Exposure method and exposure assembly for a metal mask substrate

Abstract

The application provides an exposure method and an exposure assembly for a metal mask substrate. The exposure method comprises: placing the metal mask substrate between a moving side mask and a reference side mask arranged opposite to each other, and arranging a tension breaking assembly on both ends of the surface of the moving side mask outside the effective exposure area. The tension breaking assembly is made of soft material and has a length not shorter than the width of the metal mask substrate. When the moving side mask is attached to the metal mask substrate, the thickness of the tension breaking assembly enables it to contact the metal mask substrate at the same time as the moving side mask. The technical solution provided by the application adds a tension breaking assembly to the moving side mask to block the tension generated when the metal mask substrate is pressed and directed outside the effective exposure area, reduce the inconsistency of the internal tensile stress, reduce the sliding extension of the metal mask substrate, and thus reduce the size deviation of the exposure pattern.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing, specifically to a method and assembly for exposing a metal mask substrate. Background Technology

[0002] In existing FMM (Fine Metal Mask) exposure technology, a vertical double-sided bonding contact exposure mode is typically used (i.e., the metal mask substrate is vertically placed between two vertically positioned photomasks for double-sided bonding exposure). Exposure in this mode introduces many subtle problems, affecting the yield and performance of the FMM product. For example, as described in the applicant's earlier Chinese patent application (CN116184771A), due to the inherent unevenness of the metal mask substrate (Invar roll), gas in the low-lying areas of the substrate surface is difficult to expel during vacuuming during double-sided photomask bonding. This gas accumulates between the material and the glass photomask, and the uneven bubbles generated between the photomask and the Invar material form a contour-shaped vacuum mura. This vacuum mura causes refraction and scattering of UV light, resulting in uneven aperture size.

[0003] Furthermore, in this mode, the photomask is adsorbed by a vacuum mechanism before contact, ensuring adhesion between the photomask and the substrate material. This causes the middle part of the photomask to bulge relative to the edges, resulting in a certain amount of bending at the edges (especially the top and bottom ends). Due to the bending caused by the adsorption mechanism, the upper and lower ends of the moving-side photomask cannot be sufficiently pressed down in time when it is applied to the metal mask substrate for exposure. The middle part, due to the pressure from the moving-side photomask, will cause the material to slide and extend outwards towards the upper and lower ends during the bonding process, resulting in inconsistent tensile stress within the metal mask substrate. Exposure and etching under these conditions will lead to increased dimensional deviations in the exposed pattern, affecting the yield and accuracy of the finished metal mask. Summary of the Invention

[0004] To address the aforementioned problems caused by mask bending during exposure of FMM substrates and improve the yield of FMM finished products, this invention provides an exposure method and exposure assembly for metal photomask substrates. The technical solution provided by this invention modifies the structural morphology of the photomask surface, allowing the upper and lower ends and the middle of the photomask to simultaneously adhere to the substrate. This blocks the upward and downward tension generated by the photomask pressing against the FMM substrate, reducing the deformation of the substrate during photomask adhesion, thereby improving the exposure etching accuracy and yield of the finished metal photomask.

[0005] The first aspect of this application provides a method for exposing a metal photomask substrate. The exposure method includes: placing the metal photomask substrate between a moving-side photomask and a reference-side photomask, the moving-side photomask and the reference-side photomask being vertically aligned. A strip-shaped tension-breaking assembly extending along the width direction of the metal photomask substrate is respectively disposed at the upper and lower ends of the moving-side photomask surface, outside the effective exposure area. The tension-breaking assembly is made of a flexible material, and its length is not shorter than the width of the metal photomask substrate. The moving-side photomask is moved toward the metal photomask substrate, and the metal photomask substrate is exposed after the moving-side photomask is in position. The thickness of the tension-breaking assembly is set such that when the adsorption mechanism evacuates the exposure area and the moving-side photomask adheres to the metal photomask substrate, the tension-breaking assembly and the moving-side photomask simultaneously contact the metal photomask substrate.

