JPS62207861A - Formation of film by sputtering - Google Patents

Abstract

PURPOSE:To increase the productivity by several times by arranging plural substrates between a pair of targets so that the substrates meet at right angles to the targets and by applying voltage between the targets. CONSTITUTION:Plural substrates 30, 30' are arranged in the film forming space between a pair of targets 1, 1' so that the surfaces of the substrates 30, 30' on which films are formed meet at right angles to the surfaces of the targets 1, 1'. AC or DC voltage is then applied between the targets 1, 1' to sputter both the targets 1, 1'. Films are formed on the substrates 30, 30' by a film forming substance emitted by the sputtering.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a method of forming a film on a substrate by sputtering.

"Prior Art" Conventionally, sputtering apparatuses use a target formed by pressing a solid material for film formation onto a banking plate.

The surface of this target and the surface on which the film was formed on the substrate were arranged parallel to each other.

In this method, a target is sputtered (impacted or hit) with argon ions, and the film-forming material that flies from the target hits a substrate connected to a ground level set up opposite it and forms a film there. .

During this sputtering, in addition to applying sputtering current,
A known method is to flatten the upper surface of a formed film by applying a DC (direct current) bias between the substrate and ground potential. Also known is an active sputtering method in which the flying film-forming substance reacts with a reactive gas during sputtering.

Also, when sputtering argon gas onto the target,
The DC sputtering method uses this voltage as a direct current, or A uses this voltage as an alternating current.
C sputtering method is known.

However, in all of these, the starting material is solid, and by sputtering it and forming the resulting fine particle material on a substrate placed parallel to the target surface, and adjusting the distance between the two, The purpose was to control the thickness of the film formed.

"Problem that the invention wants to solve" However, in such a method, the substrate and the target are one
:1, and when mass production is desired, the production cost is reduced to gas phase methods such as plasma CVD method, atmospheric pressure CVO method, etc.
It could not be cheaper than the law. In addition, because of the desire to improve the uniformity of the film thickness and the film quality of the formed film, no improvements have been made in terms of improving productivity.

"Means for Solving the Problem" In order to solve the problem, the present invention provides a method of covering a plurality of substrates perpendicularly or approximately perpendicularly (within an inclination of ±20° to the substrate) (hereinafter simply referred to as perpendicular) to the target surface. A forming surface is provided. If the film is to be formed on only one front side of the substrate, the film-forming material is placed on the back surfaces of the pair of substrates (the back surfaces of the two substrates are placed back to back to prevent the fine particles from getting around). .Then, these substrates are separated at respective intervals (corresponding to Fig. 2 (33)), for example, 2
A large number of them are arranged at a distance of ~10 cm. Then, the film-forming substances generated by sputtering from the target fly between the surfaces to be formed (33) of this substrate, and they adhere to the surfaces to be formed. In that case, if only one layer is used, the thickness of the coating formed becomes thinner as the distance from the target increases. For this reason, a pair of other targets are provided so as to sandwich the plurality of substrates. Then, regarding the position on the surface of the substrate to be formed, the surface to be formed that is farther from one target will be closer to the other target, and the sum of the thicknesses of the films will be approximately constant on average. You can expect to do so.

Furthermore, in the present invention, a symmetrical voltage of direct current or alternating current is applied between the pair of targets.

At this time, the substrate can be placed in its floating state (above the target, ground potential) or at ground level.

In particular, when alternating current is applied between a pair of targets, ionized argon repeatedly collides between the targets from one to the other, and from the other to one, resulting in extremely efficient sputtering. That is, a substrate having a surface to be formed and a substrate holding this substrate, for example, a transport cart (also referred to as a cart) can be electrically insulated from the main body of the sputtering apparatus.

``Function'' Also, since this board and cart can be moved perpendicularly between the targets (in Figure 2, targets are provided above and below and the cart is moved left and right), it can be made online or batched as shown in Figure 2. Lit production is now possible.

The present invention will be described below with reference to Examples.

"Example 1" FIG. 1 shows an outline of a sputtering apparatus of the present invention.

In Figure 1, the target (1), the sputtering chamber (2)
), a sputtering chamber (10) consisting of a post-sputtering chamber (3), and a load-lock chamber (11) separated by a gate (21). They are turbomolecular pumps (7) and (5
), and is further connected to the roughing pump (8), (6
) is connected to. Argon etc. are introduced from (19).

