TWI398737B - Method of mask alignment and exposing and mask assembly - Google Patents

Description

Mask aligning exposure method and reticle assembly

The present invention relates to an exposure method and a reticle assembly, and more particularly to a reticle alignment exposure method and a reticle assembly.

In the liquid crystal display panel, by using a pixel electrode on the thin film transistor substrate and a common electrode in the color filter substrate to input different voltages, different electric fields can be generated between the pixel electrode and the color filter substrate. The liquid crystal molecules can be driven to produce various steering angles to display the desired picture. The thin film transistor substrate is manufactured by a photomask process, through coating, photoresist coating, exposure, development, etching, and photoresist removal to form a desired circuit pattern on a substrate.

Please refer to FIG. 1 , wherein the arrow on the surface of the substrate 2 is a schematic diagram of the direction of the exposure scan when the exposure process is performed in the prior art. The substrate 2 is a glass substrate for fabricating a plurality of thin film transistor substrates 21 having a small size. Therefore, exposure of a thin film transistor substrate 21 can be completed by using a mask 1 having an area equal to or larger than the thin film transistor substrate 21. Process. Thereby, the exposure operation of the pattern of one thin film transistor substrate 21 can be completed by one exposure of the mask 1 (in the direction of the hollow arrow in FIG. 1, which indicates the exposure scanning direction). In addition, when the area of the substrate 2 is larger than that of the reticle 1, the exposure is performed by the carrier (not shown) of the substrate 2 and the movement of the reticle 1 (such as the direction of the solid arrow in FIG. 1 , The exposure order of the plurality of thin film transistor substrates 21 is shown, and a plurality of patterns of the thin film transistor substrate 21 can be provided on the substrate 2, and the plurality of thin film transistor substrates 21 can be simultaneously completed by dicing.

However, as the size of the liquid crystal display panel continues to increase, a plurality of masks may be required in the process to complete the exposure process of the thin film transistor substrate 21. Referring to FIG. 2, another exposure method is to design a plurality of patterns by using the same mask, and then performing the exposure process by using the plurality of patterns in a stitch mode. The bonding process of the bonding method is to divide the pattern to be exposed on the thin film transistor substrate 31 into a plurality of first exposure regions A1, a second exposure region A2 and a third exposure of the fan out area. District A3. In order to form different exposure regions, please refer to FIG. 3, the mask 4 used in the conventional bonding method has a first pattern region Z1, a second pattern region Z2 and a third pattern region Z3, and The pattern areas are respectively provided with a plurality of positioning points m2.

Referring to FIG. 4, when the substrate 3 is exposed by the reticle 4, since the reticle 4 has three different pattern regions Z1, Z2, and Z3 at the same time, when one region is performed, When the exposure operation of the three exposure areas A3 is taken as an example, the other two pattern areas Z1 and Z2 on the mask 4 are shielded by the shading mechanism B of the machine (as indicated by the hatched portion) to avoid interference caused by different pattern areas. And cause an exposure error.

In addition, in order to ensure the correct position of the exposure, before each exposure, the two sensing elements T1 and T2 disposed above the reticle 4 first detect the positioning points m1 and m2 on the substrate 3 and the reticle 4 for alignment. . Therefore, when the sensing elements T1 and T2 respectively detect that the positioning points m1 and m2 overlap to form a pair of bit marks, it means that the alignment of the substrate 3 and the photomask 4 is completed, and exposure can be performed. The direction of the solid arrow in FIG. 4 indicates the exposure order of each of the different pattern regions when the pattern of the two thin film transistor substrates 31 is exposed on the substrate 3.