[0006] The moving-side photomask surface area includes: an effective exposure area actually used for exposure, and a non-exposure area located at the edge of the moving photomask that does not serve an exposure function. The effective exposure area on the moving-side photomask surface needs to be set according to the specific size of the metal photomask product, while the edge area that is not used for exposure is designated as the non-exposure area. For specific metal photomask products, corresponding distinguishing markings (usually marking lines) are typically provided on the moving-side photomask surface to differentiate between the effective exposure area and the non-exposure area.

[0007] By increasing the height of the contact points between the upper and lower ends of the moving-side photomask (located outside the effective exposure area) and the FMM substrate, it is ensured that the upper and lower ends of the FMM substrate can be fully pressed and adhered to in a timely manner during the process of the moving-side photomask bonding with the FMM substrate. This effectively breaks the tension inside the FMM substrate pointing outward from the effective exposure area, thereby reducing the sliding extension of the FMM substrate caused by external influences (squeezing in the middle of the moving-side photomask).

[0008] Furthermore, to increase the friction and adhesion between the tension breaking assembly and the FMM substrate, thereby better blocking the upward and downward tension within the FMM substrate and reducing substrate deformation, a rough texture is provided on the surface of the tension breaking assembly to increase the friction with the metal mask substrate. In some embodiments, the tension breaking assembly is a dust-free adhesive tape. Of course, the tension breaking assembly can also be made of silicone material.

[0009] Furthermore, to smoothly release air from the surface of the FMM substrate during exposure, reduce bubbles caused by unevenness on the FMM substrate surface, and prevent these bubbles from refracting and scattering UV light during exposure, thus avoiding uneven exposure etching apertures, the exposure method provided in this application further includes: uniformly arranging a plurality of spacing adjustment components on the left and right sides of the moving-side photomask surface, outside the effective exposure area. The thickness of the spacing adjustment components is slightly greater than the thickness of the metal mask substrate, and they do not contact the metal mask substrate. During the process of the moving-side photomask contacting and adhering to the metal mask substrate, an air release channel is formed between adjacent spacing adjustment components on the same side of the moving-side photomask. The spacing adjustment components are one of tape, metal sheet, film, fabric, paper, and rubber.

[0010] Corresponding to the above-described exposure method, a second aspect of this application also provides an exposure assembly for a metal photomask substrate. The exposure assembly includes: a reference-side photomask and a movable-side photomask arranged vertically opposite each other; a metal photomask substrate is disposed between the reference-side photomask and the movable-side photomask; a strip-shaped tension breaking assembly extending along the width direction of the metal photomask substrate is respectively disposed at the upper and lower ends of the movable-side photomask outside the effective exposure area; the tension breaking assembly is made of a soft material and its length is not shorter than the width of the metal photomask substrate; the thickness of the tension breaking assembly is set such that when the movable-side photomask is attached to the metal photomask substrate in a vacuum environment created by the adsorption mechanism in the exposure area, it simultaneously contacts the metal photomask substrate with the movable-side photomask.

[0011] The technical solution provided in this application changes the structural morphology of the photomask surface, so that when the FMM substrate is exposed by double-sided bonding, the upper and lower ends and the middle of the moving side photomask are bonded to the substrate simultaneously. This blocks the tension on the upper and lower ends of the FMM substrate caused by the pressure of the middle of the photomask, reduces the deformation of the FMM substrate when the photomask is bonded, and improves the exposure etching accuracy and yield of the finished metal mask (FMM). Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of the metal mask exposure assembly provided in this application. Detailed Implementation

[0014] 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] like Figure 1 As shown, the exposure assembly for the metal mask substrate provided in this application includes: a reference-side photomask 2 and a movable-side photomask 3 arranged vertically opposite each other, with a metal mask (FMM) substrate 1 (typically suspended) disposed between the reference-side photomask 2 and the movable-side photomask 3. Before exposing the metal mask substrate 1, vacuuming (mechanical adsorption) the area where the metal mask substrate 1 is located inevitably causes bending of the reference-side photomask 2 and the movable-side photomask 3.

