JP2007162108A - Vacuum treatment equipment and trap device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the improvement of maintenance characteristics of a trap device used for an exhaust line of a vacuum treatment equipment and the stabilization of a catching performance thereof. <P>SOLUTION: An exhaust gas G introduced into the trap 36 from an exhaust gas introducing section 44 advances diagonally downward along an inner wall surface 42a of a main part 42; thereby the exhaust gas spirally falls down while gradually narrowing the radius of rotation within the main part 42a. Then, the depositional substance included in the exhaust gas G is solidified by the chill from below and is changed from a vapor phase to a solid phase, and the depositional substance in the exhaust gas G and other substances spirally fall down while being separated to the solid and to the gas. In the vicinity of the bottom of the main part 42, the gas is sucked into a trap exhaust gas pipe 48 and the solid drops into a sedidment reservoir part 46. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum processing apparatus that performs vacuum processing on a target object using a predetermined processing gas in a vacuum processing chamber, and more specifically, a depositing substance contained in exhaust gas discharged from the vacuum processing chamber. The present invention relates to a trap device that collects gas in the middle of an exhaust line and a vacuum processing apparatus including the same.

  In the manufacture of semiconductor devices and FPDs (flat panel displays), various processes such as film formation, heat treatment, dry etching, and cleaning are performed using a required processing gas in a vacuum chamber or vacuum processing chamber. Done. At that time, the gas generated in the vacuum processing chamber is drawn by the vacuum pump and discharged to the exhaust line. For example, in dry etching, a material to be processed on the surface of an object to be processed is evaporated and removed by a chemical reaction with a processing gas. At that time, the evaporated substance, that is, the reaction product in the gas phase is sent as exhaust gas to the exhaust line. In CVD (Chemical Vapor Deposition), a solid thin film substance is produced as a reaction product by a gas phase of a processing gas or a raw material gas or a thermal decomposition or a chemical reaction on the surface of an object to be processed. Gas phase reaction by-products are also produced. This reaction by-product is sent to the exhaust line as exhaust gas. In addition, part of the processing gas introduced into the vacuum processing chamber may be sent to the exhaust line without being reacted. In this way, a certain reaction product, reaction by-product, unreacted gas, or the like corresponding to the type of process is sent to the exhaust line as exhaust gas from the vacuum processing chamber in which the vacuum process is performed.

  In the exhaust system, if the exhaust gas as described above is solidified in the middle of flowing through the exhaust line and accumulates on the inner wall of a pipe or a vacuum pump, the exhaust capacity may be reduced or the vacuum pump may be damaged. Therefore, if the exhaust gas contains sedimentary substances, it is common to provide a trap device in the middle of the exhaust line that actively solidifies and deposits such substances to prevent inflow to the downstream side. (For example, refer to Patent Document 1).

Conventional trap devices include those that solidify and deposit exhaust gas on the surfaces of fins and labyrinths cooled to a constant temperature, and those that pass exhaust gas through a metal mesh filter to cause it to solidify and accumulate.
JP-A-9-27458

  However, the conventional trap apparatus has a difficulty in maintainability. The fin type or labyrinth type has a complicated flow path, and it takes a lot of work to clean and remove deposits adhering to it, and the mesh type also removes deposits from the metal mesh. It's not easy. Further, the mesh type has a drawback that it is likely to cause clogging and to reduce the exhaust capacity of the exhaust line.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a trap device that realizes improvement in maintainability and stabilization of collection performance.

  It is another object of the present invention to provide a vacuum processing apparatus that can improve exhaust performance and maintainability of an exhaust line.

  In order to achieve the above object, the trap apparatus of the present invention evacuates a vacuum processing chamber in which a predetermined vacuum processing is performed on a target object using a predetermined processing gas under reduced pressure and the vacuum processing chamber. A trap device for collecting a depositing substance contained in an exhaust gas discharged from the vacuum processing chamber, which is provided in an exhaust passage between a vacuum pump and an inner wall surface having an inverted conical shape or a cylindrical shape An airtight main body, an exhaust gas introduction part provided at the upper part of the main body for introducing exhaust gas from the vacuum processing chamber into the main body, and from a gas phase to a solid phase while descending the main body A deposit reservoir provided at the bottom of the main body to store the changed depositing substance, and a trap exhaust pipe having an inlet disposed near the bottom of the main body and an outlet connected to the vacuum pump. Have.

