Electronic device having a stacked wiring layer including Al and Ti

• US 7,202,165 B2
• Filed: 09/05/2001
• Issued: 04/10/2007
• Est. Priority Date: 10/23/1998
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Jo, Gyoo Chul
• Primary Examiner(s): Huynh; Andy
• Assistant Examiner(s): Nguyen; Dao H.
• Application Number:
  US09/945,714
• Publication Number:
  US 20020045351A1
• Time in Patent Office: 2,043 Days
• Field of Search: 257/347, 257/348, 257/349, 257/350, 257/351, 257/352, 257/353, 257/354, 257/368, 257/382, 257/383, 257/741, 257/750, 257/763, 257/764, 257/765, 438/669
• US Class Current: 438/669
• CPC Class Codes: C23F 1/02 Local etching
• CPC Class Codes: C23F 1/20 for etching aluminium or alloys thereof
• CPC Class Codes: H01L 21/32134 by liquid etching only
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate

Abstract

In the case that a stacked layer, in which another metal layer is stacked on an Al layer or Al alloy layer having a low resistance, is used as a wiring material, an etchant is provided which can etch to a substantially equal etching rate by executing only one etching on the each metal layer composing the stacked layer. A method of manufacturing a substrate for an electronic device uses the etchant, producing an electronic device having the substrate.

In order to achieve the object, the etchant has fluoric acid, periodic acid and sulfuric acid wherein the total weight ratio of the fluoric acid and periodic acid is 0.05˜30 wt %, the weight ratio of the sulfuric acid is 0.05˜20 wt %, the weight ratio of periodic acid to fluoric acid is 0.01˜2 wt %. Also each layer of wiring (5, 12, 14) formed by stacking Al layer or Al alloy layer and Ti layer or Ti alloy layer can be uniformly etched to substantially equal etching rate by the etchant.

Claims

1. A method for fabricating a display device having a plurality of pixels, comprising:

forming a first metal layer including aluminum on a substrate;

forming a second metal layer including titanium on the first metal layer; and

wet-etching the first and second metal layers in a single etching step, wherein the wet-etched first and second metal layers are substantially free of a undercut, and wherein the wet-etching uses an etchant including a fluoric acid, a periodic acid and a sulfuric acid, in which the total weight ratio of the fluoric acid and the periodic acid is 0.05˜

30 wt %, the weight ratio of the sulfuric acid is 0.05˜

20 wt %, the weight ratio of the periodic acid to fluoric acid is 0.01˜

2 wt %.

2. The method according to claim 1, wherein an etching rate of the first metal layer is substantially equal to an etching rate of the second metal layer.

3. The method according to claim 1, wherein the wet-etched first and second metal layers are a metal layer of a thin film transistor.

4. The method according to claim 1, wherein the wet-etched first and second metal layers are used for a pad of the display device.

5. The method according to claim 1, wherein said wet-etching uses an etchant producing a first electric potential between the first metal layer and a standard hydrogen electrode and a second electric potential between the second metal layer and a standard hydrogen electrode, and the potential difference between the first electric potential and the second electric potential is less than 400 millivolts.