CN105301891A - Manufacturing method for exposure mask film - Google Patents

Abstract

The present invention provides a method for producing an exposure mask capable of producing an exposure mask at a lower cost with a simpler process than conventional methods. A method of manufacturing an exposure mask for wafer processing is configured to include a groove forming step of forming a transparent plate (21) that does not reach the transparent plate (21) in a region on the front side (21a) side corresponding to the street (17) of the wafer. The groove (23) of the depth of the backside (21b), the transparent plate has the size above the wafer (11) to be processed and allows light to pass through; and the shading material embedding process, the shading material (27) buried in the groove.

Description

Manufacturing method of exposure mask

technical field

The present invention relates to a method of manufacturing an exposure mask used when processing a wafer.

Background technique

Device chips with electronic circuits such as ICs and LSIs are essential components of small and lightweight electronic devices such as mobile phones. A device chip can be manufactured, for example, by dividing the surface of a wafer made of a material such as silicon by a plurality of dividing lines called streets, forming electronic circuits in each area, and then Cut the wafer.

When cutting a wafer, for example, a high-speed rotating cutting blade is inserted into a street of the wafer, and then the cutting blade and the wafer are relatively moved in a direction parallel to the street. However, in this method, since the wafer is mechanically cut along the lanes, the bending strength of the device chip tends to decrease.

In addition, in this method, since it is necessary to position the cutting tool with respect to the streets with high precision and then cut each of the streets individually, it takes a considerably long time until the machining is completed. In particular, this problem is severe in a wafer having a large number of planned division lines to be cut.

Therefore, in recent years, a method of cutting a wafer by plasma etching has been proposed (for example, refer to Patent Document 1). In this method, since the entire surface of the wafer can be processed at one time by plasma etching, even if the number of dividing lines to be processed increases due to miniaturization of device chips or enlargement of wafers, etc., the processing time is almost Done unchanged.

In addition, since the wafer is not mechanically cut, chipping or the like during processing can be suppressed, and the bending strength of the device chip can be maintained high. Also, in this method, resists for etching are formed on the front and back surfaces of the wafer using an exposure mask (for example, refer to Patent Document 2) in which a light-shielding film made of chromium or the like is formed on the surface of a glass substrate. etchant film.

Patent Document 1: Japanese Patent Laid-Open No. 2006-114825

Patent Document 2: Japanese Patent Laid-Open No. 62-229151

However, since the above-mentioned exposure mask is manufactured through complex steps such as formation of a light-shielding film, covering of a resist film, patterning of the resist film, and etching of the light-shielding film, the cost is high. If the exposure mask is exposed, the processing cost of the wafer will also increase.

Contents of the invention

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an exposure mask manufacturing method capable of manufacturing an exposure mask at a lower cost with a simpler process than conventional methods.

According to the present invention, there is provided a method for manufacturing an exposure mask, which is a method for manufacturing an exposure mask for wafer processing, and is characterized in that the method for manufacturing an exposure mask includes: a groove forming step; forming grooves not reaching the depth of the back surface of the transparent plate having a size larger than that of the wafer to be processed and allowing light to pass through in an area on the front side corresponding to the lanes of the wafer; and a light-shielding material embedding process , and embed a light-shielding material in the groove.

In the present invention, preferably, the step of embedding the light-shielding material is performed using an embedding member having ink nozzles.

In addition, in the present invention, it is preferable that in the step of embedding the light-shielding material, the entire front surface of the transparent plate on which the groove is formed is covered with the light-shielding material, the light-shielding material is buried in the groove, and then The light-shielding material covering the front side of the transparent plate other than the groove is removed.

The manufacturing method of the exposure mask of the present invention includes: a groove forming step of forming, on the front side of the transparent plate through which light passes, grooves of a depth that does not reach the back surface of the transparent plate corresponding to the lanes of the wafer; and a light-shielding material. In the embedding step, a light-shielding material having light-shielding properties is embedded in the groove.

Therefore, an exposure mask having a light-shielding pattern corresponding to the streets of the wafer can be manufactured without going through complicated steps such as covering with a resist film, patterning the resist film, and etching the light-shielding film. Thus, according to this invention, the manufacturing method of the exposure mask which can manufacture an exposure mask cheaply by simple process can be provided compared with the conventional method.

Description of drawings

1(A) is a perspective view schematically showing a configuration example of a wafer, and FIG. 1(B) is a cross-sectional view schematically showing a configuration example of a wafer.

2(A) is a perspective view schematically showing a groove forming step, and FIG. 2(B) is a cross-sectional view schematically showing a transparent plate after the groove forming step.

3(A) is a partial side sectional view schematically showing a light-shielding material embedding step, and FIG. 3(B) is a perspective view schematically showing a transparent plate after the light-shielding material embedding step.

