Clamping structure for defect inspection of mask and automatic optical inspection machine

Abstract

The utility model discloses a clamping structure and an automatic optical inspection machine for the defect inspection of a mask plate, the clamping structure comprises a clamping jaw and a clamping block, the clamping jaw is connected with the clamping block, one surface of the clamping block contacted with the mask plate to be inspected is an inclined surface, an included angle is formed between the inclined surface and the plane of the mask plate to be inspected, and the included angle is an acute angle. According to the utility model, the contact surface of the clamping block and the mask plate is designed to be the inclined surface with the angle, and the inclined surface clamping blocks with different angles are replaced to give the mask plate with different degrees of deformation stress self-adaptive capability in the fixing process, so that the purposes of reducing the pattern deformation of the mask plate and reducing the false detection rate of AOI (Automatic Optic Inspection) scanning are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of photomask defect inspection, in particular to a clamping structure for photomask defect inspection and an automatic optical inspection machine. Background Art

[0002] A photomask (also known as a mask or photomask) is a precision pattern transfer template. It is a coated glass substrate containing a precise electronic circuit pattern and is used in the mass production of microelectronics. Through high-precision photolithography, micro- and nanoscale circuit patterns are engraved onto the photomask substrate to create a photomask.

[0003] Automated Optical Inspection (AOI) equipment is a type of inspection equipment based on optical principles and machine vision technology, and is widely used in the electronics manufacturing industry. AOI equipment is used for production process monitoring and quality control. It can detect defects in real time, identify and correct problems promptly, and ensure stable product quality.

[0004] The images depicted on the surface of photomasks during production are extremely precise. High-end mask patterns can be as small as a few tenths of a micron. Micrographic patterns are not only small in size but also highly precise. High-precision mask production typically has a tolerance of ±0.1um or less, with the minimum required to be around tens of nanometers. This high precision makes the pattern susceptible to deformation due to external factors. During AOI scanning, the mask needs to be fixed to the machine's scanning structure, and uneven force can easily cause deformation. If the deformation is excessive and exceeds the preset standard image data, false defects (misjudged defects) will appear during the AOI scan.

[0005] During defect inspection, the mask is fixed to the scanning structure of the machine. This structure is called a holder (base). The holder is equipped with a clamping jaw that connects to the sensor and air pipe. The part of the clamping jaw that contacts the mask is called the clamping block. The clamping jaw and the clamping block serve as the clamping structure for the mask. The holder is controlled by a PLC program to control the motor to move the clamping jaw forward and backward, and the cylinder to inflate the air pipe to tightly clamp the clamping jaw to achieve the desired effect.

[0006] The contact between the clamping blocks on the jaws and the mask determines the force applied to the mask after it is placed on the machine. Uneven or excessive pressure can cause deformation of the mask pattern, while too little pressure can result in poorly fixed mask, causing it to shake or even fall. Therefore, the role of the clamping blocks is very important. The clamping blocks configured on the jaws of a typical AOI scanner fit tightly against the edge of the mask when in contact, applying pressure on the surface to ensure a more uniform force on the mask. However, in actual use, due to external factors such as position errors during placement, sensor induction errors, and uneven inflation of the cylinder, the pressure applied to the mask by the flat clamping blocks is uneven, resulting in uneven stress on the pattern and deformation. This ultimately leads to a large number of false defects in the AOI process, greatly affecting production efficiency and wasting time and labor costs.

[0007] In view of this, this patent application is filed. Utility Model Content

[0008] The utility model provides a clamping structure for mask defect inspection and an automatic optical inspection machine, which are used to solve the technical problem that the clamping blocks on the current inspection machine apply uneven pressure to the mask when in contact with the mask, resulting in deformation and a large number of false defects.

[0009] The first object of the present invention is to provide a clamping structure for mask defect inspection, which adopts the following technical solutions:

[0010] The clamping jaw and the clamping block are connected to each other. The side of the clamping block that contacts the mask to be inspected is an inclined surface. There is an acute angle between the inclined surface and the plane of the mask to be inspected.

