JP2809523B2 - Wiring electrode thin film material for liquid crystal display with excellent heat resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal device having excellent heat resistance.
It relates Isupurei wiring electrode thin film material, in particular, the liquid crystal
A thin-film Al-based wiring or electrode material for semiconductor devices for displays , especially used for liquid crystal displays .
Thin film transistor is: ThinFilmTrans
liquid crystal data suitable for use in
The present invention relates to a wiring electrode thin film material for a display .

[0002]

2. Description of the Related Art Thin-film Al-based metal materials are used as electrodes and wiring materials for integrated circuits of general semiconductor devices (that is, semiconductor devices in which elements are formed on a Si wafer). A containing Al and Si or Cu
There is an l-base alloy.

[0003] Pure Al is the best in terms of low electric resistance, but is subject to stress migration (hereinafter referred to as S
M) and electromigration (hereinafter referred to as EM). Here, SM is swelling (hillock) and disconnection (improper conduction) of the thin film wiring caused by stress, and is mainly caused by heating. EM
Is a disconnection of the thin film-like wiring caused by electrophoresis, which is mainly caused by energization.

[0004] Al-based alloys containing Si or Cu have been developed to solve the above-mentioned problems.
Resistance and EM resistance are not yet sufficient, and corrosion resistance is pure Al
Not better than lower. Therefore, there is a demand for the development of new semiconductor device materials with higher reliability.

[0005] Therefore, it is conceivable to further alloy, but the metal generally tends to increase the resistance value due to the alloying. On the other hand, finer wiring (wiring Due to the narrowing of the width), the allowable upper limit value of the electric resistance value has been lowered, so that simply alloying will exceed the upper limit value, and it is presently difficult to develop a new semiconductor device material.

The electrode and wiring materials of the TFT are different from those of the general semiconductor device described above, and are relatively high temperature (about 400 ° C. or lower) during the TFT manufacturing process.
Since Al-based metal materials generate SM and lack SM resistance, high-melting metal materials such as Ti, Cr, Mo, and Ta are frequently used. However, these have a problem that the electric resistance value is large, and improvement thereof is desired.

Further, in recent years, liquid crystal displays have become larger and larger in screen size, and the wiring (address wiring) connecting each TFT element has also tended to be increased. Therefore, it is difficult to use the above-mentioned high melting point metal material. Therefore, development of a new heat resistant metal material having low wiring resistance is desired.

It is desired that the wiring resistance is about 30 μΩcm or less.
Although there are u, Cu, and Al, it is difficult to adopt Au because it is expensive, and Cu has problems in terms of adhesion and acid resistance.
Is a low melting point metal, lacks heat resistance, may cause short-circuit between layers (between lines) due to SM, and neither of them is practical.

In view of this, multilayer wiring (composite wiring) and alloying of the wiring surface by ion implantation (surface alloyed wiring) have been proposed. In this multilayer wiring, the lower layer is made of a low resistance material and the upper layer is made of a high heat resistant material, and the lower layer (low resistance) and the upper layer (SM resistance) are formed.
) To exert the combined function of The surface-alloyed wiring is obtained by ion-implanting a different element into a low-resistance material and providing a heat-resistant alloy layer on the surface thereof, and exerts the same function as described above.

However, in the case of the multilayer wiring, it is necessary to form the film twice in the manufacture thereof, and it is necessary to perform the etching for forming the wiring pattern in a separate step depending on the combination of the lower layer and the upper layer. In addition, the surface alloyed wiring requires a complicated process of ion implantation, and it is difficult to control the surface alloy layer, so that there is a problem in that the process increases and the production yield decreases. Therefore, it is presently desired to develop a new metal material for a TFT which does not have such a problem and has a low wiring resistance and excellent heat resistance.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to solve the above-mentioned problems of the prior art and to achieve heat resistance (SM resistance).
Sex, etc.), with low electric resistance with excellent resistance to EM resistance and corrosion resistance, preferably used to obtain without incurring the decrease in productivity or the like as a liquid crystal display TFT, moreover LCD de recent
TFTs in line with narrower wiring due to higher integration of semiconductor devices for displays and larger screens and larger liquid crystal displays
Liquid crystal display that can cope with the increase in Adols wiring
It is intended to provide a wiring electrode thin film material (electrode / wiring material).