However, the sensing elements T1, T2 are limited by the design of the exposure station and can only be moved from the ends of the reticle 4 to the central position C of the reticle 4, respectively. When the exposure of the peripheral line regions on both sides (herein, the third exposure region A3 is taken as an example), since the pattern regions Z1 and Z2 which are not required to be exposed on the mask 4 must be shielded, the mask 4 is also The area of the shadow area is greater than half of its overall area. This also causes the sensing component T2 to detect the positioning point for the alignment sensing, and can only be aligned by the single sensing component T1, so that the accurate alignment cannot be achieved, and thus, the two sides are even more caused. The alignment accuracy between the exposure areas A2 and A3 of the line and the central exposure area A1 is greatly reduced, so that the areas of the first exposure area A1, the second exposure area A2 and the third exposure area A3 are not aligned. Problems such as overlapping or having a gap cause a problem of uneven bonding on the liquid crystal display panel, resulting in deterioration of product quality. In addition, if only the stepping movement of the stage of the exposure machine is adopted, and the positioning points m1 and m2 are not used for positioning, since the stepping accuracy of the stage cannot ensure that the two exposure areas can be accurately engaged, there is also a joint. Uneven phenomenon.

Therefore, how to design a reticle alignment exposure method and a photomask assembly that can accurately align and improve manufacturing efficiency has become one of the important topics.

In view of the above problems, an object of the present invention is to provide a reticle aligning exposure method and a reticle assembly which can accurately align and improve manufacturing efficiency.

In order to achieve the above object, a reticle aligning exposure method according to the present invention comprises the steps of: exposing a photoresist layer on a substrate by using a first pattern region of a first reticle to form at least one a first exposure region; a second pattern region of a second mask is used to expose the photoresist layer to form a second exposure region; and a third pattern region of the second mask is used to expose the photoresist layer. To form a third exposure zone. Wherein, the first exposure zone is located between the second exposure zone and the third exposure zone.

In order to achieve the above object, a reticle assembly according to the present invention is used for exposing a photoresist layer of a substrate, the reticle assembly comprising a first reticle and a second reticle, the first reticle having a a first pattern area and a plurality of first mask positioning points, wherein the first mask positioning points are located around the first pattern area. The second mask has a second pattern area, a third pattern area and a plurality of second mask positioning points, and the second mask positioning points are located between the second pattern area and the third pattern area.

According to the present invention, the reticle aligning exposure method and the reticle assembly of the present invention independently set the first pattern region corresponding to the first exposure region on a first reticle, and the first exposure region is on the middle of the substrate. The region where the pattern is repeated can reduce the number of exposures in the intermediate portion of the substrate by increasing the area of the first pattern region on the first mask, thereby shortening the processing time and increasing the manufacturing efficiency. In addition, the second exposure area corresponding to the two peripheral line areas on the substrate and the second pattern area and the third pattern area of the third exposure area are disposed together on a second mask, and the positioning on the second mask The dot system is disposed between the second pattern area and the third pattern area to prevent the two sensing elements from simultaneously performing the mask alignment sensing, thereby causing the problem that the alignment cannot be effectively performed. Therefore, in addition to improving the alignment accuracy of the reticle and reducing the unevenness of the bonding, the present invention can also improve the process efficiency.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a reticle alignment exposure method and a reticle assembly according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements are denoted by the same reference numerals.

Referring to FIG. 5, a reticle alignment exposure method according to a preferred embodiment of the present invention can be used to fabricate a thin film transistor substrate of a liquid crystal display panel, which includes steps S1 to S3.

Referring to FIG. 5, FIG. 6A and FIG. 6B, step S1 is performed by exposing a photoresist layer 61 of a substrate 6 by using a first pattern region P1 of a first mask 51 to form at least one An exposure area E1. The photoresist layer 61 may be first coated on the substrate 6 by spin coating or slit coating, and the material of the photoresist layer 61 is, for example, a positive photoresist material or a negative light. Resistive material, here is a description of the positive photoresist material. The substrate 6 can be disposed on a carrier (not shown) for movement in the X or Y direction. In addition, a plurality of first positioning points 611, a plurality of second positioning points 612, and a plurality of third positioning points 613 are formed on the substrate 6. In this embodiment, eight first positioning points 611 and 4 are used. The second positioning point 612 and the four third positioning points 613 are exemplified, but are not intended to limit the present invention.

The first mask 51 has a first pattern area P1 and a plurality of first mask positioning points 511. In the embodiment, four first mask positioning points 511 are taken as an example for illustration. To limit the invention.

