Wafer carrier on a photolithography machine

Abstract

This utility model discloses a wafer stage for a lithography machine, including a mask fixing plate slidably connected to an integration box; a wafer support plate slidably connected to the integration box; a wafer support detachably connected to the wafer support plate; a lifting tube slidably connected to the lower part of the integration box; and a lifting suction cup movably connected to the lifting tube. The lower end of the lifting suction cup has a ball head; the upper end of the lifting tube has a hemispherical groove; and the inner wall of the hemispherical groove has negative pressure holes. The lifting suction cup has multiple degrees of freedom, allowing for flexible adjustment of the wafer stage / wafer's orientation. It also has a larger contact surface, providing more stable support and reducing stress concentration, thus better coping with metal fatigue and mechanical vibration. The lifting tube is propelled upwards by the spring force, preventing damage to the wafer and mask.

Description

Technical Field

[0001] This utility model belongs to the field of photolithography technology, and in particular relates to a wafer stage for a photolithography machine. Background Technology

[0002] To achieve nanometer-level imaging resolution, lithography machines need to increase the numerical aperture of the lenses. However, this reduces the depth of focus, which refers to the depth of focus in optical imaging. To ensure a clear and un-out-of-focus lithographic image, the surface undulations of the wafer must fall within this depth of focus. If the wafer stage is not leveled, the wafer placed on it may not be flat, have uneven thickness, or have surface undulations, leading to lithography problems at uneven areas. Even if the wafer stage is leveled, poor fixation can cause the wafer to wobble or shift during long-term operation, making it difficult to precisely control process parameters and ultimately affecting chip quality and performance.

[0003] Chinese patent document CN218547251U discloses an air-floating leveling mechanism, including a base with three cylinders vertically and evenly distributed on it. A floating plate is placed at the end of the cylinder rod. A guide shaft is vertically mounted on one side of each cylinder, and the guide shaft is movably connected to the base. A piston rod for locking the guide shaft is located inside the base, and a tension spring is provided between the guide shaft and the floating plate. When the wafer chuck on the three-point floating support contacts the photomask, the piston rod automatically locks the guide shaft, achieving leveling between the wafer chuck and the photomask.

[0004] The precision requirements for wafers during photolithography are extremely high. The aforementioned patented solution utilizes three cylinders to provide three-point floating support for the floating plate, and a piston rod to lock the guide shaft. This patented solution has a complex structure with numerous moving parts. The inherent gaps and allowances in these moving parts can lead to loosening due to metal fatigue or mechanical vibration during long-term use, disrupting the "leveling state" and further reducing photolithography quality and efficiency. Utility Model Content

[0005] To overcome the technical problem that existing technologies for three-point floating supports involve numerous and complex hardware structures, with inherent gaps and play between motion mechanisms, leading to loosening and wafer positioning errors due to metal fatigue and mechanical vibration during long-term use, this invention aims to provide a wafer stage for a lithography machine. This stage utilizes a hemispherical groove and a ball head. The ball head rotates freely within the hemispherical groove to level the stage. A negative pressure hole within the hemispherical groove holds the ball head in place, locking it in the leveled position. The ball head and hemispherical groove have a simple and compact structure with a larger contact surface, providing more stable support and better resistance to metal fatigue and mechanical vibration, ensuring accurate repeatability.

[0006] To achieve the above objectives, this utility model employs the following technical solution: a wafer stage for a lithography machine, comprising an integrated box disposed in the middle of the lithography machine; a mask fixing plate, which is horizontally slidably connected to the upper end of the integrated box; a wafer placement plate, which is horizontally slidably connected to the integrated box and located below the mask fixing plate; a wafer stage, which is detachably connected to the upper end of the wafer placement plate and is used to place wafers; a lifting tube, which is longitudinally slidably connected to the lower part of the integrated box and located below the wafer placement plate; and a lifting suction cup, which is movably connected to the upper end of the lifting tube; wherein, a ball head is provided at the center of the lower end of the lifting suction cup; a hemispherical groove is provided at the center of the upper end of the lifting tube; the outer wall of the ball head abuts against the inner wall of the hemispherical groove; at least one negative pressure hole is provided on the inner wall of the hemispherical groove; the negative pressure hole is used for negative pressure adsorption of the ball head.

[0007] Furthermore, a track box is longitudinally arranged at the lower part of the integrated box and slidably connected to the lifting pipe; a lead screw nut is longitudinally slidably connected inside the track box below the lifting pipe; a spring is arranged between the lead screw nut and the track box; two clamping cylinders are symmetrically arranged on the integrated box, and the clamping cylinders can selectively clamp the lifting pipe.

