JP3507996B2 - A pair of photomasks and a method for processing front and back surfaces of a transparent substrate using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask used in a photolithography process for forming a desired pattern on the front and back surfaces of a transparent substrate, and a method for processing the front and back surfaces of the transparent substrate using this photomask.

[0002]

9 to 14 show a conventional example, FIG. 9 is a plan view of a front side photomask, and FIG.
The plan view of the back side photomask, FIG. 11 and FIG.
FIG. 13 is a process diagram showing a method of manufacturing a hologram glass for pickup, FIG. 13 is a process diagram showing a photomask positioning procedure, and FIG. 14 is an image pickup view of an alignment scope at the time of photomask positioning.

In the figure, reference numeral 50 denotes a front side photomask having a substantially square shape in plan view, and 60 denotes a backside photomask having a substantially square shape in plan view. These photomasks 50 and 60 are shown in FIG.
It is used to manufacture the hologram glass 71 included in the hologram laser 70 shown in FIG. The hologram glass 71 is formed in a dice shape, and a hologram pattern 72 is formed on one surface thereof and a grating pattern 73 is formed on a surface facing the hologram pattern 72.

The front side photomask 50 is provided with a transfer area 51 which is circular in plan view and which corresponds to the outer shape of the target transparent substrate. In the transfer area 51, a plurality of hologram patterns 52 are arranged in a dot matrix. Has been formed. Further, the alignment marks 53A, 53
B is formed one by one.

The back side photomask 60 is provided with a transfer area 61 having a circular shape in plan view corresponding to the outer shape of the target transparent substrate. In the transfer area 61, a plurality of grating patterns 62 are arranged in a dot matrix. Has been formed. In the transfer area 61, at a position corresponding to the two alignment marks 53A and 53B of the front side photomask 50, an alignment mark 63A having the same shape as the two alignment marks 53A and 53B of the front side photomask 50 and having a narrow width. , 63B are formed.

A light shielding film such as chrome plating is entirely printed on the transfer areas 51 and 61, and the hologram pattern 52 and the grating pattern 62 are formed by the presence or absence of this light shielding film. is there.

Further, the alignment marks 53A and 53B of the front side photomask 50 described above are substantially L-shaped and rearward-facing, and are formed in a striped pattern as shown in the drawing. The part between the striped lines is dug in a concave shape. And this alignment mark 1
A striped straight bar 54 is provided at the bottom of each of 3A and 13B.
A and 54B are attached.

The alignment marks 63A and 63B of the back photomask 60 on one side are substantially L-shaped and faced rearward, and have a narrow width (for example, 10 μm) that does not block light with the line of the light-shielding film. Formed). No light-shielding film is formed in the square area in plan view around the alignment marks 63A and 63B.
Light transmission windows 64A and 64B are provided.

As described above, the conventional photomasks 50 and 6
0 is formed by allocating each one of two types of alignment marks.

Next, the hologram glass for pickup 7
The manufacturing method of No. 1 will be described.

As shown in FIG. 11A, a photoresist 81 is applied to the entire surface of a transparent wafer 80 as a transparent substrate made of soda lime glass or quartz.

As shown in FIG. 11B, the front side photomask 50 is positioned and arranged above the transparent wafer 80, and exposure is performed. The front side photomask 50 is positioned by setting the transfer area 51 to the transparent wafer 80.
The outline is overlaid.

The photoresist 81 is developed. As a result, as shown in FIG.
1 exposed portion (hologram pattern 52 and alignment mark 53 of front side photomask 50)
A and 53B portions without patterns) are selectively removed.

Patterned photoresist 8
The transparent wafer 80 is etched and ashed using the mask 1 as a mask. As a result, as shown in FIG. 11D, on the surface of the transparent wafer 80, the concave portion 82 corresponding to the unpatterned portion of the hologram pattern 52 of the front side photomask 50 and the unpatterned portions of the alignment marks 53A and 53B are corresponded. The recesses 83A and 83B are formed. It should be noted that the same group as the hologram pattern 52 is formed by the group of the concave portions 82 and the peripheral surface thereof, and the concave portions 83 are formed.
Front side photomask 5 consisting of the A and 83B groups and the surrounding surface
The same alignment marks 53A and 53B as 0 are formed.

As shown in FIG. 12A, with the back surface of the transparent wafer 80 facing upward, a photoresist 84 is applied to the entire back surface.

