CN207217551U

CN207217551U - A kind of oxide thin film transistor fine copper composite construction source-drain electrode

Info

Publication number: CN207217551U
Application number: CN201721070207.1U
Authority: CN
Inventors: 宁洪龙; 卢宽宽; 姚日晖; 胡诗犇; 刘贤哲; 郑泽科; 章红科; 徐苗; 王磊; 彭俊彪
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2017-08-25
Filing date: 2017-08-25
Publication date: 2018-04-10
Anticipated expiration: 2027-08-25

Abstract

The utility model discloses a kind of oxide thin film transistor fine copper composite construction source-drain electrode.Described oxide thin film transistor fine copper composite construction source-drain electrode include be sequentially deposited on active layer etching cushion, stick barrier layer and pure Cu electrode layers；The etching cushion is carbon film, and the barrier layer of sticking is titanium film, and the pure Cu electrode layers are pure Cu films.The water base etching liquid of dioxygen uses when being used as etching cushion, destruction to oxide active layer when can avoid etching fine copper source-drain electrode by introducing C films in the utility model, while can avoid the copper from etching, and reduces production cost and security risk.

Description

A kind of oxide thin film transistor fine copper composite construction source-drain electrode

Technical field

The utility model belongs to electronic device preparing technical field, and in particular to a kind of oxide thin film transistor fine copper is answered Close structure source-drain electrode.

Background technology

With the raising of progress and the life taste of science and technology, people propose higher requirement to display panel：Large scale, High-resolution, high refresh rate, low RC retardation ratio turn into display panel important parameter feature of future generation.Thin film transistor (TFT) (TFT) array It is the pixel driver part of current AMLCD/AMOLED display panels, conclusive work is played in above parameter attribute is realized With.

The TFT active layer materials of main flow have amorphous silicon hydride (a-Si at present:H), low temperature polycrystalline silicon (LTPS), organic partly lead Body and oxide semiconductor, wherein oxide semiconductor have higher electron mobility and uniformity, suitable for large scale LCD/LED display panels.The Peng Junbiao professors team of South China Science ＆ Engineering University is broken through with rare earth doped metal oxide Ln-IZO External IGZO technology barriers, China is possessed the oxide semiconductor material of independent intellectual property right, further expanded metal oxygen Compound TFT development prospect.

In order to realize that high-resolution is shown, TFT device sizes need " miniaturization ", using back of the body channel etching (BCE) structure It is the key of TFT device sizes " miniaturization ".BCE-TFT manufacture craft is simple, and cost is relatively low.Importantly, its raceway groove Size defines precision height, easily realizes " miniaturization " of device size.However, in oxide TFT, due to active layer easily by The etching selection ratio of most of conventional etching corrosions, source-drain electrode and active layer is very low, and this often leads to element manufacturing mistake Lose.Therefore realize that the oxide TFT keys of BCE structures are the etching selection ratio for improving source-drain electrode and active layer.

The most still material such as aluminium (Al), molybdenum (Mo), but with size of display panels of TFT electrode material at present Increase, " signal delay " phenomenon can be serious all the more, using low-resistivity copper (Cu) electrode as TFT electrode and wiring material It is the urgent demand of industry.But pure Cu electrodes are low with substrate bond strength, easy to fall off, and copper is easily diffused into active channel layer, production Raw " Cu-W ore deposit " problem.

Based on problem above, current solution method mainly has：Preparation uses the water base etching liquid of dioxygen, improves carve as far as possible Erosion selection ratio.This processing mode for different types of source-drain electrode materials and active layer oxide material, it is necessary to prepare Special etching liquid, application surface is narrow, and R＆D costs are high, unfavorable volume production.And the Cu etching liquids for preparing high selectivity can not Avoid the use of hydrogen peroxide, the dioxygen water base etching liquid shelf-life is very short, only 2 weeks or so, and transport, store it is improper have it is quick-fried Fried danger, therefore the also Yao Jian etching liquids factory near panel factory, cause corresponding cost to raise；Replaced using Cu alloy material Pure copper material makees TFT electrode and wiring material.Although this method can solve the problems, such as copper adhesive strength difference, copper closes Golden resistivity is higher than fine copper, causes copper wiring decline with the obvious advantage or even disappears.

