JPH0927454A - Mask for selective evaporation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate mask displacement during the formation of metal electrodes or the like on a semiconductor device by selective evaporation, and thereby form the electrodes excellent in pattern shape accuracy. SOLUTION: Stress buffering holes 25 are formed between the pattern area 22 of a mask 21 for selective evaporation and mask fixing areas containing fixing holes 23. This prevents the mask 21 from being floated due to thermal expansion during evaporation and from being deformed due to screw tightening pressure in the fixing areas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a selective vapor deposition mask for selectively depositing a metal film or the like on a semiconductor device or a semiconductor mounting substrate.

[0002]

2. Description of the Related Art Selective deposition of a metal film using a mask is usually well performed for the purpose of forming electrodes on a semiconductor substrate or a mounting substrate. A conventional selective vapor deposition method will be described with reference to the drawings. FIG. 3 shows a mask for selective vapor deposition,
(A) is a top view, (b) is sectional drawing in the AA line. The selective vapor deposition mask 1 generally has a thickness of 0.1 m.
A metal plate having a size of about m, and a central portion thereof is a pattern portion 2 on which a pattern for vapor deposition is formed, and a mask fixing hole for fixing the mask 1 and the wafer to a wafer holder to be described later in the peripheral portion. 3 and a holder fixing hole 4 for fixing the mask 1 and the wafer holder to a vapor deposition holder to be described later. FIG. 4 shows a wafer 6 for vapor deposition.
(A) is a plan view and (b) is a cross-sectional view taken along the line BB. FIG. 5 shows a wafer holder 7 for accommodating a wafer and fixing a mask. (A) is a plan view, (b) is its C-
It is sectional drawing in the C line. The wafer holder 7 is provided with a guide hole 9 for accommodating the wafer, a push-up hole 10 for taking out the wafer, a mask fixing screw 11, and a holder fixing hole 12.

FIG. 6 shows a state in which the wafer 6 is set in the guide hole 9 of the wafer holder 7, the selective vapor deposition mask 1 is covered thereover, and the nut 13 is fitted into the mask fixing screw 11 to set it. (A) is a top view, (b) is sectional drawing in the DD line. FIG. 9 shows an outline of the electron beam evaporation apparatus. In the vacuum chamber 41 having an opening door (not shown),
After attaching a large number of wafer holders 7 to which the wafer 6 and the mask 1 are fixed to the vapor deposition holder 40 as shown in FIG.
The door is closed, the vacuum valve 42 is opened, and the vacuum chamber 41 is evacuated by a vacuum pump (not shown). After reaching a predetermined vacuum degree, an electron beam 46 is generated from the electron gun 43, the electron beam 46 is applied to the source metal 45 in the hearth 44, the source metal 45 is heated and melted, and the source molecule 4 is evaporated.
7 is selectively vapor-deposited on the wafer 6 in the holder 7 through the mask 1. A large number of wafer holders 7 can be processed at once by changing their positions during vapor deposition by means of a rotating mechanism or the like.

[0004]

However, in the conventional selective vapor deposition method described with reference to FIGS. 6 and 9, the central portion of the mask 1 partially thermally expands due to the heat during vapor deposition, and as a result, the mask 1 Uplift 14 is easy to occur. The temperature rise during vapor deposition sometimes exceeds 100 ° C. Further, as shown in FIG. 6B, due to the screw tightening pressure when the nut 13 is tightened to the mask fixing screw 11, the deformation 15 of the mask 1 is likely to occur in the vicinity thereof.

The floating 14 due to the thermal expansion of the mask 1 and the deformation 15 of the mask due to the screw tightening pressure when the mask 1 is screwed and fixed to the wafer holder 7 cause the positional deviation of the selectively deposited metal film and the incorrect shape. Cause Figure 7
(A) is an enlarged view of one chip 8 in the wafer 6 after selective vapor deposition, and (b) is a sectional view taken along the line EE in FIG.
Due to the above-mentioned problems, the selectively vapor-deposited electrode 16 causes a mask shift, and a gap 17 between the mask 1 and the wafer 6 causes an exudation 17. In this wafer 6, the electrode 16 of the second layer is selectively vapor-deposited on the wafer on which the electrode 18 of the first layer is already formed.