  In the above configuration, the exhaust gas introduced from the upper part of the main body from the exhaust gas introduction part is cooled while descending the space in the main body, and the sedimentary substance contained in the exhaust gas is solidified to solidify from the gas phase to the solid phase. Instead, the sedimentary substance changed to the solid phase in the exhaust gas and the other substance are separated into solid and gas. In the vicinity of the bottom of the main body, the gas is sucked into the trap exhaust pipe, and the solid is collected in the deposit reservoir.

  According to a preferred aspect of the present invention, the exhaust gas introduction unit is configured to introduce the exhaust gas from the vacuum processing chamber obliquely downward along the inner wall surface of the main body. According to such a configuration, the exhaust gas introduced into the main body can be smoothly lowered spirally along the inner wall surface of the main body, and the flow (exhaust conductance) of the exhaust gas in the trap can be increased. As a more preferable aspect, a guide groove formed in a spiral shape is provided on the inner wall surface of the main body to guide the exhaust gas from the vacuum processing chamber. By such a guide groove portion, the flow of exhaust gas can be rectified in a spiral shape to reduce the generation of turbulent flow and further increase the exhaust conductance.

  According to another preferred aspect, the deposit reservoir has a cooling means for promoting the change of the depositing substance from the gas phase to the solid phase and maintaining the solid state of the depositing substance. Provided. By this cooling means, the exhaust gas coming down the space in the main body can be cooled efficiently from the bottom to the top, promoting the solidification of the sedimentary substance, and keeping the solid state of the sedimentary substance stable Can do. Further, in the configuration in which the main body is made of a heat conductive material and is cooled by the cooling means of the deposit reservoir by heat conduction, the exhaust gas can be cooled from the bottom to the top also from the inner wall surface of the main body. It is possible to further promote the coagulation or collection of the material.

  Moreover, according to another suitable one aspect | mode, an opening is formed in the lower end of a main body, and it attaches to a main body so that a deposit reservoir part can block | close the opening airtightly. In this configuration, the depositing substance accumulated in the trap device can be recovered and removed by removing the deposit reservoir from the main body.

  A vacuum processing apparatus of the present invention includes a vacuum processing chamber in which a predetermined vacuum processing is performed on a target object using a predetermined processing gas under reduced pressure, and a first vacuum pump for evacuating the vacuum processing chamber And a trap device provided in an exhaust passage between the vacuum processing chamber and the first vacuum pump for collecting sedimentary substances contained in the exhaust gas discharged from the vacuum processing chamber. The trap device has an airtight main body having an inverted conical or cylindrical inner wall surface, and an exhaust gas inlet provided at an upper portion of the main body for introducing the exhaust gas from the vacuum processing chamber into the main body. A deposit reservoir provided at the bottom of the main body and an inlet are disposed near the bottom of the main body to store the depositing substance changed from a gas phase to a solid phase while descending the main body. The outlet was connected to the vacuum pump And a trachea.

  In the above configuration, by providing the trap device of the present invention in the middle of the exhaust line, the sedimentary substance contained in the exhaust gas discharged from the vacuum processing chamber can be efficiently collected with stable performance by the trap device. Therefore, it is possible to prevent a reduction in the exhaust capacity of the exhaust line and a failure of the vacuum pump.

  According to a preferred aspect of the present invention, the second vacuum pump is provided in the exhaust path between the trap device and the first vacuum pump. In this case, since the depositing substance is collected by the trap device, it is not necessary to provide a heating means for preventing deposition in the second vacuum pump. However, a configuration in which a second vacuum pump is provided in the exhaust path between the vacuum processing chamber and the trap device is also possible.

