KR100585198B1 - Plasma generator for processing of wafer edge - Google Patents

Abstract

In the present invention, in the plasma generator for placing the wafer on the substrate in the plasma generator, the upper electrode is installed at regular intervals on the substrate, and the edge of the wafer is disposed on the bottom of the edge of the upper electrode to process the edge of the wafer, the substrate and the upper electrode Are replaced with an insulating substrate and an insulating plate, and a ring-shaped first ring electrode is provided at the bottom of the edge of the insulating plate, a ring-shaped second ring electrode is provided at the top edge of the insulating substrate, and the first and second ring electrodes are plasma A plasma generating device for wafer edge processing configured to apply a generation power source (AC power).

According to the present invention, when the wafer is placed on the substrate and the edge of the wafer is processed, the ring electrode is placed only at the edge corresponding portion of the wafer to be processed so that plasma is generated only at the edge so that the edge of the wafer can be uniformly plasma-processed. have. In addition, since plasma is generated through the ring electrode corresponding to the edge of the wafer, there is no fear of particle generation due to plasma generation. In addition, in order to plasma-process the edge of the wafer, a method of applying power to the substrate and the upper electrode may be caused by changing the mutual electrodes to generate various modes of plasma, and the voltage to be applied may be selected through a transformer. It is possible.

Description

Plasma generator for processing of wafer edges

1 is a block diagram illustrating a plasma process system.

2 is a perspective view of a plasma generator.

3 is a plasma generation control configuration diagram.

4 is a waveform diagram showing a ignition signal power supply for plasma generation;

5 is a main configuration diagram of a general plasma generating apparatus.

6 is a sectional view of principal parts of a plasma generating apparatus for wafer edge processing according to the present invention;

FIG. 7 is a bottom view of an insulating plate in the plasma generating apparatus for wafer edge treatment of FIG. 6. FIG.

8 is a block diagram of a plasma generating apparatus for wafer edge processing according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: substrate 1 ': insulation substrate

2: electrode 2 ': upper electrode

2f: first ring electrode 2s: second ring electrode

3: border groove 3 ': border groove

4: wafer 70: control part

SW1, SW2, SWa: Switch T: Transformer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generating apparatus for wafer edge processing, and more particularly, in a plasma generator in which a wafer is placed on a substrate in a plasma generator to generate plasma, with a tedley groove at the bottom of an edge of an electrode placed on an upper substrate. The edge groove relates to a plasma generator for wafer edges installed to have a size such that the edges of the wafers are exposed.

In general, plasma sources are used in various processes for manufacturing semiconductor devices, for example, etching, stripping, and cleaning. Plasma density and uniformity are important factors affecting process efficiency in plasma-based processes, and efforts to improve plasma generation density and uniformity have been continued.

Plasma processing system employing a remote plasma generator has the advantage of preventing the degradation of the process yield due to the generation of particles (particles) due to the plasma reaction by generating the plasma remotely supplied to the process chamber. However, the remote plasma generator must have a high plasma generation density because the process gas in the plasma state must be provided to the process chamber remotely.

Accordingly, efforts are being made to increase the plasma generation density of the remote plasma generator. In order to increase the plasma generation density, the AC power provided from the AC power should be transferred as much of the ionization energy as possible in the remote plasma generator.

1 is a block diagram showing an example of a plasma process system employing a remote plasma generator, the gas source 10, the remote plasma generator 20, the AC power 30, the process chamber 40, and the vacuum pump 50. It is configured to include).

The gas source 10 provides process gas to the remote plasma generator 20. The remote plasma generator 20 receives an AC signal of a predetermined frequency provided from the AC power 30 to ionize the process gas to generate plasma. For example, AC power is provided to the remote plasma generator 20.

Process gas in a plasma state generated from the remote plasma generator 20 is provided to the process chamber 40. The vacuum pump 50 keeps the internal pressure of the process chamber 40 constant and discharges the process gas that has been processed. An impedance matching device for impedance matching is configured between the remote plasma generator 20 and the AC power 30.

In such a plasma processing system, the remote plasma generator 20 remotely generates a plasma and supplies the plasma to the process chamber 40.

2 is a perspective view showing the appearance of the remote plasma generator, the remote plasma generator 20 has a main body 21 having a cylindrical shape. The upper and lower surfaces of the main body 21 each have a shape in which a central portion protrudes, and a gas inlet 22 is formed at the center of the upper surface, and a gas outlet 23 is formed at the center of the lower surface. The main body 21 has a connecting tube 24 that forms a wire passage for applying power to the internal coil 29.

3 is a block diagram showing a circuit configuration for driving a remote plasma generator. An inductor coil 29 and a core (not shown) configured in the remote plasma generator 20 operate as a single winding transformer, and the impedance matcher 64 is operated. AC power is supplied from the AC power 30 through. Impedance matcher 64 is constructed using a plurality of inductors, which are configured using variable or fixed inductors. The ignition power 60 receives power from the AC power 30 and supplies the ignition power for plasma generation to the inductor coil 29 of the remote plasma generator 20. The controller 66 performs overall control for plasma generation such as control of the switch 62 for supplying the ignition power 60, impedance matching control of the impedance matcher 64, power supply of the AC power 30, and the like. The control is performed by over current control method. In the figure, Rp denotes a plasma resistance.