As shown in FIG. 12B, the back side photomask 60 is positioned and exposed above the back side of the transparent wafer 80 by the following procedure.

The photoresist 84 is developed. As a result, as shown in FIG.
4, the exposed portion (the unpatterned portion of the grating pattern 62 of the backside photomask 60 and the inside of the light transmission windows 64A, 64B) is selectively removed.

Patterned photoresist 8
The transparent wafer 80 is etched and ashed using the mask 4 as a mask. As a result, as shown in FIG. 12D, a recess 85 corresponding to the unpatterned portion of the grating pattern 62 of the backside photomask 60 and a recess corresponding to the inside of the light transmission windows 64A and 64B are formed on the back surface of the transparent wafer 80. 86A and 86B will be formed. In addition,
The same group as the grating pattern 62 is formed by the group of the concave portions 85 and the peripheral surface thereof.

After this, the transparent wafer 80 is finely cut into chips by dicing or the like to obtain a plurality of hologram glasses 71 for pickup.

A procedure for positioning the backside photomask 60 will be described.

As shown in FIG. 13A, a pair of two alignment scopes 90 A and 90 B are attached to the transparent wafer 8.
It is placed above the back side of 0 and the alignment scope 9
By vertically moving 0A and 90B up and down, the two alignment marks 63A and 63B of the back side photomask 60 are brought into focus.

Alignment scopes 90A, 90B
14A by rotating the holding mechanism (not shown) of the back side photomask 60 horizontally and vertically, and the alignment scope 90A is displayed half by one on the display screen as shown in FIG. 14A. , 90B scope lines 91A, 91B on the back side photomask 6
Align the alignment marks 63A and 63B of 0 along.

As shown in FIG. 13B, by operating the alignment scopes 90A and 90B only in the vertical direction, the concave portions 83A and 83B corresponding to the two alignment marks formed on the surface of the transparent wafer 80 are respectively formed. To focus.

Chucking base 94 for transparent wafer 80
By horizontally and vertically operating and rotating the same, as shown in FIG. 14 (b), the alignment lines 90A and 90B of the alignment scopes 91A and 91B are aligned with each other.
The concave portions 83A and 83B corresponding to one alignment mark are aligned so as to be along.

The front side processing and the back side processing of the transparent wafer 80 described above are generally performed using different processing apparatuses.

[0026]

By the way, in the prior art,
When forming a required pattern on the front and back surfaces of the transparent wafer 80, two photomasks 50 and 60 for the front side and the back side are used. In the case of these photomasks 50 and 60, the priority order of use at the time of formation is used. Is specified. This is because the pair of alignment marks of two types are formed separately for each of these photomasks 50 and 60.

For this reason, if the front side processing device used earlier in the flow of the manufacturing line fails, all the flow of the manufacturing line must be stopped and waiting for the failed front side processing device to be repaired. Inevitably, the production efficiency is reduced.

[0028] Therefore, it is an object of the present invention to provide a photomask and a processing method that can be processed first from either the front or back surface of a transparent substrate.

[0029]

The present invention has the following structure in a photomask used in a photolithography process for forming a desired pattern on the front and back surfaces of a transparent substrate.

The pair of photomasks of the present invention has a transfer region in which a required pattern to be transferred is formed, and at least two positions in this transfer region have a first alignment of a size and shape that can be formed on a transparent substrate. Marks are respectively formed, and a second narrow mark having the same shape as the first alignment mark is formed in the vicinity of the two first alignment marks.
Alignment marks are formed respectively, and the other
The photomask has the required pattern to be transferred.
And a transfer area, in which the one of the
At least two first alignment marks for the photomask
At the position corresponding to the
Third alignment mark identical to the second alignment mark of
And the two third alignments
At least two of the one photomasks near the mark
At the position corresponding to the two second alignment marks.
The same alignment mark as the first alignment mark on the other photomask
4 alignment marks are formed.

