JPS59117220A - Sputtering device - Google Patents

Abstract

PURPOSE:To form sputtered films of uniform thickness on a large diametric wafer or wafers of a large number by a method wherein shapers of the necessary shape are arranged in front of targets, and a sputtering device is constructed so as to enable to change and control partially the formation speed of the sputtering films according to the shapers thereof. CONSTITUTION:A shapers 21 is constructed of an SiO2 plate supported holding the insulated condition, and an opening part 23 consisting of longitudinal and transverse grooves is formed at the middle region or at the central part thereof. Shape and size of the opening part 23 thereof are decided according to the various primary factors of material quality and size of the target 12, intensity of high-frequency electric power sources 19, 22, and further, the distances between the targets 12 and wafers 14, etc. Because the shapers 21 having the openings 23 of the necessary shape are provided in front of the targets 12, distribution of frequency of penetrating impacts of Ar ions to the targets, frequency of sputtering of SiO2 against the wafers from the targets, etc., are differed at the surfaces of the targets, partial difference is generated also in the fiml formation speeds to the wafers 14 facing to the targets thereof, and inequality of film thickness is corrected to attain formation of the films of uniform film thickness extending over the broad extent of the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus that achieves uniformity of a sputtered film.

Sputtering technology is used in the manufacture of semiconductor devices, and in recent years 5iO has been used as a particularly good insulating film and protective film.
A sputtered film of y (quartz) is used. When forming this sputtered quartz film, it is difficult to improve the coverage on the base step by forming the film using conventional sputtering equipment, so in recent years a sputtering method called the so-called bias sputtering method has been used. has been used.

In this sputtering method, high-frequency power is applied not only to the target but also to the substrate (wafer substrate, etc.) holder electrode, and a sputter etching action is performed at the same time as sputter deposition, thereby coating the underlying step surface of the film formed on the substrate. The objective is to form a film with a uniform thickness by improving the film surface properties and flattening the film surface while proceeding with film formation.

However, with this method, it is easy to obtain a uniform film thickness within a narrow area such as a small-diameter wafer, but when the wafer has a large diameter or a large number of wafers are processed simultaneously as in an actual sputtering device, In such a case, the sputtering area becomes large and the film thickness tends to vary between wafers. For example, as shown in FIG. 1, a substantially cylindrical holder electrode 3 is rotatably provided in the center of a casing 1 in which targets 2 are arranged at several locations around the casing 1.
An apparatus is proposed that is configured to hold the wafer 4 vertically on a surface, apply the required high frequency power to the target 2 and the holder electrode 3, and perform sputtering while maintaining the inside of the casing 1 in a predetermined gas atmosphere. has been done. However, with this structure, there is a difference in the sputtering phenomenon, especially in the vertical direction, and as shown in FIG. , a phenomenon occurs in which the film becomes large in the intermediate region between them, and a uniform film thickness cannot be obtained.

If such uneven film thickness occurs, for example, holes may be formed in the underlying passivation film (because the film is thin) at the "gaps" caused by errors in pattern overlay during through-hole processing. A problem occurs in that the A-e wiring formed in the upper part is disconnected at this portion.

An object of the present invention is to provide a sputtering apparatus that can form a film of uniform thickness on each wafer even when forming a sputtered film on a large diameter wafer or a large number of wafers.

In order to achieve this object, the present invention is configured such that a shaper of a desired shape is disposed in front of the target, and the formation rate of the sputtered film can be partially changed and adjusted by the shaper.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

3 and 4 are a plan configuration diagram and a front configuration diagram of the sputtering apparatus of the present invention, in which a substantially cylindrical holder electrode 13 is installed in the center of a box-shaped casing 11 and can be rotated horizontally by a rotating shaft 15. I support it as such. Said casing 1
1 is provided with a gas supply port 16 and an exhaust port 17 in series to maintain the inside of the casing in a required gas atmosphere (for example, Ar) and at a required gas pressure. Further, a target 12 made of quartz is supported around the four peripheries of the casing 11 using a cover 18, and a high frequency power source 19 is connected to this.

A shaper 21 is supported at the front position of each target 12 using a bracket 20. This shaper 21 will be described later.

