Exposure method and exposure assembly of metal mask substrate

Abstract

The invention provides an exposure method and an exposure assembly of a metal mask substrate. The exposure method comprises the following steps: placing a metal mask substrate between a movable side photomask and a reference side photomask which are arranged opposite to each other, and respectively arranging breaking assemblies at the upper end and the lower end of the surface of the movable side photomask and outside an effective exposure area. The breaking assembly is made of soft materials, and the length of the breaking assembly is not smaller than the width of the metal mask base material. When the movable side photomask is attached to the metal mask base material, the thickness of the breaking assembly enables the breaking assembly and the movable side photomask to make contact with the metal mask base material at the same time. According to the technical scheme provided by the invention, the tension which is generated when the metal mask base material is extruded and points to the outside of the effective exposure area is blocked by additionally arranging the tension breaking assembly on the movable side photomask, the inconsistency of internal tensile stress is reduced, and the sliding extension of the metal mask base material is reduced, so that the size deviation value of an exposure pattern is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing, in particular to a metal mask substrate exposure method and exposure assembly. BACKGROUND

[0002] In the existing FMM (Fine Metal Mask) exposure technology, a vertical double-sided contact exposure mode is usually adopted (i.e., the metal mask substrate is vertically placed between two vertically arranged photomasks for double-sided contact exposure). In this mode, exposure can cause many detailed problems, affecting the yield and performance of the FMM product. For example, as described in the applicant's early application for a Chinese patent (CN116184771A), due to the unevenness of the metal mask substrate (Invar coil material), the gas in the low-lying part of the substrate surface is not easy to exhaust when the double-sided photomask is attached and vacuumized. These gases accumulate between the material and the glass photomask, and the uneven bubbles between the photomask and the Invar material form contour lines in the form of vacuum Mura. The above-mentioned vacuum Mura can cause refraction and scattering of UV light, resulting in uneven aperture.

[0003] In addition, in this mode, the photomask is adsorbed by a vacuum mechanism before contact to ensure the attachment of the photomask to the substrate material. This causes the middle part of the photomask to protrude relative to the edges, thereby forming a certain amount of bending at the edges (especially the upper and lower ends) of the photomask. Due to the bending caused by the above-mentioned mechanism adsorption of the upper and lower ends of the moving photomask, the upper and lower ends of the metal mask substrate cannot be fully pressed in time when the moving photomask is attached to the metal mask substrate for exposure; the middle part will cause the material to slide outward to the upper and lower ends during the attachment action, causing inconsistent tensile stress inside the metal mask substrate. In this case, exposure etching will cause the size deviation of the exposed pattern to increase, affecting the yield and precision of the metal mask product. SUMMARY

[0004] To solve the above-mentioned problems caused by the bending of the photomask during exposure of the FMM substrate and improve the yield of the FMM product, the present application provides a metal mask substrate exposure method and exposure assembly. The technical solution provided by the present application changes the structure of the surface of the photomask, so that the upper and lower ends and the middle part of the photomask are attached to the substrate at the same time, blocking the tension to the upper and lower ends caused by the extrusion of the photomask to the FMM substrate, reducing the deformation of the substrate when the photomask is attached, thereby improving the exposure etching precision and yield of the metal mask product.

[0005] The first aspect of the present application provides an exposure method of a metal mask substrate. The exposure method comprises: placing the metal mask substrate between a moving side mask and a reference side mask, the moving side mask and the reference side mask being vertically opposite. A strip-shaped tension-breaking component extending along the width direction of the metal mask substrate is arranged at each of the upper and lower ends of the surface of the moving side mask outside the effective exposure area. The tension-breaking component is made of soft material, and the length of the tension-breaking component is not shorter than the width of the metal mask substrate. The moving side mask is moved towards the metal mask substrate, and the metal mask substrate is exposed after the moving side mask is moved into position. The thickness of the tension-breaking component is set such that the tension-breaking component contacts the metal mask substrate at the same time as the moving side mask contacts the metal mask substrate when the exposure area is vacuumed by the suction mechanism to make the moving side mask adhere to the metal mask substrate.

