Photomask plate based on bidirectional exposure wafer

Abstract

The invention provides a photomask plate based on a bidirectional exposure wafer, and relates to the technical field of photomask plates. According to the photomask plate, a plurality of mark points are arranged on a lower photomask plate, mark rings in one-to-one correspondence are arranged on an upper photomask plate, the positions of the mark points relative to the mark rings are monitored through cameras above the mark rings, the deviation of the lower photomask plate relative to the upper photomask plate can be found in time, and the deviation can be automatically corrected through a micrometer lead screw propeller; economic losses caused by the fact that exposure deviation is not found in time are effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of photomask plates, and in particular to a photomask plate based on a bidirectional exposure wafer. Background Art

[0002] The mask plate is a commonly used device in photolithography machines for manufacturing semiconductor devices. The essence of a photolithography machine is to expose the wafer through the mask plate and copy the pattern of the mask plate onto the wafer.

[0003] For wafers that require bidirectional exposure, an upper mask plate and a lower mask plate need to be arranged on both sides of the wafer to ensure that the wafer, the lower mask plate and the upper mask plate are aligned during the entire exposure process.

[0004] At present, in the production process of bidirectional exposure wafers, the wafer cannot be fixed on the lower mask plate. A slight movement of the wafer when the upper and lower mask plates are attached will cause exposure deviation. In addition, the lower mask plate is fixed with negative pressure. After the exposure is completed, the negative pressure will be released when the upper and lower mask plates are separated. If the frequency reaches a certain number of times, the lower mask plate will be displaced, which will also cause exposure deviation.

[0005] However, during the production process of bidirectional exposure wafers, it is impossible to detect the exposure deviation in time. It can only be discovered during the last process of cutting by a bidirectional cutting machine. However, by then the material has been scrapped, which will cause great losses. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a photomask based on a bidirectional exposure wafer, which solves the problem that the photomask of the bidirectional exposure wafer cannot be discovered in time when the exposure is offset.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A photomask based on a bidirectional exposure wafer, the photomask comprising: a lower photomask, an upper photomask, a PLC controller and four micrometer screw pushers;

[0009] The lower mask plate is provided with a plurality of marking points in the non-pattern area, the upper mask plate is provided with marking circles corresponding to the marking points one by one, the outer diameter of the marking points is the same as the inner diameter of the marking circles, and cameras corresponding to the marking circles are provided above the marking circles;

[0010] The four micrometer screw pushers are respectively aligned with the four side walls of the lower mask plate to correct the position of the lower mask plate;

[0011] The PLC controller is electrically connected to all cameras and micrometer screw propellers respectively.

[0012] Preferably, the camera is matched with a viso vision system for real-time monitoring of the relative position of the marking point and the corresponding marking circle.

[0013] Preferably, the PLC controller is also electrically connected to an audible and visual alarm. When a marking point does not coincide with the corresponding marking circle, the audible and visual alarm sounds an alarm and suspends the operation of the equipment. When all marking points coincide with the corresponding marking circles, the audible and visual alarm cancels the alarm and drives the equipment to resume operation.

[0014] Preferably, the lower mask plate is provided with a plurality of negative pressure holes in the non-pattern area; the bottom end of the negative pressure hole is connected to the first pneumatic system, and the top end can contact the wafer placed on the lower mask plate, so that the first pneumatic system can perform negative pressure adsorption on the wafer through the negative pressure hole.

[0015] Preferably, the lower mask plate is matched with a second pneumatic system, and the second pneumatic system can fix the lower mask plate by negative pressure adsorption.

[0016] Preferably, the number of marking points on the lower mask plate is not less than two.

[0017] Preferably, the number of negative pressure holes on the lower mask plate is not less than three, and they are arranged in a circular array with the center of the pattern as the center.

[0018] Preferably, the offset correction method of the mask plate based on the bidirectional exposure wafer includes:

[0019] S1. After placing the wafer at a designated position on the lower mask plate, start the first pneumatic system to adsorb the wafer to the correct position;

[0020] S2. When the upper mask plate and the lower mask plate are offset from each other, that is, when the camera detects that the corresponding marking point is offset from the marking circle, the PLC controller controls the sound and light alarm to sound an alarm and suspend the operation of the equipment;

[0021] S3. With the center of the marking circle as the origin, the offset coordinates of the corresponding marking points are collected by the camera, and the positions of the four side walls of the lower mask plate after correct correction are calculated by the offset coordinates of all marking points;

[0022] S4. Drive four micrometer screw propellers to make the free surfaces of the push plates of the four micrometer screw propellers coincide with the positions where the four side walls of the lower mask plate should be after correct calibration, thereby achieving position calibration of the lower mask plate;

[0023] S5. When the camera detects that the corresponding marking point overlaps with the marking circle, the PLC controller controls the sound and light alarm to turn off and drive the equipment to operate.

