An antistatic light cover

Abstract

This application discloses an antistatic photomask, relating to the field of semiconductor technology. The antistatic photomask includes a substrate and a metal layer deposited on the substrate. A photomask pattern is etched on the metal layer. A first annular groove, a second annular groove, and a third annular groove are sequentially arranged around the outer periphery of the photomask pattern. A first metal ring is formed between the first and second annular grooves, and a second metal ring is formed between the second and third annular grooves. The first and second metal rings form a parallel plate capacitor structure. A plurality of first conductive strips are spaced apart within the third annular groove. The parallel plate capacitor structure is electrically connected to the metal layer outside the third annular groove through the first conductive strips. This improves the antistatic capability of the photomask itself.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to an antistatic photomask. Background Technology

[0002] Photomasks are crucial production molds in the semiconductor manufacturing industry. In the manufacturing process of integrated circuits (ICs), photolithography is used to replicate the photomask pattern onto the wafer, similar to how a negative is used to transfer an image onto a photograph to obtain the desired pattern. During the fabrication and use of photomasks, static electricity easily accumulates due to contact and friction with surrounding objects. This is especially true during handling, where several steps require operators to hold the photomask. Even with anti-static devices, operators can still introduce residual static charge into the photomask. When this charge accumulates to a certain level, electrostatic discharge (ESD) occurs between the tips of the photomask pattern. The energy released during this discharge directly damages the photomask pattern, generating contaminant particles and causing incorrect patterns to be indirectly replicated onto the wafer, ultimately reducing wafer yield. Simultaneously, the photomask itself becomes unusable due to damage, further increasing semiconductor production costs.

[0003] In existing technologies, a ring-shaped isolation strip is designed around the outer perimeter of the photomask to block the flow path of external electrostatic charges to the internal patterned areas of the photomask, thereby preventing electrostatic discharge in the internal patterned areas. However, the protective capability of the isolation strip is limited by its material properties, structural dimensions, and charge tolerance threshold. When the amount of electrostatic charge on both sides of the isolation strip (external environment and inside the photomask) reaches the electrostatic breakdown threshold of the isolation strip, it will directly break down the isolation strip, forming an electrostatic path. This causes external charges to rapidly flow into the internal patterned areas of the photomask, still triggering electrostatic discharge and damaging the internal circuitry. Utility Model Content

[0004] The purpose of this application is to provide an antistatic photomask that can improve the antistatic capability of the photomask itself.

[0005] The embodiments of this application are implemented as follows:

[0006] This application provides an antistatic photomask, including a substrate and a metal layer deposited on the substrate. A photomask pattern is etched on the metal layer. A first annular groove, a second annular groove, and a third annular groove are sequentially arranged around the outer periphery of the photomask pattern. A first metal ring is formed between the first annular groove and the second annular groove, and a second metal ring is formed between the second annular groove and the third annular groove. The first metal ring and the second metal ring form a parallel plate capacitor structure. A plurality of first conductive strips are spaced apart in the third annular groove. The parallel plate capacitor structure is electrically connected to the metal layer outside the third annular groove through the first conductive strips.

[0007] Optionally, as an implementable method, a first comb-shaped metal strip is provided on the side of the first metal ring facing the second metal ring, and a second comb-shaped metal strip is provided on the side of the second metal ring facing the first metal ring, with the first comb-shaped metal strip and the second comb-shaped metal strip being alternately arranged.

[0008] Optionally, as an implementable method, the first comb-shaped metal strip includes a plurality of first comb-shaped metal strips, which are spaced apart on the first metal ring, and the second metal ring is provided with a plurality of second comb-shaped metal strips corresponding one-to-one with the first comb-shaped metal strips.

[0009] Alternatively, as one possible implementation, the side of the first metal ring facing the second metal ring has a convex ridge.

[0010] Alternatively, as one possible implementation, the side of the second metal ring facing the first metal ring has a convex ridge.

[0011] Optionally, as an implementable method, a resistance wire is further provided between the first metal ring and the second metal ring, with the two ends of the resistance wire connected to the first metal ring and the second metal ring respectively.

[0012] Alternatively, as an implementable method, the resistance wire may be a curved trace.

[0013] Alternatively, as an implementable method, the resistance wires may also include multiple wires spaced apart between the first metal ring and the second metal ring.

[0014] Optionally, as an implementable method, both the first metal ring and the second metal ring are rectangular, and there are four of each of the first and second comb-shaped metal strips, with the four first comb-shaped metal strips disposed at the four corners of the first metal ring and the four second comb-shaped metal strips disposed at the four corners of the second metal ring.

