JP2006183115A - Metal mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that, when a resist is coated by a spin coater, resist liquid spread by centrifugal force is stored at four corners of a wafer and thicknesses at the corners are increased as compared with that of a center portion, and when vapor deposition or sputtering is performed by mounting the resist film on the conventional metal mask with residues of the resist film remaining on the corners, adhesion of upper and lower masks 21, 23 to the wafer is worsened by the residues of the resist, and the accuracy of the vapor deposition pattern is degraded. <P>SOLUTION: The metal mask comprises an upper mask 2 having open windows 5 of a plurality of predetermined patterns, a middle plate 3 having an opening part 6, and a lower mask 4 having open windows 6 of a plurality of predetermined patterns. The metal mask is formed by applying triangular half etching 10, 11 to four corners of faces of the upper mask 2 and the lower mask 4 in contact with the middle plate 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal mask, and more particularly to an improved metal mask for a device processed using photolithography.

  Recently, various processing is often performed using a photolithographic technique as a processing method of a quartz substrate. For example, a photoresist is applied onto a rectangular AT-cut quartz substrate (wafer) using a spin coater, exposed through a glass mask, developed to form a desired pattern, and further etched to form a predetermined wafer. Process into shape. Then, the resist film is removed using a release agent to obtain a processed wafer. A piezoelectric device is configured by attaching electrodes or the like to the processed wafer using a metal mask.

 The metal mask is used as a jig when processing various electronic devices from semiconductor devices to piezoelectric devices such as piezoelectric vibrators. 3A and 3B are views showing the configuration of a conventional metal mask for processing the upper and lower surfaces of a substrate to be processed, wherein FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along QQ. The metal mask main body 20 generally includes an upper mask 21, an intermediate plate 22, and a lower mask 23.

As shown in FIG. 3A, the upper mask 21 has a plurality of desired pattern opening windows 25 at predetermined positions, and the lower mask has a plurality of desired pattern opening windows 26 at predetermined positions. The The intermediate plate 22 is provided with an opening having a size substantially the same as that of a substrate (wafer) 24 to be processed, for example, an AT-cut quartz crystal substrate, and the thickness of the intermediate plate 22 is substantially equal to the thickness of the wafer 24. After the middle plate 22 is fixed to the lower mask 23 and the wafer 24 is accommodated in the opening of the middle plate 22, the upper mask 21 is fixed together with the middle plate 22 and the lower mask 23. At this time, it is desirable that the backlash between the intermediate plate 22 and the wafer 24 is reduced as much as possible, and the upper and lower masks 21 and 23 and the wafer 24 are in close contact with each other. Then, a desired substance, for example, a metal material for an electrode is attached to the wafer 24 through the opening windows 25 and 26 of the upper and lower masks 21 and 23 using a vapor deposition apparatus or the like.
JP 2000-54168 A

  However, when the resist film is stripped using a stripping agent in the previous stage using the metal mask, the resist film may remain slightly at the four corners of the wafer as shown in FIG. This is because when the resist is applied by a spin coater, the resist solution spread by the centrifugal force tends to accumulate at the four corners of the wafer, so that the film becomes thicker than the central portion. If a conventional metal mask as shown in FIG. 3 is loaded and vapor deposition or sputtering is performed with the resist film residue 27 in the corner, the resist residue 27 causes the upper and lower masks 21 and 23 to adhere to the wafer. There was a problem that the accuracy of the vapor deposition pattern to be formed deteriorated. Furthermore, there is a problem that the resist film residue 27 is melted by heat during vapor deposition or sputtering, the upper and lower masks are fixed with the wafer sandwiched, and the wafer is damaged when the wafer is removed from the mask.