[0011] As an optional design, the angle is 2 to 15°.

[0012] As an optional design, both the clamping jaw and the clamping block are provided with slotted holes, and a connecting piece is provided in the slotted hole. The connecting piece can move in the slotted hole, and the clamping jaw and the clamping block are movably connected through the connecting piece.

[0013] As an optional design, the connecting member is a connecting screw.

[0014] As an optional design, a connecting spring is provided at the connection between the clamping claw and the clamping block.

[0015] As an optional design, a fixing block is provided on the clamping claw and the clamping block respectively, and the connecting spring is provided between the two fixing blocks.

[0016] As an optional design, two connecting springs are provided, one located on each side of the clamping jaw.

[0017] As an optional design, the contact surfaces between the clamping jaw and the clamping block are both inclined surfaces, and the two inclined surfaces are parallel.

[0018] As an optional design, the connecting member is arranged obliquely so that the connecting member and the side surface of the clamping jaw are not parallel.

[0019] A second object of the present invention is to provide an optical inspection machine for inspecting defects in a mask, comprising any one of the above clamping structures and further comprising a sensor, a spacer block, and an air pipe.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] The defect inspection machine of the present invention designs the contact surface between the clamping block and the mask as an angled slope. By replacing the inclined clamping blocks with different angles, the mask is given the ability to adapt to different degrees of deformation and force during the fixing process, so as to achieve the purpose of reducing the deformation of the mask pattern and reducing the AOI scanning false detection rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of the existing inspection machine structure in which the clamping block and the mask cooperate.

[0024] Figure 2 This is a diagram showing the force applied to the clamp and mask on one side in the existing inspection machine structure.

[0025] Figure 3 This is a diagram showing the force applied to the clamping block and mask on one side of the inspection machine in the present invention.

[0026] Figure 4 It is a schematic diagram of the three-dimensional structure of the clamping structure of the present invention.

[0027] Figure 5 This is a front view structural diagram of the clamping structure of the present invention.

[0028] Figure 6 This is a side structural schematic diagram of the clamping structure of the present invention.

[0029] Figure 7 This is a schematic top view of the clamping structure of the present invention.

[0030] Markings and corresponding parts names in the accompanying drawings:

[0031] 1-sensor, 2-air pipe, 3-pad, 4-clamping jaw, 5-clamping block, 501-inclined surface, 6-slotted hole, 7-connecting piece, 8-fixing block, 9-connecting spring. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The schematic implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0033] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not necessarily required to practice the present invention. In other embodiments, well-known structures, circuits, materials, or methods are not described in detail to avoid obscuring the present invention.

[0034] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout this specification do not necessarily refer to the same embodiment or example. In addition, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] In the description of the present invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0036] The existing automatic optical inspection machine includes a sensor 1, a pad 3, an air pipe 2, a clamping claw 4, and a clamping block 5. Figure 1As shown in . The sensor 1 and the spacer 3 are both placed on one side of the clamp 4. By controlling the air cylinder to inflate the air pipe 2, the clamp 4 moves and presses against the edge of the mask, playing a fixing role. The clamp 4 and the clamp 5 are fixed together as a clamping structure. The side of the clamp 5 that contacts the mask is flat and in close contact with the mask. In this case, the force on the single-sided mask is as follows Figure 2 As shown in , when jaws 4 clamp the reticle, the pressure applied to the reticle is perpendicular to the edge and directed toward the center. For example, when loading a reticle vertically, when the jaws 4 on both sides are clamped, the sensor 1 stops when it senses contact with the reticle. The reticle may be positioned to the left or right. If it is positioned to the left, the left jaw 4's clamping stroke toward the center will be shorter than the right jaw 4, resulting in greater force on the right side, leading to uneven force distribution. This will cause more deformation in the pattern toward the right, leading to excessive false defects in AOI scanning.