[0015] Optionally, as an implementable approach, the widths of the first annular groove and the third annular groove are 1mm-2mm.

[0016] The beneficial effects of the embodiments of this application include:

[0017] The antistatic photomask provided in this application includes a substrate and a metal layer deposited on the substrate. A photomask pattern is etched on the metal layer. A first annular groove, a second annular groove, and a third annular groove are sequentially arranged around the outer periphery of the photomask pattern. A first metal ring is formed between the first and second annular grooves, and a second metal ring is formed between the second and third annular grooves. The first and second metal rings form a parallel plate capacitor structure. Multiple first conductive strips are spaced apart within the third annular groove. The parallel plate capacitor structure is electrically connected to the metal layer outside the third annular groove through the first conductive strips. This design abandons the single annular isolation strip design of the prior art. Instead of relying on the "blocking" method of the isolation strip, the parallel plate capacitor structure stores and buffers external electrostatic charges through the parallel plate capacitor structure formed by the first and second metal rings. Even if the amount of external electrostatic charge far exceeds the breakdown threshold of existing isolation strips, the parallel plate capacitor structure can absorb the charge through its capacitance characteristics, preventing the formation of an electrostatic path. This fundamentally solves the problem of easy breakdown of isolation strips, significantly improving the protective capability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is one of the structural schematic diagrams of the antistatic photomask provided in the embodiments of this application;

[0020] Figure 2 This is the second schematic diagram of the structure of the antistatic photomask provided in the embodiments of this application.

[0021] Icons: 100-Antistatic photomask; 110-Substrate; 120-Metal layer; 121-Photomask pattern; 122-First annular groove; 123-Second annular groove; 124-Third annular groove; 1241-First conductive strip; 125-First metal ring; 1251-First comb-shaped metal strip; 126-Second metal ring; 1261-Second comb-shaped metal strip; 127-Resistance wire. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "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 application based on the specific circumstances.

[0026] Please refer to Figure 1 and Figure 2 This embodiment provides an antistatic photomask 100, including a substrate 110 and a metal layer 120 deposited on the substrate 110. A photomask pattern 121 is etched on the metal layer 120. A first annular groove 122, a second annular groove 123, and a third annular groove 124 are sequentially arranged around the outer periphery of the photomask pattern 121. A first metal ring 125 is formed between the first annular groove 122 and the second annular groove 123. A second metal ring 126 is formed between the second annular groove 123 and the third annular groove 124. The first metal ring 125 and the second metal ring 126 form a parallel plate capacitor structure. A plurality of first conductive strips 1241 are spaced apart in the third annular groove 124. The parallel plate capacitor structure is electrically connected to the metal layer 120 outside the third annular groove 124 through the first conductive strips 1241.

[0027] Specifically, when external electrostatic charge is introduced into the photomask through operator contact or environmental friction, the charge is first conducted to the metal layer 120 outside the third annular groove 124, and then uniformly transferred through multiple first conductive strips 1241 within the third annular groove 124 to the parallel plate capacitor structure composed of the first metal ring 125 and the second metal ring 126. Because the parallel plate capacitor structure has the characteristic of storing charge, it temporarily stores and buffers the incoming electrostatic charge, preventing the charge from directly and rapidly entering the patterned area inside the photomask. Simultaneously, the parallel plate capacitor structure can slowly release the stored electrostatic charge through its own capacitance characteristics, further reducing the risk of electrostatic charge accumulation and fundamentally preventing the occurrence of electrostatic discharge.

[0028] The widths of the first annular groove 122 and the third annular groove 124 are 1mm-2mm.

[0029] The antistatic photomask 100 provided in this embodiment includes a substrate 110 and a metal layer 120 deposited on the substrate 110. A photomask pattern 121 is etched on the metal layer 120. A first annular groove 122, a second annular groove 123, and a third annular groove 124 are sequentially arranged around the outer periphery of the photomask pattern 121. A first metal ring 125 is formed between the first annular groove 122 and the second annular groove 123, and a second metal ring 126 is formed between the second annular groove 123 and the third annular groove 124. The first metal ring 125 and the second metal ring 126 form a parallel plate capacitor structure. Multiple first conductive strips 1241 are spaced apart within the third annular groove 124. The parallel plate capacitor structure is electrically connected to the metal layer 120 outside the third annular groove 124 through the first conductive strips 1241. This design abandons the single annular isolation strip design of the prior art, and instead stores and buffers external electrostatic charges through the parallel plate capacitor structure formed by the first metal ring 125 and the second metal ring 126, rather than relying on the "blocking" method of the isolation strip. Even if the amount of external electrostatic charge far exceeds the breakdown threshold of existing isolation strips, the parallel plate capacitor structure can absorb the charge through its capacitance characteristics, thus preventing the formation of an electrostatic path. This fundamentally solves the problem of isolation strips being easily broken down, significantly improving the protective capability.

