KR20070041220A - Plasma treatment apparatus - Google Patents

Abstract

The present invention relates to a plasma processing apparatus having a gas distribution plate for supplying a process gas in a process chamber in a semiconductor processing apparatus using plasma. Plasma processing apparatus of the present invention is installed inside the process chamber and is located in the process chamber to face the susceptor, susceptor on which the substrate is seated, the process gas to the gas distribution plate and gas distribution plate for injecting the process gas to the substrate It includes a gas supply for supplying. The gas distribution plate has at least two divided spaces into which the process gas is introduced, and the gas supply unit has flow control valves that can be controlled to regulate the supply amount of the process gas supplied to the divided spaces, and a flow rate for controlling the flow control valves. It may include a control unit.

Plasma, Density, Gas Distribution Plates

Description

Plasma Treatment Equipment {PLASMA TREATMENT APPARATUS}

1 is a perspective view showing a plasma processing apparatus according to a preferred embodiment of the present invention;

2 is a front sectional view of a plasma processing apparatus according to a preferred embodiment of the present invention;

3 is a cross-sectional view taken along the line a-a shown in FIG. 2.

Explanation of symbols on the main parts of the drawings

110: process chamber

112: upper processing chamber

114: lower processing chamber

130: high frequency antenna

150: gas distribution plate

152: bulkhead

154: partition space

The present invention relates to a semiconductor processing apparatus, and more particularly, to a plasma processing apparatus having a showerhead for supplying a process gas in a process chamber in a semiconductor processing apparatus using plasma.

BACKGROUND ART In recent years, the demand for processing apparatuses for etching or film forming has increased due to high integration of semiconductor devices, large diameters of semiconductor wafers, and large areas of liquid crystal displays. The situation is the same in a plasma processing apparatus such as a plasma etching apparatus, a plasma CVD apparatus, and a plasma ashing apparatus. In other words, in order to improve the throughput, the improvement of the plasma, the coping with the large area of the workpiece (semiconductor wafer, and the glass substrate), and the realization of the cleaning have emerged as important tasks.

Examples of the plasma source used in such a plasma processing apparatus include a high frequency capacitively coupled plasma source, a microwave ECR plasma source, and a high frequency inductively coupled plasma source. Each of these is used in various processing processes in consideration of its characteristics.

Among these plasma sources, a plasma processing apparatus including a high frequency inductively coupled plasma source can generate a relatively high density of plasma under a low pressure of several mTorr by a simple and inexpensive configuration such as a simple antenna and a high frequency power source. Placing the coil in a planar area makes it possible to easily generate a plasma having a large area, and since the inside of the process chamber is simple, there is an advantage that it is possible to reduce the generation of foreign matters flying onto the object during processing.

However, these various types of plasma processing apparatus have a bias in the plasma density according to the shape of the RF antenna, which causes a problem of inferior process uniformity. In particular, since the conventional plasma processing apparatus has a structure in which the process gas is supplied through the single supply terminal of the showerhead and then sprayed almost uniformly through the injection holes, the process gas is supplied to the biased region of the plasma density. It was impossible to adjust.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object thereof is to provide a plasma processing apparatus capable of locally adjusting a supply amount of a process gas according to a variation in plasma density. Another object of the present invention is to provide a plasma processing apparatus capable of improving etching uniformity.

According to a feature of the present invention for achieving the above object, a plasma processing apparatus includes a process chamber for performing a process for a substrate in a state in which the substrate is isolated from the outside; A susceptor installed inside the process chamber and on which a substrate is seated; A gas distribution plate positioned inside the process chamber so as to face the susceptor and injecting a process gas to the substrate; And a gas supply unit supplying a process gas to the gas distribution plate. The gas distribution plate has at least two divided spaces into which the process gas is introduced, and the gas supply unit includes flow rate control valves that can be controlled to adjust a supply amount of the process gas supplied to the divided space, and the flow rate control valves. It includes a flow control fisherman to control.

