JPH06132285A - Method for forming metallic pattern - Google Patents

Abstract

PURPOSE:To remove more surely a metallic unnecessary to form a metallic pattern on a base. CONSTITUTION:While exposing a region 22 of a base 24 where a pattern is to be formed, a region 26 of the base 24 where no pattern is to be formed is covered with a mask 28. Then, via the mask 28 a metallic film 30 is formed on the base 24. On the boundary between the regions 22, 26, the metallic film 30 is subjected to a bench-cut. Then, the mask 28 is side-etched from the bench- cut part of the film 30 to protrude a film-and part 30a from the mask 28 in the form of eaves. Subsequently, the unnecessary films 30 are removed by brushing so as to hook the film-end parts 30a by a brush 36. Then, the mask 28 is removed to obtain the metallic pattern comprising the films 30 left in the region 22. This purpose can be achieved because the brushing is performed after protruding the film-end part 30a from the mask 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal pattern forming method.

[0002]

2. Description of the Related Art A lift-off method is a typical method for forming a metal thin film pattern used for electrodes and wirings of semiconductor elements. This lift-off method will be described with reference to FIG. 11A to 11C are cross-sectional views showing, step by step, main steps in forming a metal pattern by a lift-off method.

First, while exposing the underlayer 12 in the pattern forming region 10, the underlayer 12 in the pattern non-forming region 14 is covered with a resist 16 (FIG. 11A). Next, the metal film 18 is laminated on the base 12 in the pattern formation region 10 with the resist 16 interposed therebetween (FIG. 11B). At this time, the metal film 18 is cut off between the pattern forming region 10 and the pattern non-forming region 14. Then resist 16
Is dissolved in an organic solvent and removed, and the unnecessary metal film 18 on the resist 16 is removed together with the resist 16 to obtain a metal pattern 20 made of the metal film 18 remaining on the base 12 (FIG. 11C). .

The lift-off method has the advantage that the process is simple and convenient. The lift-off method is described in, for example, the literature: Gallium Arsenide Processing Techniques (19
87) Artech House, Inc. p.126-127.

[0005]

However, in the lift-off method, the desired metal pattern 20 may not be formed in some cases due to the unnecessary metal film remaining. This point will be described with reference to the drawings. 12 to 13 are plan views showing the shape of the metal pattern.

FIG. 12 shows an example in which two metal patterns 20 each having a linear planar shape are arranged in parallel, and FIGS. 13A and 13B show a planar shape close to a closed loop and a shape close to a closed loop (a pseudo closed loop shape). ) Is an example in which the metal pattern 20 is formed. The cross section taken along line XI-XI in FIGS. 12 to 13 corresponds to the cross section shown in FIG. 11. Here, in the pattern non-formation region 14, a region surrounded by the metal film 18 to be the metal pattern 20 is referred to as a region P, and the other regions are referred to as a region Q (see FIG. 11B).

If the planar shape of the metal pattern 20 to be finally obtained is as shown in FIG. 12, the unnecessary metal films 18 laminated in the regions P and Q are connected,
Even if the width l1 of the region P is narrow, the unnecessary metal film 18
The metal film 18 is hardly left without being removed.

However, when the planar shape of the metal pattern 20 to be finally obtained is a closed loop shape as shown in FIG. 13A, the metal film 18 in the region P is the metal film 1 in the region Q.
The metal film 18 in the region P remains in most cases even if the width l1 is wide, because it is not connected to 8 and is isolated.

The metal pattern 2 to be finally obtained
When the plane shape of 0 is a pseudo closed loop shape as shown in FIG. 13B, the metal films 18 in the regions P and Q are connected, but the width l2 of the connected portion of the regions P and Q is, for example, l.
When the width is narrowed to about 2 = 2 μm, the width 11 is 10 μm, for example.
Even if it is wide, the metal film 18 in the region P easily remains.

In the example of FIGS. 13A and 13B, for example, 9
The unnecessary metal film 18 in the region P has a probability of 0% and 50%.
Remains without being removed.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a metal pattern forming method capable of more reliably removing an unnecessary metal portion when forming a metal pattern.