Therefore, when the exposure operation of the first exposure region E1 is performed on the photoresist layer 61, each of the first mask positioning points 511 on the first mask 51 and the first positioning points 611 on the substrate 6 are first paired. And the two sensing elements T1 and T2 are respectively moved by the two sides above the first mask 51 to perform sensing alignment. When the alignment is completed, each of the first mask positioning points 511 and the first positioning points 611 are A first alignment mark M1 is formed (Fig. 6B). After the first sensing elements T1 and T2 respectively sense the first alignment mark M1, the exposure machine can perform the exposure operation of the first exposure area E1 to form the first exposure area E1 on the substrate 6. In the present embodiment, the two first exposure regions E1 arranged side by side are taken as an example, and the first exposure region E1 is a region on the substrate 6 where the intermediate pattern is repeated (mainly a pixel region). Non-limiting, different partitions can be used depending on the design. Since the first pattern region P1 is separately disposed on the first mask 51, the area thereof can be increased to reduce the number of exposures in the intermediate portion of the substrate 6. For example, in this embodiment, the intermediate pixel region of a large-sized thin film transistor substrate can be completed only by double exposure. Moreover, there is only one first pattern area P1 on the first mask 51, so the two sensing elements T1 and T2 can be simultaneously sensed to improve the alignment accuracy.

Referring to FIG. 5, FIG. 7A and FIG. 7B, step S2 is performed by using a second pattern region P2 of a second mask 52 on the photoresist layer 61 to form a second exposure region E2. The second pattern area P2 and the third pattern area P3 are disposed on a second mask 52, and the second mask positioning point 521 is disposed between the second pattern area P2 and the third pattern area P3. Therefore, when the exposure operation of the second exposure region E2 is performed on the photoresist layer 61, the exposure machine first shields the third pattern region P3 that is not to be exposed by the light shielding mechanism B, and each of the second mask 52 The second reticle locating point 521 is aligned with each of the second locating points 612 on the substrate 6. Wherein, since each of the second mask positioning points 521 is located between the second pattern area P2 and the third pattern area P3, the sensing elements T1 and T2 can be moved from both sides and the mask positions 521 are simultaneously sensed. Align the alignment to increase the accuracy of the alignment. By the relative movement of the substrate 6 and the second mask 52, a second alignment mark M2 is formed when the alignment is completed (as shown in FIG. 7B). After the second sensing elements T1 and T2 respectively sense the second alignment mark M2, the exposure operation of the second exposure area E2 can be performed to form the second exposure area E2.

Referring to FIG. 5, FIG. 8A and FIG. 8B simultaneously, step S3 is performed by using the third pattern region P3 of the second mask 52 to expose the photoresist layer 61 to form a third exposure region E3. When the exposure operation of the third exposure region E3 is performed on the photoresist layer 61, the exposure machine first shields the second pattern region P2 that is not required to be exposed by the light shielding mechanism B, and then uses the second mask 52. The two mask positioning points 521 are aligned with the third positioning points 613 on the substrate 6. The second mask positioning points 521 are located between the second pattern area P2 and the third pattern area P3. The measuring elements T1 and T2 can be moved from both sides and the second mask positioning points 521 are simultaneously sensed and aligned to increase the accuracy of the alignment. By the relative movement of the substrate 6 and the second mask 52, a third alignment mark M3 is formed after the alignment is completed (as shown in FIG. 8B). After the second sensing elements T1 and T2 respectively sense the third alignment mark M3, the exposure operation of the third exposure area E3 can be performed to form the third exposure area E3. Thereby, when the exposure operation of the second exposure area E2 and the third exposure area E3 on both sides is performed, the area of the shielding area required for exposure can be reduced via the second mask 52 to avoid the two sensing elements T1 and T2. It is not possible to perform the alignment sensing at the same time, resulting in a problem that cannot be effectively aligned.

In addition, it should be noted that the exposure order of the first exposure area E1, the second exposure area E2, and the third exposure area E3 is not limited, and different exposure orders may be used according to different considerations, for example, both sides may be first performed. After the exposure operation of the second exposure area E2 and the third exposure area E3 of the line, the exposure operation of the first exposure area E1 is performed.

