the substrate through multiple connecting rods one. The cylinder is fixed on the cylinder mounting plate. The telescopic end of the cylinder is vertically upward and connected to the connecting plate. The connecting plate is connected to the connecting flange through multiple connecting rods two. The probe is installed in the connecting flange. The cylinder is configured to drive the probe to move up and down to approach or move away from the wafer.

[0011] The preferred technical solution is as follows: the top of the probe is provided with a mercury electrode slot one, a mercury electrode slot two, and a vacuum adsorption slot. The vacuum adsorption slot surrounds the outer periphery of the mercury electrode slot one and the mercury electrode slot two, and separates the mercury electrode slot one and the mercury electrode slot two. The vacuum adsorption slot is connected to an external vacuum negative pressure system, and both the mercury electrode slot one and the mercury electrode slot two are connected to an external mercury liquid supply and recovery system. The mercury liquid in the mercury electrode slot one and the mercury electrode slot two also serves as electrodes connected to an external carrier concentration testing system.

[0012] Due to the application of the above technical solution, the beneficial effects of this utility model are as follows: Solving the testing challenges of wafers with special structures: Through the dual mercury electrode groove design of the coplanar testing mechanism, it can effectively test the carrier concentration of lightly doped epitaxial layers of PN junction structures or insulating substrate wafers without relying on the back side of the wafer for conductivity, breaking through the applicability limitations of traditional top and bottom structures; Enhancing the safety of mercury use: The material positioning mechanism and the material gripping and rotating module work together to achieve the "face down" testing posture of the wafer. The coplanar testing mechanism supplies and recovers mercury from below the wafer. Combined with the sealing effect of the vacuum adsorption tank, the risk of mercury leakage is completely avoided. Achieving high-precision positioning and continuous testing: The material transfer module achieves precise linear transfer of wafers through screw-guide rail transmission, while the material gripping and rotating module aligns wafer test coordinate points through worm gear-worm wheel transmission (large transmission ratio and high precision), supporting continuous testing of multiple test points and improving testing efficiency; Ensuring test stability: The suction cup, stage, and substrate are all positioned by vacuum negative pressure adsorption, combined with the probe's adaptive bonding design (vacuum adsorption groove assisted positioning), ensuring stable contact between the wafer and the probe during testing and reducing test data errors. Attached Figure Description

[0013] Figure 1This is a schematic diagram of the overall structure of the testing device involved in this utility model.

[0014] Figure 2 This is a schematic diagram of the material loading and positioning mechanism involved in this utility model.

[0015] Figure 3 This is a schematic diagram of the material transfer and rotation mechanism involved in this utility model.

[0016] Figure 4 This is a schematic diagram of the coplanar testing mechanism involved in this utility model.

[0017] Figure 5 This is a schematic diagram of the probe structure involved in this utility model. Detailed Implementation

[0018] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0019] Please see Figures 1-5 It should be noted that in the description of this utility model, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "horizontal," "vertical," and "suspended," etc., do not indicate that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0020] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Example

[0021] like Figures 1 to 5As shown, according to an overall technical concept of this utility model, a wafer coplanar testing device is provided, including a base 1. The base 1 is provided with a material positioning mechanism 2, a material transfer and rotation mechanism 3, and a coplanar testing mechanism 4. The material positioning mechanism 2 is used to position the wafer so that the wafer is in a test posture with the lightly doped epitaxial layer facing down. The material transfer and rotation mechanism 3 is used to pick up the wafer from the material positioning mechanism 2 and send the wafer to the coplanar testing mechanism 4, and to control the wafer to rotate in a test posture to a position where the test coordinate point corresponds to the test end of the coplanar testing mechanism 4. The coplanar testing mechanism 4 is used to test the carrier concentration of the lightly doped epitaxial layer of the wafer.

[0022] like Figures 1 to 5 As shown, in an exemplary embodiment of this utility model, the material transfer and rotation mechanism 3 is composed of a material transfer module 31 and a material gripping and rotation module 32. The material transfer module 31 is disposed on the base 1 and is used to drive the material gripping and rotation module 32 to move between the loading / unloading station and the inspection station. The material gripping and rotation module 32 is used to grip or release the wafer and control the wafer rotation.

[0023] like Figures 1 to 5 As shown, in an exemplary embodiment of this utility model, the material transfer module 31 consists of a motor 311, a lead screw 312, a lead screw nut 313, a guide rail assembly 314, and a slide block 315. The motor 311 is fixed on the base 1 and is used to drive the lead screw 312 to rotate. The guide rail assembly 314 is fixed on the base 1 and is arranged parallel to the lead screw 311. The slide block 315 slides on the guide rail assembly 314. The lead screw nut 313 is screwed on the lead screw 311 and is fixedly connected to the slide block 315. The motor 311 is used to drive the lead screw 312 to rotate and drive the slide block 315 to slide back and forth on the guide rail assembly 314, realizing the switching of the slide block 315 between the loading / unloading station and the inspection station.