  Further, as a preferred embodiment, in order to keep the depositing substance in a gas phase in the exhaust path from the exhaust port of the vacuum processing chamber to the exhaust gas inlet of the trap device container, A heating means for heating to a predetermined temperature is provided.

  According to the trap device of the present invention, improvement in maintainability and stabilization of collection performance can be realized by the configuration and operation as described above. According to the vacuum processing apparatus of the present invention, the exhaust performance and maintenance performance of the exhaust line can be improved by the configuration and operation as described above.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a configuration of a vacuum processing apparatus according to an embodiment of the present invention. This vacuum processing apparatus is configured as a low pressure CVD apparatus, and has a vacuum processing chamber or vacuum chamber 10 having an airtight structure.

  In the central portion of the vacuum processing chamber 10, a mounting table 12 for placing and supporting an object to be processed, such as a semiconductor wafer W, is disposed. A perforated plate or shower head 14 having a large number of gas outlets is provided on the upper portion of the processing chamber 10 so as to face the mounting table 12, and a buffer chamber 16 is formed on the shower head 14. A plurality of source gases are supplied as processing gases from a source gas supply source (not shown) to the buffer chamber 16 through the supply pipe 18 and mixed here, and then mixed from the shower head 14 to the semiconductor wafer W on the mounting table 12. It is designed to be discharged toward the camera. Inside the mounting table 12, a heater 20 made of, for example, a resistance heating element is provided to give the excitation energy of the CVD reaction as heat.

  The source gas supplied from the shower head 14 to the surface (surface to be processed) of the semiconductor wafer W undergoes thermal decomposition or chemical reaction in the vapor phase or on the wafer surface, and forms a thin film as a solid reaction product. At that time, a gas phase reaction by-product is also generated. An exhaust port 22 is formed at the bottom of the vacuum processing chamber 10, and an exhaust line 24, which will be described later, is connected to the exhaust port 22 for exhausting the interior of the vacuum processing chamber 10 to a vacuum. Reaction byproducts and unreacted source gas generated in the CVD process performed in the vacuum processing chamber 10 are discharged from the exhaust port 22 to the exhaust line 24. A gate valve 26 for opening and closing the wafer loading / unloading port 26 is attached to the side wall of the vacuum processing chamber 10.

  The exhaust line 24 has two stages of vacuum pumps for roughing and low-pressure vacuuming, such as a dry pump 30 and a turbo molecular pump (TMP) 32, and an exhaust port 22 of the vacuum processing chamber 10. The main exhaust pipe 34 and the branch exhaust pipe 36 for connection to 30 and 32, and the trap 36 of this embodiment provided in the middle of the main exhaust pipe 34 are provided. Here, a tape heater 40 is wound around a section from the start end of the main exhaust pipe 34 (the exhaust port 22 of the vacuum processing chamber 10) to the trap 38. The tape heater 40 is for preventing the exhaust gas from solidifying in the pipe upstream of the trap 38, and the exhaust gas is discharged at a temperature higher than the sublimation temperature of a predetermined depositing substance contained in the exhaust gas. Heat. The wall surface of the vacuum processing chamber 10 is also heated to a predetermined temperature by an appropriate heating means (not shown) in order to prevent the exhaust gas from solidifying and accumulating.

  The branch exhaust pipe 36 branches from the vicinity of the starting end of the main exhaust pipe 34, bypasses the trap 38 and the turbo molecular pump 32, and joins the main exhaust pipe 34 before the dry pump 30. The branch exhaust pipe 36 is used with the on-off valve 41 turned on (open) only when the vacuum processing chamber 10 is exhausted from atmospheric pressure to about 0.1 to 1 Pa, for example, and executes the CVD process. When not used. Since the exhaust gas containing the depositing substance generated in the CVD process does not flow through the branch exhaust pipe 36, it is not necessary to apply the tape heater 40 to the branch exhaust pipe 36.