4(A) is a cross-sectional view schematically showing a modified example of the light-shielding material embedding step, and FIG. 4(B) is a perspective view schematically showing a modified example of the light-shielding material embedding step.

Label description

11: chip;

11a: front;

11b: back;

11c: peripheral;

13: device area;

15: remaining peripheral area;

17: interval road (separation predetermined line);

19: device;

21: transparent board;

21a: front;

21b: back;

23: groove;

25: liquid;

27: shading material;

29: shading film (shading material);

2: cutting tool;

4: Ink nozzle (embedded component);

12: Grinding device;

14: Hold the workbench;

16: spindle;

18: wheel seat;

20: grinding wheel;

20a: wheel base;

20b: Grinding abrasives.

detailed description

Embodiments of the present invention will be described with reference to the drawings. The manufacturing method of the exposure mask of this embodiment includes a groove forming step (see FIG. 2(A) and FIG. ).

In the groove forming step, grooves having a depth not reaching the back surface of the transparent plate are formed corresponding to the streets of the wafer on the front side of the transparent plate through which light is transmitted. In the light-shielding material embedding step, a light-shielding material having light-shielding properties is embedded in the groove of the transparent plate. Next, the manufacturing method of the exposure mask of this embodiment is described in detail.

First, a wafer processed using the exposure mask of this embodiment will be described. 1(A) is a perspective view schematically showing a configuration example of a wafer, and FIG. 1(B) is a cross-sectional view schematically showing a configuration example of a wafer.

As shown in FIG. 1(A) and FIG. 1(B), the wafer 11 is, for example, a substantially circular plate formed of a semiconductor material such as silicon, and the front surface 1a is divided into a central device region 13 and a surrounding device region. 13 of the remaining area 15 of the periphery.

The device region 13 is further divided into a plurality of regions by streets (planned division lines) 17 arranged in a grid pattern, and devices 19 such as ICs are formed in each region. The outer periphery 11c of the wafer 11 is chamfered and has an arc shape.

In the manufacturing method of the exposure mask of this embodiment, the exposure mask provided with the light-shielding pattern corresponding to the street 17 of the said wafer 11 is manufactured. Specifically, first, a groove forming step is performed in which grooves corresponding to the streets 17 of the wafer 11 are formed on the transparent plate. 2(A) is a perspective view schematically showing a groove forming step, and FIG. 2(B) is a cross-sectional view schematically showing a transparent plate after the groove forming step.

As shown in FIG. 2(A) and FIG. 2(B), the transparent plate 21 serving as the base material of the exposure mask is a substantially circular plate-shaped object formed of a transparent material such as glass or resin, and its diameter is, for example, The diameter of the wafer 11 is larger. However, the transparent plate 21 may also be formed to have the same diameter as the wafer 11 . That is, the transparent plate 21 only needs to be larger than the size of the wafer 11 .

In addition, this transparent plate 21 has arbitrary optical characteristics required for an exposure mask. Specifically, for example, the transparent plate 21 is transparent to light of a predetermined wavelength used to harden the resist material. However, the transparent plate 21 does not necessarily need to be transparent with respect to visible light.

In the groove forming step, as shown in FIG. 2(A), the cutting blade 2 rotating at high speed is cut into the front surface 21a of the transparent plate 21, and the cutting blade 2 and the transparent plate 21 are relatively moved in the horizontal direction. In this case, the cutting tool 2 cuts into regions corresponding to the streets 17 of the wafer 11 . In addition, the cutting depth of the cutting blade 2 is set so that the cutting blade 2 does not reach the back surface 21 b of the transparent plate 21 .

Accordingly, grooves 23 having a depth not reaching rear surface 21B of transparent plate 21 can be formed on the front surface 21 a side of transparent plate 21 corresponding to streets 17 of wafer 11 . When the grooves 23 corresponding to all the streets 17 of the wafer 11 are formed, the groove forming process ends.

After the groove forming step, a light-shielding material embedding step is performed in which a light-shielding material having light-shielding properties is buried in the groove 23 of the transparent plate 21 . 3(A) is a partial side sectional view schematically showing a light-shielding material embedding step, and FIG. 3(B) is a perspective view schematically showing the transparent plate 21 after the light-shielding material embedding step.

In the light-shielding material embedding process, for example, as shown in (A) of FIG. A typical light-shielding liquid 25 is dropped into the tank 23 .

Then, by drying and hardening the liquid 25 supplied into the groove 23, as shown in FIG. 3(A) and FIG. Shaped shading material 27 . When the light-shielding material 27 is buried in all the grooves 23 of the transparent plate 21, an exposure mask is formed.

As described above, the manufacturing method of the exposure mask of the present invention includes the step of forming grooves corresponding to the streets 17 of the wafer 11 on the side of the front surface 21a of the transparent plate 21 through which light is transmitted. The groove 23 whose depth does not reach the back surface 21b of the transparent plate 21; and a light-shielding material embedding step of embedding a light-shielding material 27 in the groove 23 in the light-shielding material embedding step.