[0008] Specifically, the lifting suction cup has two V-shaped openings on its two opposite sidewalls; the openings of the V-shaped openings face upwards; and the track box has four limiting rods located in the corresponding V-shaped openings.

[0009] The spring force pushes the lifting suction cup upward, so that the limiting rod is located at the inner bottom of the corresponding V-shaped opening groove; the spring prevents the lifting force of the lifting suction cup from being too large and causing damage to the wafer and mask.

[0010] Specifically, a lead screw motor is provided at the lower end of the track box; a lead screw is provided on the output shaft of the lead screw motor and threadedly connected to the lead screw nut; the lead screw passes through the lead screw nut, the spring, and the lifting tube in sequence from bottom to top.

[0011] Specifically, the upper ends of the two opposite side walls of the lifting tube are respectively provided with V-shaped slots in the longitudinal direction; the moving end of the clamping cylinder is provided with a V-shaped plug that is slidably connected to the V-shaped slot; the V-shaped slot includes two sections arranged vertically, wherein the width of the V-shaped slot in the upper section is smaller than the width of the V-shaped slot in the lower section.

[0012] Furthermore, a handle is provided on the upper end of the platen support away from the lifting suction cup; a through hole is longitudinally provided on the upper end of the platen support near the lifting suction cup; two conical columns are provided on the upper end of the platen support around the through hole, and the two conical columns are evenly distributed along the circumference of the through hole; the lower end of the platen support is provided with two conical holes, each facing the two conical columns.

[0013] Furthermore, a linear module is horizontally arranged on the upper part of the lithography machine directly above the integration box; an exposure section is arranged on the moving end of the linear module; and multiple UV-LED lamp groups are arranged at the lower end of the exposure section.

[0014] Furthermore, the lower part of the integrated box is provided with a multi-directional fine-tuning part; the track box is disposed on the moving end of the multi-directional fine-tuning part; the upper end of the track box is provided with two lateral extension arms; the plate support is slidably connected to the upper ends of the two lateral extension arms.

[0015] Furthermore, a U-shaped frame is provided at the upper end of the integration box; the mask plate fixing plate is slidably connected in the opening of the U-shaped frame; locking cylinders for locking the mask plate fixing plate are provided on both sides of the opening of the U-shaped frame.

[0016] Furthermore, a disc is provided at the center of the upper end of the lifting suction cup; multiple evenly distributed adsorption grooves are provided on the disc; and a vacuum extraction hole communicating with the adsorption grooves is provided on the side wall of the lifting suction cup.

[0017] Compared to existing technologies, the advantages of this invention are as follows: This invention incorporates a hemispherical groove and a ball head between the lifting suction cup and the lifting tube. The lifting suction cup possesses multiple degrees of freedom, allowing for flexible adjustment of the wafer stage / plate's orientation. The hemispherical groove and ball head structure is simple, compact, and streamlined, facilitating assembly and manufacturing. Simultaneously, the larger contact surface ensures more stable support for the wafer from the lifting suction cup. The larger contact surface also reduces stress concentration, better mitigating metal fatigue and mechanical vibration. The lifting tube is propelled upwards by the spring force, preventing excessive forces between the wafer and the mask, thus protecting both from damage. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the integrated box of this utility model;

[0020] Figure 3 This is a structural schematic diagram of the U-shaped frame and the support platform of this utility model;

[0021] Figure 4This is a structural schematic diagram of the plate-holding platform and track box of this utility model;

[0022] Figure 5 This is a schematic diagram of the lifting tube and lifting suction cup of this utility model;

[0023] Figure 6 This is a schematic diagram of the bottom structure of the support platform of this utility model;

[0024] Figure 7 This is a schematic diagram of the bottom structure of the lifting suction cup of this utility model;

[0025] Figure 8 This is a cross-sectional structural diagram of the track box of this utility model.

[0026] In the diagram: 11. Lithography machine; 12. Integration box; 21. Linear module; 22. Exposure section; 31. Track box; 311. Limiting rod; 312. Lateral extension arm; 32. Lifting tube; 321. Hemispherical groove; 322. V-slot; 323. Negative pressure hole; 33. Lead screw nut; 34. Spring; 35. Lifting suction cup; 351. V-shaped opening groove; 352. Ball head; 353. Disc; 354. Adsorption groove; 36. Lead screw motor; 361. Lead screw; 37. Clamping cylinder; 371. V-plug; 38. Multi-directional fine adjustment section; 41. Wafer placement plate; 411. Conical column; 412. Through hole; 413. Handle; 42. Wafer placement plate; 421. Conical hole; 51. U-shaped frame; 52. Mask fixing plate; 53. Locking cylinder. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0028] In the description of this utility model, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In this description of the utility model, "a number" means two or more, unless otherwise explicitly specified.