A variety of deficiencies for more than, there is provided a kind of technique is simple, the oxide thin film transistor of process safety, function admirable Novel pure copper compound structure source-drain electrode is highly significant.

Utility model content

In order to solve the shortcomings that above prior art and weak point, the purpose of this utility model is to provide a kind of oxidation Thing thin film transistor (TFT) fine copper composite construction source-drain electrode

The utility model purpose is achieved through the following technical solutions：

A kind of oxide thin film transistor fine copper composite construction source-drain electrode, described oxide thin film transistor fine copper are answered Close etching cushion that structure source-drain electrode includes being sequentially deposited on active layer, stick barrier layer and pure Cu electrode layers；It is described Etching cushion is carbon (C) film, and the barrier layer of sticking is titanium (Ti) film, and the pure Cu electrode layers are pure Cu films.

Preferably, the thickness of the etching cushion is 3~15nm.

Preferably, the thickness for sticking barrier layer is 5~20nm.

Preferably, the thickness of the pure Cu electrode layers is 20~100nm.

The utility model principle is：During oxide TFT is prepared, due to amorphous oxide semiconductor film easily by Most of conventional etching corrosions, active layer is frequently resulted in directly on active layer by the graphical source-drain electrode of wet etching The corrosion that is etched even removes and can not complete the preparation of device.In order to solve this problem, industry common practice be Before etching source-drain electrode, one layer of etching barrier layer (ESL) is first deposited on active layer, the barrier layer is almost not etched liquid corruption Erosion, to protect active channel, the structure of formation is referred to as ESL structures.But as the development of technology, ESL structural disadvantages highlight, Limit its application in the art.First, in ESL structures, the definition of active channel needs two step photoetching processes：First, carving " contact hole " that source-drain electrode and active layer are formed on barrier layer is lost, second, source-drain electrode is graphical.Two step photoetching processes are accumulated Tired deviation of the alignment limits the precision of active channel size, and this is unfavorable for " miniaturization " of TFT device sizes.Secondly, ESL knots The etching barrier layer introduced in structure adds one of film growth and photo-mask process, accordingly adds cost.ESL structures with present The a-Si of panel factory owner stream：The BCE architectural differences that H TFT are used are larger, and existing production line is difficult to turn into non-by upgrading Eutectic oxide TFT production lines, cause cost to increase.

It is to be based at following 2 points that the utility model replaces etching barrier layer using C films as etching cushion：First, C films ten Divide stabilization, do not reacted with etching liquid, can protect active channel not by etching corrosion；Second, C films are good conductors, therefore need not Consider the problem of source-drain electrode is with active layer " contact hole ".Have both the C films of both the above advantageous property as etching cushion, can To reduce the photo-mask process for forming source-drain electrode and active layer " contact hole " together, so as to reduce accumulation deviation of the alignment, raising has Source raceway groove defines precision, is more beneficial for device " miniaturization ".C films etching cushion on active channel can pass through O₂plasma Processing or O₂High annealing is translated into CO under atmosphere₂And remove.Whole production procedure is consistent with BCE structures TFT, has Beneficial to the upgrading of existing product line.In addition, C films can be prepared by magnetron sputtering method, technique is simple, and cost is low, is adapted to big It is prepared by area thin film.

Because fine copper film is not easy that stronger bonding action occurs with glass substrate or monocrystalline substrate, cause fine copper film Adhesive strength on above-mentioned substrate is very poor, can ensure fine copper film adhesive strength as barrier layer is sticked using Ti films While, stop diffusion of the copper atom to active channel, avoid " Cu-W ore deposit " problem.In addition, Ti has very high intensity, it is carved Lose characteristic and copper difference is smaller, etch and etched using same etching liquid, correspondingly reduce etch step and the kind of etching liquid The use of class, simplification of flowsheet, improve production efficiency.

Relative to prior art, the utility model has the following advantages that and beneficial effect：

Oxide thin film transistor fine copper composite construction source-drain electrode of the present utility model, have resistivity low, etching is simultaneous The advantages of capacitive is good, and technique is simple, and cost is cheap.

Brief description of the drawings

Fig. 1 is the structural representation of oxide thin film transistor fine copper composite construction source-drain electrode of the present utility model.