On the other hand, on the circumferential surface of the holder electrode 13, a large number of wafers 14 forming a quartz sputtered film are arranged and supported in the vertical and circumferential direction. It is preferable that the wafer 14 be disposed within the vertical dimension of the target 12, particularly in the vertical direction. Further, a high frequency power source 22 is connected to the holder electrode 13.

- The shaper 21 is made of Si supported in an insulating state.
As shown in FIG. 5, an opening 23 consisting of vertical and horizontal grooves is formed in the middle band or center of the plate. The shape and dimensions of this opening 23 are determined by the target 1 described above.
It is determined by various factors such as the material and thickness of the wafer 2, the strength of the high frequency power source 19 and 20, and the distance between the wafer 12 and the wafer 14. In this example, it is formed by one longitudinal groove 23a provided at the center position and four lateral grooves 23b orthogonal to the longitudinal groove 23a and having irregular widths. Note that a minute gap is formed between the shaper 21 and the target 12.

According to the above configuration, sputtering is started by supplying a required reaction gas into the casing 11, setting the interior to a predetermined vacuum pressure, and applying high frequency power to the target 12 and the holder electrode 13, respectively. That is, ions in the gas,
For example, Ar ions are bombarded by the target 12 by an electric field, and the impact sputters S r 02, which is deposited on the surface of the wafer 14 to form a film. At this time, some of the Ar ions collide with the surface of the wafer 14 due to the high frequency power (bias) applied to the holder electrode 13 and cause reverse sputtering, that is, sputter etching. Sharpen the corners and flatten the surface. Therefore, by continuing this process, a SiO film with a flat surface will be formed on the wafer. For this action, a shaper 2 having an opening 23 of a desired shape is placed in front of the target 12.
1 is installed, the frequency of Ar ion collisions with the target and the S i O from the target to the wafer are
,.

The distribution of sputtering frequency etc. becomes different on the target surface, which causes the wafer 14 facing
Local differences also occur in the rate of film formation. Therefore, the non-uniformity in film thickness that has conventionally occurred is corrected by this difference in speed, and a film with a uniform thickness is formed over a wide range of the wafer.
A uniform film can be formed over each wafer placed above and below the wafer. Since the holder electrode 13 rotates slowly during sputtering, it goes without saying that the circumferential thickness distribution of the wafers arranged in the circumferential direction can be made uniform.

Therefore, by being able to form a uniform film, there will be no problems such as cutting of the A-wiring when processing through-holes, and by making it possible to make the film thickness of the quartz sputtered film uniform, it will be possible to realize high-speed logic LSIs. You can also try it out.

Here, the shape of the opening 23 of the shaper 21 is shown as an example, and as described above, it is preferable to change and adjust the shape as appropriate depending on factors such as the target material and shape.

As described above, the sputtering apparatus of the present invention is configured as a so-called bias sputtering structure and is provided with a shaper having an opening of a desired shape in front of the target.
The sputtered film formation speed can be partially adjusted depending on the shape of the opening, making it possible to form a uniform sputtered film over a wide area, such as large diameter wafers or multiple wafers on a holder electrode. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a conventional bias sputtering device, FIG. 2 is a diagram explaining a problem, FIGS. 3 and 4 are cross-sectional views of the sputtering device of the present invention from a plane and a front direction, and FIG. 5 is a front view of the shaper. 11...Casing, 12...Target, 13.
... Holder electrode, 14... Wafer, 19... High frequency power source, 21... Shaper, 22... High frequency power source, 23... Opening. Figure 1/ Figure 2 Figure 3/2

Claims (1)

[Claims] 1. Bias sputtering is performed by applying high frequency power to each of a target supported in a reaction casing and a Holter electrode disposed in the casing and supporting a wafer. A shaper having an opening of a desired shape is disposed in front of the target, and by changing the shape of the opening, the distribution of film formation rate on the wafer can be changed and adjusted. A sputtering device characterized by: 2. The sputtering apparatus according to claim 1, wherein the shaper is formed of an Si02 plate, and the opening is formed by vertical grooves and horizontal grooves formed in the center of the shaper.