4 is a diagram illustrating an example of a supply waveform of AC power and ignition power.

Referring to FIG. 4, process gas provided from the gas source 10 flows into the main body 21 through the gas inlet 22 of the remote plasma generator 20. At this time, the AC power VAC from the AC power 30 and the ignition power Vignite from the ignition power 60 are combined and supplied to the inductor coil 29 during the ignition section 70. At this time, the induction magnet is generated by the inductor coil 29, and the magnetic flux is strengthened by the magnetic core. An induction field is generated that forms a closed loop in the direction that bridges the magnetic core again by the magnetism induced by the inductor coil 29. In addition, an inner plate of the core barrel is used as an extended lead of the coil 29, and when the ignition power supply (Vignite) is supplied, the inner plate functions as a spark plug (igniter).

The process gas introduced into the main body 21 in the ignition section 70 is ionized by receiving energy to generate plasma. In the normal plasma generation section 72, the switch 62 is cut off, the supply of ignition power Vignite is stopped, and only AC power VAC supplied from the AC power 30 is supplied. The plasma gas is supplied to the process chamber 40 through the gas outlet 23. In the above, the ignition power (Vignite) and the AC power (VAC) supplied in the ignition section 70 is a synchronous method, but may be asynchronous. AC power VAC supplied from the AC power 30 may use a sine wave.

Although the inner plate of the core barrel functions as a spark plug without using a separate spark plug, a separate spark plug may be used.

5 is a configuration showing the main structure of a plasma generator for wafer edge processing in general, where a wafer 4 requiring plasma processing is placed on the substrate 1 and an electrode 2 is placed on the substrate 1 having a predetermined space thereon. Install). An edge groove 3 for securing a plasma generation space is formed at the bottom edge of the electrode 2. The AC 2 is applied to the electrode 2 and the substrate 1 to generate the plasma 5. The supply of the plasma generation gas and the configuration of the igniter are omitted. However, in this manner, the edge thickness of the electrode 2 becomes thin due to the edge groove 3, so that the electrode 2 is easily damaged, and particles caused by damage of the electrode are buried in the wafer, resulting in defective processing of the wafer. In addition, there is a problem that the particles on the wafer generates a capacitance to cause a malfunction of the plasma generator.

The present invention is to solve this problem, an object of the present invention is to provide a plasma generating apparatus that allows the plasma to be irradiated to the edge with a constant thickness when the plasma is irradiated to the wafer edge.

Another object of the present invention is to provide a plasma generator that allows plasma to be generated in a scattered state so that the wafer edge can be uniformly irradiated.

To this end, the present invention is configured to form an electrode on the portion where the edge portion of the wafer is exposed. The electrode may be formed on the bottom of the edge of the insulating plate, or may be configured to form a deep groove of the upper electrode so that the edge is exposed.

That is, in the present invention, in the plasma generator, the wafer is placed on the substrate in the plasma generator, the upper electrode is installed at a predetermined interval on the substrate, and the edge groove of the edge of the upper electrode is provided to process the edge of the wafer.

Replace the substrate and the upper electrode with an insulating substrate and an insulating plate, respectively

A ring-shaped first ring electrode is provided on the bottom of the edge of the insulating plate,

A ring-shaped second ring electrode is provided on the upper edge of the insulating substrate.

The first and second ring electrodes are to provide a wafer edge processing plasma generator configured to apply a plasma generation power source (AC power).

Forming a groove on the bottom of the edge of the insulating plate,

The first ring electrode is installed in the edge groove.

The first ring electrode is provided on the edge of the wafer to be placed.

The second ring electrode is provided on the bottom surface of the edge of the wafer.

In another aspect of the present invention, in the plasma generator, the wafer is placed on a substrate in the plasma generator, the upper electrode is disposed at a predetermined interval on the substrate, and the edge of the wafer is disposed on the bottom surface of the upper electrode to process the edge of the wafer.

One switch functioning to select ground at each end of the top electrode and substrate,

Another switch for selecting a power source so that the opposite polarity of the selection of the one switch is conducted at each other end of the upper electrode and the substrate;

It is an object of the present invention to provide a plasma generating apparatus for wafer edge processing comprising a control unit for controlling the operation of the two switches.

The other switch has both contacts alternately turned on, one of which is on the secondary side of the transformer,

The other contact is configured to supply power through the primary side of the transformer.

The primary side of the transformer is configured to variably receive input power through another switch that selects the number of turns to vary the input power.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 6 is a sectional view of principal parts of the plasma generating apparatus for wafer edge processing according to the present invention, and FIG. 7 is a bottom view of an insulating plate of the plasma generating apparatus for wafer edge processing in FIG.

