JPS63290269A - Sputtering device - Google Patents

Abstract

PURPOSE:To efficiently form a good-quality thin Al film on a semiconductor substrate by providing a backing plate consisting of a cooling water layer and heating layer to an Al target at the time of growing the thin Al film by sputtering on the substrate. CONSTITUTION:The backing plate consisting of the cooling water layer 32 having cooling water passages 33 and the heating layer 34 having heaters 35 for heating is mounted to the rear face of the Al target to be used at the time of forming the thin Al film on the semiconductor substrate such as Si wafer by a sputtering method using Al as the target. The cooling water layer 32 is cooled by cooling water during sputtering to prevent overheating of the Al target 12 by bombardment of the Ar ions and to steadily grow the thin Al film on the substrate. In addition, the gases such as N2, O2, H2O and CO2 adsorbed by the Al target before sputtering are heated by the heating layer 34 and are thereby released. The quality of the thin Al film on the substrate is thus improved.

Description

[Detailed Description of the Invention] [Summary] The banking plate of the sputtering gun target of the sputtering device has a two-layer structure consisting of an ffi through which cooling water flows and a layer in which a heater is embedded and can be heated to promote gas release from inside the target. Improves film quality.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a sputtering apparatus, and more particularly to an improvement of a backing plate for a sputter gun target of a sputtering apparatus.

[Conventional technology]

When forming aluminum (AI) wiring on a semiconductor substrate (for example, a silicon wafer), a thin film of ^l is grown on the substrate using a sputtering device, and the AI thin film is patterned to form the wiring. Form.

An example of the arrangement of the sputtering device is shown in FIG. 2. In the figure, 21A, 228, and 23C are load locks, 22 is a pretreatment chamber, and 23 is a sputtering device. In operation, the wafer is placed into the load lock 21A from the atmosphere, the load lock 21A is evacuated to a vacuum, and the wafer is then placed into the vacuum-maintained pretreatment chamber 22 where it is evaporated by ion milling. The surface of the wafer is cleaned, and then the wafer is transferred to the sputtering device 23 via a load lock 21B, and when a predetermined sputtering is completed, the wafer is taken out to the atmosphere via a load lock 21G. In such operations, wafers are handled by means called wafer handlers.

The sputtering device has the configuration shown in Figure 3.
In the figure, 11 is a grounded sputtering chamber (hereinafter simply referred to as a chamber), and 12 is, for example, A7! Lm for thin film growth
' target, 13 is the banking plate, 14 is the anode, 15 is the main valve, 16 is the conductance valve, 17 is the main exhaust pump (cryo pump), 18 is the valve, 19 is the rotary pump for pulling the cryopump 17, 2o is a wafer, and a vacuum on the order of 10-' Torr is maintained within chamber 11 by the illustrated pump arrangement. The anode 14 is connected to the chamber 11 and grounded, and the backing plate 13 serves as a cathode and is insulated from the chamber 11. chamber 11
Since the inside is maintained at the vacuum level described above, the backing plate 13 also has the function of insulating the chamber 11 from the atmosphere.

To perform sputtering, argon (Ar) is introduced into the chamber 11, a discharge is caused between the anode 14 and the target 12 (cathode), and plasma is generated.
A is applied to the Al target 12 heated to 00 to 300°C.
R ions are bombarded to knock out AN from the target and deposit it on the wafer 20 to grow an Al thin film.

The assembly of the target 12 and the backing plate 13 is also called a sputtering gun or a sputtering gun.
Its detailed structure is shown in the sectional view of FIG. As mentioned above, the target 12 becomes high temperature due to collision with Ar ions, so it is necessary to cool the target during sputtering.
3a, and cooling water is passed therethrough so that the temperature of the Af target does not exceed 300°C.

[Problem that the invention seeks to solve]

In sputtering, after opening the sputter processing chamber, that is, chamber 11 to the atmosphere, or using N2 + 0
2, etc., or after active span tanning, it is necessary to quickly discharge the gas trapped inside the target. Note that the chamber is also opened to the atmosphere when the aforementioned wafer handler breaks down and must be repaired.

In conventional sputter guns, efforts are made only to cool the target, and it can be said that efforts are made to cool the target without regard to discharging the gas adsorbed inside the target. However, as the degree of integration increases, there are stricter requirements for film quality, and it has become a problem that the incorporation of gases such as N21021H, CO2, etc. causes deterioration of the film thickness.

Especially A7! In the case of the target, gas outgassing from the Al target due to its high hygroscopicity has become a problem.

Conventionally, a heater (sheath heater) was installed on the inner wall of a chamber made of SuS to degas the inner wall of the chamber. The means for heating the target itself either receives indirect heat from this chamber or is provided with a lamp heater or the like inside, and is moved in front of the target when necessary.

However, in conventional examples, the sheath heater on the inner wall of the chamber is extremely difficult to heat up, the lamp heater (usually an infrared lamp) has a complicated structure, often malfunctions, and the heater does not touch the target during sputtering. There is also a problem in preventing materials from adhering.

