A constant gap exposure stage system for proximity lithography machines

Abstract

This invention discloses a constant gap exposure stage system for a proximity lithography machine, belonging to the field of semiconductor equipment technology. The system includes a mask frame, a mask plate, three gap plates, three gear and rack mechanisms, three linear cylinders, a sample wafer, a wafer support stage, a ball joint, two locking cylinders, a lifting drive mechanism, and a main controller. The mask plate is fixed to the bottom of the mask frame, and a vacuum groove on the lower surface of the mask frame holds the mask plate in place. The three gap plates are respectively mounted on the mask frame via gear and rack mechanisms and driven by linear cylinders. The sample wafer is placed on the wafer support stage and held in place by the vacuum groove, with its upper surface facing the lower surface of the mask plate. The wafer support stage is fixed to the ball joint, which is held in place by a spherical vacuum groove on the top of the lifting drive mechanism. The two locking cylinders and the main controller are all fixed to the lifting drive mechanism. This invention can automatically align the sample wafer with the mask plate and precisely maintain the exposure gap.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor equipment technology, and specifically relates to a constant gap exposure stage system for a proximity lithography machine. Background Technology

[0002] In contact lithography equipment, the photomask is in direct contact with the silicon wafer (i.e., the sample). Friction between them can cause scratches and particulate contamination on the photomask surface, shortening its lifespan, reducing sample yield, and significantly increasing application costs. Contact can damage the photoresist layer or the photomask itself, and dust blocking light can cause resolution issues. In actual production, photomasks need to be replaced or cleaned every 15-25 exposures. Furthermore, photomasks are susceptible to photoresist contamination, which accelerates wear, leading to decreased pattern sharpness, poor resolution, and even pattern size variations and alignment deviations.

[0003] Due to direct contact, air and particulate matter can also create bubbles between the silicon wafer (sample) and the photomask, affecting the lithography quality and even causing fatal defects. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A constant gap exposure stage system for a proximity lithography machine, comprising:

[0006] Mask frame, mask plate, 3 gap plates, 3 gear rack mechanisms, 3 linear cylinders, sample piece, support platform, ball cup, 2 locking cylinders, lifting drive mechanism, main controller;

[0007] The mask is located below the mask holder and is fixedly connected to the mask holder. A vacuum groove is provided on the lower surface of the mask holder to clamp the mask.

[0008] All gap plates are fixed to the corresponding gear and rack mechanism, all gear and rack mechanisms are fixed to the mask frame, and all linear cylinders are fixed to the corresponding gear and rack mechanism.

[0009] The sample is located directly below the mask, with the upper surface of the sample facing the lower surface of the mask.

[0010] The support platform is located below the sample, and the sample is placed on the upper surface of the support platform. A vacuum groove is provided on the upper surface of the support platform to clamp the sample.

[0011] The support platform is fixed to the ball cup, two locking cylinders are fixed to the lifting drive mechanism, the top of the lifting drive mechanism is provided with a spherical vacuum groove for clamping the ball cup, and the main controller is fixed to the lifting drive mechanism.

[0012] The present invention has the following beneficial effects:

[0013] This invention employs non-contact leveling technology to automatically align the sample and the photomask and precisely maintain the exposure gap. This not only avoids mechanical damage to the photomask from the sample and reduces exposure pattern defects, but also extends the lifespan of the photomask while ensuring lithography quality, and significantly improves system efficiency. Attached Figure Description

[0014] Figure 1 This is a structural diagram of the constant gap exposure stage system for a proximity lithography machine according to the present invention, wherein 1-mask holder, 2-mask plate, 3-gap plate, 4-gear and rack mechanism, 5-linear cylinder, 6-sample, 7-support stage, 8-ball cup, 9-locking cylinder, 10-lifting drive mechanism, 11-main controller;

[0015] Figure 2 This is a schematic diagram of the internal structure of the mask frame of the present invention, wherein 1-mask frame, 3-spacer plate, 4-gear rack mechanism, and 5-linear cylinder. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0017] like Figure 1 , Figure 2 As shown, the present invention provides a constant gap exposure stage system (hereinafter referred to as the system) for a proximity lithography machine, comprising: a mask holder 1, a mask plate 2, three gap plates 3, three gear rack mechanisms 4, three linear cylinders 5, a sample 6, a support stage 7, a ball cup 8, two locking cylinders 9, a lifting drive mechanism 10, and a main controller 11.

[0018] The lifting drive mechanism 10 can be a motor, cylinder, or other drive mechanism with similar functions, and the main controller 11 can be a microcontroller, single-chip microcomputer, or other control module with similar functions. The mask plate 2 is located below the mask frame 1 and is fixedly connected to it. A vacuum groove is provided on the lower surface of the mask frame 1 to hold the mask plate 2 in place. All gap plates 3 are fixedly connected to the gear and rack mechanism 4, all gear and rack mechanisms 4 are fixedly connected to the mask frame 1, and all linear cylinders 5 are fixedly connected to the gear and rack mechanism 4. The sample plate 6 is located directly below the mask plate 2, and its upper surface is opposite to the lower surface of the mask plate 2. The support platform 7 is located below the sample plate 6, and the sample plate 6 is placed on its upper surface. A vacuum groove is provided on the upper surface of the support platform 7 to hold the sample plate 6 in place. The support platform 7 is fixedly connected to the ball cup 8. The locking cylinder 9 is fixedly connected to the lifting drive mechanism 10. The top of the lifting drive mechanism 10 has a spherical vacuum groove to hold the ball cup 8 in place. The main controller 11 is fixedly connected to the lifting drive mechanism 10. Linear cylinder 5 drives gear and rack mechanism 4 to move linearly, and gear and rack mechanism 4 drives gap plate 3 to complete rotational movement. Ball cup 8 is used for leveling sample 6; locking cylinder 9 is used to stop the movement of lifting drive mechanism 10.

