JP2019163506A - Sputtering apparatus - Google Patents

Abstract

To provide a sputtering apparatus capable of preventing generation of an electrolytic corrosion in a cooling-water flowing water channel.SOLUTION: A sputtering apparatus 200 according to an embodiment has a target 231 arranged in a grounded state in a vacuum chamber 21 which can be evacuated, a backing plate 232 to which the target 231 can be mounted in the vacuum chamber 21, an anode 236 which is arranged in the vacuum chamber 21 and generates plasma P, a water channel 21c for cooling the target 231 via the backing plate 232, and a DC power supply 235 for applying a DC voltage between the target 231 and the anode 236.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a sputtering apparatus.

  In a sputtering apparatus using a conventional DC power supply, it is common to use an anode by grounding other components including a vacuum chamber. Using the target as a cathode, discharge is performed by the potential difference.

  In the sputtering apparatus, when sputtering is performed, ions generated by the plasma collide with the target, so that the temperature of the target rises. Therefore, the target is cooled. For example, Patent Document 1 describes a sputtering cathode cooling mechanism in which a target is indirectly cooled by a cooling medium via a base plate.

Japanese Patent Laying-Open No. 2015-0864449

  As the cooling medium, water is generally used (hereinafter referred to as cooling water). Since a negative voltage is applied to the target, which is a cathode, to generate a potential difference, a potential difference also occurs in the cooling water, and galvanic corrosion occurs in the water channel through which the cooling water flows. Although it is conceivable to coat the inside of the water channel with an insulating material, if the inside of the water channel is coated with an insulating material, the cooling efficiency is lowered.

  The problem to be solved by the present invention is to provide a sputtering apparatus that can prevent electrolytic corrosion from occurring in a cooling member that cools a target.

  In order to solve the above problems, a sputtering apparatus according to an embodiment includes a target disposed in a grounded state in a vacuum chamber that can be depressurized, a backing plate that attaches the target to the vacuum chamber, and the vacuum. An anode disposed in the tank, a cooling member that cools the target through the backing plate, and a DC power source that applies a DC voltage between the target and the anode. The anode may be bowl-shaped.

  The sputtering apparatus according to the embodiment includes a grounded target, a backing plate connected to the target, a cooling member that cools the target with cooling water via the backing plate, and a bowl-shaped anode. And a DC power source for applying a DC voltage between the target and the anode, and the anode is hermetically closed in a state where one end provided with an opening is electrically insulated from the target, A vacuum chamber that can be depressurized is formed inside the anode.

  A parallel plate type may be used. The DC power supply may apply a positive DC voltage to the anode.

  ADVANTAGE OF THE INVENTION According to this invention, the sputtering device which can prevent that an electric corrosion generate | occur | produces in the cooling member which cools a target can be provided.

It is a schematic diagram of the sputtering device of embodiment concerning this invention. It is the schematic diagram which made the distance between TS of the sputtering device of embodiment concerning this invention close. It is the schematic diagram which made the anode of the sputtering device of embodiment concerning this invention the bowl shape, and was arrange | positioned facing the target. It is a schematic diagram in case the bowl-shaped anode of the sputtering device of embodiment concerning this invention serves as a vacuum chamber.

  An embodiment of the present invention (hereinafter referred to as this embodiment) will be described with reference to the drawings. In addition, this embodiment is specifically a parallel plate type single wafer type magnetron sputtering apparatus.

  As shown in FIG. 1, the sputtering apparatus 200 includes a vacuum chamber 21, a stage 22, a sputtering source 23, an exhaust device (not shown), a gas introduction unit, and a load lock that carries in and out the workpiece W.

  The vacuum chamber 21 is a grounded vacuum vessel and can be decompressed by an exhaust device (not shown). A stage 22 is provided inside the vacuum chamber 21. The stage 22 is a mounting table that holds the workpiece W, and is provided at the bottom of the vacuum chamber 21. The stage 22 has a lifting mechanism (not shown). Note that the side surface of the stage 22 may be insulated so that plasma is not generated between an anode 236 (described later) and the stage 22.

  An opening 21 b is provided on the side wall of the vacuum chamber 21. The opening 21b is an opening for inserting an anode 236, which will be described later, into the vacuum chamber 21, and is provided at a position where the plasma P can be generated between the opening 21b and the target 231 described later. A water channel 21 c is formed inside the upper wall of the vacuum chamber 21. The water channel 21c is connected to a chiller (not shown) outside the sputtering apparatus 200, and cools the target 231 via a backing plate 232 described later by circulating cooling water. That is, the water channel 21 c is a cooling member that cools the target 231.

  The sputtering source 23 includes a target 231, a backing plate 232, a magnet 234, a DC power source 235, an anode 236, an insulator 24, and a copper wire 238.