[0030] In this utility model, unless otherwise explicitly specified and limited, terms such as "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or 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 according to the specific circumstances.

[0031] See Figures 1-8 A wafer stage for a lithography machine includes an integration box 12 disposed in the middle of the lithography machine 11, a linear module 21 horizontally disposed on the upper part of the lithography machine 11 and located directly above the integration box 12, and an exposure section 22 disposed on the moving part of the linear module 21; the lower end of the exposure section 22 is provided with a plurality of UV-LED lamp groups.

[0032] The upper end of the integrated box 12 is provided with a U-shaped frame 51; a mask fixing plate 52 is slidably connected in the opening of the U-shaped frame 51; a plurality of locking cylinders 53 for locking the mask fixing plate 52 are symmetrically arranged in the opening of the U-shaped frame 51.

[0033] The upper part of the integrated box 12 is slidably connected to a wafer support plate 41 below the mask fixing plate 52; the upper end of the wafer support plate 41 is detachably connected to a wafer support platform 42 for supporting wafers; a handle 413 is provided on the upper end of the wafer support plate 41 away from the integrated box 12; a through hole 412 is longitudinally provided on the upper end of the wafer support plate 41 near the integrated box 12; two conical pillars 411 are provided on the upper end of the wafer support plate 41 around the through hole 412, and the two conical pillars 411 are evenly distributed along the circumference of the through hole 412; the lower end of the wafer support platform 42 is provided with two conical holes 421 that are respectively opposite to the two conical pillars 411.

[0034] The integrated box 12 is located directly below the U-shaped frame 51 and has a track box 31. A lifting tube 32 is slidably connected longitudinally inside the track box 31. A lead screw nut 33 is slidably connected longitudinally inside the track box 31. A spring 34 is provided between the lifting tube 32 and the lead screw nut 33. A lead screw motor 36 is provided at the lower end of the track box 31. A lead screw 361 is provided on the output shaft of the lead screw motor 36 and is threadedly connected to the lead screw nut 33. The lead screw 361 passes through the lead screw nut 33, the spring 34, and the lifting tube 32 from bottom to top.

[0035] The upper end of the lifting tube 32 is movably connected to a lifting suction cup 35; a ball head 352 is provided at the center of the lower end of the lifting suction cup 35; a hemispherical groove 321 is provided at the center of the upper end of the lifting tube 32; the outer wall of the ball head 352 abuts against the inner wall of the hemispherical groove 321; at least one negative pressure hole 323 is provided on the inner wall of the hemispherical groove 321; the negative pressure hole 323 is used for negative pressure adsorption of the ball head 352; a disc 353 is provided at the center of the upper end of the lifting suction cup 35; a plurality of evenly distributed adsorption grooves 354 are provided on the disc 353; a vacuum extraction hole communicating with the adsorption grooves 354 is provided on the side wall of the lifting suction cup 35.

[0036] The lower part of the integrated box 12 is provided with a multi-directional fine-tuning part 38; the track box 31 is disposed on the moving end of the multi-directional fine-tuning part 38; the multi-directional fine-tuning part 38 is capable of horizontal translation in the X and Y directions and horizontal rotation of the track box 31; the upper end of the track box 31 is provided with two lateral extension arms 312; the plate support plate 41 is slidably connected to the upper end of the two lateral extension arms 312.

[0037] The lifting suction cup 35 has two V-shaped opening grooves 351 on its two opposite side walls; the openings of the V-shaped opening grooves 351 face upwards; the track box 31 has four limiting rods 311 located in the corresponding V-shaped opening grooves 351.

[0038] The upper ends of the two opposite side walls of the lifting tube 32 are respectively provided with V-shaped slots 322 longitudinally; the upper end of the track box 31 is symmetrically provided with two clamping cylinders 37; the moving end of the clamping cylinder 37 is provided with a V-shaped plug 371 that is slidably connected to the V-shaped slot 322; the V-shaped slot 322 includes two segments arranged vertically, wherein the width of the upper segment of the V-shaped slot 322 is smaller than the width of the lower segment of the V-shaped slot 322.

[0039] Working process: Open the locking cylinder 53 to pull the mask fixing plate 52 out of the U-shaped frame 51, place the mask under the mask fixing plate 52, and use negative pressure to adsorb the mask; then insert the mask fixing plate 52 back into its original position, close the locking cylinder 53, and clamp the mask fixing plate 52 in place. Pull the handle 413 to pull out the wafer stage placement plate 41, place the wafer on the wafer stage 42, and push the wafer stage placement plate 41 back to its original position.

