JPH02298263A - Sputtering device - Google Patents

Abstract

PURPOSE:To uniform the state of a film formed on a material to be treated by providing a mechanism capable of changing the relative position of both a target and the material to be treated. CONSTITUTION:Both a target 4 and the material to be treated such as a semiconductor wafer 2 are oppositely provided to the inside of a vacuum chamber 1. When the target main body 4a is sputtered and consumed, the position of a sputtering gun 5 is adjusted so that the distances D1, D2 between the surface of the target main body 4a receiving sputtering and the surface of the semiconductor wafer 2 are made equal. For example, a ball screw 8 penetrating a housing 7 is provided to the rear of the sputtering gun 5. This sputtering gun 5 is moved by rotating a handle 9 for rotation provided to the end part of the ball screw 8. Thereby the state of a film formed between the surfaces is uniformed.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a sputtering apparatus.

(Prior Art) In general, sputtering apparatuses are often used for forming films on objects to be processed, such as semiconductor wafers, for example, forming thin metal films.

In such a sputtering apparatus, an object to be processed, such as a semiconductor wafer, is provided so as to face a target made of a predetermined material provided in an airtight container, and a voltage is applied between these targets and the semiconductor wafer, and a voltage is applied inside the airtight container. Introduce sputtering gas.

Then, this sputtering gas is turned into plasma, and ions in the plasma collide with a target, which is an electrode at a negative voltage, to perform sputtering, and are deposited on the surface of a semiconductor wafer provided on the anode side to form a thin film.

Furthermore, the planar magnetron sputtering apparatus is configured to form a magnetic field for confining plasma near the surface of the target using, for example, a plasma control magnet provided on the back side of the target. That is, a magnetic field is formed near the surface of the target that is substantially parallel to the target surface, and high-density discharge plasma perpendicular to this magnetic field is concentrated on the target surface to perform high-speed sputtering.

By the way, in such sputtering equipment, when the magnets are fixedly arranged, it is difficult to uniformly distribute the magnetic field on the target surface, so ions concentrate in areas where the magnetic field is strong, and sputtering is concentrated in these areas. This causes problems such as a decrease in uniformity in film formation and a decrease in target utilization efficiency. Therefore, for example, by rotating a plasma control magnet consisting of a plurality of permanent magnets arranged in an ellipse so as to scan an annular region of the target and moving the plasma in this annular region, sputtering can be uniformly achieved. There are also sputtering equipments that aim to achieve this goal.

(Problem to be solved by the invention) However, even in the above-mentioned sputtering apparatus, the 4M
, IBM and high integration, for example, when depositing a film on a large number of semiconductor wafers, the uniformity of the film formation state between surfaces, that is, variations in step coverage, film thickness, etc. for each semiconductor wafer, etc. It is desired to form a uniform film with a small amount of film.

The present invention has been made in response to such conventional circumstances, and aims to provide a sputtering apparatus that can achieve a more uniform film formation state from surface to surface than in the prior art.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides a sputtering apparatus in which a target and a workpiece are provided in a vacuum chamber so as to face each other, and a film is formed on the workpiece by sputtering the target. The apparatus is characterized in that a mechanism is provided that changes the relative position of the target and the object to be processed.

(Function) A detailed investigation by the present inventors revealed that in a conventional sputtering apparatus in which a target and a workpiece, such as a semiconductor wafer, are provided in a vacuum chamber so as to face each other, when the target is sputtered and consumed, the surface of the target When the distance between the semiconductor wafer and the semiconductor wafer gradually changes, and many semiconductor wafers are processed with the same target, it has been found that the film formation condition, such as step coverage and film thickness, becomes non-uniform between the semiconductor wafers. did.

Therefore, the sputtering apparatus of the present invention is provided with a mechanism that can change the relative position of the target and the workpiece, and even if the target is worn out due to sputtering, for example, the sputtering apparatus of the present invention uses this mechanism to By moving the relative positions of the target and the object to be processed so that the distance between the target and the object to be processed is constant, the state of the film formed on the object to be processed is made uniform.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In the vacuum chamber 1 of the sputtering apparatus, a mounting table 3 for holding an object to be processed, such as a semiconductor wafer 2, is provided, and a sputter gun 5 equipped with a target 4 is provided so as to face the mounting table 3. It is being

This sputter gun 5 is provided so as to pass through a circular hole 1a provided in the vacuum chamber 1, and there is a space between the circular hole 1a and the sputter gun 5 that can be expanded and contracted so as to keep the gap airtight. A cylindrical bellows 6 is provided. Further, at the rear of the sputter gun 5, a mechanism is disposed so as to pass through a housing 7 fixed to the vacuum chamber 1, for example, as a mechanism that allows the position of the sputter gun 5 to be moved relative to the vacuum chamber 1. A ball screw 8 is provided, and by rotating a rotating handle 9 provided at the end of the ball screw 8, the sputter gun 5 is moved in the direction of the arrow shown in the figure. The distance between the target 4 and the semiconductor wafer 2 is adjustable.