[0031]

The transparent front and back surface processing method of a substrate of the present invention includes the steps of applying a photoresist on the front surface or the back surface of the one surface of the transparent substrate, according to claim 1 on one surface of the photoresist of the transparent substrate is coated One of the photomasks is placed and the photomask is positioned at a required position on the transparent substrate; a step of exposing the photoresist through the photomask and developing the photoresist; and a step of masking the photoresist. And etching the transparent substrate to obtain a concave portion corresponding to a required pattern of the photomask and a concave portion corresponding to the first alignment mark or the fourth alignment mark on the transparent substrate, and the other surface of the front surface or the back surface of the transparent substrate. The step of applying photoresist to the transparent substrate and the other Upwardly disposed other one of the photomask of claim 1 of, by relatively moving the photomask and the transparent substrate, a second photomask
The alignment mark or the third alignment mark and the first alignment mark or the fourth alignment mark formed on the transparent substrate.
The step of positioning the concave portion corresponding to the alignment mark by superimposing it, the step of exposing the photoresist through the photomask and developing the photoresist, and the transparent substrate being etched by using the photoresist as a mask And a step of obtaining a concave portion corresponding to a required pattern of the photomask on the substrate.

[0033]

The pair of photomasks of the present invention has two photomasks.
Since two types of alignment marks are formed, if a pair of photomasks are used for the front side and the back side during the photolithography process on the front and back surfaces of the transparent substrate to be processed, whichever surface Even in the case of first processing, the photomask used later can be accurately positioned with respect to the processed surface of the transparent substrate.

[0034] Thus, in the case of performing processing using a photomask of a pair of the present invention in separate devices, when one processor has failed, so that processing can be executed using the other processor before Therefore, it is not necessary to stop the production line as in the conventional case.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in FIGS. 1 to 6 show an embodiment of the present invention. FIG. 1 is a plan view of a front side photomask, FIG. 2 is a plan view of a backside photomask, and FIGS. 3 and 4 are hologram glasses for pickup. 5 is a process diagram showing the manufacturing method of FIG. 5, FIG. 5 is a process diagram showing a photomask positioning procedure, and FIG.

In the figure, 10 is a photomask for the front side which is substantially square in plan view, and 20 is a photomask for the back side which is substantially square in plan view. These photomasks 10 and 20 are shown in FIG.
It is used to manufacture the hologram glass 71 included in the hologram laser 70 shown in FIG. The hologram glass 71 is formed in a dice shape, and a hologram pattern 72 is formed on one surface thereof and a grating pattern 73 is formed on a surface facing the hologram pattern 72.

The front side photomask 10 is provided with a transfer area 11 which is circular in a plan view and corresponds to the outer shape of the transparent wafer 30 to be processed. In this transfer area 11, a plurality of hologram patterns 12 are formed in a dot matrix. It is formed into a shape. In addition, the transfer area 11 is 180
The first alignment mark 13 having a size and shape that can be formed on the transparent substrate to be processed is provided at two locations apart from each other.
A and 13B are formed, and second alignment marks 14A and 14 having the same shape as the first alignment marks 13A and 13B and having a narrow width are formed at the inner positions thereof.
B is formed.

The backside photomask 20 is provided with a transfer area 21 which is circular in plan view and corresponds to the outer shape of the transparent wafer 30 to be processed. In this transfer area 21, a plurality of grating patterns 22 are formed in a dot matrix. It is formed into a shape. In addition, at a position near the outer peripheral edge of the transfer region 21 corresponding to the two first alignment marks 13A and 13B of the front side photomask 10, the third alignment marks 14A and 14B that are the same as the second alignment marks 14A and 14B of the front side photomask 10 are provided. Alignment marks 23A and 23B are formed. Further, in the transfer area 21, the two second alignment marks 14A and 14B of the front side photomask 10 are formed.
Fourth alignment marks 24A and 24B that are the same as the first alignment marks 13A and 13B of the front-side photomask 10 are formed at positions corresponding to.

A light shielding film such as chrome plating is printed on the transfer areas 11 and 21, and the hologram pattern 12 and the grating pattern 22 are formed by the presence or absence of the light shielding film. is there.

The first alignment mark 13 described above is also used.
A, 13B and fourth alignment marks 24A, 24B
Has a substantially L-shape and a shape facing rearward thereof, and is formed in a striped pattern as shown in the drawing, and a portion between the striped lines formed of the light shielding film is dug in a concave shape. Then, striped linear bars 15A, 15B, 25A, 25B are provided below the first alignment marks 13A, 13B and the fourth alignment marks 24A, 24B, respectively.