[0037] To solve this problem, Figure 4 、 5 As shown in Figures 6 and 7, this embodiment provides a clamping structure for mask defect inspection, including a clamping jaw 4 and a clamping block 5. The clamping jaw 4 is connected to the clamping block 5. The side of the clamping block 5 that contacts the mask to be inspected is an inclined surface 501. In this way, there is an angle between the inclined surface 501 and the plane of the mask to be inspected, and this angle is an acute angle. When in contact, the clamping block 5 and the mask are not tightly fitted, but have a certain adaptive adjustment space. Figure 3 As shown in .

[0038] In this embodiment, clamp block 5 is designed with an inclined surface. The advantage of this design is that the inclined clamp block 5 has a small angle, which provides a certain amount of self-adjustment margin for the clamping force of the mask. Therefore, during repeated clamping cycles, the mask will slightly move from the side with greater force to the side with less force, depending on the force situation. The position of the contact point on the inclined surface of clamp block 5 with the mask will change. By continuously changing the position of the contact point, the pressure applied to the mask on the left and right sides is gradually evened out. The two forces on the mask on the left and right sides approach balance and their directions tend to be aligned. This design minimizes the deformation of the pattern, making it less likely to cause false defects during AOI scanning. This demonstrates the adaptive ability of the inclined clamp block 5.

[0039] Preferably, the angle designed in this embodiment is 2-15°, which is also the inclination angle of the inclined surface of the clamping block 5 .

[0040] Example 2:

[0041] On the basis of Example 1, a slotted hole 6 is designed to be provided on both the clamping jaw 4 and the clamping block 5, and a connecting member 7 is provided in the slotted hole 6. The connecting member 7 is preferably designed to be a connecting screw, which can move in the slotted hole 6, so that the clamping jaw 4 and the clamping block 5 are movably connected through the connecting member 7.

[0042] Preferably, a fixing block 8 is provided on each of the clamping jaw 4 and the clamping block 5, and a connecting spring 9 is provided between the two fixing blocks 8 to form an elastic connection between the clamping jaw 4 and the clamping block 5 through the connecting spring 9. Two connecting springs 9 are provided, one on each side of the clamping jaw 4.

[0043] The slotted hole 6 and connecting spring 9 create a flexible connection between the clamping jaw 4 and the clamping block 5. On conventional scanning equipment, the clamping jaw 4 and the clamping block 5 are completely fixed together, and the contact type when clamping the upper mask product is hard-to-hard. This hard contact causes the deformation state after clamping to depend on the moment when the clamping jaw 4 stops moving, lacking the ability to evenly alleviate stress. In this embodiment, the clamping block 5 and the clamping jaw 4 are connected in a flexible manner instead of a fixed connection. Due to the flexible structure, the clamping block 5 can slide parallel to the inclined surface within a certain range when clamping. This approach allows the clamping block 5 to have a certain amount of adjustment space for the overall force applied when the mask is clamped, providing coarse adjustment of the adaptive capability, and also acting as a shock absorber during platform movement.

[0044] More preferably, this embodiment also features fine-tuning of the adaptive capability, specifically by making the contact surfaces between the clamping jaws 4 and the clamping block 5 be inclined planes, with the two inclined planes being parallel. This inclined plane design allows for fine-tuning, forming a system for adaptively adjusting stress.

[0045] To ensure a closer fit between the inclined surfaces of the jaws 4 and the clamping block 5, the present embodiment further arranges the connecting member 7 at an angle, so that the connecting member 7 and the side surfaces of the jaws 4 are non-parallel. When the angle of the connecting member 7 is greater, the inclined surfaces between the connecting member 7, the jaws 4, and the clamping block 5 may become perpendicular. This oblique screw fixation ensures a closer fit between the inclined surfaces of the clamping block 5 and the jaws 4, and the connecting spring 9 provides a pull-back force after translation in the inclined direction.