[0024] The present invention provides a photomask based on a bidirectional exposure wafer. Compared with the prior art, it has the following beneficial effects:

[0025] In the present invention, the photomask plate is provided with a plurality of marking points on the lower photomask plate, and a one-to-one corresponding marking circle is provided on the upper photomask plate. By monitoring the position of the marking points relative to the marking circle through the camera above the marking circle, the deviation of the lower photomask plate relative to the upper photomask plate can be detected in time, and the deviation can be automatically corrected by the micrometer screw pusher, thereby effectively avoiding the economic loss caused by the failure to detect the exposure deviation in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 Schematic diagram of the structure of the photomask plate in an embodiment of the present invention.

[0028] Figure 2 Schematic diagram of the structure of the lower mask plate in an embodiment of the present invention.

[0029] Figure 3 Schematic diagram of the structure of the upper photomask in an embodiment of the present invention.

[0030] The reference numerals in the figure are set as: lower mask plate 10, marking point 11, negative pressure hole 12, upper mask plate 20, marking circle 21, camera 22, micrometer screw propeller 30. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The embodiment of the present application solves the problem that the exposure deviation of the photomask plate of the bidirectional exposure wafer cannot be discovered in time by providing a photomask plate based on the bidirectional exposure wafer.

[0033] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] Example:

[0035] like Figure 1-Figure 3As shown, the present invention provides a photomask based on a bidirectional exposure wafer, the photomask comprising: a lower photomask 10, an upper photomask 20, a PLC controller and four micrometer screw pushers 30;

[0036] The lower mask plate 10 is provided with a plurality of marking points 11 in the non-pattern area, the upper mask plate 20 is provided with marking circles 21 corresponding to the marking points 11 one by one, the outer diameter of the marking points 11 is the same as the inner diameter of the marking circle 21, and a corresponding camera 22 is provided above the marking circle 21;

[0037] The four micrometer screw pushers 30 are respectively aligned with the four side walls of the lower mask plate 10 to correct the position of the lower mask plate 10;

[0038] The PLC controller is electrically connected to all cameras 22 and micrometer screw propellers 30 respectively.

[0039] The camera 22 is matched with a viso vision system for real-time monitoring of the relative position of the marking point 11 and the corresponding marking circle 21; when the marking point 11 and the corresponding marking circle 21 do not coincide, the PLC controller drives the appropriate micrometer screw pusher 30 to correct the position of the lower mask plate 10 according to the relative position of the two.

[0040] The PLC controller is also electrically connected to an audible and visual alarm. When a marking point 11 does not coincide with a corresponding marking circle 21, the audible and visual alarm sounds an alarm and suspends the operation of the equipment. When all marking points 11 coincide with the corresponding marking circles 21, the audible and visual alarm cancels the alarm and drives the equipment to resume operation.

[0041] like Figure 2 As shown, the lower mask plate 10 is provided with a plurality of negative pressure holes 12 in the non-pattern area; the bottom end of the negative pressure hole 12 is connected to the first pneumatic system, and the top end can contact with the wafer placed on the lower mask plate 10, so that the first pneumatic system can perform negative pressure adsorption on the wafer through the negative pressure hole 12 to prevent the wafer from being displaced relative to the lower mask plate 10.

[0042] The lower mask plate 10 is matched with a second pneumatic system, and the second pneumatic system can fix the lower mask plate 10 by negative pressure adsorption.

[0043] like Figure 2 As shown, the number of marking points 11 on the lower mask plate 10 is not less than two.

[0044] like Figure 2 As shown, the number of negative pressure holes 12 on the lower mask plate 10 is not less than three, and they are arranged in a circular array with the center of the pattern as the center.

[0045] The method for correcting the offset of a photomask based on a bidirectional exposure wafer comprises:

[0046] S1. After placing the wafer at a designated position on the lower mask plate 10, start the first pneumatic system to adsorb the wafer at the correct position;

[0047] S2. When the upper mask plate 20 and the lower mask plate 10 are offset, that is, the camera 22 detects the corresponding mark point 11 relative to the mark circle 21, the sound and light alarm is controlled by the PLC controller and the equipment is suspended;

[0048] S3. With the center of the marking circle 21 as the origin, the offset coordinates of the corresponding marking point 11 are collected by the camera 22, and the offset coordinates of all marking points 11 are calculated to determine the position of the four side walls of the lower mask plate 10 after the correction is correct;

[0049] S4 drives four micrometer screw propellers 30, so that the free surface of the push plate of the four micrometer screw propellers 30 coincides with the position where the four side walls of the lower mask plate 10 should be correctly corrected, to achieve position correction of the lower mask plate 10;

[0050] S5. When the camera 22 detects that the corresponding marking point 11 coincides with the marking circle 21, the PLC controller controls the sound and light alarm to be turned off and drives the equipment to operate.