In the case of an Al target, gas release is not sufficient even if the above measures are taken, and when forming an Al thin film, dummy wafers are prepared, and after forming an Al thin film on about 50 dummy wafers (dummy ranking), regular I'm trying to move on to operations.

Such dummy rankings consume target materials, power, labor, and time, and although they are slanted, gas release from the targets is a problem.

The present invention was created in view of these points, and an object of the present invention is to provide a sputter gun that allows gas to be released from the target.

[Means for solving problems]

FIG. 1 is a sectional view of a sputter gun according to the present invention, in which 31 is a backing plate, 32 is a layer for cooling 2, and 33 is a backing plate.
34 is a cooling water passage, 34 is a heating layer, and 35 is a heater.

In the present invention, the banking plate 31 to which the target 12 is fixed has a cooling layer 32 that cools the target 12 by flowing cooling water through a cooling water passage 33, and a heater 3.
It has a two-layer structure including a heating layer 34 for gas emission from the target in which numerals 5 are embedded.

[Effect]

In order to promote gas release from inside the target,
Heating the banking plate that is directly bonded to the target is effective. However, during sputtering, the target becomes high temperature because it is exposed to plasma containing Ar ions and the like. Therefore, the structure must also include a cooling mechanism.

Therefore, the backing plate has a double structure, with a first cooling layer through which water can flow to cool the target during sputtering, and a second cooling layer embedded with a heater that can heat the target after it is exposed to the atmosphere or after sputtering if necessary. Add a heating layer.

With the above structure, gas release of N2 + 02 + HzO, CO2, etc. taken into and adsorbed inside the target is promoted, and a clean film thickness can be obtained. In particular, AJ, which is often used for IC wiring, is very hygroscopic and easily absorbs gas, so it is very effective.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Returning to FIG. 1 again showing the structure of the sputter gun, the target 12 and the backing plate 31 made of copper (Cu) are fixed with a high melting point adhesive or screws (not shown).

The backing plate 31 consists of a first cooling layer 32 and a second heating layer 34, and the cooling layer 32 is provided with a cooling water passage 33 for flowing cooling water therein.

A heater (for example, Ni alloy) 35 is embedded in the second heating layer 34 . During sputtering, cooling water of 10 to 20 ff/Tll1n is passed through the cooling water passage of the cooling N32. On the other hand,
After sprinkling or opening to the atmosphere, the cooling water is stopped, and the heater 35 embedded in the heating layer is activated to heat the target to about 400° C. and vent the gas contained in the target.

The configuration of the cooling water layer 32 described above is the same as in the conventional example, and the heating layer 34 is integrated with the cooling water layer 32 by, for example, screws not shown. The arrangement of the heater 35 can be the same as a normal heating means used in a CvD device or the like, and it is preferable to arrange the heating wires as described above, for example, radially.

In the operation of the above-described embodiment of the present invention, regular sputtering can be carried out by performing the above-mentioned dummy running only 10 times (compared to 115 in the conventional example), which saves target material, power, labor, and time. It was remarkable. Note that these 10 dummy runs were performed to remove a thin oxide film on the surface of the All target rather than to vent gas from the target.

Although the above description has been made using an Al target as an example, the scope of the present invention is not limited to that case, but also extends to cases where targets made of other materials are used.

〔Effect of the invention〕

As described above, according to the present invention, the backing plate has a two-layer structure consisting of a cooling layer and a heating layer, so that the gas contained in the target of the sputtering gun is efficiently vented, and the workability of thin film growth is improved. This not only improves efficiency but also is effective in improving the quality of the grown film.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sputtering gun according to the present invention, FIG. 2 is a diagram showing the arrangement of a sputtering device, FIG. 3 is a diagram of a sputtering device, and FIG. 4 is a sectional view of a conventional sputtering gun. 1 to 4, 11 is sputtering, 12 is a target, 13 is a backing plate, 13a is a cooling water passage, 14 is an anode, 15 is a main valve, 16 is a conductance valve, 17 is a main exhaust pump, 18 is a Valve, 19 is a rotary pump, 20 is a wafer, 21^, 21B, 21C is a load lock, 22 is a pretreatment chamber, 23 is a sputtering device, 31 is a backing plate, 32 is a cooling water layer, 33 is a cooling water passage, 34 is a heating layer, and 35 is a heater. Agent: Patent Attorney Hajime Kuki Agent: Patent Attorney Yoshiyuki Osuga 75. Rei Zaigotamoto, *shi day jlI;
II Figure 1 Suba Tutarinku 11 [I Figure 2 of Claw 1]

Claims (1)

[Claims] In the sputter gun of the sputtering apparatus, the backing plate (31) that fixes the target (12) has a first cooling system that cools the target by flowing cooling water into the cooling water passage (33) during sputtering. The water layer (32) and the target (12) are degassed.
2) embedded with a heater (35) for heating the
A sputtering device characterized by having a two-layer structure consisting of a heating layer (34).