In view of the above problems, it is an object of the present invention to provide a selective vapor deposition mask which eliminates the above-mentioned problems, has a good pattern shape, and is capable of performing selective vapor deposition with good alignment accuracy between the mask and a deposition target substrate. It is in.

[0007]

In order to solve the above problems, the present invention provides a pattern portion for performing selective vapor deposition on a deposition substrate and a fixing portion for fixing the deposition substrate to a holder with the deposition substrate interposed therebetween. In the mask for selective vapor deposition having, a stress buffering portion is provided between the fixed portion and the pattern portion.

Particularly, it is preferable that the stress buffering portion is formed of a hole and the hole is formed of an elongated hole. Furthermore, it is preferable that the stress buffering portion covers 50% or more of the periphery of the pattern portion.

[0009]

By taking the above-mentioned means to form a mask for selective vapor deposition having a stress buffer between the fixed portion and the pattern portion, thermal expansion of the pattern portion, screwing pressure of the fixed portion, etc. The stress can be absorbed by the buffer portion, and the deformation of the mask can be avoided. The simplest stress buffering part is to have a long and narrow slit-shaped hole, and if the stress buffering part covers 50% or more of the periphery of the pattern part, the stress absorption in the buffering part is sure. To be done.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a mask for selective vapor deposition according to the first embodiment of the present invention, for example, a Fe—N film having a thickness of 0.15 mm.
It consists of an i alloy plate. (A) is the top view, (b) is sectional drawing in the FF line. Mask 2 of FIG. 1 (a)
1 is a buffer hole 25 having an elongated shape between the mask fixing hole 23 and the pattern portion 22 in addition to the central pattern portion 22, the mask fixing hole 23, and the holder fixing hole 24 like a conventional mask. Are provided on all sides.

FIG. 2 shows a state in which the wafer 26 and the mask 21 are firmly fixed to the wafer holder 7 shown in FIG. 5 so as not to move. (A) is a plan view, (b) is its G-
It is sectional drawing in the G line. The wafer 26 is inserted into the guide hole 9 of the wafer holder 7, and the mask 21 shown in FIG.
2 is visually aligned, and the nut 1 is attached to the mask fixing screw 11 provided on the wafer holder 7 as shown in FIG.
3 is tightly fixed so that the wafer 26 and the mask 21 do not move. At this time, it is better to sandwich the washer 19.

As shown in FIG. 2, the wafer 26 and the mask 21
The holder 7 to which is fixed is attached to the vapor deposition holder 40 in the vacuum chamber 41 of the electron beam vapor deposition apparatus shown in FIG. After the vacuum valve 42 is opened and a vacuum pump (not shown) is used to set a predetermined degree of vacuum, an electron beam 46 is generated from the electron gun 43, and the electron beam 46 is applied to the source metal 45 in the source hearth 44. It melts and is blown as vapor deposition source molecules 47, and is selectively vapor deposited on the wafer 26 through the mask 21. In the present embodiment, the wafer 26 on which Al electrodes have already been formed
Then, three layers of Ti / Ni / Au were continuously and selectively vapor deposited.

FIG. 8A is an enlarged view of one chip 28 in the wafer 26 after the selective vapor deposition using the selective vapor deposition mask 21 of the embodiment of the present invention, and FIG. 8B is the H-H line thereof. FIG. In the present invention, the mask deformation 14 due to the thermal expansion and the mask deformation 15 due to the screwing pressure as shown in FIG. 6 in the conventional method are prevented by the buffer hole 25 provided in the mask 21 in the present invention. Particularly, in order to avoid the deformation of the mask due to the screw tightening pressure, it is more preferable to sandwich the washer 19 under the nut 13. As a result, as shown in FIGS. 8A and 8B, no mask displacement due to the above-described defects and no seeping due to the gap between the mask 21 and the wafer 26 are observed, and the mask 38 is accurately aligned with the electrode 38 of the first layer. Thus, the electrode 36 having the three layers of Ti / Ni / Au selectively deposited is obtained.