The board is inserted through the load lock door (4).

It is also inserted through the door on the left side of the drawing (4°).

These are held on a pedestal (9).

FIG. 2 shows a view taken from above of the section taken along line AA' in FIG. 1.

FIG. 2 shows the apparatus of FIG. 1 from above.

In Figure 2, the load lock chamber (11), gate (2
1) It has a sputtering chamber (10) and a pair of targets (1), (1°). a plurality of substrates (30),
(30') is held on a cart (31), and each substrate is placed at a predetermined interval (33) of 2 to 10 cm on its surface to be formed.
They are spaced apart.

These boards (30), (30') and cart (
31) opens the gate (21) from the transport system (34°) of the load-lock chamber using the transport system (34) and enters the sputtering pre-chamber (34°).
2). Furthermore, after this, these substrates are transferred from the sputtering prechamber (2) to a pair of target lathes (1),
(1') to the right while forming a film on the surface of the substrate, and is transferred to the post-sputtering chamber (3).

During movement in the film forming space (40), film forming particles that fly from the target adhere to the surface to be formed, thereby forming a film.

Targets (1) and (1') consist of the following parts. That is, so-called targets (12), (12') provided by pressing a solid material for film formation, backing plates (13), (13'') on the back side thereof, and magnets (14), (14').

Cooling water population (15), (15'), outlet (1
6), (16'), shield plate (17)
, (17'). These are Teflon insulating films (18
), (18'') electrically separates the sputtering apparatus main body, substrate, and cart from each other. A pair of current introduction terminals (20) and (20') are connected to them.

A voltage as shown in FIG. 3 is applied to this terminal. D.C.
If sputtering is to be performed, use one target (1).
A voltage (22) is applied to , and a voltage (22'') is applied to the other target (1').Then, the substrate is at zero potential (
23), if each target has some asymmetry, the voltages (22) and (22') are adjusted, but basically the substrate (33) is made to have a ground potential.

When this paired DC sputtering method is used, it is suitable that the target is a conductor (a transparent conductive film such as injem tin oxide or tin oxide, or a metal such as aluminum, molybdenum, or chromium).

In this case, the substrate is at ground potential.

On the other hand, as shown in FIG. 3(B), when performing AC sputtering, voltage (22) is applied to one target layer (1), and voltage (22) is applied to the other target layer (1'). is the voltage (
22') is applied, and the substrate is at zero potential or floating potential.

In such AC sputtering, a resistive material or an insulating material is used as the material for the target. For example, transparent conductive films with poor conductivity, titanium nitride 1, aluminum nitride, silicon oxide, tantalum oxide, alumina,
Silicon nitride, etc.

In this ACC sputtering method, the substrates (30), (3
0°) is electrically insulated from the transport system (34) to create a floating structure (thereby, it is possible to prevent current leakage from this substrate at the ground level, and argon ions are transferred from one target to the other). As a result, a self-potential (self-bypass potential) is generated on the substrate, and this voltage and the charged particles repel each other, causing the target or argon, etc. to fly and prevent sputtering on the surface to be formed. Even so, an extremely favorable condition occurs in which sputtering does not occur or is difficult to occur on the substrate surface, and a film can be formed in the same manner as in the thermal CVO method.

By performing these OC or AC sputtering methods in pairs, the film thickness characteristics shown in FIG. 4 can be obtained. This drawing shows the thickness distribution in the distance direction from one target to the other target in FIG. That is, if only one target (1) is used, the curve (25) in FIG. The film thickness distribution was as shown in Figure 4 (CB), and the thickness could be made almost uniform over the entire surface.

Of course, in FIG. 1, the length of the target (1) can be made longer than the length of the substrate to improve vertical uniformity. Furthermore, variations between substrates can be adjusted by controlling the conveyance speed of the cart.

Furthermore, an experimental example for obtaining the characteristics shown in FIG. 4(B) is shown below.

Experimental example 1 IT as material for target (12), (12″)
O (indium tin oxide) is used. The distance between the targets is 30cm%, the substrate is 20cm x 60cm, and 2
The 0 cm side is shown in Figure 2.

Each target has the same output, for example its DC
The output is 1000 directs total 2KW), 3000W (total 6
It was changed to -). The pressure of argon is 4 Xl0-'P
a, oxygen pressure of 5.3XIO-''Pa. The film growth rate was 800 people/min and 2800 people/min at the center, and 900 people/min and 3000 people/min at the ends.

