JPS6057941A - Sputtering device - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks in a quartz target, to lengthen life and to form a thin-film having excellent quality by forming a metallic layer integrally shaped to the back of the target by a material, wetting properties thereof with a fixing material are excellent and alloying porperties thereof at the high melting point are low. CONSTITUTION:A Cr layer 17 is integrally formed previously to the back of a quartz board 14, nd the quartz board 14 is fixed to a packing plate 15 by wetting properties between the Cr layer 17 and a fixing material 16 (an alloy layer of In/Sn). Consequently, thermal stress is not concentrated because heat generated by a collision and a reaction with the quartz board 14 of Ar ions is dissipated rapidly to the packing plate 15 through the Cr layer 17 and the In/Sn alloy layer 16 and there is no air gap at that time. Accordingly, the generation of cracks in the quartz board 14 can be prevented, and the generation of foreign matters and a contamination to a formed film can be obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to sputtering technology, and particularly to sputtering technology with a quartz target.

[Background technology]

Sputtering apparatuses are used particularly in the field of semiconductor manufacturing technology to form thin films on semiconductor wafers. Among these, it is effectively used to form a quartz (Sint) film, which is an insulating thin film.A quartz plate is used as a so-called target, and by bombarding it with Ar ions, etc., quartz (Sint) is removed from the surface of the quartz plate. This method scatters particles (particles) and deposits them on the wafer surface.

By the way, the above-mentioned quartz target conventionally has an AQ thin layer 2 and an In/S n layer (In, S
The quartz plate 1 is fixed to the backing plate 4 by an n-alloy layer (hereinafter the same) 3. Here I n
/S n layer is a backing plate 4 made of Cu material
The AQ thin layer 2 is integrally formed on the back surface of the quartz plate 1 by vapor deposition or the like, and serves as a fixing material (brazing material) for fixing the quartz plate 1 to the (2) In/Sn layer 3. It functions to improve adhesion. Further, the AQ thin layer 2 is employed because it is low cost and can be easily deposited on the quartz plate 1 (low temperature possible).

However, since the AQ thin layer 2 has a high adhesion with the In/Sn layer 3, in other words, it is easy to form an alloy of AQ and In/Sn, depending on the adhesion conditions and quartz film formation conditions, the AQ thin layer 2 A part of the Afl thin layer 2 may be eluted into the In/S n layer 3, and a void 5 may be formed in a part of the Afl thin layer 2 as shown in the figure. When such a gap 5 is generated, the heat conduction efficiency between the quartz plate 1 and the In/S n layer 3 or the backing plate 4 in this region, that is, the cooling efficiency, decreases, and the heat generated in the quartz plate 1 during sputtering is reduced. Thermal stress caused by this is concentrated in the voids 5 and causes cracks to occur in the quartz plate 1. When the crack occurs, electric field concentration occurs at the crack edge, causing edge chipping, and chipped large-sized quartz particles adhere to the wafer surface and cause defects, or In/S is exposed through the crack.
In and Sn are sputtered (knocked out) from the n-layer 3 and attached to the wafer surface as contaminants. For this reason, a cracked target cannot be used any more, which causes a shortened lifespan of the target.

[Purpose of the invention]

The purpose of the present invention is to effectively prevent the occurrence of cracks in a quartz target and to extend the life of the target.
On the other hand, it is an object of the present invention to provide a sputtering apparatus that can prevent foreign matter from entering the thin film to be formed, and can form a good thin film by preventing contamination.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, by forming the metal layer integrally formed on the back surface of the quartz target with a material that adheres to the backing plate (3) and having good wettability but low alloying properties at high melting points, the back surface of the target This prevents the generation of voids in the target, thereby preventing the generation of cracks in the target, thereby extending the life of the target and making it possible to form a high-quality thin film.

[Embodiment 1] FIG. 2 shows an embodiment of the present invention. As shown in the figure, in the sputtering apparatus, a target 11 and an electrode 12 are disposed facing each other in a chamber 10 that can be evacuated, and the space between the target 11 and the electrode 12 is maintained within the chamber 10 at a predetermined degree of vacuum, for example, in an Ar gas atmosphere. By applying an RF lightning voltage between the target 11 and the electrode 12, plasma can be generated between the target 11 and the electrode 12. In this example, since a quartz plate 14 is used as the target 1.1 and a semiconductor wafer 13 is attached to the electrode 12, Ar ions generated by the plasma collide with the quartz plate 14 and knock out quartz molecules. This is deposited on the surface of the wafer 13 to form a 5in2 thin film.

(4) The target 11 has a structure in which the quartz plate 14 is fixed on a backing plate 15 made of Cu material supported by the chamber 10, and the fixing material is In/S.
n alloy metal 16 is used. For this fixing, a Cr layer 17 is integrally formed on the back surface of the quartz plate 14, and the quartz plate 14 is fixed to the backing plate 15 by the wettability of the Cr layer 17 and the fixing material 16.