[0051] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. In the embodiment of the present invention, the photomask plate is provided with a plurality of marking points 11 on the lower photomask plate 10, and a one-to-one corresponding marking circle 21 is provided on the upper photomask plate 20. The position of the marking point 11 relative to the marking circle 21 is monitored by a camera 22 above the marking circle 21, so that the misalignment of the lower photomask plate 10 relative to the upper photomask plate 20 can be detected in time, and the misalignment can be automatically corrected by the micrometer screw pusher 30, so as to effectively avoid the economic loss caused by the failure to detect the exposure misalignment in time.

[0053] 2. In the embodiment of the present invention, the mask plate is provided with a plurality of negative pressure holes 12 in the non-pattern area of ​​the lower mask plate 10 , which can firmly fix the wafer in the correct position without affecting the exposure, and effectively prevent the wafer from being displaced relative to the lower mask plate 10 .

[0054] 3. In the embodiment of the present invention, an audible and visual alarm is used to alert the staff to pay attention to the workstation where the lower mask plate 10 is offset, and to remind the staff to inspect and repair the workstation that is often offset to avoid frequent downtime that affects production efficiency.

[0055] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photomask based on a bidirectional exposure wafer, characterized in that: The mask plate comprises: a lower mask plate (10), an upper mask plate (20), a PLC controller and four micrometer screw thrusters (30); The lower mask plate (10) is provided with a plurality of marking points (11) in the non-pattern area, the upper mask plate (20) is provided with marking circles (21) corresponding one to one with the marking points (11), the outer diameter of the marking points (11) is the same as the inner diameter of the marking circle (21), and cameras (22) corresponding one to one are provided above the marking circles (21); The four micrometer screw propellers (30) are respectively aligned with the four side walls of the lower mask plate (10) to correct the position of the lower mask plate (10); The PLC controller is electrically connected to all cameras (22) and micrometer screw propellers (30) respectively.

2. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The camera (22) is matched with a viso vision system for real-time monitoring of the relative position of the marking point (11) and the corresponding marking circle (21).

3. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The PLC controller is also electrically connected to an audible and visual alarm. When a marking point (11) does not coincide with a corresponding marking circle (21), the audible and visual alarm sounds an alarm and suspends the operation of the equipment. When all marking points (11) coincide with corresponding marking circles (21), the audible and visual alarm cancels the alarm and drives the equipment to resume operation.

4. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The lower mask plate (10) is provided with a plurality of negative pressure holes (12) in the non-pattern area; the bottom ends of the negative pressure holes (12) are connected to the first pneumatic system, and the top ends are capable of contacting a wafer placed on the lower mask plate (10), so that the first pneumatic system can perform negative pressure adsorption on the wafer through the negative pressure holes (12).

5. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The lower light mask plate (10) is matched with a second pneumatic system, and the second pneumatic system can perform negative pressure adsorption and fixation on the lower light mask plate (10).

6. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The number of marking points (11) on the lower light mask plate (10) is not less than two.

7. The photomask based on bidirectional exposure wafer according to claim 4, characterized in that: The number of negative pressure holes (12) on the lower mask plate (10) is not less than three, and they are arranged in a circular array with the center of the pattern as the center.

8. The photomask based on bidirectional exposure wafer according to claim 1, characterized in that: The method for correcting the offset of a photomask based on a bidirectional exposure wafer comprises: S1. After placing the wafer at a designated position on the lower mask plate (10), start the first pneumatic system to adsorb the wafer at the correct position; S2. When the upper mask plate (20) and the lower mask plate (10) are offset from each other, that is, the camera (22) detects that the corresponding marking point (11) is offset from the marking circle (21), the PLC controller controls the sound and light alarm to sound and suspend the operation of the equipment; S3. With the center of the marking circle (21) as the origin, the offset coordinates of the corresponding marking point (11) are collected by the camera (22), and the positions of the four side walls of the lower mask plate (10) after correct calibration are calculated by the offset coordinates of all marking points (11); S4 drives four micrometer screw propellers (30), so that the free surface of the push plate of the four micrometer screw propellers (30) coincides with the position where the four side walls of the lower mask plate (10) should be correctly corrected, thereby achieving position correction of the lower mask plate (10); S5. When the camera (22) detects that the corresponding marking point (11) overlaps with the marking circle (21), the PLC controller controls the sound and light alarm to be turned off and drives the equipment to operate.

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