CN102522323A

CN102522323A - ITO (Indium Tin Oxide) patterning method

Info

Publication number: CN102522323A
Application number: CN2011104515677A
Authority: CN
Inventors: 邹建华; 徐苗; 王磊; 陶洪; 兰林锋; 彭俊彪
Original assignee: GUANGZHOU NEW VISION OPTOELECTRONIC CO Ltd; South China University of Technology SCUT
Current assignee: Guangzhou New Vision Optoelectronic Co., Ltd.
Priority date: 2011-12-28
Filing date: 2011-12-28
Publication date: 2012-06-27

Abstract

The invention discloses an ITO (Indium Tin Oxide) patterning forming method which comprises the following steps of: depositing an ITO thin film on a substrate; depositing a SiO2 thin film on the ITO thin film; coating a photosensitive photoresist on the SiO2 thin film; patterning SiO2 by exposing and developing; etching the exposed SiO2 by dry etching so as to expose the ITO thin film on the lower layer; removing the photoresist; corroding the exposed ITO thin film on the lower layer by wet processing; etching the residual SiO2 on the ITO thin film by dry etching to obtain a substrate with a required ITO pattern. According to the invention, the SiO2 is used as a mask for ITO etching, so that the phenomena of short circuit and broken circuit of a device, which are generated when the photoresist is used as the mask, are avoided, flammable, explosive and dangerous gas and expensive special equipment for etching are prevented from being used and the production cost is reduced.

Description

A kind of ITO patterning method

Technical field

The present invention relates to a kind of ITO method of patterning, particularly a kind of ITO patterning method of on planar substrates, forming.

Background technology

(Indium Tin Oxide, ITO) film has high conductivity (10 as a kind of transparent conductive film that is prepared from semi-conducting material to mix the indium oxide of tin ⁴~ 10 ⁵Ω ^-1* cm ^-1), high visible light transmissivity (greater than 90 %), combine firmly with substrate of glass, numerous good physical properties such as anti scuffing; And good chemical stability and some other characteristic of semiconductor; Be prepared into electrode pattern easily, be widely used in solar cell, solid-state flat-panel display device many aspects such as (comprising LCD, OLED, FED, PDP).In these are used, need ITO be processed specific figure and serve as the device transparency electrode.

At present, the ITO patterning is mainly taked following several method:

Wet etching, general step is:

At first in vacuum coating equipment, on substrate, form one deck ito thin film through the sputter mode; On ito thin film, evenly be coated with one deck photoresist afterwards; Re-use light shield and form the patterning photoresist through steps such as exposure, developments; Remove the photoresist of patterning so that the method etching of wet etching is intact at last with liquid parting not by the ito thin film that photoresist covered afterwards, form needed ITO pattern.

Dry etching, general steps be with above-mentioned 1 wet etching, step in the end just, the mode that adopts the wet liquid medicine etching changed into adopt gas CH ₄Deng carrying out dry etching.

The lift-off method, general step is following:

At first on substrate, be coated with one deck photoresist; Then, develop the photoresist on the part of the ITO pattern of desire formation on the substrate is removed through exposure; On the substrate of patterning photoresist, plate ito thin film afterwards through vacuum coating equipment; At last to including the substrate of patterning photoresist and ito thin film, carry out demoulding and handle, remaining photoresist and the ito thin film that adheres to are above that removed, obtain the required substrate that contains the ito thin film pattern.

Yet following problem can appear in these traditional I TO patterning method:

In the wet etching process, owing to use strong acid or strong oxidizer, the long meeting of etch period causes the easy lateral corrasion of photoresist or comes off; Cause ito thin film pattern line irregularity, even occur opening circuit, the time is too short; It is incomplete the ITO etching to occur, short circuit phenomenon occurs.In addition on the one hand, adopt the ito thin film of different condition growth, employed etching reagent also needs adjustment, has further increased the difficulty of control etching technics.

Dry etching ITO is owing to using explosive property gas, such as CH ₄, increase dangerous; In addition, special equipment is also relatively more expensive, also causes cavity to pollute easily, can pollute substrate in the technical process, causes increasing base board defect.

The Lift-off method; Owing to need long-time ultrasonic depolymerization; Can cause some thinner metal wires or ITO thread breakage on the substrate easily; The scattering effect that produces owing to sputter simultaneously can produce burr at the ITO pattern edge and short circuit phenomenon occur, and therefore, the Lift-off method is difficult to obtain the technology wide than fine rule.