[0016] The aforementioned bending phenomenon causes the central part of the FMM substrate 1 to be compressed and stretched upwards and downwards when the moving-side photomask 3 is attached to the FMM substrate 1, resulting in additional deviations in the size of the metal mask exposure pattern. In the exposure assembly of the metal mask substrate provided in this application, strip-shaped tension assemblies 31 and 32 extending along the width direction of the metal mask substrate are respectively provided at the upper and lower ends of the moving-side photomask 3, outside the effective exposure area. The tension assemblies 31 and 32 are made of a soft material and their length is not shorter than the width of the metal mask substrate 1. When the thickness of the tension assemblies 31 and 32 is set such that, in a vacuum environment created by the adsorption mechanism in the exposure area, the moving-side photomask 3 is attached to the metal mask substrate 1, the tension assemblies 31 and 32 simultaneously contact and adhere to the metal mask substrate 1 with the moving-side photomask 3 (mainly protruding from the center of the photomask).

[0017] The aforementioned exposure assembly increases the height of the contact points between the bending positions (bending caused by the adsorption mechanism) at the upper and lower ends of the moving-side photomask 3 and the FMM substrate 1 through the tension breaking components 31 and 32. This ensures that the upper and lower ends of the FMM substrate 1 can be fully and timely pressed together during the bonding process of the moving-side photomask 3 with the FMM substrate 1. By pressing the FMM substrate 1 with the tension breaking components 31 and 32, the tension pointing from the inside of the FMM substrate 1 towards the outside of the effective exposure area is broken from the upper and lower ends of the moving-side photomask 3. This reduces the sliding extension / stretching of the FMM substrate 1 caused by the squeezing of the middle of the moving-side photomask 3, thereby reducing the dimensional deviation of the metal mask exposure pattern.

[0018] Corresponding to the aforementioned exposure assembly for a metal photomask, this application also provides a method for exposing a metal photomask substrate. The exposure method includes: placing the metal photomask substrate between a moving-side photomask and a reference-side photomask, the moving-side photomask and the reference-side photomask being vertically aligned; and respectively, at the upper and lower ends of the moving-side photomask surface, outside the effective exposure area, a strip-shaped tension-breaking assembly extending along the width direction of the metal photomask substrate is disposed. The tension-breaking assembly is made of a flexible material and its length is not shorter than the width of the metal photomask substrate. The moving-side photomask is moved to fit against the metal photomask substrate, and the metal photomask substrate is exposed after the moving-side photomask is in position. The thickness of the tension-breaking assembly is set such that when the adsorption mechanism evacuates the exposure area and the moving-side photomask fits against the metal photomask substrate, the tension-breaking assembly and the moving-side photomask simultaneously contact and fit against the metal photomask substrate.

[0019] Specifically, the thickness of the tension breaking component can be determined based on the height difference between the surface area of ​​the center of the moving-side photomask and the surface area of ​​the moving-side photomask where the tension breaking component is located, obtained when the adsorption mechanism evacuates the exposure area (under the same vacuum parameters as the exposure process). Setting the thickness of the tension breaking component to this height difference ensures that when the surface of the moving-side photomask is attached to the surface of the metal mask substrate, the tension breaking component and the moving-side photomask simultaneously contact and adhere to the metal mask substrate. Furthermore, "moving to position" refers to the effective exposure area of ​​the moving-side photomask surface and the surface of the metal mask substrate being in a state that meets the exposure requirements (non-exposure areas do not need to be attached). In actual production, this can be set through optical monitoring or by checking whether the exposed FMM product meets the requirements.

[0020] Clearly, the flexibility of the tension breaking assembly ensures that the moving-side photomask will not be damaged when it is bonded to the FMM substrate. Furthermore, the thickness of the tension breaking assembly can be determined by measuring the amount of bending relative to the center / most convex position of the moving-side photomask at its designated location, when the adsorption mechanism evacuates the exposure area.