One of the second alignment marks 14A, 1
The 4B and the third alignment marks 24A and 24B are substantially L-shaped and have a shape facing rearward thereof, and are formed with a narrow width (for example, about 10 μm) that does not block light with the line of the light blocking film. . This second alignment mark 1
4A, 14B and third alignment marks 24A, 24B
The light shielding film is not formed in the area of the square shape in plan view around the area, and the area is defined as the light transmitting windows 16A, 16B, 26A, 26B.

Thus, the photomask 10 of the present invention,
By forming two types of alignment marks on each of the two, 20 of which photomask 1 is used in the photolithography process on the front and back surfaces of the transparent substrate to be processed.
0 or 20 can be used, and photomask 1
The order of use of 0 and 20 is arbitrary.

Next, the hologram glass for pickup 7
The manufacturing method of No. 1 will be described. Here, the case where the processing is first performed from the front surface side to the back surface side of the transparent substrate will be described as an example.

As shown in FIG. 3A, a photoresist 31 is applied to the entire surface of a transparent wafer 30 as a transparent substrate made of soda lime glass or quartz.

As shown in FIG. 3B, the front side photomask 10 is positioned above the front side of the transparent wafer 30 and exposed. The front side photomask 1
The positioning of 0 is performed by superimposing the transfer area 11 on the outer shape of the transparent wafer 30.

The photoresist 31 is developed. As a result, as shown in FIG.
Exposed at (the hologram pattern 12 of the front side photomask 10, the first alignment mark 13
A and 13B portions without patterns and light transmission windows 16A, 1
The portion corresponding to the inside of 6B) is selectively removed.

Patterned photoresist 3
The transparent wafer 30 is etched and ashed using the mask 1 as a mask. As a result, as shown in FIG.
The concave portion 3 corresponding to the unpatterned portion of the hologram pattern 12 of the front side photomask 10 on the surface of the transparent wafer 30.
2. Recesses 33A and 33B corresponding to the unpatterned portions of the first alignment marks 13A and 13B and the light transmission window 16
Corresponding recesses 34A and 34B are formed inside A and 16B. In addition, the same group as the hologram pattern 12 is formed by the group of the concave portions 32 and the peripheral surface thereof,
The same group of the first alignment marks 13A, 13B of the front side photomask 10 is formed by the group of recesses 33A, 33B and the peripheral surface thereof.

As shown in FIG. 4A, with the back surface of the transparent wafer 30 facing upward, a photoresist 35 is applied to the entire back surface.

As shown in FIG. 4B, the backside photomask 20 is positioned and exposed above the backside of the transparent wafer 30 by the following procedure.

The photoresist 35 is developed. As a result, as shown in FIG.
Exposed at (the grating pattern 22 of the backside photomask 20, the fourth alignment mark 2)
4A, 24B each patternless portion and the light transmission window 26A,
26B) is selectively removed.

Patterned photoresist 3
The transparent wafer 30 is etched and ashed using the mask 5 as a mask. As a result, as shown in FIG.
On the back surface of the transparent wafer 30, concave portions 36 corresponding to the unpatterned portions of the grating pattern 22 of the backside photomask 20, concave portions 37A and 37B corresponding to the unpatterned portions of the fourth alignment marks 24A and 24B, and the light transmitting window 2 are formed.
Corresponding concave portions 38A and 38B are formed inside 6A and 26B. The group of concave portions 36 and the peripheral surface thereof form the same grating pattern 22, and the group of concave portions 37A and 37B and the peripheral surface thereof form the fourth alignment marks 24A and 2A of the backside photomask 20.
Form the same as 4B.

After this, the transparent wafer 30 is finely cut into chips by dicing or the like to obtain a plurality of hologram glasses 71 for pickup.

A procedure for positioning the backside photomask 20 described above will be described.

As shown in FIG. 5A, the pair of alignment scopes 40 A and 40 B are provided on the transparent wafer 30.
Placed above the back side of the
By vertically moving the A and 40B up and down, the two third alignment marks 23A and 23B of the back side photomask 20 are brought into focus.

Alignment scopes 40A, 40B
6A by rotating the holding mechanism (not shown) of the back-side photomask 20 in a horizontal and vertical direction, and the alignment scope 40A is displayed half by half on one display screen as shown in FIG. 6A. , 40B scope line 41A, 41B backside photomask 20
The third alignment marks 23A and 23B are aligned.