6 and 7, in the plasma generating apparatus for wafer edge treatment according to the present invention, in the plasma generating apparatus of FIG. 5, the substrate 1 and the upper electrode 2 are respectively insulated from the insulating substrate 1 ′ and the insulating plate ( 2 '), a ring-shaped first ring electrode 2f is provided at the bottom of the edge of the insulating plate 2', and a ring-shaped second ring electrode 2s is provided at the top edge of the insulating substrate 1 '. do. At this time, the first and second ring electrodes 2f and 2s are configured to apply an AC power for plasma generation.

In addition, an edge groove 3 'is formed on the bottom of the edge of the insulating plate 2', and the first ring electrode 2f is provided on the edge groove 3 '. The first ring electrode 2f is provided on the edge of the wafer 4 to be placed. The second ring electrode 2s is provided on the bottom surface of the edge of the wafer 4.

8 is a configuration diagram showing another embodiment of the present invention.

Referring to FIG. 8, in a plasma generator in which an electrode is placed on a substrate on which a wafer is placed, an upper electrode 2 and a switch SW2 functioning to select ground at each end of the substrate 1 and the upper electrode ( 2) and a switch SWa for selecting a power source so that the polarity of the switch SW2 is reversed at the other end of the substrate 1 and the control unit 70 for controlling the operation of the switches SW2 and SWa. Consists of including.

The switch SWa has contacts SWa1 and SWa2 that are alternately turned on, one contact SWa1 is on the secondary side of the transformer T, and the other contact SWa2 is powered through the primary side of the transformer T. Configure to supply

The primary side of the transformer (T) is configured to receive a variable supply of input power through a switch (SW1) for varying the input power by selecting the number of turns of the coil. In FIG. 8, reference numeral 2d denotes an insulating layer.

On the other hand, in the first embodiment of the present invention as shown in Figs. 6 and 7 configured as described above, the edge groove is formed on the bottom surface of the insulating plate 2 'by placing the wafer 4 on the insulating substrate 1'. 3 'is configured to expose the edge of the wafer 4, and the first ring electrode 2f is provided in the edge groove 3' of the bottom surface of the insulating plate 2 'of the portion corresponding to the exposed edge portion. In addition, since the second ring electrode 2s is also provided on the substrate portion corresponding to the first ring electrode 2f, the plasma is irradiated constantly to the edge of the wafer 4. In addition, since the first and second ring electrodes 2f and 2s face each other at positions corresponding to each other, there is no fear of particle generation due to plasma generation, and power is applied only at the edge part, thereby preventing power loss due to power supply. have.

In addition, in the second embodiment of the present invention as shown in FIG. 8, the control unit 70 switches the switch SW2 to the contact a1 and the switch SWa to switch the contact SWa1 through the port P1. On) (the operation and selection of the switch itself is a conventional technique, so the description thereof is omitted), and the voltage transformed through the secondary side of the transformer T is applied to the contact SWa1 and the electrode 2 , A voltage of a different polarity is applied from the ground to the substrate 1 via the switch SW2, the contact a1. In this case, since the edge groove 3 formed on the bottom surface of the edge constituting the electrode 2 is configured to have a depth to expose the wafer 4, the plasma passes through the edge groove 3 of the wafer 4. Irradiated evenly to the edges.

In addition, according to the present invention, the contact point of the switch SW2 is applied through the contact point a2 and the contact point SWa2 by the control unit 70 to change the polarity to generate the plasma. This may adjust the generation intensity of the plasma in various forms, and by repeatedly changing the generation movement direction of the plasma so that the generated plasma is uniformly irradiated to the edge of the wafer 4 in large quantities.

The present invention described above is not limited to the above-described embodiments and drawings, and various permutations, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those who have

As described above, in the present invention, when placing a wafer on a substrate and processing an edge of the wafer, a ring electrode is placed only at an edge corresponding portion of the wafer to be processed so that plasma is generated only at the edge so that the edge of the wafer is uniformly plasma-processed. In addition, since plasma is generated through the ring electrode corresponding to the edge of the wafer, there is no fear of particle generation due to plasma generation. In addition, the present invention can generate a plasma of various modes by changing the mutual electrodes to the method of applying power to the substrate and the upper electrode in order to plasma process the edge of the wafer, the voltage to be applied can also be selected through the transformer Can be used for general purposes.

Claims (7)

delete delete delete delete In the plasma generating apparatus for placing the wafer on the substrate in the plasma generator, the upper electrode is installed at a predetermined interval on the substrate and the edge of the wafer by processing the edge of the wafer with a border groove on the bottom of the upper electrode, A switch SW2 functioning to select ground at each end of the upper electrode 2 and the substrate 1, Selecting a power supply so that the polarity of the switch SW2 and the polarity of the switch SW2 are conducted at opposite ends of the upper electrode 2 and the substrate 1, the contact points SWa1 and SWa2 alternately turned on, and one contact SWa1 The switch SWa is configured to supply power through the secondary side of the transformer T, and the other contact SWa2 is supplied through the transformer T primary side. And a controller (70) for controlling the operation of the switches (SW2, SWa). delete delete

Images