# US 7,071,037 B2 · Semiconductor device and manufacturing method thereof

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- Number: US 7,071,037 B2
- Document ID: US7071037B2
- Status: Granted
- Kind: B2
- Application number: 10/086,628
- Filed: 2002-03-04
- Published: 2002-11-21
- Granted: 2006-07-04
- Earliest claimed: 2001-03-06
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Hideomi Suzawa; Yoshihiro Kusuyama; Shunpei Yamazaki
- Web page: https://patentgrep.com/patent/US7071037B2

## CPC

- H10D 30/6715: {characterised by the doping profiles, e.g. having lightly-doped source or drain extensions}
- H10D 30/0316: {of lateral bottom-gate TFTs comprising only a single gate}
- H10D 30/0321: {comprising silicon, e.g. amorphous silicon or polysilicon}
- H10D 30/6732: {Bottom-gate only TFTs}
- H10D 30/6746: {Amorphous silicon}
- H10D 62/10: Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies
- H10D 86/0231: {using masks, e.g. half-tone masks}
- H10D 86/441: {Interconnections, e.g. scanning lines}
- H10D 86/443: {adapted for preventing breakage, peeling or short circuiting}
- H10D 86/60: wherein the TFTs are in active matrices
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

The present invention has an object to provide an active-matrix liquid crystal display device that realizes the improvement in productivity as well as in yield. In the present invention, a laminate film comprising the conductive film comprising metallic material and the second amorphous semiconductor film containing an impurity element of one conductivity type and the amorphous semiconductor film is selectively etched with the same etching gas to form a side edge of the first amorphous semiconductor film 1001 into a taper shape. Thereby, a coverage problem of a pixel electrode 1003 can be solved and an inverse stagger type TFT can be completed with three photomask. Selected figure is FIG. 15.

## Claims

### Claim 1

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film covering the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a metal film over the second amorphous semiconductor film;
etching the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the metal film; and
etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

### Claim 2

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film covering the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a metal film over the second amorphous semiconductor film;
etching the metal film, the second amorphous semiconductor film, the first amorphous semiconductor film and the insulating film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the metal film; and
etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

### Claim 3 (depends on 1, 2)

The method of manufacturing the semiconductor device according to one of claim 1 and claim 2, wherein in the former etching step, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film are etched with a chlorine type gas.

### Claim 4 (depends on 1, 2)

The method of manufacturing the semiconductor device according to one of claim 1 and claim 2, wherein in the latter etching step, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film are etched with a chlorine type gas.

### Claim 5 (depends on 3)

The method of manufacturing the semiconductor device according to claim 3, wherein the chlorine type gas contains at least one selected from the group consisting of Cl2, BCl3, HCl and SiCl4.

### Claim 6

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film over the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming one of an aluminum film and a titanium film over the second amorphous semiconductor film;
etching the one of the aluminum film and the titanium film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the one of the aluminum film and the titanium film; and
etching the transparent conductive film, the one of the aluminum film and the titanium film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
wherein the first amorphous semiconductor film is etched into the taper shape with a mixture gas of Cl2 and BCl2.

### Claim 7

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film over the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a tantalum film over the second amorphous semiconductor film;
etching the tantalum film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the tantalum film; and
etching the transparent conductive film, the tantalum film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
wherein the first amorphous semiconductor film is etched into the taper shape with a mixture gas of Cl2 and CF4.

### Claim 8

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film over the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a tungsten film over the second amorphous semiconductor film;
etching the tungsten film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the tungsten film; and
etching the transparent conductive film, the tungsten film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
wherein the first amorphous semiconductor film is etched into the taper shape with one of a mixture gas of Cl2, CF4 and O2 and a mixture gas of Cl2, SF6 and O2.

### Claim 9 (depends on 4)

The method of manufacturing the semiconductor device according to claim 4, wherein the chlorine type gas contains at least one selected from the group consisting of Cl2, BCl3, HCl and SiCl4.

### Claim 10 (depends on 6, 7, 8)

The method of manufacturing the semiconductor device according to any one of claims 6–8, wherein a chlorine type gas is used in the step of etching the transparent conductive film, the one of the aluminum film, the titanium film, the tantalum film and the tungsten film and the second amorphous semiconductor film.

### Claim 11 (depends on 10)

The method of manufacturing the semiconductor device according to claim 10, wherein the chlorine type gas contains at least one selected from the group consisting of Cl2, BCl3, HCl and SiCl4.

### Claim 12

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film covering the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a metal film over the second amorphous semiconductor film;
etching the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film without changing an etching gas to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the metal film; and
etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

### Claim 13

A method of manufacturing a semiconductor device, comprising:
forming a gate wiring over an insulating surface;
forming an insulating film covering the insulating surface and the gate wiring;
forming a first amorphous semiconductor film over the insulating film;
forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
forming a metal film over the second amorphous semiconductor film; etching the metal film, the second amorphous semiconductor film, the first amorphous semiconductor film and the insulating film without changing an etching gas to form a side edge of the first amorphous semiconductor film into a taper shape;
forming a transparent conductive film in contact with the metal film; and
etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

### Claim 14 (depends on 12)

The method of manufacturing the semiconductor device according to claim 12, wherein a chlorine type gas is used as the etching gas.

### Claim 15 (depends on 13)

The method of manufacturing the semiconductor device according to claim 13, wherein a chlorine type gas is used as the etching gas.

### Claim 16 (depends on 12, 13)

The method of manufacturing the semiconductor device according to one of claim 12 and claim 13, wherein a chlorine type gas is used in the step of etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film.

### Claim 17 (depends on 14, 15)

The method of manufacturing the semiconductor device according to one of claim 14 and claim 15 wherein the chlorine type gas contains at least one selected from the group consisting of Cl2, BCl3, HCl and SiCl4.

### Claim 18 (depends on 16)

The method of manufacturing the semiconductor device according to claim 16, wherein the chlorine type gas contains at least one selected from the group consisting of Cl2, BCl3, HCl and SiCl4.

### Claim 19 (depends on 1, 2)

The method of manufacturing the semiconductor device according to one of claim 1 and claim 2, wherein the former etching step contains etching treatments using a chlorine type solution and etching gases.

### Claim 20 (depends on 6, 7, 8)

The method of manufacturing the semiconductor device according to any one of claims 6–8, wherein the latter etching step contains etching treatments using a chlorine type solution and etching gases.

### Claim 21 (depends on 12, 13)

The method of manufacturing the semiconductor device according to one of claim 12 and claim 13, wherein the latter etching step contains etching treatments using a chlorine type solution and etching gases.