[0024] like Figures 1 to 5 As shown, in an exemplary embodiment of this utility model, the material gripping and rotating module consists of a second motor 321, a worm (not shown), a worm wheel (not shown), a rotating shaft 322, a bracket 323, a bearing seat 324, and a suction cup 325. The bracket 323 is fixed on the slide 315, the bearing seat 324 is fixed on the top of the bracket 323, the rotating shaft 322 is vertically arranged and its top end is rotatably connected to the bearing seat 323 through a bearing, the suction cup 325 is coaxially fixed on the bottom end of the rotating shaft 322, and the bottom of the suction cup 325 is provided with multiple sets of vacuum negative pressure holes, all of which are connected to an external vacuum negative pressure system. The worm wheel is coaxially fixed on the outer periphery of the rotating shaft 322, and the second motor 321 is fixed on the slide 315 and is used to drive the worm to rotate. The worm and the worm wheel are meshed.

[0025] like Figures 1 to 5As shown, in an exemplary embodiment of this utility model, the material positioning mechanism 2 is located at the loading and unloading station. The material positioning mechanism 2 consists of a lifting cylinder 21 and a support platform 22. The lifting cylinder 21 is fixed on the base 1 and is used to drive the support platform 22 to lift. The top of the support platform 22 is provided with a stepped groove 221. The stepped surface of the stepped groove 221 is used to support the edge of the wafer. Multiple sets of vacuum negative pressure holes are provided on the stepped surface. All sets of vacuum negative pressure holes are connected to an external vacuum negative pressure system.

[0026] like Figures 1 to 5 As shown, in an exemplary embodiment of this utility model, the coplanar testing mechanism 4 is located at the testing station. The coplanar testing mechanism 4 consists of a substrate 41, a cylinder mounting plate 42, a cylinder 43, a connecting plate 44, a first connecting rod 45, a second connecting rod 46, a connecting flange 47, and a probe 48. The substrate 41 is fixed on the base 1. The substrate 41 is provided with multiple sets of vacuum negative pressure holes 3, all of which are connected to an external vacuum negative pressure system. The substrate 41 is also provided with a through hole 411. The probe 48 is configured to move up and down in the through hole 411. The cylinder mounting plate 42 is located on the bottom side of the substrate 41 through multiple first connecting rods 45. The cylinder 43 is fixed on the cylinder mounting plate 42. The telescopic end of the cylinder 43 is vertically upward and connected to the connecting plate 44. The connecting plate 44 is connected to the connecting flange 47 through multiple second connecting rods 46. The probe 48 is installed in the connecting flange 47. The cylinder 43 is configured to drive the probe 48 to move up and down to approach or move away from the wafer.

[0027] like Figures 1 to 5 As shown, in an exemplary embodiment of this utility model, the top of the probe 48 is provided with a mercury electrode first 481, a mercury electrode second 482, and a vacuum adsorption tank 483. The vacuum adsorption tank 483 surrounds the outer periphery of the mercury electrode first 481 and the mercury electrode second 482, and separates the mercury electrode first 481 and the mercury electrode second 482. The vacuum adsorption tank 483 is connected to an external vacuum negative pressure system, and both the mercury electrode first 481 and the mercury electrode second 482 are connected to an external mercury liquid supply and recovery system. The mercury liquid in the mercury electrode first 481 and the mercury electrode second 482 also serves as electrodes connected to an external carrier concentration testing system.

[0028] In actual use, the vacuum adsorption tank 483 is connected to an external negative pressure system, and the mercury electrode tank 481 and mercury electrode tank 482 are connected to an external mercury supply system. By applying negative pressure to the vacuum adsorption tank 483, due to the height difference between the surface of the vacuum adsorption tank 483 and the surfaces of the mercury electrode tanks 481 and 482, the negative pressure enters the mercury electrode tanks 481 and 482, drawing the mercury into them. It should be noted that the mercury electrode tanks 481 and 482 are also equipped with metal conductive wires, which are used to connect the mercury to the external electrical measurement system for electrical measurement.

[0029] Therefore, this utility model has the following advantages: Solving the testing challenges of wafers with special structures: Through the dual mercury electrode groove design of the coplanar testing mechanism, it can effectively test the carrier concentration of lightly doped epitaxial layers of PN junction structures or insulating substrate wafers without relying on the back side of the wafer for conductivity, breaking through the applicability limitations of traditional top and bottom structures; Enhancing the safety of mercury use: The material positioning mechanism and the material gripping and rotating module work together to achieve the "face down" testing posture of the wafer. The coplanar testing mechanism supplies and recovers mercury from below the wafer. Combined with the sealing effect of the vacuum adsorption tank, the risk of mercury leakage is completely avoided. Achieving high-precision positioning and continuous testing: The material transfer module achieves precise linear transfer of wafers through screw-guide rail transmission, while the material gripping and rotating module aligns wafer test coordinate points through worm gear-worm wheel transmission (large transmission ratio and high precision), supporting continuous testing of multiple test points and improving testing efficiency; Ensuring test stability: The suction cup, stage, and substrate are all positioned by vacuum negative pressure adsorption, combined with the probe's adaptive bonding design (vacuum adsorption groove assisted positioning), ensuring stable contact between the wafer and the probe during testing and reducing test data errors.