According to an embodiment of the present invention, the flow control part controls the flow control valves to adjust the process gas supply amount to the divided spaces according to the measurement result of the plasma density inside the process chamber and the process uniformity of the substrate.

According to an embodiment of the present invention, the flow control part controls the flow control valve corresponding to the region so that the process gas supply amount is increased in the region where the plasma density is low or the process uniformity of the substrate is low.

For example, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description.

An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. In addition, in the drawings, the same reference numerals are denoted together for components that perform the same function.

The basic intention of the present invention is to improve plasma density and process uniformity, and in order to achieve this, the inventors divide the inside of the showerhead into several zones, and adjust the supply amount of the process gas supplied to each zone, To improve density and process uniformity.

(Example)

1 is a perspective view showing a plasma processing apparatus according to a preferred embodiment of the present invention, Figure 2 is a front sectional view of the plasma processing apparatus according to a preferred embodiment of the present invention. 3 is a cross-sectional view taken along the line a-a shown in FIG. 2.

The plasma processing apparatus 100 includes a process chamber 110 in which a plasma formation space is provided.

The process chamber is composed of an upper processing chamber 112 and a lower processing chamber 114. The upper processing chamber 112 has a reaction tube 116 made of a dielectric window so that RF power can be transmitted therethrough. The reaction tube 116 is made of a dielectric such as quartz glass and has a cylindrical shape.

The lower processing chamber 114 is formed wider than the upper processing chamber 112, and has an annular cover 115 at an upper portion thereof, and the upper processing chamber 112 is installed at the annular cover. An electrostatic chuck 118 (also referred to as a susceptor) supporting the substrate W is provided below the lower processing chamber 114. An RF power source (not shown) is connected to the electrostatic chuck 118 to bias the ions and radicals from the plasma generated in the process chamber 110 to collide with the surface of the wafer W with sufficiently high energy. To provide a voltage. A vacuum suction port 119 connected to a vacuum pump (not shown) is formed at the bottom of the process chamber 110, through which molecules in the plasma, etching products, and the like are exhausted.

The high frequency antenna 130 is installed outside the reaction tube 116 of the upper processing chamber 112. The high frequency antenna 130 plays a role of generating plasma by RF power. An RF power source (not shown) is connected to the high frequency antenna to allow RF current to flow. A magnetic field is generated by the RF current flowing through the high frequency antenna 130, and an electric field is induced inside the process chamber 110 by the change of the magnetic field over time. The induced electric field ionizes the process gas introduced into the process chamber 110 to generate a plasma in the process chamber. The generated plasma impinges on the wafer W to be processed, eg etched, as desired.

On the other hand, the process chamber 110 may be provided with a microwave interferometer 140 which is a density measuring device for measuring the plasma density. The microwave interferometer 140 is provided with a window facing each other with a plasma interposed on the wall of the process chamber 110, and incident a microwave (for example, monochromatic laser light) to the plasma from the light emitting unit 142 installed outside one window. At the same time, it is a device that detects the microwaves passing through the plasma and emitted from the light receiving unit 144 provided outside the other window, and calculates the electron density according to the phase difference between the incident and the emitted microwaves.

In the present embodiment, a microwave interferometer method is used as a device for measuring the density of plasma. In addition to this device, various measuring devices such as Langmuir probes and electron beam irradiation plasma vibration probes may be used. . The probe is installed in a state in which the metal probe is vertically exposed in the plasma, and the electron density is determined in accordance with the current flowing through the metal probe when the DC probe voltage or the DC bias voltage in which the metal probe is superimposed is applied. It is a device to obtain. The electron beam irradiation plasma vibration method is a device in which thermal filaments are placed in a process chamber and electron density is calculated in accordance with the frequency of plasma vibration generated when irradiating an electron beam to the plasma from the thermal filaments. Although not shown in the drawings, the plasma processing apparatus 100 of the present invention may be provided with a known etching rate measuring apparatus for measuring the etching uniformity of the substrate.