[0012]

In order to achieve this object, in the metal pattern forming method of the first invention, (a) the base of the pattern formation region is exposed while the base of the pattern non-formation region is masked. And (b) stacking a metal film on the base of the pattern formation region through a mask and breaking the metal film between the pattern formation region and the pattern non-formation region, and (c) the mask A step of side-etching through the stepped portion of the metal film to project the metal film end portion of the pattern non-formation region in a canopy shape from the mask, and (d) a pattern non-formation region projecting in a canopy shape from the mask After removing the metal film from the mask by brushing, the step of removing the mask is included.

Further, in the metal pattern forming method of the second invention, (a) a step of exposing the base of the pattern forming region while covering the base of the pattern non-forming region with a mask, and (b) using the metal film as a mask. A step of stacking the metal film on the base of the pattern formation region through the step of cutting this metal film between the pattern formation region and the pattern non-formation region, and (c) mask side etching through the stepped part of the metal film. And projecting the metal film end portion of the pattern non-formation region from the mask in an eaves-like shape, and bending the metal film end portion away from the mask due to the internal stress of the metal film, and (d) pattern non-formation And a step of removing the metal film in which the region is warped by brushing after removing the mask.

[0014]

According to the first aspect of the invention, the metal film in the pattern non-formation region is brushed in a state of protruding from the mask in an eaves-like shape, and is peeled from the mask. Therefore, since the brush is well caught by the metal film protruding from the mask in the shape of an eaves, the metal film in the pattern non-formation region, which is unnecessary for forming the metal pattern, can be more surely removed.

Further, according to the second aspect of the present invention, the mask is side-etched so that the metal film end portion of the pattern non-formation region is bent back due to the internal stress thereof, and then the mask is removed. Since the film is removed by brushing, the metal film in the unnecessary pattern non-formed area can be removed more reliably.

The reason is considered as follows. That is, when the planar shape of the metal pattern to be finally obtained is a closed loop shape or a pseudo closed loop shape, the pattern non-formation area P (FIG. 11) surrounded by this metal pattern is formed.
Attention is paid to the metal films of (B) and FIGS. 13 (A) to (B). If the mask is removed after the edge of the metal film in the region P is warped, after the mask is removed, the edge of the film is kept flat so that the center of the metal film in the region P is not warped. Act on. Therefore, since the metal film in the region P has a flat plate shape in the central portion and the end portions are warped, the metal film in the region P is likely to be caught, and as a result, the metal film in the region P can be removed more reliably. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the drawings are merely schematic representations so that the present invention can be understood, and therefore the present invention is not limited to the illustrated examples.

First, a first embodiment of the first invention will be described. 1 to 3 are sectional views showing step by step the main steps in the first embodiment of the first invention.

First, while exposing the base 24 of the pattern formation region 22, the base 24 of the pattern non-formation region 26 is covered with a mask 28 (step (a), FIG. 1).
(A)).

In this embodiment, the base 24 is a field effect transistor, a resistor and other electric circuit elements (not shown).
And a insulating film 24b covering the substrate surface of the substrate 24a on the side where the electric circuit elements are formed. A metal pattern as a wiring metal is formed on the insulating film 24b through the steps described below. The insulating film 24b includes
Although not shown, a contact hole for connecting the electric circuit element and the metal pattern as the wiring metal is formed.

Further, the mask 28 is formed of a resist, for example, a negative resist LMR manufactured by Fuji Chemical Co., Ltd. Mask 28
In forming the film, a resist LMR is applied on the insulating film 24b to a thickness of about 1.0 μm, and then the resist LMR is formed.
Is exposed and developed using a photolithography technique to form a predetermined shape, and a mask 28 made of a resist LMR having a predetermined shape is obtained. The mask 28 covers the base 24 of the pattern non-formation area 26 and the base 24 of the pattern formation area 22.
Has a window 28a for exposing. According to the resist LMR, the cross-sectional shape of the window 28a is such that the opening width of the window 28a is the base 2
It is possible to make an inverse taper shape such that it becomes narrower smoothly as it goes away from 4.

Next, the metal film 30 is laminated on the underlayer 24 of the pattern forming region 22 via the mask 28, and the metal film 30 is cut off between the pattern forming region 22 and the pattern non-forming region 24 (step (b)). , FIG. 1B).

In this embodiment, a film having a weak internal stress, for example, a single layer film made of Al, In or Sn is laminated as the metal film 30. In order to break the metal film 30 between the pattern formation region 22 and the pattern non-formation region 26, the cross-sectional shape of the window 28a should be an inverse taper shape or the mask end face 28.
It is preferable that b is erected vertically to the base 24.