Finally, when all of the exposure areas E1, E2, and E3 on the substrate 6 are exposed, the development process can be performed.

It should be noted that, in this embodiment, the first alignment mark M1 (shown in FIG. 6B), the second alignment mark M2 (shown in FIG. 7B), and the third alignment mark M3 (as shown in FIG. 8B). The pattern is not the focus of this case, but can be designed according to different needs. And the three can also form the same pattern, and the end is to make the optical masks 51, 52 and the substrate 6 accurately aligned as a priority.

In addition, as shown in FIG. 9, after the exposure process of the large-sized substrate 6' is completed, a plurality of thin film transistor substrates can be formed by dicing. Here, two thin film transistor substrates will be described as an example. Therefore, the exposure of the first exposure region E1 can be performed first by the first mask 51 (the direction of the solid arrow in FIG. 9 indicates the order of exposure when the first exposure region E1 is exposed), and the second light is used. The cover 52 performs exposure of the second exposure area E2 and the third exposure area E3 (the direction of the hollow arrow in FIG. 9 indicates the order of exposure when the second exposure area E2 and the third exposure area E3 are exposed), that is, the substrate A pattern of two thin film transistor substrates is formed on 6'. Among them, it should be noted that the exposure order is not limited, and different exposure sequences may be used depending on the design.

Referring to FIG. 6A and FIG. 7A simultaneously, a photomask assembly of the present invention is used for exposing a photoresist layer 61 of a substrate 6. The photomask assembly includes a first mask 51 and a second mask. 52. The first mask 51 has a first pattern area P1 and a plurality of first mask positioning points 511. The first mask positioning points 511 are located around the first pattern area P1. The second mask 52 has a second pattern area P2 and a third pattern area P3 and a plurality of second mask positioning points 521. The second mask positioning points 521 are located in the second pattern area P2 and the third pattern area. Between P3.

Since the first reticle 51 and the second reticle 52 of the reticle assembly have been described in detail in the foregoing embodiments, they are not described herein again.

In summary, the reticle aligning method and the reticle assembly according to the present invention independently set the first pattern area corresponding to the first exposure area on a first reticle, and the first exposure area is on the middle of the substrate. The region where the pattern is repeated can reduce the number of exposures in the intermediate portion of the substrate by increasing the area of the first pattern region on the first mask, thereby shortening the processing time and increasing the manufacturing efficiency. In addition, the second exposure area corresponding to the two peripheral line areas on the substrate and the second pattern area and the third pattern area of the third exposure area are disposed together on a second mask, and the positioning on the second mask The dot system is disposed between the second pattern area and the third pattern area to prevent the two sensing elements from simultaneously performing the mask alignment sensing, thereby causing the problem that the alignment cannot be effectively performed. Therefore, in addition to improving the alignment accuracy of the reticle and reducing the unevenness of the bonding, the present invention can also improve the process efficiency.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1, 4. . . Mask

2, 3, 6, 6'. . . Substrate

21, 31. . . Thin film transistor substrate

51. . . First mask

511. . . First mask positioning point

52. . . Second mask

521. . . Second mask positioning point

61. . . Photoresist layer

611. . . First anchor point

612. . . Second anchor point

613. . . Third anchor point

A1, E1. . . First exposure area

A2, E2. . . Second exposure zone

A3, E3. . . Third exposure zone

B. . . Shading mechanism

C. . . Central location

M1, m2. . . location point

M1. . . First alignment mark

M2. . . Second alignment mark

M3. . . Third alignment mark

P1, Z1. . . First pattern area

P2, Z2. . . Second pattern area

P3, Z3. . . Third pattern area

S1~S3. . . Process steps of the reticle alignment exposure method of the present invention