As a result, the continuous movement speed of the substrate and cart from the sputtering pre-chamber to the sputtering post-chamber in FIG. 2 was set to 10 cm/min. The distance between each substrate is 10 cm. If 40 substrates (20 pairs) to be sputtered are loaded into one cart and a film is formed, an average film thickness of 2,700 layers can be obtained on each substrate in 10 minutes. In other words, the area of one board is 1200 cm", so the area is 48000 cm"
/10 minutes, making it possible to obtain film formation productivity several times higher than that of conventional sputtering equipment.

In this case, a sheet resistance of 4×10 −′ΩcITl was obtained with the substrate at room temperature. This substrate is placed in the sputtering chamber from below.
When heated to 350℃ with a halogen lamp in the rear chamber, 2
X10-'Ω/cm, which was approximately 172.

In order to double this thickness, the substrate and cart may be moved back and forth once from the pre-sputtering chamber (2) to the post-sputtering chamber (3) in FIG. 1. Others are described in Example 1. Of course, even if this continuous movement speed is 172, a film thickness of two cups can be expected as well.

Experimental Example 2 Aluminum is used as the material for targets (12) and (12'). Argon was set to 4×10 −′Pa, and no oxygen was introduced. The DC output was 3000 W (total 6000 W), and the rest was the same as in Experimental Example 1. Then there's Arminny.

A film was formed on the substrate, and its thickness was 1000 mm/min at the edges and 900 mm/min at the center.

Experimental Example 3 In Prison Example 1, the voltage applied was alternating current and the substrate was at a floating potential. Then, this sheet resistance could be further reduced to 6 x lO-'Ωcm at a substrate temperature of 300°C. This sheet resistance was about 1/4 of that of Experimental Example 1 for a transparent conductive film of the same thickness, and the effect of floating potential was remarkable.

Heating may be performed when the substrate passes through the sputtering prechamber.

"Effect" As is clear from the above explanation, the present invention aims to form a large amount of film on the substrate by applying symmetrical voltages to a pair of targets and placing the substrate between them. It is.

As a result, productivity can be several times higher than that obtained by making the formation surface of the substrate and the target surface parallel to each other, which has been known in the past.

Furthermore, by making the substrate floating in the AC sputtering method, argon and film-forming particles will not sputter the surface of the substrate on which it is to be formed, so damage to the film that has already been formed can be reduced. . As a result, the method was extremely effective for creating films that improve film quality by imparting microcrystalline properties to films formed of indium tin oxide and the like.

Conversely, by grounding the substrate in the DC sputtering method or AC sputtering method, the particles of the coating on the surface of the substrate can be extremely strongly bonded to each other. In that case, the substrate can be an organic insulating thin film or a metal substrate, and the adhesion between the substrate and the film to be formed can be improved, and in addition, the productivity can be easily improved.

The present invention can be implemented in-line by adding a gate to the unload chamber in the sputtering apparatus on the right side of the drawing as shown in FIG.

In this case, it is also possible to continuously form a coating by moving the plurality of carts shown in FIG. 2 continuously.

[Brief explanation of drawings]

FIG. 1 shows an overall view of the sputtering apparatus of the present invention. FIG. 2 is a longitudinal sectional view taken along line AA' in FIG. 1. FIG. 3 shows the characteristics of the voltage applied between a pair of targets. FIG. 4 shows the thickness distribution of the coating formed on the substrate.

Claims (1)

[Claims] 1. A pair of targets, and a plurality of substrates whose formation surfaces are perpendicular to the surface of the target are arranged in a film forming space between the targets, and A method for forming a film by sputtering, characterized in that a film is formed on the substrate using a flying film-forming substance by sputtering both targets. 2. A method for forming a film by sputtering according to claim 1, characterized in that an alternating current or direct current voltage is applied between a pair of targets. 3. In claim 2, the film is formed by a sputtering method, characterized in that when sputtering is performed by applying a DC voltage, the plurality of substrates are arranged to be grounded to have an intermediate potential between a pair of targets. Method. 4. Claim 2 is characterized in that when sputtering is performed by applying an alternating current voltage, the plurality of substrates are arranged at potentials that are electrically floating relative to the pair of targets and the ground potential. A method of creating a film using sputtering.