[0046] Example 3:

[0047] An automatic optical inspection machine for inspecting defects in a mask is provided, comprising a clamping structure as in Example 1 or Example 2, and further comprising a sensor 1, a pad 3, and an air pipe 2, which adopts the same structure and connection relationship as an existing inspection machine, such as Figure 1 As shown in , no further description is given here.

[0048] The clamping structure for mask defect inspection and the defect inspection machine of the utility model have the following technical advantages:

[0049] (1) The contact surface between the clamping block 5 and the mask in the clamping structure is changed from a flat surface to an angled inclined surface. By replacing the inclined clamping block 5 with different angles (2 degrees to 15 degrees), the mask is given different degrees of deformation force self-adaptation during the fixing process, so as to achieve the purpose of reducing the deformation of the mask pattern and reducing the AOI scanning error rate.

[0050] (2) The structural connection between the clamping block 5 and the clamping jaw 4 is changed from a fixed structure to a movable structure, and a connecting spring 9 is designed so that the clamping block 5 can obtain a certain degree of movable space for adaptive adjustment during the clamping process, so that the contact between the mask and the clamping block 5 can reach the optimal state under different stress conditions.

[0051] (3) The contact surface between the clamping block 5 and the clamping jaw 4 is designed to be an inclined surface. This inclined surface design allows the clamping block 5 to finely adjust the position of the mask during the clamping process, and together with the coarse adjustment of the movable connection structure, it constitutes the entire adaptive stress adjustment system.

[0052] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above are only specific implementation methods of the utility model and are not used to limit the scope of protection of the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model should be included in the scope of protection of the utility model.

Claims

1. A clamping structure for mask defect inspection, characterized in that: The invention comprises a clamping jaw (4) and a clamping block (5), wherein the clamping jaw (4) is connected to the clamping block (5), and a side of the clamping block (5) in contact with the mask to be inspected is an inclined surface, and an angle is formed between the inclined surface and the plane of the mask to be inspected, and the angle is an acute angle.

2. The clamping structure for mask defect inspection according to claim 1, characterized in that: The angle is 2 to 15 degrees.

3. The clamping structure for mask defect inspection according to claim 1, characterized in that: The clamping jaw (4) and the clamping block (5) are both provided with a slotted hole (6), a connecting piece (7) is provided in the slotted hole (6), and the connecting piece (7) can move in the slotted hole (6), and the clamping jaw (4) and the clamping block (5) are movably connected through the connecting piece (7).

4. The clamping structure for mask defect inspection according to claim 3, characterized in that: The connecting piece (7) is a connecting screw.

5. The clamping structure for mask defect inspection according to claim 3 or 4, characterized in that: A connecting spring (9) is provided at the connection between the clamping claw (4) and the clamping block (5).

6. The clamping structure for mask defect inspection according to claim 5, characterized in that: A fixing block (8) is provided on the clamping claw (4) and the clamping block (5), respectively, and the connecting spring (9) is provided between the two fixing blocks (8).

7. The clamping structure for mask defect inspection according to claim 6, characterized in that: Two connecting springs (9) are provided, and are respectively located on both sides of the clamping jaw (4).

8. The clamping structure for mask defect inspection according to claim 6 or 7, characterized in that: The contact surfaces between the clamping jaw (4) and the clamping block (5) are both inclined surfaces, and the two inclined surfaces are parallel.

9. The clamping structure for mask defect inspection according to claim 8, characterized in that: The connecting member (7) is arranged obliquely so that the connecting member (7) and the side surface of the clamping jaw (4) are arranged non-parallel.

10. An automatic optical inspection machine for inspecting defects in a mask, characterized in that: The invention comprises the clamping structure according to any one of claims 1 to 9, and further comprises a sensor (1), a cushion block (3), and an air pipe (2).

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