  The trap 38 is provided between the open / close valve of the main exhaust pipe 34 or an APC (Adaptive Pressure Controller) 45 and the turbo molecular pump 32 at a location relatively close to the exhaust port 22 of the vacuum processing chamber 10. The APC 45 is switched to an off (closed) state only when roughing is performed by the branch exhaust pipe 36, and is maintained in an on (open) state at the normal time. As will be described later, the trap 38 introduces exhaust gas from the vacuum processing chamber 10, deposits and deposits substances (reaction by-products and unreacted gas) contained in the introduced exhaust gas, and solidifies and deposits the remaining substances in the trap. Send gas downstream. For this reason, there is little possibility of depositing substances adhering to the exhaust passages of the main exhaust pipe 34, the turbo molecular pump 32, and the dry pump 30 on the downstream side of the trap 38, and heating means such as the tape heater 40 is not necessary. .

  2 and 3 are a top view and a longitudinal sectional view of the trap 38. FIG. Hereinafter, the configuration and operation of the trap 38 will be described in detail with reference to these drawings.

  The trap 38 includes a hollow airtight housing or main body 42 having an inner wall surface 42 a formed in a funnel shape, that is, an inverted conical shape, an exhaust gas introduction portion 44 provided on the upper portion of the main body 42, and a lower end portion of the main body 42. And a trap exhaust pipe 48 inserted vertically into the main body 42 from above.

  The main body 42 is made of, for example, stainless steel (SUS), and has an upper surface closed and a lower surface opened. The exhaust gas introduction part 44 is connected to the upstream main exhaust pipe 34 and is formed so as to introduce the exhaust gas G flowing through the main exhaust pipe 34 in an obliquely downward direction along the inner wall surface 42a of the main body 42. ing. A preferable material of the main body 42 is a heat conductive material, and more preferably a heat conductive material (metal, heat conductive polymer, heat conductive ceramic, carbon, etc.) having a thermal conductivity of 1.0 W / mk or more.

  The sediment reservoir 46 is configured as a bottomed cylindrical container having an open top surface, and is fitted to the lower end of the container 42 so as to airtightly close the lower end opening of the container 42 and is detachably attached with a bolt 50 or the like. Is done. For example, a water-cooled cooling jacket 52 is integrally coupled to the deposit reservoir 46. The cooling jacket 52 is made of a material having good thermal conductivity, such as aluminum or stainless steel (SUS), and has a passage 52a through which cooling water whose temperature is adjusted to a constant temperature flows. The material of the deposit reservoir 46 is also preferably a material having good thermal conductivity, such as aluminum or stainless steel (SUS), whereby the cool air of the cooling jacket 52 is conducted to the deposit reservoir 46 and further the deposit reservoir. It can also conduct to the inner wall of the main body 42 via 46. The trap exhaust pipe 48 is inserted from above along the central axis of the main body 42 so that the opening or inlet 48 a at the tip of the trap exhaust pipe 48 is located near the bottom of the main body 42. Outside the main body 42, the other end or outlet 48b of the trap exhaust pipe 48 is connected to the main exhaust pipe 34 leading to the turbo molecular pump 32 (FIG. 1).

  In the trap 38 having such a configuration, the exhaust gas G introduced from the exhaust gas introduction portion 44 descends in a spiral shape while gradually reducing the rotation radius in the main body 42 by proceeding obliquely downward along the inner wall surface 42a of the main body 42. . At this time, sedimentary substances (reaction by-products and unreacted gases) contained in the exhaust gas G are generated by cool air from below, that is, cool air from the cooling jacket 52 and further cool air from the inner wall surface of the main body 42. ) Is solidified to change from the gas phase to the solid phase, and the sedimentary substance and the other substances in the exhaust gas G are spirally lowered while being separated into solid and gas. In the vicinity of the bottom of the main body 42, the gas is sucked into the trap exhaust pipe 48, and the solid falls into the deposit reservoir 46. Since the deposit reservoir 46 is cooled by the cooling jacket 52, the solid or deposit S that has once entered the deposit reservoir 46 remains in a solid phase and does not change to the gas phase again.