Therefore, an exposure mask having a light-shielding pattern corresponding to the streets 17 of the wafer 11 can be manufactured without going through complicated steps such as covering with a resist film, patterning the resist film, and etching the light-shielding film. Thus, according to this Embodiment, the manufacturing method of the exposure mask which can manufacture an exposure mask cheaply by simple process can be provided compared with the conventional method.

In addition, the present invention is not limited to the description of the above-mentioned embodiments, and can be implemented with various modifications. For example, in the above-mentioned embodiment, although the so-called inkjet method of dripping the liquid 25 through the inkjet nozzle 4 is used to embed the light-shielding material 27 in the groove 23, the method of embedding the light-shielding material 27 in the groove 23 does not Not limited to this.

4(A) is a cross-sectional view schematically showing a modified example of the light-shielding material embedding step, and FIG. 4(B) is a perspective view schematically showing a modified example of the light-shielding material embedding step. In the light-shielding material embedding step of the modified example, first, as shown in FIG. The light-shielding film 29 is, for example, a metal film formed by sputtering, CVD (chemical vapor deposition), or the like, and is partially embedded in the groove 23 as shown in FIG. 4(A) .

Next, a part of the light-shielding film 29 is removed to expose the front surface 21 a of the transparent plate 21 . Removal of the light-shielding film 29 is performed using the grinding apparatus 12 shown to FIG.4(B), for example. The grinding device 12 includes a holding table 14 that suction-holds the transparent plate 21 . A rotation mechanism (not shown) is provided below the holding table 14, and the holding table 14 is rotated around a vertical axis by the rotation mechanism.

The surface (upper surface) of the holding table 14 serves as a holding surface for sucking and holding the back surface 21 b side of the transparent plate 21 . A negative pressure from a suction source (not shown) is applied to the holding surface through a suction channel (not shown) formed inside the holding table 14 to generate a suction force for sucking the transparent plate 21 .

A spindle 16 that rotates about a vertical axis is arranged above the holding table 14 . The main shaft 16 is raised and lowered by a lifting mechanism (not shown). A disc-shaped wheel base 18 is fixed to the lower end side of the main shaft 16 , and a grinding wheel 20 is attached to the wheel base 18 .

The grinding wheel 20 includes a wheel base 20a formed of a metal material such as aluminum or stainless steel. A plurality of grinding stones 20b are fixed over the entire circumference of the annular lower surface of the wheel base 20a.

When removing the light-shielding film 29, first, the back surface 21b side of the transparent plate 21 is brought into contact with the holding surface of the holding table 14, and the negative pressure of the suction source is applied. Thus, the transparent plate 21 is suction-held on the holding table 14 in a state where the light-shielding film 29 covering the front surface 21 a is exposed above.

Next, while rotating the holding table 14 and the main shaft 16 in predetermined directions, the main shaft 16 is lowered, and the grinding wheel 20 b is brought into contact with the light shielding film 29 as shown in FIG. 4(B) . The spindle 16 is lowered at a feed rate suitable for grinding the light-shielding film 29 .

When the light-shielding film 29 is ground until the front surface 21a of the transparent plate 21 is exposed, the light-shielding material 27 which is a part of the light-shielding film 29 remains in the groove 23 as shown in FIG. 3(B) . In this manner, even when the light-shielding material embedding step of the modified example is performed, an exposure mask similar to that of the above-mentioned embodiment can be manufactured.

In addition, in the above modification, although the light-shielding film 29 is ground to leave the light-shielding material 27 remaining in the groove 23, it is also possible to remove the light-shielding film 29 by another method such as etching and leave the light-shielding material 27 in the groove. 23 in.

In addition, as long as the structure, method, etc. of the said embodiment do not deviate from the scope of the objective of this invention, it can change suitably and implement.

Claims (3)

1. A method for manufacturing an exposure mask, which is a method for manufacturing an exposure mask for wafer processing, characterized in that, The manufacturing method of described exposure mask comprises: A groove forming process of forming grooves of a depth not reaching the back surface of a transparent plate having a size larger than the wafer to be processed and making light through; and In the light-shielding material embedding step, a light-shielding material having light-shielding properties is embedded in the groove. 2. The method of manufacturing an exposure mask according to claim 1, wherein: This light-shielding material embedding step is performed using an embedding member having ink nozzles. 3. The method of manufacturing an exposure mask according to claim 1, wherein: In the light-shielding material embedding step, the light-shielding material is covered on the entire front surface of the transparent plate where the groove is formed, the light-shielding material is buried in the groove, and then the front surface of the transparent plate other than the groove is covered. The light-shielding material is removed.