[0030] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A wafer coplanar testing apparatus, comprising a base, wherein the base is provided with a material positioning mechanism, a material transfer and rotation mechanism, and a coplanar testing mechanism, characterized in that: The material positioning mechanism is used to position the wafer so that it maintains a test posture with the lightly doped epitaxial layer facing down; the material transfer and rotation mechanism is used to pick up the wafer from the material positioning mechanism and send the wafer to the coplanar test mechanism, and to control the wafer to rotate in a test posture to a position where the test coordinate point corresponds to the test end of the coplanar test mechanism; the coplanar test mechanism is used to test the carrier concentration of the lightly doped epitaxial layer of the wafer.

2. The wafer coplanar testing device according to claim 1, characterized in that: The material transfer and rotation mechanism consists of a material transfer module and a material gripping and rotation module. The material transfer module is mounted on the base and is used to drive the material gripping and rotation module to move between the loading / unloading station and the inspection station. The material gripping and rotation module is used to grip or release the wafer and control the wafer rotation.

3. The wafer coplanar testing device according to claim 2, characterized in that: The material transfer module consists of a motor, a lead screw, a lead screw nut, a guide rail assembly, and a slide block. The motor is fixed to the base and drives the lead screw to rotate. The guide rail assembly is fixed to the base and arranged parallel to the lead screw. The slide block slides on the guide rail assembly. The lead screw nut is screwed onto the lead screw and fixedly connected to the slide block. The motor drives the lead screw to rotate and causes the slide block to slide back and forth on the guide rail assembly, realizing the switching of the slide block between the loading / unloading station and the inspection station.

4. The wafer coplanar testing device according to claim 3, characterized in that: The material gripping and rotating module consists of a second motor, a worm gear, a worm wheel, a rotating shaft, a bracket, a bearing seat, and a suction cup. The bracket is fixed on the slide, and the bearing seat is fixed on the top of the bracket. The rotating shaft is vertically arranged, and its top end is rotatably connected to the bearing seat via a bearing. The suction cup is coaxially fixed on the bottom end of the rotating shaft. The bottom of the suction cup is provided with multiple sets of vacuum negative pressure holes, all of which are connected to an external vacuum negative pressure system. The worm wheel is coaxially fixed on the outer periphery of the rotating shaft. The second motor is fixed on the slide and is used to drive the worm gear to rotate. The worm gear is meshed with the worm wheel.

5. The wafer coplanar testing device according to claim 2, characterized in that: The material positioning mechanism is located at the loading and unloading station. The material positioning mechanism consists of a lifting cylinder and a support platform. The lifting cylinder is fixed on the base and is used to drive the support platform to lift. The top of the support platform is provided with a stepped groove. The stepped surface of the stepped groove is used to support the edge of the wafer. Multiple sets of vacuum negative pressure holes are provided on the stepped surface. All sets of vacuum negative pressure holes are connected to an external vacuum negative pressure system.

6. The wafer coplanar testing device according to claim 2, characterized in that: The coplanar testing mechanism is located at the testing station. The coplanar testing mechanism comprises a substrate, a cylinder mounting plate, a cylinder, a connecting plate, connecting rod one, connecting rod two, a connecting flange, and a probe. The substrate is fixed to the base. The substrate has multiple sets of vacuum negative pressure holes three, all of which are connected to an external vacuum negative pressure system. The substrate also has through holes. The probe is configured to move vertically within these through holes. The cylinder mounting plate is located on the bottom side of the substrate via multiple connecting rods one. The cylinder is fixed to the cylinder mounting plate. The telescopic end of the cylinder is vertically upward and connected to the connecting plate. The connecting plate is connected to the connecting flange via multiple connecting rods two. The probe is installed in the connecting flange. The cylinder is configured to drive the probe to move up and down to approach or move away from the wafer.

7. The wafer coplanar testing device according to claim 6, characterized in that: The probe has a mercury electrode slot one, a mercury electrode slot two, and a vacuum adsorption tank at its top. The vacuum adsorption tank surrounds the mercury electrode slot one and the mercury electrode slot two, separating them. The vacuum adsorption tank is connected to an external vacuum negative pressure system, and both the mercury electrode slot one and the mercury electrode slot two are connected to an external mercury liquid supply and recovery system. The mercury liquid in the mercury electrode slot one and the mercury electrode slot two also serves as electrodes connected to an external carrier concentration testing system.

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