T1, T2. . . Sensing element

1 is a schematic diagram of a workflow of a conventional exposure method; FIG. 2 is a schematic view of a substrate formed by a bonding method according to another conventional exposure method; FIG. 3 is a schematic view of a photomask used in a conventional bonding method; 4 is a schematic diagram of a working flow of a conventional bonding mode exposure method; FIG. 5 is a flow chart of a reticle alignment exposure method according to a preferred embodiment of the present invention; FIG. 6A is a photomask according to a preferred embodiment of the present invention. FIG. 6B is a schematic diagram of a first alignment mark formed by a reticle alignment exposure method according to a preferred embodiment of the present invention; FIG. 7A is a reticle pair according to a preferred embodiment of the present invention; FIG. 7B is a schematic diagram of a second alignment mark formed by a reticle alignment exposure method according to a preferred embodiment of the present invention; FIG. 8A is a reticle alignment of a preferred embodiment of the present invention; FIG. 8B is a schematic diagram of a third alignment mark formed by a reticle alignment exposure method according to a preferred embodiment of the present invention; and FIG. 9 is a light of a preferred embodiment of the present invention. One of a large work flow schematic alignment exposure process for the substrate.

S1-S3. . . Process steps of the reticle alignment exposure method of the present invention

Claims (18)

A reticle aligning exposure method, comprising: exposing a first pattern region of a first reticle to a photoresist layer of a substrate to form at least one first exposure region; using one of the second reticle The second pattern region is exposed to the photoresist layer to form a second exposure region; and a third pattern region of the second mask is used to expose the photoresist layer to form a third exposure region, wherein The first exposure zone is located between the second exposure zone and the third exposure zone. The reticle aligning exposure method of claim 1, wherein the step of forming the first exposure region comprises the following sub-step: respectively: the first reticle having the plurality of first reticle positioning points respectively A plurality of first positioning points formed on the substrate are aligned to form the first exposure region by exposure. The reticle aligning exposure method of claim 2, wherein each of the first reticle locating points is aligned with each of the first locating points to form a first aligning mark. The reticle aligning exposure method of claim 1, wherein the step of forming the second exposure region comprises the substep of: the second reticle having the plurality of second reticle positioning points respectively A plurality of second positioning points formed on the substrate are aligned to form the second exposure region by exposure. The reticle aligning exposure method of claim 4, wherein each of the second reticle locating points is aligned with each of the second locating points to form a second aligning mark. The reticle alignment exposure method of claim 4, wherein the second reticle positioning point is located between the second pattern area and the third pattern area. The reticle aligning exposure method of claim 1, wherein the step of forming the third exposure region comprises the following sub-step: respectively: the second reticle having the plurality of second reticle positioning points respectively A plurality of third positioning points formed on the substrate are aligned to form the third exposure region by exposure. The photomask aligning exposure method of claim 7, wherein each of the second reticle positioning points is aligned with each of the third locating points to form a third aligning mark. The reticle aligning exposure method of claim 1, wherein the material of the photoresist layer is a positive photoresist material or a negative photoresist material. The reticle aligning exposure method according to claim 1, which is used for fabricating a thin film transistor substrate. A photomask assembly for exposing a photoresist layer to a substrate, the photomask assembly comprising: a first photomask having a first pattern region and a plurality of first mask positioning points, the first a mask positioning point is located around the first pattern area; and a second mask has a second pattern area, a third pattern area, and a plurality of second mask positioning points, and the second mask positioning points Located between the second pattern area and the third pattern area. The reticle assembly of claim 11, wherein the substrate is formed with a plurality of first positioning points, and the first reticle is aligned with each of the first positioning points by the first reticle positioning points. The first exposure region is formed by exposure. The photomask assembly of claim 12, wherein each of the first mask positioning points is aligned with each of the first positioning points to form a first alignment mark. The reticle assembly of claim 11, wherein the substrate is formed with a plurality of second positioning points, and the second reticle is aligned with each of the second locating points by the second reticle positioning points. The second exposure region is formed by exposure. The photomask assembly of claim 14, wherein each of the second mask positioning points is aligned with each of the second positioning points to form a second alignment mark. The reticle assembly of claim 11, wherein the substrate is formed with a plurality of third positioning points, and the second reticle is aligned with each of the third locating points by the second reticle positioning points. The third exposure region is formed by exposure. The photomask assembly of claim 16, wherein each of the second mask positioning points is aligned with each of the third positioning points to form a third alignment mark. The photomask assembly of claim 11, wherein the photoresist layer is made of a positive photoresist material or a negative photoresist material.