[0006] The surface area of the moving side mask comprises: an effective exposure area actually used for exposure, and a non-exposure area at the edge of the moving mask which does not play a role in exposure. The effective exposure area of the surface of the moving side mask needs to be set according to the size of the specific metal mask product, and the edge area not used for exposure is set as the non-exposure area. For a specific metal mask product, corresponding distinguishing marks (usually mark lines) are usually provided on the surface of the moving side mask to distinguish the effective exposure area and the non-exposure area.

[0007] By increasing the height of the positions at the upper and lower ends of the moving side mask (outside the effective exposure area) which contact the FMM substrate, it is ensured that the upper and lower ends of the FMM substrate can be timely and sufficiently pressed during the adhesion of the moving side mask to the FMM substrate, and the tension inside the FMM substrate directed outside the effective exposure area is timely broken to effectively reduce the sliding extension of the FMM substrate caused by external influences (extrusion of the middle part of the moving side mask).

[0008] Further, in order to increase the friction and adsorption force between the tension-breaking component and the FMM substrate, so as to better block the tension inside the FMM substrate to the upper and lower ends and reduce the deformation of the substrate, rough textures are provided on the surface of the tension-breaking component to increase the friction between the metal mask substrate. In some embodiments, the tension-breaking component is a dust-free adhesive tape. Of course, the tension-breaking component can also be made of silica gel material.

[0009] Further, in order to smoothly release the air on the surface of the FMM substrate during the exposure process, reduce the air bubbles caused by the uneven surface of the FMM substrate, and avoid the refraction and scattering of UV light caused by the air bubbles during the exposure process, the exposure method provided by the present application further comprises: uniformly arranging a plurality of spacing adjusting components on the left and right sides of the surface of the moving side mask outside the effective exposure area. The thickness of the spacing adjusting component is slightly greater than the thickness of the metal mask substrate, and the spacing adjusting component does not contact the metal mask substrate. In the process of contacting and adhering the moving side mask to the metal mask substrate, an air release channel is formed between the adjacent spacing adjusting components on the same side of the moving side mask. The spacing adjusting component is one of an adhesive tape, a metal sheet, a film, a fabric, paper, and rubber.

[0010] Corresponding to the above-mentioned exposure method, the second aspect of the present application also provides a metal mask substrate exposure assembly. The exposure assembly comprises: a reference side mask and a moving side mask arranged vertically opposite to each other, and a metal mask substrate arranged between the reference side mask and the moving side mask; one strip-shaped tension breaking component extending along the width direction of the metal mask substrate is arranged at each end of the surface of the moving side mask outside the effective exposure area; the tension breaking component is made of soft material and has a length not shorter than the width of the metal mask substrate; the thickness of the tension breaking component is set to enable the moving side mask to contact the metal mask substrate at the same time as the moving side mask contacts the metal mask substrate in a vacuum environment of the exposure area by the suction mechanism.

[0011] The technical solution provided by the present application changes the structure of the mask surface, so that the upper and lower ends and the middle part of the moving side mask simultaneously adhere to the substrate when the FMM substrate is exposed on both sides, block the tension from the middle part of the mask to the upper and lower ends of the FMM substrate, reduce the deformation of the FMM substrate when the mask adheres, and improve the exposure etching precision and yield of the finished metal mask (FMM). BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0013] Figure 1 The structure diagram of the metal mask exposure assembly provided by the present application is shown in the figure. DETAILED DESCRIPTION

[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 exposure assembly of the metal mask above, the application also provides an exposure method of a metal mask substrate. The exposure method comprises: placing the metal mask substrate between a moving side mask and a reference side mask, wherein the moving side mask and the reference side mask are vertically opposite; and setting a strip-shaped tension-breaking assembly extending along the width direction of the metal mask substrate at 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 its length is not shorter than the width of the metal mask substrate. The moving side mask is moved to adhere to the metal mask substrate, and the metal mask substrate is exposed after the moving side mask is moved into position. The thickness of the tension-breaking assembly is set to be such that when the exposure area is vacuumized by the suction mechanism, the tension-breaking assembly and the moving side mask contact and adhere to the metal mask substrate at the same time.