  Thus, the accumulation amount of the deposit S increases in the deposit reservoir 46 in proportion to the accumulation time of the CVD process performed in the vacuum processing chamber 10. During this time, the passage through which the exhaust gas G flows or the exhaust passage in the main body 42 is not narrowed and clogging does not occur, and the sediment collection rate can be kept constant. Furthermore, the deposit S accumulated in the deposit reservoir 46 can be removed by once removing the deposit reservoir 46 from the main body 42, and maintenance is extremely simple. In addition, when deposits adhere to the inner wall surface of the main body 42, the upper surface of the main body 42 is configured to be a lid that can be airtightly closed, so that the deposits can be easily washed away from the inner wall surface of the main body 42. .

  As described above, in this embodiment, the sedimentary substance contained in the exhaust gas discharged from the vacuum processing chamber 10 in which the low pressure CVD is performed is collected by the trap 38 with an efficient and stable collection rate. 24, exhaust gas from which sedimentary substances have been removed can be sent to the main exhaust pipe 34, the turbo molecular pump 32, and the dry pump 30 located downstream of the trap 38, and heating means for preventing deposition is required. Stable exhaust capacity and pump function can be maintained.

  4 to 6 show other examples relating to the arrangement of the traps 38 in this embodiment. In the embodiment shown in FIG. 4, a plurality of, for example, two traps 38 are provided in parallel in the exhaust path of the exhaust line 24. Such a parallel system doubles the ability or rate of collecting sedimentary substances from the exhaust gas discharged from the vacuum processing chamber 10, and therefore is preferably applied to applications where a large amount of sedimentary substances are contained in the exhaust gas. be able to.

  In the embodiment shown in FIG. 5, a plurality of, for example, two traps 38 are provided in series in the exhaust passage of the exhaust line 24. In such a series system, even if the sedimentary substance contained in the exhaust gas from the vacuum processing chamber 10 cannot be completely collected by the first trap 38, the remaining trap is collected by the latter trap 38. It is advantageous to increase.

  In the embodiment of FIG. 6, a trap 38 is provided on the downstream side of the drag pump 32 in the exhaust line 24. In this case, it is desirable not only to apply the tape heater 40 to the main exhaust pipe 34 located on the upstream side of the trap 38, but also to include a heating means for preventing the deposition of depositing substances on the turbo molecular pump 32. The sedimentary substance contained in the exhaust gas from the vacuum processing chamber 10 passes through the main exhaust pipe 34 and the turbo molecular pump 32 in a gas phase and is introduced into the trap 38, and is trapped in the trap 38 as described above. Will be gathered.

  7 and 8 show another example relating to the structure of the trap 38 itself in this embodiment. In the embodiment shown in FIG. 7, a substantially funnel-shaped guide plate 56 having a spiral groove 54 for guiding or rectifying the exhaust gas G is provided in the main body 42. In this configuration, the exhaust gas G introduced from the exhaust gas introduction port 44 travels obliquely downward while being guided by the groove portion 54 of the guide plate 56, so that the laminar flow smoothly drops in a spiral manner without causing turbulent flow. Thereby, the exhaust conductance in the trap 38 can be further improved, and the sedimentary substance can be collected efficiently without lowering the exhaust capacity of the exhaust line 24.

  In the embodiment shown in FIG. 8, the main body 42 has a substantially cylindrical shape. The exhaust gas introduction portion 44 is preferably formed so as to introduce the exhaust gas G flowing through the main exhaust pipe 34 obliquely downward along the inner wall surface 42a of the main body 42, as in the above-described embodiment. Further, an umbrella-shaped baffle is provided around the lower end opening or the inlet 48a of the trap exhaust pipe 48 to reduce backflow or turbulence. Other configurations are the same as those in the above-described embodiment. In this cylindrical type as well, a substantially cylindrical guide plate 56 having a spiral guide groove can be provided.

  The preferred embodiments of the present invention have been described above, but the above-described embodiments do not limit the present invention. Those skilled in the art can make various modifications and changes in specific embodiments without departing from the technical idea and technical scope of the present invention. The vacuum processing apparatus and trap apparatus of the present invention are not limited to the above-described reduced pressure CVD, but can be applied to dry etching and other types of vacuum processing.