[0019] The mask frame 1 is a horizontal reference plane, and a vacuum groove is provided on the lower surface to fix the mask plate 2 under the mask frame 1 by negative pressure.

[0020] Each of the three spacer plates 3 has a steel ball embedded at its end. The steel ball has elastic deformation recovery capability and can be replaced by beryllium bronze or other materials that have both elasticity and wear resistance. The three spacer plates 3 are of equal thickness, and the distance between the uppermost part of the spacer plate 3 and the mask surface is 0.5 mm, or other suitable values ​​can be taken according to the elastic deformation range.

[0021] The upper surface of the support platform 7 is provided with a vacuum groove, which fixes the sample 6 above the support platform 7 by negative pressure.

[0022] The system uses the mask holder 1 and mask plate 2 as horizontal references. A lifting drive mechanism 10 drives a three-point elastic support mechanism, which includes three gap plates 3, three gear and rack mechanisms 4, and three linear cylinders 5, essentially mechanical springs. When the support platform 7 and sample plate 6 rise, they contact and level with the mask plate 2 via three automatically extended steel balls of equal diameter. Then, the locking cylinder 9 locks the three-point elastic support mechanism, and the lifting drive mechanism 10 stops rising, thus achieving and maintaining parallelism between sample plate 6 and mask plate 2. Next, the lifting drive mechanism 10 descends to a preset end point and stops. The three steel balls retract and return. Finally, the lifting drive mechanism 10 moves upward again until the gap between sample plate 6 and mask plate 2 reaches a preset value, at which point it stops rising, achieving close-proximity exposure between sample plate 6 and mask plate 2. This system can automatically level sample plate 6 and mask plate 2 and maintain a certain exposure gap, extending the service life of mask plate 2. In this system, the mask holder 1 is made of 7075 aerospace aluminum alloy, and undergoes aging treatment and surface black hard anodizing to ensure its surface wear resistance and avoid wear problems on the adsorption surface caused by frequent mask replacements during use. The spacer 3 is made of 65Mn (65 manganese steel), and through quenching and medium-temperature tempering processes, the surface hardness reaches HRC 55 (Rockwell hardness C scale 55), which has good toughness and impact resistance and is not easy to break. The standard thickness of the spacer 3 is 0.1 mm-0.5 mm, and different thicknesses can be selected according to different mask sizes. The main controller 11 can be a PLC (programmable logic controller) or a microcontroller, or other devices with the same function. The lifting drive mechanism 10 can be a lead screw guide, linear slide, or other mechanical devices with the same function.

[0023] The above description is merely an embodiment of the present invention and does not limit the scope of the invention. Any equivalent structural or procedural transformations made based on the description and drawings of this invention, or direct or indirect applications in other related system fields, are similarly included within the protection scope of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A constant gap exposure worktable system for a proximity photolithography machine, characterized by, include: Mask frame, mask plate, 3 gap plates, 3 gear rack mechanisms, 3 linear cylinders, sample piece, support platform, ball cup, 2 locking cylinders, lifting drive mechanism, main controller; The mask is located below the mask holder and is fixedly connected to the mask holder. A vacuum groove is provided on the lower surface of the mask holder to clamp the mask. All gap plates are fixed to the corresponding gear and rack mechanism, all gear and rack mechanisms are fixed to the mask frame, and all linear cylinders are fixed to the corresponding gear and rack mechanism. The sample is located directly below the mask, with the upper surface of the sample facing the lower surface of the mask. The support platform is located below the sample, and the sample is placed on the upper surface of the support platform. A vacuum groove is provided on the upper surface of the support platform to clamp the sample. The support platform is fixed to the ball cup, two locking cylinders are fixed to the lifting drive mechanism, the top of the lifting drive mechanism is provided with a spherical vacuum groove for clamping the ball cup, and the main controller is fixed to the lifting drive mechanism.

2. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The lifting drive mechanism is a motor or a cylinder.

3. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The main controller is a microcontroller or a single-chip microcomputer.

4. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, Each spacer is fitted with a steel ball at its end. The steel ball has the ability to recover from elastic deformation and is made of beryllium bronze.

5. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The three gaps are of equal thickness, and the distance between the uppermost part of each gap and the mask surface is 0.5 mm.

6. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, A linear cylinder drives a gear and rack mechanism to perform linear motion, and the gear and rack mechanism drives a gap plate to complete rotational motion; a ball cup is used for leveling the sample; a locking cylinder is used to stop the movement of the lifting drive mechanism.

7. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The mask holder is a horizontal reference plane, and a vacuum groove is provided on the lower surface of the mask holder to fix the mask plate under the mask holder by negative pressure.

8. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The upper surface of the substrate holder is equipped with a vacuum groove, which is used to fix the sample on the substrate holder by negative pressure.

9. The constant gap exposure stage system for a proximity lithography machine according to claim 1, characterized in that, The three-point elastic support mechanism consists of three gap plates, three gear and rack mechanisms, and three linear cylinders.

10. The constant gap exposure stage system for a proximity lithography machine according to claim 9, characterized in that, The three-point elastic support mechanism is essentially a mechanical spring, used to lock and maintain the parallelism between the sample and the mask after the sample has been leveled by contact with the mask through a locking cylinder.

Images