[0012]

Means for Solving the Problems In order to achieve the above object, a wiring electrode thin film material for a liquid crystal display according to the present invention has the following configuration. That is, according to claim 1
Wiring electrode thin film material for a liquid crystal display is made of Al-based alloy containing 0.4 ~5at% of Ta as an alloying element
Also, it is a wiring electrode thin film material for liquid crystal displays having excellent heat resistance, which is formed by sputtering . The wiring electrode for a liquid crystal display according to claim 2.
The thin film material contains 0.4 to 5 at% of Ta as an alloy component, and contains 0.05 to 1.0 at% of one or more of Mn, Cr, and Zr. the total amount Ri from <br/> name Al-based alloy is 0.45 ~6at%, and it LCD wiring electrode thin having excellent heat resistance, characterized in that is formed by sputtering
It is a film material.

[0013]

According to the present invention, targets made of Al-based alloys having various compositions are manufactured, Al-based alloy thin films for semiconductor device wiring are formed by sputtering, and the composition and heat resistance (SM resistance) of the Al-based alloy thin films are formed. ), EM resistance, corrosion resistance, and electrical resistance, and based on the following findings obtained as a result.

That is, Al containing Ta as an alloy component
It has been found that the base alloy thin film is excellent in heat resistance (SM resistance and the like), EM resistance and corrosion resistance, and has low electric resistance. Specifically, heat resistance and EM resistance are superior to conventional Al-based alloys containing pure Al or Si or Cu.
It has been found that it can be made to be at the same level as high melting point metal materials such as i, Cr, Mo, Ta, etc., that corrosion resistance can be improved over pure Al, and that electric resistance can be improved to about 30 μΩcm or less.

[0015] At this time, the content of Ta is required to be at least 0.4 at%, resistance to S is less than 0.4 at%
M properties and corrosion resistance are insufficient and are not good. As the content increases, the SM resistance improves. However, when the content exceeds 5 at%, the electric resistance exceeds 30 μΩcm, and the object of the present invention cannot be achieved. Therefore, the content of Ta is 0.1 .
It is necessary to set it to 4 to 5 at%.

Since the above Al-based alloy thin film can be produced by the same method as the conventional Al-based alloy thin film containing Si or the like, it does not cause a decrease in productivity as in the case of composite wiring or surface alloyed wiring by ion implantation. .

Further, one or two of Mn, Cr and Zr
More than species (hereinafter referred to as Mn etc.)
%, Heat resistance (SM resistance, etc.), EM resistance and corrosion resistance are further improved. At this time, Mn, etc .: 0.05 at
%, The improvement effect is hardly recognized, and 1.0a
If it exceeds t%, the electric resistance increases, and the Mn or the like and the Ta
When the total amount exceeds 6 at%, the electrical resistance increases. Therefore, when adding Mn or the like, Mn
Etc .: 0.05 to 1.0 at%, and Mn etc. and T
It has been found that it is necessary to make the total amount with a 6 at% or less.

Therefore, the liquid crystal display according to the present invention
As described above, the wiring electrode thin film material is made of Ta as an alloy component.
Of an Al-based alloy containing 0.4 to 5 at%.
Sex, etc.), with low electric resistance with excellent resistance to EM resistance and corrosion resistance, preferably used to obtain without incurring the decrease in productivity or the like as a liquid crystal display TFT, moreover LCD de recent
TFTs in line with narrower wiring due to higher integration of semiconductor devices for displays and larger screens and larger liquid crystal displays
(A thin film material for a wiring electrode for a liquid crystal display according to claim 1).

Further, Ta is contained at 0.4 to 5.0 at%,
And one or more of Mn, Cr and Zr is 0.0
It is made of an Al-based alloy containing 5 to 1.0 at% and having a total amount of these alloy components of 0.45 to 6 at%. By doing so, heat resistance (SM resistance and the like), EM resistance and corrosion resistance are further improved (the wiring electrode thin film material for a liquid crystal display according to claim 2).

A liquid crystal comprising the Al-based alloy according to the present invention.
The wiring electrode thin film material for a display can be formed by a sputtering method. In this case, an Al-based alloy manufactured by a melting / casting method or a powder sintering method (hereinafter, referred to as a smelting Al alloy target) must be used. Is desirable. Such an ingot Al alloy target is uniform in composition, and has a uniform sputter rate and emission angle, so that an Al-based alloy film (ie, a wiring / electrode material) can be obtained, and therefore, more excellent reliability can be obtained. Distribution for LCD display
A wire electrode thin film can be manufactured. Among them, the target manufactured by the melting and casting method has an oxygen content of 100 ppm.
Or less, so that it is easy to keep the film formation rate constant, and the oxygen content of the Al-based alloy film can be reduced,
It becomes easier to reduce the electric resistance and improve the corrosion resistance of the Al-based alloy film.