Summary of the invention

Shortcoming and deficiency that the present invention exists in order to overcome prior art; A kind of ITO patterning method is provided; The present invention can solve difficult technique control in the conventional wet process; Avoid using flammable explosive gas in the dry etching and causing chamber contamination easily, and avoid opening circuit and short circuit phenomenon of lift-off method generation.

The present invention adopts following technical scheme:

A kind of ITO patterning method may further comprise the steps:

(1) on substrate, deposits one deck ito thin film, one deck SiO successively ₂Film;

(2) SiO in (1) ₂Be coated with light sensitive photoresist on the film;

(3) through after light shield, exposure, the development SiO being exposed in the light sensitive photoresist removal of substrate desire formation ITO pattern ₂, remaining part Si O ₂Still covered by light sensitive photoresist;

(4) SiO through exposing in the dry etching etching (3) ₂, expose the ito thin film of lower floor;

(5) remove the remaining part Si O of covering in (3) ₂Light sensitive photoresist;

(6) ito thin film through exposing in the wet etching treatment (4);

(7) handle remaining SiO in (5) through dry etching ₂, obtain the substrate of required ITO pattern.

Substrate in the said step (1) is glass substrate, flexible base, board or silicon material substrate.

The depositional mode of ito thin film adopts the vacuum magnetic-control sputtering mode in the said step (1).

SiO in the said step (1) ₂The thin film deposition mode adopts plasma to strengthen vapour deposition mode or vacuum magnetic-control sputtering mode.

Adopt dry method removing method or wet method to remove light sensitive photoresist in the said step (5).

Described photoresist dry method removing method can adopt coupling plasma mode or the reactive ion etching mode of inducing.

Described photoresist wet method is removed mixed liquor or the potassium hydroxide solution that light sensitive photoresist adopts monoethanolamine and dimethyl sulfoxide (DMSO).

The employed corrosive agent of wet etching is the mixed liquor of chloroazotic acid, hydrochloric acid or iron chloride and water in the said step (6).

In said step (4), (7), the gas that dry etching adopts is the gas of carbon containing, fluorine element, preferred CHF ₃, C ₃F ₈

Said step (5), (6) can exchange.

The present invention is through depositing one deck SiO earlier on ITO ₂, spin coating one deck photoresist will not need the SiO in the place of ITO pattern through making public, developing again ₂Expose out, remove through dry etching and cover the SiO on the ITO ₂, remove photoresist afterwards, there is not SiO through wet etching again ₂The ITO that covers falls to cover the SiO on the ITO through dry etching at last ₂This employing SiO ₂As the mask of ITO etching, increase the tack of mask layer and ITO, and corrosion resistance, through dry method and wet method combined technology, obtain the substrate of required ITO pattern.

The present invention's beneficial effect specific as follows:

(1) the present invention is in etching ITO process; Use SiO2 as mask, inorganic SiO2 tack and corrosion resistance are superior to organic photoresist, have avoided in the wet etching process; Because the long-time photoresist mask that causes that in soup, soaks comes off; Corrode, and cause ito thin film pattern line irregularity, in addition occur opening circuit, short circuit phenomenon;

(2) etching agent used herein is a chloroazotic acid, can corrode the ITO of amorphous state and crystalline state, has avoided the change owing to the ITO membrance casting condition, and employed etching reagent also needs corresponding adjustment, and the difficulty of the control etching technics that increases;

(3) the present invention has avoided among the general dry etching ITO, and the explosive property gas that need use is such as CH ₄, and avoided using expensive proprietary etching ITO equipment, also avoid the not volatile product that produces in the direct use dry etching ITO process and caused the pollution of substrate and cavity;

(4) the present invention has avoided in the Lift-off method owing to need long-time ultrasonic depolymerization again, and opening circuit of causing, and because the short circuit phenomenon that the scattering effect of sputter generation causes.

Description of drawings

Figure 1A-1I is the basic step sketch map of a kind of ITO patterning method of the present invention;

Fig. 2 is a schematic flow sheet of the present invention.

Shown in the figure:

The 11--substrate, 12--ITO film, 13--light sensitive photoresist, 14--light shield, 15--SiO ₂Film.