  The target 231 has a disk shape and is made of a film forming material for forming a film on the surface of the workpiece W. Further, the target 231 is arranged in a state of being grounded in the vacuum chamber 21 through the backing plate 232 so as to face the work W held on the stage 22. The shape of the target 231 is not limited to a disk shape, and may be a flat plate such as a rectangle or an ellipse. Further, the number of targets 231 is not limited to one and may be two or more.

  The backing plate 232 is a member for attaching the target 231 to the vacuum chamber 21. For example, the backing plate 232 is a circular plate having a diameter larger than that of the target 231, and the outer periphery thereof is fixed to the vacuum chamber 21 with screws. The backing plate 232 is bonded to the target 231 with, for example, indium. The backing plate 232 is preferably made of a material that can be electrically connected to the vacuum chamber 21 in order to ground the target 231. For example, a metal such as copper, aluminum, and stainless steel.

On the surface opposite to the surface on which the target 231 on the upper wall of the vacuum chamber 21 is attached, a magnet 234 is disposed with a gap. The magnet 234 can be rotated by a driving unit 234a, and magnetron sputtering can be performed by the magnet 234.
An insulator 24 is inserted into the opening 21b of the vacuum chamber 21 in an airtight manner. The insulator 24 is a member that insulates the anode 236 from the vacuum chamber 21 and has a cylindrical shape with one end being a flange shape. A seal member (not shown) is provided between one end of the insulator 24 and the side wall of the vacuum chamber 21 to maintain a vacuum. An O-ring or the like may be used as the seal member.

  A copper wire 238 is inserted into the insulator 24. The copper wire 238 is a copper cylinder, and the space between the copper wire 238 and the insulator 24 is kept airtight by a seal member (not shown). One end of the copper wire 238 is connected to the anode 236.

  The anode 236 is an electrode for generating plasma P that is disposed in the vacuum chamber 21. The anode 236 is a rectangular plate, for example, and functions as an electrode. For example, a metal such as copper, aluminum, and stainless steel.

  The other end of the copper wire 238 is connected to the DC power source 235. The DC power supply 235 is a DC power supply that can apply a DC voltage between the target 231 and the anode 236, and applies a positive DC voltage to the anode 236. Thereby, the anode 236 functions as an anode. In the present embodiment, the target 231 and the anode 236 act as electrodes.

  Next, the operation of the sputtering apparatus 200 will be described. The vacuum chamber 21 is always evacuated to a vacuum by an exhaust device (not shown). The workpiece W is carried into a load lock (not shown) by a transfer means (not shown). The inside of the load lock is evacuated to a vacuum, and when the degree of vacuum is reached, the workpiece W is transferred into the vacuum chamber 21.

  Next, an inert gas is introduced from a gas introduction unit (not shown), and the inside of the vacuum chamber 21 is set to a predetermined pressure. The inert gas is, for example, argon gas. The method of adjusting to a predetermined pressure may be adjusted by controlling the flow rate of the introduced gas, or may be adjusted by controlling the exhaust speed of the exhaust device.

  When the predetermined pressure is reached, the DC power supply 235 applies a positive voltage to the anode 236. Then, since the vacuum chamber 21 and the target 231 are grounded, an electric field is generated in the vacuum chamber 21. The generated electric field ionizes the inert gas and generates electrons. Since the generated electrons are captured by the magnetic field of the magnet 234, plasma is formed in the vicinity of the target 231. Thereby, the target 231 is sputtered, the film forming material is deposited on the surface of the workpiece W, and a film is formed.

  When adjusting the distance between the target 231 and the workpiece W (hereinafter referred to as the distance between TSs), the stage 22 may be adjusted by moving it up and down by an elevating mechanism (not shown) closer to the target 231. Further, as shown in FIG. 2, the distance between TSs may be adjusted by bringing the target 231 closer to the stage 22.

  The sputtering source 23a is different from FIG. 1 in that it includes a cooling member 233 and an inter-TS distance adjusting member 239.

  An opening 21a is provided in the upper wall of the vacuum chamber 21, and a sputtering source 23a is disposed there. The sputtering source 23 a includes a cooling member 233 and an inter-TS distance adjusting member 239 in addition to the configuration of the sputtering source 23.

  The target 231 is attached to the cooling member 233 via a backing plate 232. The cooling member 233 is a disk-shaped plate and is made of the same material as the vacuum chamber 21. A water channel 233a for cooling the target 231 is formed inside. The cooling member 233 to which the target 231 is attached is attached to the opening 21 a of the vacuum chamber 21 via the inter-TS distance adjusting member 239.

  The inter-TS distance adjusting member 239 is a cylinder and is made of the same material as the vacuum chamber 21. The inter-TS distance adjusting member 239 has an opening 239a, and is attached to the opening 21a so that the opening 239a is spaced toward the stage 22 side.