[0040] The lead screw motor 36 rotates in the forward direction, driving the lead screw nut 33 to move upward. The lead screw nut 33, through the spring 34, pushes the lifting tube 32 upward, which in turn pushes the lifting suction cup 35 upward. The lifting suction cup 35 lifts the wafer stage 42 and together pushes the wafer upward until it abuts against the lower end of the mask, or against multiple spacers (each spacer has the same thickness) at the lower end of the mask. Under the reaction force, the ball head 352 rotates within the hemispherical groove 321, and the wafer and mask are automatically leveled. Subsequently, the negative pressure hole 323 draws air to adsorb the ball head 352, thus locking the posture of the lifting suction cup 35 and the lifting tube 32.

[0041] Then, the exposure unit 22 performs photolithography by moving horizontally through indirect and close exposure methods. During the operation, the clamping cylinder 37 extends its V-shaped plug 371 to press against the V-shaped slot 322 to position the lifting tube 32, further ensuring the positional accuracy of the lifting suction cup 35.

[0042] The above description is only a specific embodiment of the present utility model, but the technical features of the present utility model are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present utility model are covered by the patent scope of the present utility model.

Claims

1. A wafer stage for a lithography machine, characterized by: Including An integration box is located in the middle of the lithography machine; A mask fixing plate is horizontally slidably connected to the upper end of the integration box; A substrate placement plate is horizontally slidably connected to the integrated box and located below the mask fixing plate; A wafer support stage, which is detachably connected to the upper end of the wafer support stage placement plate, is used to place wafers. A lifting pipe is slidably connected longitudinally to the lower part of the integrated box, and the lifting pipe is located below the platen placement plate; A lifting suction cup, which is movably connected to the upper end of the lifting tube; The lifting suction cup has a ball head at its lower center; the lifting tube has a hemispherical groove at its upper center; the outer wall of the ball head abuts against the inner wall of the hemispherical groove; the inner wall of the hemispherical groove has at least one negative pressure hole; the negative pressure hole is used to adsorb the ball head under negative pressure.

2. The wafer stage of claim 1, wherein: The lower part of the integrated box is longitudinally provided with a track box that is slidably connected to the lifting pipe; a lead screw nut is longitudinally slidably connected inside the track box below the lifting pipe; a spring is provided between the lead screw nut and the track box; two clamping cylinders are symmetrically arranged on the integrated box, and the clamping cylinders can selectively clamp the lifting pipe.

3. The wafer stage of claim 2, wherein: The lifting suction cup has two V-shaped openings on its two opposite sidewalls; the openings of the V-shaped openings face upwards; and the track box has four limiting rods located in the corresponding V-shaped openings.

4. The wafer stage of claim 2, wherein: A lead screw motor is installed at the lower end of the track box; a lead screw is installed on the output shaft of the lead screw motor and threadedly connected to the lead screw nut; the lead screw passes through the lead screw nut, the spring, and the lifting tube from bottom to top.

5. The wafer stage as described in claim 2, characterized in that: The upper ends of the two opposite side walls of the lifting tube are respectively provided with V-shaped slots in the longitudinal direction; the moving end of the clamping cylinder is provided with a V-shaped plug that is slidably connected to the V-shaped slot; the V-shaped slot includes two sections arranged vertically, wherein the width of the V-shaped slot in the upper section is smaller than the width of the V-shaped slot in the lower section.

6. The wafer table of any of claims 1-5, wherein: A handle is provided on the upper end of the platen support away from the lifting suction cup; a through hole is longitudinally provided on the upper end of the platen support near the lifting suction cup; two conical columns are provided on the upper end of the platen support around the through hole, and the two conical columns are evenly distributed along the circumference of the through hole; two conical holes are provided at the lower end of the platen support, each facing the two conical columns.

7. The wafer table of any of claims 1-5, wherein: A linear module is horizontally arranged on the upper part of the lithography machine, directly above the integration box; an exposure section is arranged on the moving end of the linear module; and multiple UV-LED lamp groups are arranged at the lower end of the exposure section.

8. The wafer table of any of claims 2-5, wherein: The lower part of the integrated box is provided with a multi-directional fine-tuning part; the track box is provided on the moving end of the multi-directional fine-tuning part; the upper end of the track box is provided with two lateral extension arms; the plate support is slidably connected to the upper end of the two lateral extension arms.

9. The wafer table of any of claims 1-5, wherein: The upper end of the integrated box is provided with a U-shaped frame; the mask plate fixing plate is slidably connected in the opening of the U-shaped frame; locking cylinders for locking the mask plate fixing plate are provided on both sides of the opening of the U-shaped frame.

10. The wafer table of any of claims 1-5, wherein: A disc is provided at the center of the upper end of the lifting suction cup; multiple evenly distributed adsorption grooves are provided on the disc; and a vacuum extraction hole communicating with the adsorption grooves is provided on the side wall of the lifting suction cup.

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