Semiconductor device and method for producing same

• US 8,685,803 B2
• Filed: 12/03/2010
• Issued: 04/01/2014
• Est. Priority Date: 12/09/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Chikama, Yoshimasa, Nishiki, Hirohiko, Ohta, Yoshifumi, Mizuno, Yuuji, Hara, Takeshi, Aita, Tetsuya, Suzuki, Masahiko, Takei, Michiko, Nakagawa, Okifumi, Harumoto, Yoshiyuki
• Primary Examiner(s): Stark, Jarrett
• Assistant Examiner(s): Ahmed, Shahed
• Application Number:
  US13/514,081
• Publication Number:
  US 20120241750A1
• Time in Patent Office: 1,215 Days
• Field of Search: 257/71, 257/E29.273, 257/59, 257/72, 257/258, 257/E31.053, 438/149, 438/151
• US Class Current: 438/149
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1244 for preventing breakage, peeling or short circuiting
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement

Abstract

A semiconductor device includes: a thin film transistor having a gate line (3a), a first insulating film (5), an island-shaped oxide semiconductor layer (7a), a second insulating film (9), a source line (13as), a drain electrode (13ad), and a passivation film; and a terminal portion having a first connecting portion (3c) made of the same conductive film as the gate line, a second connecting portion (13c) made of the same conductive film as the source line and the drain electrode, and a third connecting portion (19c) formed on the second connecting portion. The second connecting portion is in contact with the first connecting portion within a first opening (11c) provided in the first and second insulating films; the third connecting portion (19c) is in contact with the second connecting portion within a second opening (17c) provided in the passivation film; and the second connecting portion (13c) covers end faces of the first and second insulating films within the first opening (11c), but does not cover an end face of the passivation film (15) within the second opening (17c). As a result, the taper shape of a contact hole of the terminal portion can be controlled with a high precision.

Claims

1. A method for producing a semiconductor device, the semiconductor device comprising:

a substrate;

a thin film transistor formed on the substrate; and

a terminal portion for electrically connecting the thin film transistor to external wiring;

the thin film transistor including;

a gate line provided on the substrate;

a first insulating film formed on the gate line;

an island-shaped oxide semiconductor layer formed on the first insulating film, the island-shaped oxide semiconductor layer having a channel region and having a source region and a drain region located at opposite sides of the channel region;

a second insulating film provided in contact with the oxide semiconductor layer;

a source line provided on the second insulating film and electrically connected to the source region;

a drain electrode provided on the second insulating film and electrically connected to the drain region; and

a passivation film being provided on the source line and the drain electrode and covering the thin film transistor; and

the terminal portion including;

a first connecting portion made of a same conductive film as the gate line;

a second connecting portion formed on the first connecting portion and made of a same conductive film as the source line and the drain electrode; and

a third connecting portion formed on the second connecting portion;

wherein

within a first opening provided in the first insulating film and the second insulating film, the second connecting portion is in contact with the first connecting portion;

within a second opening provided in the passivation film, the third connecting portion is in contact with the second connecting portion; and

the second connecting portion covers end faces of the first insulating film and the second insulating film within the first opening, but does not cover an end face of the passivation film within the second opening, and a part of the second connecting portion is located between the second insulating film and the passivation film,

the method comprising;

(A) a step of forming a conductive film for a gate line on a substrate, and patterning the conductive film to form a gate line and a first connecting portion;

(B) a step of forming a first insulating film on the gate line and the first connecting portion;

(C) a step of forming on the first insulating film an oxide semiconductor layer to become an active layer of a thin film transistor;

(D) a step of forming a second insulating film covering the oxide semiconductor layer and the first insulating film;

(E) a step of etching the first and second insulating films to form in the second insulating film an opening for forming a source contact and an opening for forming a drain contact by using the oxide semiconductor layer as an etchstop, such that the oxide semiconductor layer is exposed through the openings, and form a first opening in the second insulating film and the first insulating film, such that a surface of the first connecting portion is exposed through the first opening;

(F) a step of forming a conductive film for source/drain electrodes on the second insulating film, and patterning the conductive film to form a source line which is in contact with the oxide semiconductor layer within the opening for forming a source contact, a drain electrode which is in contact with the oxide semiconductor layer within the opening for forming a drain contact, and a second connecting portion which is in contact with the first connecting portion within the first opening;

(G) a step of forming a passivation film on the source line, the drain electrode, and the second connecting portion;

(H) a step of forming a second opening in the passivation film, such that the second connecting portion is exposed through the second opening; and

(I) a step of forming a third connecting portion on the passivation film, the third connecting portion being in contact with the second connecting portion within the second opening.

2. The method for producing a semiconductor device of claim 1, wherein,

step (H) comprises a step of forming in the passivation film an opening for exposing the drain electrode;

and

step (I) is a step of forming a transparent conductive film on the passivation film, and patterning the transparent conductive film to form the third connecting portion and a pixel electrode, the pixel electrode being in contact with the drain electrode within the opening for exposing the drain electrode.

3. The semiconductor device produced by the method of claim 1.