JP2005057182A - Plasma processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To so suppress the generation of the dust of particles as to be able to perform a stable process by considering the maintaining of a process characteristic and considering the maintainability about the ceiling board portion of a plasma processor, in order to suppress reaction products generated in etching and suppress the generation of the particles caused by ion bombardment to the constituent components in the processing chamber of the plasma processor. <P>SOLUTION: Conventional structures of the ceiling portion of a plasma processing chamber are so reconsidered with respect to the places and portions in the processing chamber whereto reaction products are stuck especially easily and a plasma is concentrated easily as to provide a ceiling-board outer-periphery ring made of a resin-based raw material in the outer-periphery portion of the ceiling board. By using the component made of the resin-based raw material in the outer-periphery portion of this ceiling board, there is provided the structure having a characteristic that reaction products generated in etching are stuck thereto hardly, an excellent corrosion resistance to the plasma, and a relaxant quality of ion bombardment. Also, in order to relax the ion bombardment to the portion of ions concentrating especially easily, there is so altered the shape of the outer-periphery portion structure of the ceiling board as to consider the incident angles of ions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for etching a semiconductor substrate or an insulator formed on the semiconductor substrate, a metal thin film, or the like by gas plasma, and in particular, in the plasma processing, suppressing an etching reaction product generated during the etching process. And a plasma processing apparatus that suppresses generation of particles due to ion collision.

  Conventionally, as disclosed in Patent Document 1, plasma processing has been frequently used for processing semiconductor substrates. In the plasma treatment, a reactive gas is excited using a high frequency, a magnetic field or the like to etch an object to be processed, or a film generated by a gas phase reaction is deposited on a substrate.

  FIG. 3 is a cross-sectional view of a dry etching apparatus shown as an example of a conventional plasma processing apparatus. In the figure, 1 is a processing chamber for performing dry etching, 2 is an exhaust port for evacuating the processing chamber 1, 3 is a gas introducing port for introducing a dry etching gas into the processing chamber 1, and 4 is entered from a gas introducing port 3. A gas blowout port for jetting the processed gas into the processing chamber 1, 5 is a high frequency coil, 6 is a top plate made of a dielectric material such as quartz or alumina ceramics, 7 is a substrate peripheral ring, and 8 is applied with a high frequency. A lower electrode, 9 is a substrate to be etched, 10 and 11 are blocking capacitors, 12 is a high-frequency power source 1, 13 is a high-frequency power source 2, and 14 is a reaction product generated and adhered during etching.

  The operation of the dry etching apparatus configured as described above will be described below.

  The substrate 9 is transported and installed on the lower electrode 8 by a transporter (not shown). Next, the inside of the processing chamber 1 is evacuated from the exhaust port 2 until a predetermined degree of vacuum is reached, a reactive gas necessary for etching is introduced from the gas inlet 3, and the reactive gas is discharged from the gas outlet 4. Erupts.

  The gas is uniformly introduced into the processing chamber from a large number of openings provided at the lower or upper portion of the processing chamber. The apertures are usually arranged uniformly or arranged so that the reactive gas densities are equal, and the gas is uniformly blown over the entire surface of the substrate. After the gas flow rate and pressure are stabilized, a voltage is applied to the lower electrode 8 from the high-frequency power source 12 via the blocking capacitor 10 to generate gas plasma. In order to create a high-density plasma region, a high-frequency coil 5 for sending electromagnetic waves is provided on the top plate 6 made of a dielectric material such as quartz or alumina ceramics. A high-frequency coil 5 is connected to the high-frequency coil 5 via a blocking capacitor 11. A voltage is applied from the power source 13 and the substrate 9 placed on the lower electrode 8 is etched using the generated gas plasma.

  In a processing chamber configuration of a dry etching apparatus using a high-density plasma as in the past, reaction product adhesion due to etching, or separation of deposits due to ion collision, and the side wall of the processing chamber and the top of the dielectric Due to deterioration and consumption, the generation of particles from the outer peripheral portion of the top plate such as quartz is particularly caused. In particular, in the plasma processing apparatus, the outer peripheral portion of the top plate 6 and the processing chamber side wall junction may be exposed to plasma, which may cause generation of particles.