Above the upper processing chamber 112, a gas distribution plate (GDP) 150, also known as a shower head 150, is installed. The gas distribution plate 150 is divided into a plurality of divided spaces 154 (in this embodiment, a central space and eight outer spaces surrounding the central space) by the partition walls 152. The gas distribution plate 150 has nine gas inlet ports 156 for receiving process gas into each partition space 154.

The gas supply unit 160 for supplying the process gas to the gas distribution plate 150 has branch lines 162 connected to each of the gas inlet ports 156, and the branch line 162 has a supply amount of process gas. Flow control valves 164 are provided to adjust the flow rate, and they are controlled by the flow control unit 166. The gas supply unit 160 adjusts the flow rate to compensate the etch rate or the plasma density based on the data detected from the etch rate measuring device (not shown) or the plasma density meter 140 measuring the etch rate for each region of the substrate. Each of the valves 164 is adjusted to control the process gas provided to the divided spaces 154 of the gas distribution plate 150.

 The process gas is provided to the respective spaces 154 through the respective branch lines 162, and the process gas is supplied into the process chamber through the injection holes 159 formed at the bottoms of the respective spaces.

For example, the gas distribution plate may be provided with an unactivated process gas, or may be provided with activated gas (radical and ionized gas) by a remote plasma source.

A process for improving the etching uniformity in the plasma processing apparatus of the present invention is as follows. First, the etching rate of the previously etched substrate is measured (or the plasma density inside the process chamber). The flow rate control unit controls the flow rate control valve of each branch line based on the substrate etch rate and the plasma density measured from the etch rate measuring device and the plasma density meter. For example, when the center portion of the substrate has a lower etch rate than the other portions, the corresponding flow control valve is adjusted so that the process gas supply to the central space of the gas distribution plate corresponding to the center portion of the substrate is increased. will be. As such, the plasma processing apparatus of the present invention may achieve the effect of improving the etching uniformity with respect to the substrate by performing this process every time or repeatedly every predetermined number of times.

In general, the plasma density is affected by the flow of the process gas. Where the amount of process gas is high, the density is high, whereas where the amount of process gas is low, the plasma density is relatively low. Therefore, in the present invention, the plasma density and the process uniformity were measured to compensate for this by increasing the supply amount of the process gas where the density is low and the etching rate is small. Therefore, an increase in the process gas supply amount in the non-uniform area increases the plasma density and the etching occurs actively, leading to the improvement of the etching rate.

The foregoing detailed description illustrates the present invention. In addition, the foregoing description merely shows and describes preferred embodiments of the present invention, and the present invention can be used in various other combinations, modifications, and environments. And, it is possible to change or modify within the scope of the concept of the invention disclosed in this specification, the scope equivalent to the written description, and / or the skill or knowledge in the art. The above-described embodiments are for explaining the best state in carrying out the present invention, the use of other inventions such as the present invention in other state known in the art, and the specific fields of application and uses of the present invention. Various changes are also possible. Accordingly, the detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to include other embodiments.

As described above, the plasma processing apparatus of the present invention can locally adjust the supply amount of the process gas according to the non-uniformity of the plasma density, thereby having a special effect of improving the etching uniformity.

Claims (3)

In the plasma processing apparatus: A process chamber for performing a process on the substrate with the substrate isolated from the outside; A susceptor installed inside the process chamber and on which a substrate is seated; A gas distribution plate positioned inside the process chamber so as to face the susceptor and injecting a process gas to the substrate; And A gas supply unit supplying a process gas to the gas distribution plate; The gas distribution plate has at least two divided spaces into which the process gas is introduced, The gas supply unit includes a flow regulating valve that can be controlled to adjust the supply amount of the process gas supplied to the divided space, and a flow control unit for controlling the flow regulating valves. The method of claim 1, The flow control unit And controlling the flow rate regulating valves to adjust the process gas supply amount to the divided spaces according to the measurement result of the plasma density inside the process chamber and the process uniformity of the substrate. The method according to claim 1 or 2, The flow control unit And controlling the flow rate control valve corresponding to the region so that a process gas supply amount is increased in a region having a low plasma density or a process uniformity of the substrate.

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