Embodiment

Shown in basic step sketch map of the present invention shown in accompanying drawing 1A-1I, the schematic flow sheet of the present invention shown in the accompanying drawing 2:

A kind of ITO patterning method comprises the steps:

In step 21, like Figure 1A, a clean substrate 11 is provided, this substrate 11 is the thick TFT special glass of 0.7 a mm substrate;

In step 22, see Figure 1B, on said substrate 11, adopting the magnetically controlled sputter method deposit thickness is the ito thin film 12 of 150 nm, the magnetron sputtering condition is RF power=1000 W, Ar/O2=65/0.5 sccm;

In step 23, see Fig. 1 C, on said ito thin film 12, deposit the SiO2 film 15 of one deck 300nm again, depositional mode adopts and strengthens plasma gas-phase deposit (PECVD), and depositing temperature is 250 ℃, deposition gases SiH ₄/ N ₂O=4/300 sccm, operation pressure 100 Pa, deposition power 150 W;

In step 24, see Fig. 1 D, at this SiO ₂Even coating light sensitive photoresist 13 on the film 15, photoresist 13 adopt auspicious red 304, and photoresist thickness is 1.4 um;

In step 25, see Fig. 1 E, through light shield 14, the light sensitive photoresist 13 that desire on this substrate 11 forms the ITO pattern is removed in exposure, development, exposes SiO ₂Film 15;

In step 26, see Fig. 1 F, the SiO that exposes through the dry etching etching ₂Film 15, the dry etching occurring mode is for inducing coupling plasma mode (ICP), etch period 180 s; Upper electrode power 400 W, lower electrode power 400 W, substrate He cooling pressure is 200 Pa; The He chilling temperature is controlled to be 0 ℃, etching technics gas Ar flow 100sccm, C ₃F ₈Flow 10 sccm, etching technics pressure position is 0.6 Pa;

In step 27, see Fig. 1 G, remove all the other photoresists 13 through the dry method mode of removing photoresist; The dry etching occurring mode is for inducing coupling plasma mode (ICP), times 300 s that removes photoresist, upper electrode power 400 W; Lower electrode power 400 W; Substrate He cooling pressure is 200 Pa, and the He chilling temperature is controlled to be 0 ℃, etching technics gas O ₂Flow 48 sccm, etching technics pressure position is 0.6 Pa;

In step 28, see Fig. 1 H, corrode not by SiO through wet treatment ₂The ito thin film 12 of film 15 protections, it is industrial chloroazotic acid that etching adopts reagent;

In step 29, see Fig. 1 I, through the SiO on required ito thin film 12 patterns of dry etching etching ₂Film 15, etching condition obtain the substrate of required ITO pattern with 26 steps.

In sum, the present invention proposes a kind of ITO patterning method, is characterized in SiO ₂Film is as the ITO pattern mask; Effectively avoided when the wet etching process makes mask with photoresist because the tack and the erosion resisting of photoresist are poor; Cause photoresist to come off and side direction device short circuit and the breaking phenomena that reason causes that be corroded; And avoided direct dry etching ITO need use flammable explosive gas and the chamber that causes and the pollution of substrate, also avoided the lift-off method because the long-time ultrasonic depolymerization of needs, and opening circuit of causing; The short circuit phenomenon that causes with the scattering effect that produces owing to sputter, and then improve the yields and stability of device.

Claims

1. ITO patterning method is characterized in that may further comprise the steps:

(2) SiO in (1) ₂Be coated with light sensitive photoresist on the film;

(4) SiO through exposing in the dry etching etching (3) ₂After expose ito thin film;

(6) ito thin film through exposing in the wet etching treatment (4);

2. a kind of ITO patterning method according to claim 1 is characterized in that the substrate in the said step (1) is glass substrate, flexible base, board or silicon material substrate.

3. a kind of ITO patterning method according to claim 1 is characterized in that the depositional mode of ito thin film in the said step (1) adopts the vacuum magnetic-control sputtering mode.

4. a kind of ITO patterning method according to claim 1 is characterized in that SiO in the said step (1) ₂The thin film deposition mode adopts plasma to strengthen vapour deposition mode or vacuum magnetic-control sputtering mode.

5. a kind of ITO patterning method according to claim 1 is characterized in that adopting in the said step (5) dry method removing method or wet method to remove light sensitive photoresist;

Described photoresist dry method removing method can adopt coupling plasma mode or the reactive ion etching mode of inducing;

Described photoresist wet method removing method adopts the mixed liquor or the potassium hydroxide solution of monoethanolamine and dimethyl sulfoxide (DMSO).

6. a kind of ITO patterning method according to claim 1 is characterized in that the employed corrosive agent of wet etching is the mixed liquor of chloroazotic acid, hydrochloric acid or iron chloride and water in the said step (6).

7. a kind of ITO patterning method according to claim 1 is characterized in that in said step (4), (7), and the gas that dry etching adopts is the gas of carbon containing, fluorine element.

8. a kind of ITO patterning method according to claim 1 is characterized in that said step (5), (6) exchange.