A conventional top plate 6 made of quartz, alumina ceramics or the like is used as an electromagnetic wave derivative of the high-frequency coil 5 installed in the upper part of the processing chamber, and has been improved in shape, size, etc. so as to satisfy process characteristics. In some cases, surface blasting or the like is applied to improve the adhesion of reaction products generated during etching as a measure against particles. However, as the miniaturization process progresses, countermeasures against particles have become necessary, so the maintenance cycle is shortened.
JP 11-297675 A

  The present invention was made in order to eliminate structural defects in the top plate portion formed of a dielectric material such as quartz in the conventional plasma processing and the processing chamber side wall upper portion in contact with the top plate, and maintenance around the top plate portion. Therefore, the present invention provides a method for suppressing particle generation while always realizing a stable process in consideration of the property and cost.

  In order to solve the above problems, in the present invention, at least the surface of the outer peripheral portion of the top plate is formed of a high-functional resin material such as polyimide resin different from the top plate, and the outer peripheral portion of the top plate and the side wall of the processing chamber A structure in which the joint is formed without a gap is used.

  The present invention relates to the structure and parts of the top plate part that reduces the amount of reaction products deposited in the processing chamber constituent parts, further mitigates ion collision due to plasma concentration, and suppresses particle generation from the processing chamber constituent parts. A forming method is provided. As a result, particles due to the processing chamber are reduced, leading to an improvement in yield, and further, cost reduction of parts and improvement in apparatus maintenance can be achieved.

  The dry etching apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a sectional view of a dry etching apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a processing chamber for performing dry etching, 2 is an exhaust port for evacuating the processing chamber 1, 3 is a gas introduction port for introducing a dry etching gas into the processing chamber 1, and 4 is from a gas introduction port 3. Gas blow-out port for jetting the process gas into the processing chamber 1, 5 is a high-frequency coil, 6 is a top plate, 7 is a substrate peripheral ring, 8 is a lower electrode to which a high frequency is applied, and 9 is a substrate to be etched. 10 and 11 are blocking capacitors, 12 is a high frequency power source 1, 13 is a high frequency power source 2, and 15 is a top plate outer ring for fixing the top plate.

  The operation of the dry etching apparatus configured as described above will be described below with reference to FIG. As shown in FIG. 1, the substrate 9 is placed on the lower electrode 8 by a transporter (not shown), and the inside of the processing chamber 1 is evacuated from the exhaust port 2 until a predetermined degree of vacuum is reached. When the processing chamber reaches a predetermined degree of vacuum, an etching gas is introduced from the gas inlet 3 and ejected from the plurality of gas outlets 4 into the processing chamber. After the gas flow rate and pressure are stabilized, a voltage is applied to the lower electrode 8 from the high frequency power source 12 via the blocking capacitor 10 to generate gas plasma.

In order to create a high-density plasma region, a top plate 6 made of a dielectric material such as quartz or alumina ceramics and a high frequency coil 5 for sending electromagnetic waves are provided above the top plate outer ring 15. A voltage is applied from a high-frequency power source 13 via 11. Using this gas plasma, the substrate 9 placed on the lower electrode 8 is etched. As a result, a reaction product 14 is generated in the processing chamber 1. In this embodiment, a case where Si etching is performed at a pressure of 1 Pa using a process gas of Cl ₂ + O ₂ in a plasma apparatus using inductively coupled plasma will be described.

  The inventor first analyzed the interior of the processing chamber after etching 1000 substrates in a conventional processing apparatus. As a result, a large amount of reaction products adhered to the outer peripheral portion of the top plate was observed. As a result of analyzing the reaction product, the same material components as those of the processing chamber side wall and the top plate 6 were detected together with the components of the reaction product. In addition, the particle adhering to the substrate was analyzed and the dust source was pursued. As a result, deposits of the same components as the particles found on the substrate were found at specific locations in the reaction product generated during etching and the processing chamber side wall and the quartz top plate forming material. From these situations, it has been found that particles are scattered in the processing chamber by receiving a concentrated ion bombardment at a specific location due to ion bombardment generated during the plasma treatment simultaneously with the generation and adhesion of the reaction product by etching.