As shown in FIG. 5B, by operating the alignment scopes 40 A and 40 B only in the vertical direction, 2 formed on the surface of the transparent wafer 30 respectively.
Recesses 33A, 33B corresponding to the first alignment marks
Focus on the group.

Chucking table 44 for transparent wafer 30
6B by operating the horizontal and vertical directions as well as the horizontal direction, the concave portions 33 corresponding to the first alignment marks of the transparent wafer 30 are formed in the scope lines 41A and 41B of the alignment scopes 40A and 40B, as shown in FIG. 6B.
Align the A and 33B groups together.

With respect to the example of the manufacturing method described above, an example in which the process proceeds from the rear surface side to the front surface side of the transparent wafer 30 will be described with reference to FIGS. 7 and 8.

As shown in FIG. 7A, a photoresist 31 is applied on the entire back surface of a transparent wafer 30 as a transparent substrate made of soda lime glass or quartz.

As shown in FIG. 7B, the backside photomask 20 is positioned and disposed above the backside of the transparent wafer 30 and exposure is performed. The back side photo mask 2
The positioning of 0 is performed by overlapping the transfer area 21 on the outer shape of the transparent wafer 30.

The photoresist 31 is developed. As a result, as shown in FIG.
The position exposed in (the unpatterned part of the grating pattern 22 of the backside photomask 20, the unpatterned part of the fourth alignment marks 24A and 24B, and the part corresponding to the inside of the light transmission windows 26A and 26B) is selectively removed. To be done.

Patterned photoresist 3
The transparent wafer 30 is etched and ashed using the mask 1 as a mask. As a result, as shown in FIG.
On the back surface of the transparent wafer 30, a concave portion 32 corresponding to the unpatterned portion of the grating pattern 22 of the backside photomask 20, concave portions 33A and 33B corresponding to the unpatterned portions of the fourth alignment marks 24A and 24B, and the light transmitting window 2 are formed.
Corresponding recesses 34A and 34B are formed inside 6A and 26B. The group of recesses 32 and the peripheral surface thereof form the same grating pattern 22, and the group of recesses 33A and 33B and the peripheral surfaces thereof form the fourth alignment marks 24A, 2 of the backside photomask 20.
Form the same as 4B.

As shown in FIG. 8A, with the surface of the transparent wafer 30 facing upward, a photoresist 35 is applied to the entire surface.

As shown in FIG. 8B, the front side photomask 10 is positioned and exposed above the front side of the transparent wafer 30 by the following procedure.

The photoresist 35 is developed. As a result, as shown in FIG.
Exposed at (the hologram pattern 12 of the front side photomask 10, the first alignment mark 13
A and 13B portions without patterns and light transmission windows 16A, 1
6B) is selectively removed.

Patterned photoresist 3
The transparent wafer 30 is etched and ashed using the mask 5 as a mask. As a result, as shown in FIG.
The concave portion 3 corresponding to the unpatterned portion of the hologram pattern 12 of the front side photomask 10 on the surface of the transparent wafer 30.
6, concave portions 37A and 37B corresponding to the unpatterned portions of the first alignment marks 13A and 13B, and the light transmission window 16
Corresponding recesses 38A and 38B are formed inside A and 16B. In addition, the same group as the hologram pattern 12 is formed by the group of the concave portions 36 and the peripheral surface thereof,
The same group of the first alignment marks 13A, 13B of the front side photomask 10 is formed by the group of concave portions 37A, 37B and the peripheral surface thereof.

After this, the transparent wafer 30 is finely cut into chips by dicing or the like to obtain a plurality of hologram glasses 71 for pickup.

The above-described positioning procedure for the front-side photomask 10 is almost the same as that in FIGS. 5 and 6 described above, and therefore the description thereof is omitted here.

The present invention is not limited to the above embodiment. In other words, for the required pattern to be transferred,
For example, various types such as a beam splitter can be considered.
Also, the first to fourth alignment marks are not limited to the shapes described in the embodiments, and various types can be considered.

[0070] photomask one pair of the present invention, because they form two types of alignment marks, respectively, in the photolithographic process of the front and rear surfaces of the transparent substrate to be processed, a pair of the photomask of this invention When used for the front side and the back side, it becomes possible to accurately position the photomask to be used later with respect to the processed surface of the transparent substrate regardless of which of the front and back surfaces of the transparent substrate is processed first. . Thus, one pair of the photomask of the present invention be used in the pattern forming method of the front and back surfaces of the transparent substrate, it is possible to the processing order of the front and rear surfaces of the transparent substrate and any.