Next, the mask 28 is side-etched through the stepped portion of the metal film 30 so that the metal film end portion 30a of the pattern non-formation region 26 is projected from the mask in an eaves shape (step (c), FIG. 2 (A)).

In this embodiment, the mask 28 is side-etched by ashing with oxygen plasma. In the side etching of the mask 28, the underlayer 24 on which the metal film 30 is laminated is placed in the reaction chamber of the barrel type ashing device, and then oxygen gas is introduced into the reaction chamber. Then, a high-frequency electric field of 100 W is applied to the oxygen gas to generate oxygen plasma, and the mask 28 is etched by the oxygen plasma. The pressure in the reaction chamber is maintained at 1 Torr during the etching. The mask 28 portion covered with the metal film 30 is not etched, and the end surface 28b on the side of the mask 28 not covered with the metal film 30 is selectively etched. The end surface 28b on the side of the mask 28 is etched for about 10 minutes and set back by about 1 μm, and the metal film end portion 3
0a is made to protrude from the end surface 28b on the side of the mask 28 in an eaves shape.

Even if the mask 28 side portion supporting the metal film end portion 30a is removed by etching away the mask 28 side portion, the metal film 30 has little internal stress, and therefore hardly warps.

Next, the metal film 30 in the pattern-unformed region 22 projected from the mask 28 in an eaves-like shape is removed from the mask 28 by brushing, and thereafter the mask 28 is removed (step (d), FIG. B) -FIG. 3 (B)).

In this embodiment, nylon fiber bristles 36a
The brush 36 having Then, while the pure water is sprayed and the bristles 36a are brought into contact with the surface of the base 24 on the side where the unnecessary metal film 30 remains in the pattern non-formation region 22, the brush 36 is rotated about a rotation axis T orthogonal to the base 24.
Rotate around 1000 rpm (Fig. 2
(B)), and removes the unnecessary metal film 30 by hooking it with the bristles 36a (FIG. 3A). The metal film 30 in the pattern formation region 22 that is not removed by the brushing becomes the metal pattern 34 to be formed on the base 24.

According to the experiments by the present inventors, the unnecessary metal film 30 in the pattern non-formation region 22 can be reliably removed by performing the brushing for about 10 minutes.

After removing the unnecessary metal film 30, the mask 28 is dissolved and removed with an organic solvent such as an n-methyl-2-pyrrolidone solution (FIG. 3B). Besides removing the mask 28 with an organic solvent, the mask 28 may be removed by ashing with oxygen plasma, for example.

Next, a second embodiment of the first invention will be described. 4 to 6 are sectional views showing stepwise the main steps in the second embodiment of the first invention. In the description of this embodiment, detailed description of the same points as in the first embodiment of the first invention will be omitted.

First, while exposing the base 24 of the pattern forming region 22, the base 24 of the pattern non-forming region 26 is covered with a mask 28 (step (a), FIG. 4).
(A)).

Next, the metal film 30 is laminated on the underlayer 24 of the pattern forming region 22 through the mask 28, and the metal film 30 is cut off between the pattern forming region 22 and the pattern non-forming region 24 (step (b)). , FIG. 4B).

In this embodiment, the metal film 30 has an internal stress that causes the end 30a of the film 30 to warp in a direction away from the mask 28 when the film end 30a is projected from the mask 28 like an eaves shape. As such a metal film 30, a Ti film, a Pt film, and an A film, which are sequentially stacked from the side of the base 24, are formed.
The Ti film, the Pt film, and the Au film are each formed by a vacuum deposition method using a multilayer film made of a u film to have a film thickness of 1000 Å (A °), 1000 A °, and 7000 A.
Laminate to about °.

Next, the mask 28 is side-etched through the stepped portion of the metal film 30 so that the metal film end portion 30a of the pattern non-formation region 26 is projected like an eaves shape from the mask (step (c), FIG. 5 (A)).

In this embodiment, since the metal film 30 has the internal stress as described above, if the side of the mask 28 supporting the metal film end 30a disappears by etching away the side of the mask 28, the metal film The film end portion 30a warps due to the internal stress. The metal film 30 is a multi-layer film or a single-layer film, and the metal film end portion 30a is masked by the mask 28 by arbitrarily selecting the formation conditions of the metal film 30, for example, the material and the film thickness.
You can bend it away from you. A Ti film, Pt in which a metal film 30 is sequentially stacked from the side of the base 24
In the case of a multilayer film including a film and an Au film, the metal film end portion 3
The warp amount of 0a depends on the film thickness of Ti and Pt, but is about 0.5 μm, for example.