FIG. 10 shows a mask for selective vapor deposition according to the second embodiment of the present invention. In this case, the buffer hole 6 of the mask 61
5 is provided in a circular arc shape around the mask fixing hole 63 between the pattern portion 62 and the pattern portion 62. FIG. 11 is a mask for selective vapor deposition according to the third embodiment of the present invention. In this case, the buffer hole 85 of the mask 81 is provided in a mesh shape between the pattern portion 82 and the mask fixing hole 83. As described above, the buffer hole is not limited to the elongated hole, and various modifications can be considered.

Although the example of electron beam vapor deposition is shown in the above example, the selective vapor deposition mask of the present invention can also be used in vapor deposition by a sputtering method or a CVD method. Further, the substance to be vapor-deposited is not limited to the metal film, but may be an insulating substance or a semiconductor.

[0016]

As described above, when the deposition target substrate such as the mask and the wafer is fixed to the holder and the selective deposition of the metal film or the like is performed in the deposition apparatus, the selective deposition mask is surrounded by the pattern portion. By using a mask provided with a buffer portion for stress buffering, thermal expansion during vapor deposition, stress due to screw tightening of the fixing portion, etc. is relieved, deformation of the mask does not affect the vapor deposition film, and Shape accuracy is improved. Also,
If the mask alignment with the existing pattern is performed, the mask alignment accuracy is improved.

[Brief description of drawings]

1A is a plan view of a mask for selective vapor deposition according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line FF thereof.

FIG. 2A is a plan view showing a state in which a wafer and a mask for selective vapor deposition according to an embodiment of the present invention are set in a holder, and FIG.
Sectional drawing in the GG line

FIG. 3A is a plan view of a conventional mask for selective vapor deposition,
(B) is sectional drawing in the AA line.

FIG. 4A is a plan view of a silicon wafer, and FIG.
Sectional drawing in the BB line

FIG. 5A is a plan view of the holder, and FIG.
Sectional view along line C

6A is a plan view showing a state where a wafer and a conventional mask for selective vapor deposition are set in a holder, and FIG. 6B is a DD view thereof.
Sectional view at the line

FIG. 7A is a plan view of a chip selectively vapor-deposited using a conventional selective vapor deposition mask, and FIG. 7B is a cross-sectional view taken along the line EE.

FIG. 8A is a plan view of a chip selectively vapor-deposited by using the selective vapor deposition mask of the embodiment of the present invention, and FIG. 8B is a cross-sectional view taken along the line HH.

FIG. 9 is a schematic diagram of an electron beam vapor deposition apparatus.

FIG. 10 is a plan view of a mask for selective vapor deposition according to a second embodiment of the present invention.

FIG. 11 is a plan view of a mask for selective vapor deposition according to a third embodiment of the present invention.

[Explanation of symbols]

 1, 21, 61, 81 Mask 2, 22, 62, 82 Pattern part 3, 23, 63, 83 Mask fixing hole 4, 24 Holder fixing hole 6, 26 Wafer 8, 28 Chip 7 Wafer holder 9 Guide hole 10 Projection Hole 11 Mask fixing screw 12 Holder fixing hole 13 Nut 14 Lifting 15 Deformation 16, 36 Electrode 17 Exudation 18, 38 First layer electrode 19 Washer 25, 65, 85 Buffer hole 40 Evaporation holder 41 Vacuum chamber 42 Vacuum valve 43 Electron gun 44 Hearth 45 Source metal 46 Electron beam 47 Firing molecule 48 Support rod

Claims (4)

[Claims] 1. A pattern portion for performing selective vapor deposition,
A selective vapor deposition mask having a fixing portion for fixing a deposition target substrate to a holder with the substrate being sandwiched therebetween, wherein the selective vapor deposition mask includes a stress buffer portion between the fixing portion and the pattern portion. 2. The mask for selective vapor deposition according to claim 1, wherein the stress buffering portion comprises a hole. 3. The mask for selective vapor deposition according to claim 2, wherein the stress buffering portion comprises an elongated hole. 4. The selective deposition mask according to claim 2, wherein the stress buffering portion covers 50% or more of the periphery of the pattern portion.