  Therefore, in the present invention, plasma is concentrated to alleviate ion bombardment for the purpose of reducing the deposition amount of the reaction product and suppressing the separation of the deposit due to the concentration of the plasma at a specific portion during the etching process. It is equipped with parts made of an independent resin material for the outer periphery of the top plate, and considering the incident angle of ions, it eliminates the sharp connection between the processing chamber side wall and the top plate, thereby concentrating the plasma. Changed to a processing chamber structure that suppresses generation of particles. In particular, in order to suppress the generation of particles in the outer peripheral portion of the top plate where the reaction product 14 is often adhered, a top plate outer peripheral ring 15 formed of a resin material is installed on the outer peripheral portion in addition to the conventional integrated top plate. .

  In this case, the top plate outer ring 15 suppresses the generation of particles from the outer peripheral portion by reducing ion bombardment caused by the plasma processing with respect to the ground contact portion with the processing chamber side wall as an integrated structure up to the upper portion of the processing chamber side wall. it can. Since the outer periphery of the top plate and the upper part of the side wall of the processing chamber are presumed to be the places where the ion bombardment is most intense, it is possible to efficiently suppress particles by forming both of them as a single body from a material resistant to plasma. Compared to the case where the processing chamber side wall and the top plate are connected as in the conventional apparatus, the structure is made resistant to ion bombardment by changing the joint to a place where the plasma concentration is relatively low.

  In addition, as shown in FIG. 2, the top plate outer ring 15 has an R shape or a taper shape with no sharp corners for the purpose of reducing the ion bombardment in consideration of the incident angle of ions during plasma processing. By making the structure strong against concentrated plasma, it is more effective in generating particles. By changing the structure and materials in the processing chamber, the adhesion of reaction products to the conventional processing equipment is suppressed, and the reaction products and the inside of the processing chamber have a structure and material that resists ion bombardment. It has been confirmed that the particles are reduced. By changing only the most severely worn outer peripheral part to a resin-based material, the cost of parts can be reduced, and at the same time, maintainability can be improved.

  The present invention provides a processing chamber configuration capable of suppressing particles efficiently and at low cost only for a portion estimated to be the most dust generation source of particles during plasma processing in a dry etching apparatus processing chamber. Note that, as with the etching apparatus according to this embodiment, as a particle reduction measure in the processing chamber, various plasma processing apparatuses that perform film formation or etching using high-density plasma can be used.

  The plasma processing apparatus of the present invention is useful for improving the yield by reducing particles due to the processing chamber, and further useful for reducing the cost of parts and improving the maintainability of the apparatus.

Sectional drawing which shows the dry etching apparatus in one embodiment of this invention Sectional view showing the configuration after changing the part shape Sectional view showing a conventional dry etching apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Exhaust port 3 Gas inlet 4 Gas outlet 5 High frequency coil 6 Top plate 7 Substrate ring 8 Lower electrode 9 Substrate 10, 11 Blocking capacitor 12, 13 High frequency power supply 14 Reaction product 15 Top plate outer ring

Claims (3)

In a plasma processing apparatus, comprising: a high frequency generating means provided in an upper portion of a processing chamber; a top plate portion made of a dielectric made of quartz or alumina ceramic; and means for generating plasma in the processing chamber separately from the high frequency generating means. The plasma processing apparatus, wherein the outer peripheral portion of the top plate and the processing chamber side wall junction are formed without a gap. 2. The plasma processing according to claim 1, wherein an outer peripheral portion of the top plate and a processing chamber side wall upper portion connected to the top plate have an integral structure formed of a material different from that of the top plate and the processing chamber side wall. apparatus. 3. The plasma processing apparatus according to claim 1, wherein the different material is a polyimide resin material formed by introducing imide, amide, ether bond or the like.

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