Next, the metal film 30 in the pattern-unformed region 22 projected from the mask 28 in an eaves-like shape is removed from the mask 28 by brushing, and then the mask 28 is removed (step (d), FIG. B) to FIG. 6 (B)).

In this embodiment, the pattern non-formed area 26
The brush 36 is rotated while hooking the bristles 36a on the bent metal film end portion 30a (see FIG. 5).
(B)), thereby removing the unnecessary metal film 30 from the mask 28 (FIG. 6A), and thereafter removing the mask 28 (FIG. 6B).

According to the experiments conducted by the present inventors, the unnecessary metal film 30 in the pattern non-formation region 22 can be reliably removed by brushing for about 2 to 3 minutes.
Therefore, the time required for removing the unnecessary metal film 30 can be shortened as compared with the first embodiment.

Next, an embodiment of the second invention will be described. 7 to 9 are sectional views showing stepwise the main steps of the embodiment of the second invention, and FIG. 10 is a plan view showing the same steps as FIG. 8A. In the description of this embodiment, detailed description of the same points as in the first embodiment of the first invention will be omitted.

First, while exposing the base 24 of the pattern forming region 22, the base 24 of the pattern non-forming region 26 is covered with a mask 28 (step (a), FIG. 7).
(A)).

Next, the metal film 30 is laminated on the base 24 of the pattern forming region 22 via the mask 28, and the metal film 30 is cut off between the pattern forming region 22 and the pattern non-forming region 26 (step (b)). , FIG. 7B).

In this embodiment, the metal film 30 has an internal stress that causes the end 30a of the metal film 30 to warp in a direction away from the mask 28 when the film end 30a is projected from the mask 28 in an eaves shape. As such a metal film 30, a Ti film, a Pt film, and an A film, which are sequentially stacked from the side of the base 24, are formed.
The Ti film, the Pt film, and the Au film are each formed by a vacuum deposition method using a multilayer film made of a u film to have a film thickness of 1000 Å (A °), 1000 A °, and 7000 A.
Laminate to about °.

Next, the mask 28 is side-etched through the stepped portion of the metal film 30 so that the metal film end portion 30a of the pattern non-formation region 26 protrudes from the mask 28 in an eaves-like shape. 30a is bent back in the direction away from the mask 28 by the internal stress of the metal film 30 (step (c), FIGS. 8A and 10).

In this embodiment, since the metal film 30 has the internal stress as described above, if the side of the mask 28 supporting the metal film end 30a disappears by removing the side of the mask 28 by etching, the metal film 30 is removed. The film end portion 30a warps due to the internal stress. The metal film end portion 30a bent back by the side etching of the mask 28 is shown by hatching in FIG.

Next, the warped metal film 30 in the pattern non-formation region 26 is removed by brushing after removing the mask 28 (step (d), FIGS. 8B to 9).
(B)).

In this embodiment, the mask 28 is immersed in an organic solvent for the resist, for example, n-methyl-2-pyrrolidone solution, and the mask 28 is dissolved and removed with the organic solvent (FIG. 8).
(B)). At this time, most of the unnecessary metal film 30 in the pattern non-formation region 26 is removed (lifted off) together with the mask 28, while the metal film 30 in the pattern formation region 22 is removed.
Does not peel off from the base 24 even if the mask 28 is removed, and thus remains as a metal pattern 34 on the base 24, since it is in direct contact with the base 24 without passing through the mask 28. still,
Reference numeral 32 in FIG. 8B indicates an organic solvent remaining between the underlayer 24 and the unnecessary metal film 30 that cannot be lifted off and remains.

Ideally, it is desired that all the unnecessary metal film 30 in the pattern non-formation region 26 is removed together with the mask 28, but the metal pattern 34 to be formed on the base 24.
If the plane shape of the pattern is a closed loop shape or a pseudo closed loop shape, the unnecessary metal film 30 in the pattern non-formation region P (26) (see FIGS. 8 and 10) surrounded by the metal pattern 34 is formed.
Often remain without being lifted off.