Note that any mechanism other than the above may be used as the mechanism for adjusting the distance between the target 4 and the semiconductor wafer 2. For example, it may be an electric type using a drive motor or the like; Any method may be used to move the E stand 3.

Further, the target 4 is made of a solid material having a diameter of about 120100 mm, for example, made of aluminum, silicon, tungsten, titanium, molybdenum, chromium, cobalt, nickel, or an alloy containing these, selected according to the material of the thin film to be formed. A target body 4a formed into a molded shape, and backing plates 1 and 4 joined to form a flange on the back side of the target body 4a.
It is composed of b. A cylindrical coolant circulation gap 11 is provided on the back side of the target 4 to cool the target 4 from the back side by circulating a coolant, such as cooling water, through a coolant circulation pipe 10. .

Furthermore, a plasma control magnet 12 is provided in this refrigerant circulation gap 11. That is, this plasma control magnet 12 has, for example, an elliptical shape, a semicircular shape,
Nt on the inside of polygonal shapes! ! i! The plasma control magnet 12 is composed of a plurality of permanent magnets (not shown) arranged so that the outer side is the south pole and a support plate that supports these permanent magnets.
It is connected to a drive mechanism 14 via an airtight seal, such as a magnetic fluid seal 13, provided at the center of the rear part of the drive mechanism 1, and is configured to be rotatable.

In the sputtering apparatus of this embodiment having the above configuration, the inside of the vacuum chamber 1 is first roughly vacuumed to a degree of vacuum of, for example, lo-1 to 10-' Torr. Next, the degree of vacuum in the vacuum chamber 1 is evacuated to a high degree of vacuum of about lo-5 to 1 O-a Torr, and then sputtering gas, for example Ar gas, is introduced into the vacuum chamber 1, and the inside of the vacuum chamber 1 is evacuated. 10
' to 10-' Torr.

Then, a negative voltage is applied to the target 4 by a sputtering power source (not shown) to generate plasma between the target 4 and the semiconductor wafer 2.

Then, this plasma is transferred to the plasma control magnet 12.
The particles are confined in the vicinity of the target 4 by the magnetic field formed by the target body 4a, and sputtering of the target 4 (target body 4a) within this area is performed, and the particles ejected from the target body 4a adhere to the surface of the semiconductor wafer 2. , a thin film having a desired composition is formed. At this time, when the plasma control magnet 12 is rotated by the drive mechanism 14, the plasma moves over almost the entire surface of the target body 4a, and this sputtering occurs uniformly over almost the entire target body 4a.

In the sputtering apparatus of this embodiment, as shown in FIG. 2, from a state in which the target body 4a is not worn out (shown in the upper flat part of FIG. 2), the target body 4a gradually increases.
When the target body 4a is sputtered and is consumed (as shown in the upper flat part of FIG. 2), the position of the sputtering gun 5 is adjusted so that the distances MDI and D2 between the target body 4a receiving sputtering and the surface of the semiconductor wafer 2 are respectively equal. Adjust. For this position adjustment, the relationship between the plasma generation time and the amount of target consumption may be stored in a memory as data, and the distance between the target and the wafer may be adjusted based on the read output value of this memory. In this case, the amount of consumption of the target may be detected by detecting the height based on the difference from the non-consumed position that is in the shadow, and the amount of movement may be adjusted.

Therefore, even when forming films on a large number of semiconductor wafers 2 using the same target 4, each semiconductor wafer 2 can be formed under similar conditions, and each semiconductor wafer 2 can be A uniform film with little variation can be formed.

In the above embodiment, the distance between the target and the wafer is grq
Although the above example has been described, sputtering may be performed by moving the position of the wafer in contact with the target in a scanning manner so that the target is uniformly consumed.

[Effects of the Invention] As described above, according to the present invention, it is possible to make the film formation state more uniform between surfaces than in the past.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a sputtering apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the state of a target in the sputtering apparatus of FIG. 1. 1... Vacuum chamber, 2... Semiconductor wafer, 3... Mounting table, 4... Target, 4a... Target body, 4b・・・・・・
・Backing plate, 5... Sputter gun,
6... Bellows, 7... Housing,
8...Ball screw, 9...Rotating nodle, 10...Piping for cooling medium circulation,
11... Gap for refrigerant circulation, 12... Magnetosoto for plasma control, 13... Magnetic fluid seal, 14... Drive mechanism. Applicant: Tokyo Electron Ltd.＞1 Agent: Patent Attorney Sasa Suyama - (1 other person) Figure 2

Claims (1)

[Claims] (1) A target and a workpiece are provided in a vacuum chamber so as to face each other, and the relative positions of the target and the workpiece are variable in a sputtering apparatus that sputters the target to form a film on the workpiece. A sputtering apparatus characterized by being provided with a mechanism for.