[0071] Thus, in the photolithography process, in the case of performing processing using a photomask of a pair in a separate device, when one processor has failed, so that processing can be executed using the other processor Because
Unlike the conventional method, the production line does not have to be stopped, and the production efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of a front-side photomask according to an embodiment of the present invention.

FIG. 2 is a plan view of a backside photomask according to an embodiment of the present invention.

FIG. 3 is a process drawing showing a method of manufacturing a hologram glass for pickup of the present invention.

FIG. 4 is a process drawing showing the method of manufacturing a hologram glass for pickup of the present invention.

FIG. 5 is a process drawing showing the positioning procedure of the photomask of the present invention.

FIG. 6 is an image pickup view of the alignment scope at the time of positioning the photomask of the present invention.

FIG. 7 is a process drawing showing another method for manufacturing the hologram glass for pickup of the present invention.

FIG. 8 is a process drawing showing another method for manufacturing the hologram glass for pickup of the present invention.

FIG. 9 is a plan view of a conventional front side photomask.

FIG. 10 is a plan view of a conventional backside photomask.

FIG. 11 is a process diagram showing a conventional method of manufacturing a hologram for a pickup.

FIG. 12 is a process drawing showing a conventional method for manufacturing a hologram glass for a pickup.

FIG. 13 is a process diagram showing a conventional photomask positioning procedure.

FIG. 14 is an image pickup view of an alignment scope at the time of positioning a conventional photomask.

FIG. 15 is a partially cutaway perspective view showing a general hologram laser.

[Explanation of symbols]

10 Front side photo mask 20 Backside photomask 30 transparent wafer 11,21 Transfer area 12 Hologram pattern 22 Grating pattern 13A, 13B First alignment mark 14A, 14B Second alignment mark 23A, 23B Third alignment mark 24A, 24B 4th alignment mark

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03F 1/00-1/16

Claims (2)

(57) [Claims] 1. A pair of photomasks used in a photolithography process for forming a desired pattern on the front and back surfaces of a transparent substrate, wherein one photomask has a transfer region in which a desired pattern to be transferred is formed. A first alignment mark having a size and shape that can be formed on the transparent substrate is formed at least at two positions in the transfer area, and the first alignment mark and the same shape are formed in the vicinity of the two first alignment marks. In addition, a narrow second alignment mark is formed on each of the two photomasks , and the other photomask has a desired pattern to be transferred.
The transfer area is formed, and in the transfer area, the
At least two first alignments of one photomask
To the position corresponding to the
Third alignment that is the same as the second alignment mark on the mask
And the third mark is formed on each
Of the photo mask on the one side near the
Both at the positions corresponding to the two second alignment marks,
Same as the first alignment mark of the one photomask
A pair of photomasks, wherein one fourth alignment mark is formed . 2. A desired pattern is formed on the front and back surfaces of a transparent substrate.
It is a processing method to form a photoresist on one surface of the transparent substrate
The process of applying and one side of this transparent substrate where the photoresist is applied
Arranging one of the photomasks according to claim 1,
Positioning the photomask at the required position on the transparent substrate
And expose the photoresist through the photomask,
Developing the photoresist, and etching the transparent substrate using the photoresist as a mask.
The required pattern of the photomask on the transparent substrate by
The recess corresponding to the turn and the first alignment mark
Or a step of obtaining a recess corresponding to the fourth alignment mark
And a photoresist on the other side of the front or back of the transparent substrate.
Applying process and the other side of this transparent substrate where the photoresist is applied
One of the photomasks according to claim 1 is arranged on one side,
Relative movement of the photomask and transparent substrate
The second alignment mark of the photomask or
The third alignment mark and the first alignment mark formed on the transparent substrate.
Compatible with liment mark or 4th alignment mark
The step of overlapping and positioning the concave portion to be formed, and exposing the photoresist through the photomask,
Developing the photoresist, and etching the transparent substrate using the photoresist as a mask.
The required pattern of the photomask on the transparent substrate by
And a step of obtaining recesses corresponding to turns, the method for processing the front and back surfaces of a transparent substrate.