Therefore, after removing the mask 28, the metal film 30 remaining in the pattern non-formation region P is removed.
The metal film 30 in the pattern non-formation region P is removed by brushing. Therefore, while the pure water is sprayed and the bristles 36a of the brush 36 are brought into contact with the surface of the base 24 on the side where the metal film 30 remains, the brush 36 is rotated (FIG. 9A), and the area P is reached. The metal film 30 in the region P is removed by hooking the turned-up film end portion 30a of the remaining metal film 30 on the bristles 36a (FIG. 9B).

In this embodiment, the mask 28 is removed after the metal film end portion 30a of the pattern non-formation region 26 including the region P is turned back. Therefore, after the mask 28 is removed, the metal which is turned back is bent. The metal film 3 in which the film edge portion 30a is the region P
0 It is considered that it acts to keep the central portion in a flat plate shape so as not to bend back. Therefore, it is considered that the metal film 30 in the region P has a flat plate shape in the central portion and the end portions are warped, so that the unnecessary metal film 30 in the region P can be easily removed by brushing.

Further, in this brushing, the area P
In order to facilitate the removal of the unnecessary metal film 30 of the above, after the mask 28 is removed with an organic solvent, the metal film 30 in the region P floats on the organic solvent (see FIG. 8B) or It is desirable to be close. In order to do so, the organic solvent used for removing the mask 28 is a low-viscosity organic solvent such as a viscosity of 0.316 centipoise (c).
It is more advantageous to use an organic solvent having a higher viscosity, for example, n-methyl-2-pyrrolidone of about 1.65 cP than using acetone of about P). As the highly viscous organic solvent, it is preferable to use one having a viscosity of about 0.7 to about 5 cP.

According to the experiments conducted by the inventors of the present application, the unnecessary metal film 30 in the region P can be surely removed by brushing for about 30 seconds, which is unnecessary as compared with the first embodiment. The time required to remove the metal film 30 could be shortened.

When the plane shape of the metal pattern 34 is a closed loop, the area P surrounded by the metal pattern 34 is formed.
In the range of the width l1 of 10 to 500 μm (see FIG. 13A for l1), the unnecessary metal film 30 in the region P could be reliably removed by brushing. In addition, when the planar shape of the metal pattern 34 is a pseudo closed loop, the area P1 surrounded by the metal pattern 34 has an l1 of 10 to 500 μm.
In addition, in the range of 12 to 2 μm (see FIG. 13B for 11 and 12), the unnecessary metal film 30 in the region P could be reliably removed by brushing.

In the conventional lift-off method, the mask is removed and the unnecessary metal film is lifted off without going through the step of warping the end of the unnecessary metal film. In this case, the area P
In many cases, the unnecessary metal film of wrinkles is entirely wrinkled and remains on the base in a state of being partially in contact with the base. Therefore, even if brushing is performed, the unnecessary metal film in the region P is not removed in most cases. It will remain.

The present invention is not limited to the above-mentioned embodiments, and therefore, the shapes, dimensions, forming materials, forming methods, numerical conditions and other conditions of each constituent can be arbitrarily changed.

For example, in the first and second inventions, the underlayer 24 may be formed of Si, Ge or other compound semiconductor, or may be formed of any suitable material other than the compound semiconductor. good.

In the first and second inventions, the mask 2
8 is formed of a material other than resist, for example, a multilayer film, and the window 2
The cross-sectional shape of 8a may be a reverse taper shape in which the opening width of the window 28a becomes stepwise narrower as it goes away from the base 24. Alternatively, the mask end surface 28b which is the side wall of the window 28a may be erected perpendicularly to the base 24.

As a material for forming the mask 28, the physicochemical property is different from that of the metal pattern 34 or the underlying layer 24 in addition to this, and only the mask 28 is selectively etched without etching the metal pattern 34 or the underlying layer 24. A material that can be etched can be used. For example, mask 28
Is formed from a SiN film or a SiO ₂ film, and when the mask 28 is side-etched, S is used instead of oxygen plasma.
When the mask 28 is removed by etching with plasma of F ₆ gas, CF ₄ gas or other gas containing fluorine, a diluted hydrofluoric acid solution may be used instead of the n-methyl-2-pyrrolidone solution.

In the first and second inventions, when the unnecessary metal film 30 is removed, the brush 36 is rotated and the metal film 30 is slid against the base 24. The brush 36 may be used.