[0030] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, a first comb-shaped metal strip 1251 is provided on the side of the first metal ring 125 facing the second metal ring 126, and a second comb-shaped metal strip 1261 is provided on the side of the second metal ring 126 facing the first metal ring 125. The first comb-shaped metal strip 1251 and the second comb-shaped metal strip 1261 are arranged alternately.

[0031] Specifically, based on the parallel plate capacitor structure of the basic scheme, the staggered arrangement of the first and second comb-shaped metal strips 1261 further increases the relative area between the first metal ring 125 and the second metal ring 126, and the staggered arrangement of the comb teeth forms multiple sets of "miniature parallel plate capacitors". When external electrostatic charge is transferred to the second metal ring 126 through the first conductive strip 1241, the charge will not only form a capacitor for storage in the main body of the first and second metal rings 126, but will also be dispersed and stored between the staggered comb teeth, further increasing the total capacitance value of the parallel plate capacitor structure and enhancing its ability to store and buffer electrostatic charge.

[0032] Meanwhile, the staggered comb structure can effectively disperse the charge distribution, avoid the accumulation of charge in local areas of the metal ring, reduce the risk of tip discharge caused by excessive local charge density, and further ensure the electrostatic safety of the pattern area inside the photomask.

[0033] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, the first comb-shaped metal strip 1251 includes multiple first comb-shaped metal strips 1251, which are spaced apart on the first metal ring 125. The second metal ring 126 is provided with multiple second comb-shaped metal strips 1261 that correspond one-to-one with the first comb-shaped metal strips 1251.

[0034] Specifically, multiple spaced comb-shaped metal strips allow for "zonal storage" of electrostatic charge in the annular direction of the first and second metal rings 126. When external electrostatic charge is transferred to the second metal ring 126, the charge is evenly distributed to each of the second comb-shaped metal strips 1261, and then transferred to the first metal ring 125 through the staggered first comb-shaped metal strips 1251. Each comb group undertakes a portion of the charge storage task, preventing excessive concentration of charge in a certain area of ​​the metal ring.

[0035] Meanwhile, the spaced comb teeth form multiple independent electrostatic buffer units. Even if one comb tooth group suffers minor damage due to an accident, the other comb tooth groups can still work normally, ensuring that the overall antistatic performance is not affected and improving the fault tolerance and reliability of the structure.

[0036] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, the side of the first metal ring 125 facing the second metal ring 126 has a convex ridge.

[0037] Furthermore, the side of the second metal ring 126 facing the first metal ring 125 has a raised ridge.

[0038] The convex ridge structures on opposite sides of the first and second metal rings 126 form a "double convex ridge coupling," further expanding the capacitive coupling area and local electric field strength between them. When external electrostatic charge is transferred to the second metal ring 126, the charge will first accumulate in the convex ridge area of ​​the second metal ring 126, and then be quickly transferred to the convex ridge area of ​​the first metal ring 125 for storage through strong coupling with the convex ridge of the first metal ring 125, forming a "bidirectional guidance and efficient storage" charge buffering mechanism.

[0039] The double-convex ridge structure can also reduce charge loss in the non-coupled area of ​​the metal ring, allowing more charge to concentrate in the capacitive area between the convex ridges, further improving charge storage efficiency and reducing the risk of charge leakage.

[0040] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, a resistance wire 127 is also provided between the first metal ring 125 and the second metal ring 126, with the two ends of the resistance wire 127 connected to the first metal ring 125 and the second metal ring 126 respectively.

[0041] Specifically, based on the basic capacitor buffer mechanism, the resistor line 127 constructs a dual anti-static system of "capacitor storage + resistor slow release". When external static charge is stored in the parallel plate capacitor structure (including the comb strip), the resistor line 127 will slowly release the stored charge to the outside of the photomask with an extremely low current (conducted to the external grounding device through the outer metal layer 120 of the third annular groove 124), avoiding long-term accumulation of charge in the capacitor structure.

[0042] Meanwhile, if a sudden surge of large amounts of static charge occurs, the resistance wire 127 can limit the conduction speed of the charge, preventing the charge from accumulating rapidly in the capacitor structure and causing breakdown, thus playing a "current limiting protection" role and further improving the stability of the anti-static system.