  At one end where the opening 239a of the inter-TS distance adjusting member 239 is provided, an inner flange 239b is formed over the entire circumference. The innermost edge of the inner flange 239b is an opening 239a. A cooling member 233 having a target 231 attached to the upper surface of the inner flange 239 b is provided via a backing plate 232. Between the backing plate 232 and the inner flange 239b, an O-ring (not shown) is provided over the entire circumference, and the opening 239a is hermetically sealed.

  An outer flange 239c is formed at the other end of the inter-TS distance adjusting member 239. Between the lower surface of the outer flange 239c and the upper wall of the vacuum chamber 21, an unillustrated O-ring is provided over the entire circumference, and the opening 21a is hermetically sealed.

  A plurality of TS distance adjusting members 239 are prepared so that the distance D from the upper surface of the inner flange 239b to the lower surface of the outer flange 239c is different. The distance between TS is adjusted by changing the distance D. Specifically, an inter-TS distance adjusting member 239 having a distance D that is an arbitrary inter-TS distance is selected and disposed in the opening 21a. Thereby, it can be set as the distance between arbitrary TS. Thus, in the sputtering apparatus in which the target 231 is a flat plate, the inter-TS distance can be adjusted by the inter-TS distance adjusting member 239.

  The magnet 234 is disposed on the surface of the cooling member 233 opposite to the surface on which the target 231 is attached, with the cooling member 233 interposed therebetween.

  Further, the shape of the anode 236 is not limited to a plate shape. For example, a bowl shape may be used. The saddle shape is a cylindrical shape having one end provided with an opening and the other closed end. As shown in FIG. 3, the stage 22 is provided inside the anode 236. The stage 22 may be electrically connected to the anode 236 or may be insulated. Moreover, it is good also as a floating. The inner wall of the vacuum chamber 21 may be insulated so that plasma P is not generated between the inner wall of the vacuum chamber 21 and the anode 236. When the anode 236 is bowl-shaped, the area ratio of the cathode to the anode is the same as that of a conventional sputtering apparatus. For this reason, plasma is stably generated.

  And as shown in FIG. 4, the above-mentioned cage-like anode 236 may also serve as a vacuum chamber. The anode 236 is airtightly attached to the cooling member 233 via the insulator 24. In other words, the anode 236 is hermetically closed with one end provided with an opening electrically insulated from the target 231, and forms a vacuum chamber V that can be decompressed inside the anode 236. The cooling member 233 has a disk shape having a diameter larger than that of the anode 236 and is grounded. Since the target 231 is connected to the cooling member 233 via the backing plate 232, the target 231 is cooled and grounded. A safety cover 25 is attached to the outer periphery of the cooling member 233 so as to cover the anode 236. With such a configuration, the anode 236 and the DC power source 235 can be connected outside the apparatus, so that the connection is facilitated.

  If the target is grounded in this way and a positive voltage is applied to the anode, the sputtering source can be easily attached and electrolytic corrosion can be prevented.

As mentioned above, although embodiment of this invention and the modification of each part were demonstrated, this embodiment and the modification of each part are shown as an example, and are not intending limiting the range of invention. These novel embodiments described above can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention and included in the invention described in the claims.

21 Vacuum chamber 21a Opening 21b Opening 21c Water channel 22 Stage 23, 23a Sputtering source 24 Insulator 25 Safety cover 200 Sputtering device 231 Target 232 Backing plate 233 Cooling member 233a Water channel 234 Magnet 234a Driving unit 235 DC power source 236 Anode 238 Copper wire 239 TS distance adjusting member 239a Opening 239b Inner flange 239c Outer flange D Distance P Plasma V Vacuum chamber W Workpiece

Claims (5)

A target arranged in a grounded state in a vacuum chamber capable of depressurization;
A backing plate for attaching the target to the vacuum chamber;
An anode which is disposed in the vacuum chamber and is an electrode for generating plasma;
A cooling member for cooling the target through the backing plate;
A DC power source for applying a DC voltage between the target and the anode;
A sputtering apparatus comprising: The sputtering apparatus according to claim 1, wherein the anode has a bowl shape. A sputtering device, a grounded target,
A cooling member for cooling the target through a backing plate;
A bowl-shaped anode,
A DC power source for applying a DC voltage between the target and the anode;
Have
A sputtering apparatus, wherein the anode is hermetically closed in a state where one end provided with an opening is electrically insulated from the target, and forms a vacuum chamber capable of depressurization inside the anode. The sputtering apparatus according to claim 1, wherein the target is a flat plate. The sputtering apparatus according to claim 1, wherein the DC power source applies a positive DC voltage to the anode.

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