[0021] Furthermore, to increase the friction between the surface of the tension break assembly and the FMM substrate to better block the upward and downward tension within the FMM substrate and reduce substrate deformation, a rough texture is provided on the surface of the tension break assembly to increase the friction with the metal mask substrate. Preferably, the tension break assembly can also be made of silicone material. In some embodiments, the tension break assembly is a dust-free adhesive tape.

[0022] Furthermore, to smoothly release air from the surface of the FMM substrate during the exposure process of the photomask bonding with the FMM substrate (the surface of the FMM substrate is uneven, hindering the expulsion of air molecules from the surface of the FMM substrate during photomask bonding), and to reduce the air bubbles generated during photomask bonding with the FMM substrate, this application provides an exposure method that further includes: uniformly arranging a plurality of spacing adjustment components on the left and right sides of the moving-side photomask surface, in areas outside the effective exposure area. The thickness of the spacing adjustment components is slightly larger than the thickness of the metal mask substrate, and they contact the reference-side photomask but not the metal mask substrate. During the process of the moving-side photomask contacting the metal mask substrate, an air release channel is formed between adjacent spacing adjustment components on the same side of the moving-side photomask. The spacing adjustment components can be one of tape, metal sheet, film, fabric, paper, and rubber.

[0023] The above description is merely an embodiment of this application and is not intended to limit this application. For those skilled in the art, the technical solutions provided in this application can be modified and varied in various ways. 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. A method for exposing a metal photomask substrate, characterized in that, The exposure method includes: placing a metal photomask substrate between a moving-side photomask and a reference-side photomask, the moving-side photomask and the reference-side photomask being vertically aligned; setting a strip-shaped tension-breaking component extending along the width direction of the metal photomask substrate at each of the upper and lower ends of the moving-side photomask surface, outside the effective exposure area; the tension-breaking component is made of a flexible material and its length is not shorter than the width of the metal photomask substrate; moving the moving-side photomask towards the metal photomask substrate, and exposing the metal photomask substrate after the moving-side photomask is in place; the thickness of the tension-breaking component is set such that when the adsorption mechanism evacuates the exposure area and the moving-side photomask adheres to the metal photomask substrate, the tension-breaking component and the moving-side photomask simultaneously contact the metal photomask substrate.

2. The exposure method as described in claim 1, characterized in that, The surface of the tension breaking assembly is provided with a rough texture.

3. The exposure method as described in claim 2, characterized in that, The exposure method further includes: uniformly arranging a plurality of spacing adjustment components on the left and right sides of the moving side photomask surface, in the area outside the effective exposure area, wherein the thickness of the spacing adjustment components is slightly greater than the thickness of the metal mask substrate; during the process of the moving side photomask contacting the metal mask substrate, the spacing adjustment components do not contact the metal mask substrate, and an air release channel is formed between adjacent spacing adjustment components on the same side of the moving side photomask.

4. The exposure method as described in claim 3, characterized in that, The tension breaking assembly is made of silicone material.

5. The exposure method as described in claim 3, characterized in that, The tension breaking assembly is a dust-free adhesive tape; the spacing adjustment assembly is one of the following: adhesive tape, metal sheet, film, fabric, paper, and rubber.

6. An exposure assembly for a metal photomask substrate, characterized in that, The exposure assembly includes: a reference-side photomask and a moving-side photomask arranged vertically opposite each other, with a metal mask substrate disposed between the reference-side photomask and the moving-side photomask; a strip-shaped tension breaking component extending along the width direction of the metal mask substrate is respectively disposed at the upper and lower ends of the moving-side photomask surface, outside the effective exposure area; the tension breaking component is made of a soft material and its length is not shorter than the width of the metal mask substrate; the thickness of the tension breaking component is set such that when the adsorption mechanism evacuates the exposure area and the moving-side photomask is attached to the metal mask substrate, the tension breaking component and the moving-side photomask simultaneously contact the metal mask substrate.

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