[0019] Specifically, the thickness of the tension-breaking assembly can be determined according to the height difference between the surface area of the center of the moving side mask and the surface area of the moving side mask where the tension-breaking assembly is located when the exposure area is vacuumized by the suction mechanism (under the same vacuumization parameters as the exposure process). The thickness of the tension-breaking assembly is set to be the height difference, so as to ensure that the surface of the moving side mask contacts and adheres to the surface of the metal mask substrate at the same time when the surface of the moving side mask adheres to the surface of the metal mask substrate. In addition, the "moving into position" means that the effective exposure area of the surface of the moving side mask adheres to the surface of the metal mask substrate in a state meeting the exposure requirements (the non-exposure area does not have to adhere). In actual production, the setting can be achieved by optical monitoring or by whether the exposed FMM product meets the requirements.

[0020] Obviously, the softness of the tension-breaking assembly can ensure that the moving side mask will not be damaged when adhering to the FMM substrate. In addition, the thickness of the tension-breaking assembly can be set by measuring the bending amount of the tension-breaking assembly relative to the middle part / the most protruding part of the moving side mask when the exposure area is vacuumized by the suction mechanism.

[0021] Further, in order to increase the friction between the surface of the tension-breaking assembly and the FMM substrate to better block the tension from the inside of the FMM substrate to the upper and lower ends and reduce the deformation of the substrate, rough textures are arranged on the surface of the tension-breaking assembly to increase the friction between the tension-breaking assembly and the metal mask substrate. Preferably, the tension-breaking assembly can also be made of silica gel material. In some embodiments, the tension-breaking assembly is a dust-free adhesive tape.

[0022] Further, in order to smoothly release the air on the surface of the FMM substrate (the surface of the FMM substrate is uneven, which hinders the discharge of air molecules on the surface of the FMM substrate when the mask is attached), reduce the bubbles generated when the mask is attached to the FMM substrate, and avoid the refraction and scattering of UV light caused by these bubbles during exposure, resulting in uneven etching aperture. The exposure method provided by the present application further comprises: uniformly arranging a plurality of spacing adjusting components on the left and right sides of the moving mask surface, outside the effective exposure area. The thickness of the spacing adjusting component is slightly larger than the thickness of the metal mask substrate, and it is in contact with the reference mask and not in contact with the metal mask substrate. During the process of the moving mask contacting the metal mask substrate, the moving mask forms an air release channel between adjacent spacing adjusting components on the same side.

[0023] The above only describes the embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the technical solutions provided by the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of exposing a metal mask substrate, characterized by, The exposure method comprises the following steps: placing a metal mask substrate between a moving side mask and a reference side mask, which are arranged vertically opposite to each other; arranging a strip-shaped tension-breaking component extending along the width direction of the metal mask substrate at both ends of the surface of the moving side mask outside the effective exposure area; the tension-breaking component is made of soft material and its length is not shorter than the width of the metal mask substrate; moving the moving side mask towards the metal mask substrate, and exposing the metal mask substrate after the moving side mask is moved into position; the thickness of the tension-breaking component is set such that the tension-breaking component and the moving side mask contact the metal mask substrate at the same time when the moving side mask is attached to the metal mask substrate by vacuumizing the exposure area by a suction mechanism.

2. The exposure method according to claim 1, wherein The surface of the tension-breaking component is provided with rough texture.

3. The exposure method according to claim 2, wherein The exposure method further comprises the following steps: uniformly arranging a plurality of spacing adjusting components with a thickness slightly greater than the thickness of the metal mask substrate at both sides of the surface of the moving side mask outside the effective exposure area; in the process of the moving side mask contacting the metal mask substrate, the spacing adjusting components do not contact the metal mask substrate, and an air release channel is formed between adjacent spacing adjusting components on the same side of the moving side mask.

4. The exposure method according to claim 3, wherein The tension-breaking component is made of silica gel material.

5. The exposure method according to claim 3, wherein The tension-breaking component is a dust-free adhesive tape; and the spacing adjusting component is one of an adhesive tape, a metal sheet, a film, a fabric, paper and rubber.

6. An exposure assembly for a metal mask substrate, characterized by The exposure component comprises a reference side mask and a moving side mask arranged vertically opposite to each other, and a metal mask substrate arranged between the reference side mask and the moving side mask; a strip-shaped tension-breaking component extending along the width direction of the metal mask substrate is arranged at both ends of the surface of the moving side mask outside the effective exposure area; the tension-breaking component is made of 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 the tension-breaking component and the moving side mask contact the metal mask substrate at the same time when the moving side mask is attached to the metal mask substrate in a vacuum environment by a suction mechanism.

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