The Al-based alloy film according to the present invention has fine crystal grains and excellent surface smoothness due to the effect of Ta alloy,
Therefore, fine workability is improved. In the case of the conventional pure Al film, the characteristics (mainly, the resistance value) of the film are significantly affected by various conditions at the time of film formation, for example, the residual gas pressure and components.
On the other hand, the Al-based alloy film according to the present invention also has an effect of being hardly affected by the influence.

[0022]

EXAMPLES Example 1 An Al alloy thin film having a thickness of 2000 mm was formed on a soda lime glass substrate by DC magnetron sputtering using ingots of ingots having various Ta contents. The thin film was processed into a stripe pattern having a width of 10 μm by lithography and wet etching, and this was used as a sample.

After subjecting the above sample to vacuum heat treatment at 400 ° C. for 1 hour, the number of hillocks generated on the surface of the stripe pattern was measured to determine the hillock density. The result is shown in FIG. It can be seen that the addition of Ta significantly reduces the hillock density and improves the SM resistance.

(Example 2) An Al alloy thin film having a thickness of 500 形成 was formed on a transparent polycarbonate resin substrate having a thickness of 1.27 mm by the same sputtering method using the same target as in Example 1. Then, a thickness of an acrylic resin on the thin film:
A 10 μm protective film was applied by spin coating, and this was used as a sample.

The above sample was subjected to a PC as an environmental acceleration test.
T (Pressure Cooker Test; temperature: 105 ° C., pressure: 1.2 atm, humidity: 100% RH) was performed to evaluate the corrosion resistance of the film. Corrosion resistance wavelength: 780
The reflectivity due to laser light of nm is measured before and after PCT,
Evaluation was made based on the change (decrease) before and after the change. PCT: 60
FIG. 2 shows the amount of decrease in reflectance after time. It can be seen that the addition of Ta significantly reduces the amount of decrease in reflectance and is excellent in corrosion resistance.

(Example 3) Thickness formed by the same method as in Example 1: 20
An Al alloy thin film having a thickness of 100 ° is formed by a similar method to a width of 100 mm.
After processing into a stripe sample of μm, length: 10 mm,
The specific resistance of the sample was measured by a four probe method. The result is shown in FIG. The specific resistance increases as the Ta amount increases. Although the upper limit of the specific resistance varies depending on the application type of the semiconductor device, the electrode and wiring material of the TFT for a liquid crystal display is about 10 times the specific resistance of pure Al (about 30 μΩc).
m), and in order to secure this value, the Ta amount is 5 at.
%. The above 30 μΩcm is
Specific resistance (50 μΩcm) of conventional high melting point metal materials such as Ti
Therefore, the material of the semiconductor device of the present invention sufficiently responds to the increase in the length of the Adles wiring of the TFT accompanying the increase in the screen size and the size of the liquid crystal display. Obviously, it can be obtained and preferably used.

[0027]

According to the present invention, a wiring electrode for a liquid crystal display according to the present invention is provided.
Very thin film material may be any material that an action has such a structure described above, heat resistance (SM, etc.), with low electric resistance with excellent resistance to EM resistance and corrosion resistance, T for a liquid crystal display
It can be used suitably for FT without deteriorating productivity, etc. In addition, the width of wiring has been narrowed due to recent high integration of semiconductor devices for liquid crystal displays , and TFTs have been This has the effect of being able to cope with an increase in address wiring.

[Brief description of the drawings]

FIG. 1 is a view showing a relationship between a Ta amount and a hillock density for an Al alloy thin film according to Example 1.

FIG. 2 is a diagram showing the relationship between the amount of Ta and the amount of decrease in reflectance in an environmental acceleration test for an Al alloy thin film according to Example 2.

FIG. 3 is a diagram showing the relationship between the amount of Ta and the specific resistance of an Al alloy thin film according to Example 3.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-47-23071 (JP, A) JP-A-1-191829 (JP, A) JP-A-1-268806 (JP, A) JP-A-62 235452 (JP, A) JP-A-4-153624 (JP, A)

Claims (2)

(57) [Claims] 1. An alloying element containing 0.4 to 5 at% of Ta.
Together of Al-based alloy containing, by sputtering
A liquid crystal display with excellent heat resistance characterized by being formed
Wiring electrode thin film material for display . 2. An alloy component containing 0.4 to 5 at% of Ta.
An Al-based alloy containing 0.05 to 1.0 at% of one or more of Mn, Cr, and Zr and having a total amount of these alloy components of 0.45 to 6 at%. Do Ri, and a liquid crystal display wiring electrodes having excellent heat resistance, characterized in that it is formed by sputtering
Thin film material.