FIG. 9 shows an example of a dry etching apparatus to which the trap apparatus of the present invention is applied. This plasma etching apparatus is configured as a capacitively coupled plasma etching apparatus having a parallel plate type electrode structure, and has a cylindrical shape made of aluminum whose inner wall surface is covered with an alumina film or an yttrium oxide (Y ₂ O ₃ ) film. A vacuum chamber (processing vessel) 110 is provided. The vacuum chamber 110 is grounded for safety.

  A cylindrical susceptor support 114 is disposed at the bottom of the chamber 110 via an insulating plate 112 such as ceramic, and a susceptor 116 made of, for example, aluminum is provided on the susceptor support 114. The susceptor 116 constitutes a lower electrode having a parallel plate type electrode structure, on which, for example, a semiconductor wafer W is placed as a substrate to be processed.

  On the upper surface of the susceptor 116, an electrostatic chuck 118 for holding the semiconductor wafer W with an electrostatic attraction force is provided. This electrostatic chuck 118 is obtained by sandwiching an electrode 120 made of a conductive film between a pair of insulating layers or insulating sheets, and a DC power source 122 is electrically connected to the electrode 120. The semiconductor wafer W is attracted and held on the electrostatic chuck 118 by a Coulomb force by a DC voltage from a DC power source. A focus ring 124 made of, for example, silicon is arranged on the upper surface of the susceptor 116 around the electrostatic chuck 118 to improve etching uniformity. A cylindrical inner wall member 126 made of, for example, quartz is attached to the side surfaces of the susceptor 116 and the susceptor support base 114.

  Inside the susceptor support 114, for example, a refrigerant chamber 128 extending in the circumferential direction is provided. A refrigerant of a predetermined temperature, for example, cooling water, is circulated and supplied to the refrigerant chamber 128 via pipes 130a and 130b from an external chiller unit (not shown). The processing temperature of the semiconductor wafer W on the susceptor 116 can be controlled by the temperature of the coolant. Further, a heat transfer gas such as He gas from a heat transfer gas supply mechanism (not shown) is supplied between the upper surface of the electrostatic chuck 118 and the back surface of the semiconductor wafer W via the gas supply line 132.

  An upper electrode 134 is provided above the susceptor 116 so as to face the susceptor 116 in parallel. A space between both electrodes 116 and 134 constituting the parallel plate electrode structure is a plasma generation space PS. The upper electrode 134 is opposed to the semiconductor wafer W on the susceptor (lower electrode) 116 and forms a surface in contact with the plasma generation space PS, that is, an opposed surface.

  The upper electrode 134 has a ring-shaped or donut-shaped outer upper electrode 136 that is disposed to face the susceptor 116 at a desired interval, and is insulated from the outer upper electrode 136 in the radial direction. And a disc-shaped inner upper electrode 138. The outer upper electrode 136 and the inner upper electrode 138 have the former (136) as the main and the latter (138) as the auxiliary relationship for plasma generation.

  The inner upper electrode 138 includes a large number of gas ejection holes 160a made of a semiconductor material such as Si or SiC, and a conductive material that detachably supports the electrode plate 160, for example, aluminum whose surface is anodized. An electrode support 162 made of

  The inner upper electrode 138 is also a part of an upper gas introduction mechanism described later, and two upper buffer chambers, that is, an upper central buffer chamber 166 divided by an annular partition member 164 made of, for example, an O-ring inside the electrode support 162. And an upper peripheral buffer chamber 168 are provided. The upper central buffer chamber 166 and the numerous gas ejection holes 160a provided on the lower surface thereof constitute an upper central shower head 166a, and the upper peripheral buffer chamber 168 and the numerous gas ejection holes provided on the lower surface thereof. 160a constitutes an upper peripheral shower head 168a. The upper central shower head 166a and the upper peripheral shower head 168a can select or control the gas type, gas mixing ratio, gas flow rate, and the like independently of each other.