[0043] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, resistor line 127 is a curved trace.

[0044] Specifically, the curved trace extends the actual length of the resistor wire 127. With the same material and diameter, the longer trace length allows for more precise and controllable resistance value of the resistor wire 127, further optimizing the charge release speed. Simultaneously, the curved structure increases the contact area between the resistor wire 127 and the air within the second annular groove 123, which facilitates heat dissipation of the resistor wire 127 during charge release, preventing damage to the resistor wire 127 due to current heating and ensuring long-term stable operation.

[0045] Furthermore, the resistance wires 127 also include multiple wires, which are spaced apart between the first metal ring 125 and the second metal ring 126.

[0046] Specifically, multiple spaced resistor lines 127 form a "distributed slow-release network," which evenly distributes the charge stored in the capacitor structure to each resistor line 127, achieving synchronous slow release through multiple paths and preventing a single resistor line 127 from experiencing reduced release efficiency or damage due to excessive load. Simultaneously, the distributed layout ensures more uniform charge release in the ring direction, preventing charge distribution imbalance caused by excessively rapid release of localized charges.

[0047] In addition, multiple resistor lines 127 form a "redundant slow release channel". Even if one resistor line 127 fails, the other resistor lines 127 can still work normally, ensuring that the charge slow release function is not interrupted and further improving the system reliability.

[0048] In one possible embodiment of this application, such as Figure 1 and Figure 2 As shown, both the first metal ring 125 and the second metal ring 126 are rectangular. There are four first comb-shaped metal strips 1251 and four second comb-shaped metal strips 1261. The four first comb-shaped metal strips 1251 are located at the four corners of the first metal ring 125, and the four second comb-shaped metal strips 1261 are located at the four corners of the second metal ring 126.

[0049] The corners of a rectangular metal ring are where charges tend to concentrate most easily (the electric field strength at the corners is higher than that on the straight sides). Placing the comb teeth at the corners can specifically enhance electrostatic protection at those corners. When external electrostatic charges are transferred to the rectangular metal ring, the comb teeth at the corners will preferentially absorb and store the charges, preventing the charges from accumulating at the corners and forming a high electric field. At the same time, the staggered comb teeth achieve uniform distribution of the charges.

[0050] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An antistatic photomask, characterized in that, The device includes a substrate and a metal layer deposited on the substrate. A photomask pattern is etched on the metal layer. A first annular groove, a second annular groove, and a third annular groove are sequentially arranged around the outer periphery of the photomask pattern. A first metal ring is formed between the first annular groove and the second annular groove, and a second metal ring is formed between the second annular groove and the third annular groove. The first metal ring and the second metal ring form a parallel plate capacitor structure. A plurality of first conductive strips are spaced apart in the third annular groove. The parallel plate capacitor structure is electrically connected to the metal layer outside the third annular groove through the first conductive strips.

2. The antistatic photomask according to claim 1, characterized in that, The first metal ring has a first comb-shaped metal strip on the side facing the second metal ring, and the second metal ring has a second comb-shaped metal strip on the side facing the first metal ring. The first comb-shaped metal strip and the second comb-shaped metal strip are arranged alternately.

3. The antistatic photomask according to claim 2, characterized in that, The first comb-shaped metal strip includes multiple strips, which are spaced apart on the first metal ring. The second metal ring is provided with multiple second comb-shaped metal strips that correspond one-to-one with the first comb-shaped metal strips.

4. The antistatic photomask according to claim 2, characterized in that, The side of the first metal ring facing the second metal ring has a convex ridge.

5. The antistatic photomask according to claim 2, characterized in that, The side of the second metal ring facing the first metal ring has a raised ridge.

6. The antistatic photomask according to claim 2, characterized in that, A resistance wire is also provided between the first metal ring and the second metal ring, with the two ends of the resistance wire connected to the first metal ring and the second metal ring respectively.

7. The antistatic photomask according to claim 6, characterized in that, The resistance wires are curved.

8. The antistatic photomask according to claim 6, characterized in that, The resistance wires also include multiple wires, which are spaced apart between the first metal ring and the second metal ring.

9. The antistatic photomask according to claim 3, characterized in that, Both the first metal ring and the second metal ring are rectangular. There are four of each of the first and second comb-shaped metal strips. The four first comb-shaped metal strips are located at the four corners of the first metal ring, and the four second comb-shaped metal strips are located at the four corners of the second metal ring.

10. The antistatic photomask according to claim 1, characterized in that, The width of the first annular groove and the third annular groove is 1mm-2mm.

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