Further, in the second invention, the metal film 30 is formed by side etching the mask 28.
Either a multi-layer film or a single-layer film may be used as long as it warps away from the film, and the material for forming the film may be arbitrarily changed. The metal film 30 is a multilayer film composed of a Ti film, a Pt film, and an Au film.
A multilayer film including an i film and an Al film (this multilayer film is suitable for forming a gate electrode of a field effect transistor), or an AuGe film, a Ni film, and an A film that are sequentially stacked from the underlayer 24 side.
It may be a multilayer film made of a u film (this multilayer film is suitable for forming an ohmic electrode). Since the Ti film and the Ni film have large internal stress, the metal film 30 is easily warped. Also W, M
A film made of o, Ta or other refractory metal, or an alloy containing refractory metal, such as WSi, MoSi or TaN.
Since the film made of is a film having a strong internal stress, these films may be used as the metal film 30 in a single layer. Also, A
l film, In film, Sn film or other film having weak internal stress and difficult to warp. Therefore, even if the film is not suitable as the metal film 30 in a single layer, this hard to warp film is combined with a film having strong internal stress and easily warping. If the multi-layer film is a metal film 30, the metal film 30 is a film that is hard to warp.
Can be used for.

[0061]

As is apparent from the above description, according to the metal pattern forming method of the first invention, the metal film in the pattern non-forming region is brushed in a state of protruding from the mask in the shape of an eaves, Peel off the mask. Therefore,
Since the brush is well hooked on the metal film protruding from the mask in the shape of an eaves, the metal film in the pattern non-formation region, which is unnecessary for forming the metal pattern, can be more surely removed.

Further, according to the metal pattern forming method of the second invention, the mask is side-etched so that the end portions of the metal film in the pattern non-formation region are warped due to the internal stress, and then the mask is removed, and then the pattern Since the metal film in the non-formation region is removed by brushing, the metal film in the unnecessary pattern non-formation region can be removed more reliably.

[Brief description of drawings]

1A to 1B are cross-sectional views schematically showing main steps of a first embodiment of the first invention.

2A to 2B are sectional views schematically showing main steps of a first embodiment of the first invention.

3A to 3B are cross-sectional views schematically showing main steps of a first embodiment of the first invention.

4A to 4B are sectional views schematically showing main steps of a second embodiment of the first invention.

5A to 5B are cross-sectional views schematically showing main steps of a second embodiment of the first invention.

6A to 6B are sectional views schematically showing main steps of a second embodiment of the first invention.

7A to 7B are sectional views schematically showing main steps of an embodiment of the second invention.

8 (A) to (B) are sectional views schematically showing main steps of an embodiment of the second invention.

9A to 9B are cross-sectional views schematically showing main steps of an embodiment of the second invention.

FIG. 10 is a plan view schematically showing main steps of an example of the second invention.

11A to 11C are cross-sectional views for explaining a lift-off method.

FIG. 12 is a plan view showing an example of a planar shape of a metal pattern.

13A to 13B are plan views showing another example of the planar shape of the metal pattern.

[Explanation of symbols]

 22: Pattern forming region 24: Base 26: Pattern non-forming region 28: Mask 30: Metal film 34: Metal pattern 36: Brush

Claims (3)

[Claims] 1. A process of (a) covering a base of a pattern non-formation region with a mask while exposing the base of the pattern formation region, and (b) a metal film as a base of the pattern formation region through the mask. A step of stacking and cutting the metal film between the pattern formation region and the pattern non-formation region; and (c) side-etching the mask through the stepped part of the metal film to form no pattern. A step of projecting a metal film end portion of the region in a canopy shape from the mask; and (d) removing the mask after the metal film of the pattern-unformed region projecting from the mask in a canopy shape is removed from the mask by brushing. And a step of forming a metal pattern. 2. The metal pattern formation according to claim 1, wherein the metal film has an internal stress that causes the end of the metal film to warp in a direction away from the mask when the end portion of the metal film is projected like a canopy from the mask. Method. 3. A step of: (a) covering a base of the pattern non-formation area with a mask while exposing the base of the pattern formation area; and (b) forming a metal film on the base of the pattern formation area through the mask. A step of stacking and cutting the metal film between the pattern formation region and the pattern non-formation region; and (c) side-etching the mask through the stepped part of the metal film to form no pattern. A step of projecting a metal film end portion of the region in a canopy shape from the mask, and bending the metal film end portion away from the mask due to an internal stress of the metal film; and (d) warping the pattern non-formed region. And a step of removing the metal film by brushing after removing the mask.