Therefore, according to this structure, especially the structure of this target 11, even if the quartz plate 14 is fixed to the metal stamp plate 15 with In/Srz #gold 16, the Cr material has a high melting point. The material is In/S, and the Cr material is In/S.
Since the n-alloy has low alloying properties, the I of the Cr layer 17
No elution into the n/S n alloy layer 16 occurs, and therefore no voids are generated in the Cr layer 17.

As a result, Ar ions are transferred to the quartz plate 14 during sputtering operation.
The heat generated by the collision reaction with the Cr layer 17. I
It is quickly dissipated to the backing plate 15 through the n/Sn alloy layer 16, and since there are no voids at this time, no concentration of thermal stress occurs. As a result, it is possible to prevent the occurrence of cracks in the quartz plate 14, and it is possible to prevent the generation of foreign matter and contamination of the formed film due to chips caused by the occurrence of cracks.

[Embodiment 2] FIG. 3 shows another embodiment of the target. In this example, Cu
When fixing the quartz plate 14 to the backing plate 15 made of In/Sn alloy layer 16, the quartz plate 24 has a thin Cr layer 18 and a Cu layer 19 formed in multiple layers on the back surface. are different. That is, the Cr thin layer 18 and the C
In the multilayer structure including the u layer 1.9, the minimum necessary layer thickness is ensured using inexpensive Cu, so the cost can be lower than in the case of a single Cr layer. In addition, the Cr layer 18 firmly adheres to the quartz plate 14, while the Cu layer 19 has good wettability with the In/Sn alloy and is a high melting point 77 material with low alloying properties, so there is no elution during adhesion. Air gaps can be prevented. Therefore, in this example as well, the occurrence of cranks on the quartz plate 14 can be prevented, making it possible to form a high-quality film.

In addition, in the case of a multi-layer structure, the AQ layer 20 and the Cr layer 21 may be integrally formed on the quartz plate 14 as shown in FIG. On the other hand, the Cr layer 21 can be made thinner by the thickness of the AQ layer 20, which is effective in reducing costs.

〔effect〕

(1) A metal layer consisting of a bonding material such as an In/Sn alloy and a high melting point material with good wettability and low alloying properties is integrally formed on the back surface of the quartz plate, so when the quartz plate is fixed to the backing plate. The metal layer is not eluted to the adhesive material side, and the generation of voids on the back side of the quartz plate can be prevented.

(2) Since no voids are formed on the back side of the quartz plate, there is no concentration of thermal stress and cracks are prevented, which in turn prevents the generation of foreign matter and contamination of the film, making it possible to form a high-quality film. At the same time, the life of the target can be extended.

(3) Since the metal layer on the back side of the quartz plate has a multilayer structure of Cr and other metals (7), the thickness of the Cr layer to ensure the required layer thickness can be reduced accordingly, reducing the cost of the target. can be achieved.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. For example, the material of the metal layer may be a metal other than Cr as long as it satisfies the above-mentioned conditions, and the target material may be a material other than quartz.

[Application field]

The above explanation has mainly been about the case where the invention made by the present inventor is applied to a sputtering apparatus for manufacturing semiconductors and 7-piece devices, which is the field of application that is the background of the invention.
The invention is not limited to this, and can be applied to thin film formation techniques in general.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional target, Fig. 2 is a sectional view (8) of a sputtering apparatus according to an embodiment of the present invention, Fig. 3 is a sectional view of a target of another embodiment, and Fig. 4 is a sectional view of a sputtering apparatus according to an embodiment of the present invention. It is a sectional view of a modification. 10...Chamber, 1]...Target, 12...
- Electrode, 13... Wafer, 14... Quartz plate, 15
...Backing plate, 16...In/S
n alloy layer, 17... Cr layer, 18... Cr layer, 1
9...Cu layer, 20...AQ layer, 21-CrM. Figure 1, f to Figure 2 Figure 3/4 Figure 4 0

Claims (1)

[Claims] 1. A metal layer is integrally formed on the back surface of a target placed in a sputtering device, and a bonding material layer is interposed between the metal layer and the backing plate to fix the target to the backing plate. In the sputtering apparatus, the metal layer is made of a high melting point metal material that has high wettability with the fixing material but has low alloying properties. 2. The sputtering apparatus according to claim 1, wherein the metal layer is formed on the back surface of the target by vapor deposition or other methods. 3. The target is made of a quartz plate, a Cr layer or a multi-metal layer consisting of a Cr layer and a Cu g Moy A 0 layer is formed on the back surface of the target, and a Cu backing plate is formed using an In and Sn alloy as a fixing material. A sputtering apparatus according to claim 1 or 2, wherein the sputtering apparatus is fixed to a sputtering apparatus.