Embodiment

The utility model is described in further detail with reference to embodiment and accompanying drawing, but implementation of the present utility model Mode not limited to this.

Embodiment 1

As shown in figure 1, oxide thin film transistor fine copper composite construction source-drain electrode of the present utility model includes sinking successively Accumulate the etching cushion 3 on the active layer 4 of oxide thin film transistor, stick barrier layer 2 and pure Cu electrode layers 1；The quarter Erosion cushion 3 is carbon (C) film, and the barrier layer 2 of sticking is titanium (Ti) film, and the pure Cu electrode layers 1 are pure Cu films.5 in Fig. 1 It is the grid of oxide thin film transistor for the insulating barrier of oxide thin film transistor, 6,7 be the lining of oxide thin film transistor Bottom.

Preferably, the thickness of the etching cushion is 3~15nm.

Preferably, the thickness for sticking barrier layer is 5~20nm.

Preferably, the thickness of the pure Cu electrode layers is 20~100nm.

Above-mentioned oxide thin film transistor fine copper composite construction source-drain electrode can be made by following steps：

(1) be sequentially depositing on the active layer of thin film transistor (TFT) 3~15nm carbon (C) film as etching cushion, 5~ 20nm titanium (Ti) film is as sticking the pure Cu films on barrier layer and 20~100nm as source-drain electrode；

(2) spin coating photoresist, exposure imaging：Retain the photoresist of active channel top half, and make active layer, etching slow Rush layer, stick barrier layer and pure Cu films non-active channel region portions photoetching offset plate figure；

(3) the pure Cu films of non-active channel region are sequentially etched, stick barrier layer, etching cushion and active layer；

(4) photoresist retained at the top of active channel is removed, pure Cu films are exposed；

(5) pure Cu film layers are etched and stick barrier layer, it is graphically formed TFT source-drain electrode；

(6) the etching cushion on active channel surface is removed；

(7) photoresist of source-drain electrode surface is removed.

Active layer described in step (1) is metal oxide semiconductor material.The metal oxide semiconductor material bag Include indium gallium zinc oxide (IGZO), indium-zinc oxide (IZO) or mix lanthanum indium-zinc oxide (Ln-IZO).

With magnetically controlled sputter method, from sputtering method, ion sputtering method, chemical gaseous phase depositing process, evaporation in step (1) One or more method deposition-etch cushions in method and electrochemical method, stick barrier layer and pure Cu films.

The double slit mask exposure method of using is exposed at the top of active channel described in step (2), and non-active channel region is using general Logical mask exposure method.

Etching method described in step (3) includes wet etching or dry etching.

The photoresist retained at the top of removing active channel described in step (4) uses dry etching.

Lithographic method described in step (5) includes wet etching or dry etching.

The method of the etching cushion on active channel surface is removed described in step (6) includes O₂Plasma processing and O₂Atmosphere Enclose middle annealing.

Photoetching gluing method is removed described in step (7) includes stripper method or dry etching.

Above-described embodiment is the preferable embodiment of the utility model, but embodiment of the present utility model is not by above-mentioned The limitation of embodiment, it is other it is any without departing from Spirit Essence of the present utility model with made under principle change, modify, replace Generation, combination, simplify, should be equivalent substitute mode, be included within the scope of protection of the utility model.

Claims

A kind of 1. oxide thin film transistor fine copper composite construction source-drain electrode, it is characterised in that：Described sull is brilliant Body pipe fine copper composite construction source-drain electrode include be sequentially deposited on active layer etching cushion, stick barrier layer and pure Cu electricity Pole layer；The etching cushion is carbon film, and the barrier layer of sticking is titanium film, and the pure Cu electrode layers are pure Cu films.
A kind of 2. oxide thin film transistor fine copper composite construction source-drain electrode according to claim 1, it is characterised in that： The thickness of the etching cushion is 3~15nm.
A kind of 3. oxide thin film transistor fine copper composite construction source-drain electrode according to claim 1, it is characterised in that： The thickness for sticking barrier layer is 5~20nm.
A kind of 4. oxide thin film transistor fine copper composite construction source-drain electrode according to claim 1, it is characterised in that： The thickness of the pure Cu electrode layers is 20~100nm.