According to a first aspect of the present invention, there is provided a metal mask comprising an upper mask, an intermediate plate having an opening for accommodating a rectangular workpiece substrate, and a lower mask. A metal mask in which triangular half-etching is performed at positions corresponding to the four corners of the substrate to be processed on the surface in contact with the plate is characterized.
The invention according to claim 2 is a metal mask comprising an upper mask, a middle plate having an opening for accommodating a rectangular substrate to be processed, and a lower mask, and is in contact with the middle plate of the upper mask and the lower mask. A metal mask having a strip-like half-etching is formed at a position corresponding to the periphery of the substrate to be processed.

  In the metal mask according to the present invention, even if there is a resist film residue at the four corners on the wafer after photolithography, the periphery of the upper mask and the lower mask is half-etched so that the residue does not hit the upper and lower masks. Therefore, there is an advantage that the mask pattern does not deteriorate due to the resist film residue, and the wafer and the upper and lower masks do not adhere even if the metal mask is filled with the wafer and heated in vacuum.

  1A and 1B are diagrams showing an embodiment of a metal mask according to the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along the line Q-Q. The metal mask main body 1 includes an upper mask 2, an intermediate plate 3, and a lower mask 4. The upper mask 2 and the lower mask 4 each have a plurality of opening windows 5 and 6 each having a desired pattern at a predetermined position. Is formed. In addition, an opening is formed in the intermediate plate 3, and the opening 7 is accommodated in the opening so that the shape of the opening is substantially equal to the outer shape of the rectangular substrate 7; The thickness of 3 is set substantially equal to the thickness of the substrate 7 to be processed.

  Further, the upper mask 2 and the lower mask 4 are thinned by performing triangular half etching at positions corresponding to the four corners of the substrate 7 to be processed on the surface in contact with the intermediate plate 3, and resist film residues are formed at the four corners on the substrate 7 to be processed. Even if there is, the residue is prevented from hitting the upper and lower masks. It is sufficient that the half etching depth is about 0.05 mm.

  2A and 2B are diagrams showing the configuration of the metal mask of the second embodiment, where FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line Q-Q. Components that are the same as those shown in FIGS. 1A and 1B are given the same reference numerals. A feature of the second invention resides in that strip-shaped half etchings 10 and 11 are performed at positions corresponding to the periphery of the substrate 7 to be processed on the surface in contact with the middle plate of the upper mask and the lower mask. By performing half etching 10 and 11, even when there is a resist film residue at the four corners on the substrate 7 to be processed, the residue does not hit the upper and lower masks. Even if the filled metal mask main body is heated in vacuum, the resist film residue on the substrate 7 to be processed does not adhere to the upper and lower masks 2 and 4.

  In the above description, an example in which one workpiece substrate is accommodated in one metal mask is exemplified. However, the present invention is applied to a large metal mask for mass production batch processing in which a plurality of exemplified metal masks are connected and integrated in a planar direction. Also good.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic block diagram which showed the structure of the metal mask based on this invention, the figure (a) is a top view, and the figure (b) is sectional drawing. It is a figure which shows the structure of 2nd Example, The figure (a) is a top view, The figure (b) is sectional drawing. It is a figure which shows the structure of the conventional metal mask, The figure (a) is a top view, The figure (b) is sectional drawing. It is a top view which shows the resist film residue of the four corners on a to-be-processed substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal mask main body 2 Upper mask 3 Middle board 4 Lower mask opening window 7 Substrate to be processed 8, 9, 10, 11 Half etching part

Claims (2)

In a metal mask comprising an upper mask, an intermediate plate having an opening for accommodating a rectangular workpiece substrate, and a lower mask,
A metal mask, wherein triangular half-etching is performed at positions corresponding to the four corners of the substrate to be processed on the surface in contact with the middle plate of the upper mask and the lower mask. In a metal mask comprising an upper mask, an intermediate plate having an opening for accommodating a rectangular workpiece substrate, and a lower mask,
A metal mask, wherein a strip-shaped half-etching is performed at a position corresponding to a peripheral edge of a substrate to be processed on a surface in contact with a middle plate of the upper mask and the lower mask.

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