The electrode plate 160 of the upper electrode 134 is a replacement part that is consumed by exposure to plasma. Moreover, since reaction products adhere to the surfaces of the electrode plate 160 and the gas ejection holes 160a, maintenance work for removing them is also necessary. For this reason, the chamber 110 is configured to be vertically divided by X ₁ -X ₁ shown in FIG. 9, and an internal member can be taken out by opening and removing the upper assembly.

  A first high-frequency power source 154 is electrically connected to the electrode support 162 of the internal upper electrode 138 through a matching unit 146, an upper power feed rod 148, a connector 150, and a lower power feed tube 170. A variable capacitor 172 that can variably adjust the capacitance is provided in the middle of the lower power feed rod 170.

The variable capacitor 172 has an outer electric field strength directly below the outer upper electrode 136 (or input power to the outer upper electrode 136 side) and an inner electric field strength immediately below the inner upper electrode 138 (or input power to the inner upper electrode 138 side). It is for adjusting the ratio or balance. By changing the capacitance C ₁₇₂ of the variable capacitor 172, the impedance or reactance of the waveguide (inner waveguide) on the lower feeding cylinder 170 side is increased or decreased, and the voltage drop of the waveguide (outer waveguide) on the feeding cylinder 152 side is increased. The relative ratio with the voltage drop of the inner waveguide can be changed, and as a result, the ratio between the outer electric field strength (outer input power) and the inner electric field strength (inner input power) can be adjusted.

  Further, a refrigerant chamber or a refrigerant passage (not shown) is provided above the outer upper electrode 136 and the inner upper electrode 138, and the temperature of the upper electrode 134 is kept constant by flowing the refrigerant through the refrigerant passage by an external chiller unit. Can be controlled.

  An exhaust port 174 is provided at the bottom of the vacuum chamber 110, and a vacuum pump 178 is connected to the exhaust port 174 through an exhaust pipe 176. An on-off valve or APC 175 and the trap of this embodiment are disposed in the middle of the exhaust pipe 176. 38 is provided. The vacuum pump 178 includes, for example, a turbo molecular pump, and depressurizes the plasma processing space in the vacuum chamber 110 to a desired degree of vacuum. During the etching process, the chemistry between the etching gas and the material to be etched on the surface of the wafer W is obtained. The gas phase reaction product generated by the reaction functions to be discharged from the chamber 110 to the exhaust pipe 176 through the exhaust port 174.

  In this plasma etching apparatus, a second high-frequency power source 182 is electrically connected via a matching unit 180 to a susceptor 116 that is a lower electrode of a parallel plate electrode structure. The second high frequency power source 182 outputs a high frequency voltage of 2 MHz to 20 MHz, for example, 2 MHz. Here, the second high-frequency power source 182 has a role of drawing ions from the high-density plasma to the semiconductor wafer W side.

  The inner upper electrode 138 is electrically provided with a low pass filter (LPF) 184 for passing the high frequency (2 MHz) from the second high frequency power supply 182 to the ground without passing the high frequency (60 MHz) from the first high frequency power supply 154. It is connected to the. The low-pass filter (LPF) 184 may be preferably formed of an LR filter or an LC filter, but a sufficiently large reactance with respect to the high frequency (60 MHz) from the first high-frequency power source 154 even with only one conductor. You can give it, so you can do it. On the other hand, the susceptor 116 is electrically connected to a high pass filter (HPF) 186 for passing a high frequency (60 MHz) from the first high frequency power supply 154 to the ground.

  In this plasma etching apparatus, a gas introduction mechanism for introducing a processing gas (etching gas) into the chamber 110 serves as a gas introduction unit for introducing an etching gas into the plasma generation space PS in the vacuum chamber 110. As described above, the upper gas introduction part (upper center shower head 166a and upper peripheral shower head 168a) for introducing gas from the upper electrode 138 side is provided, and the side gas introduction part 204 for introducing gas from the side wall side of the vacuum chamber 110 is provided. It has. As shown, the side gas inlet 204 has a side shower head 208 that is attached to the sidewall of the vacuum chamber 110.

  The processing gas supply source 188 sends an etchant gas to the gas supply pipe 190 at a desired flow rate and sends a dilution gas to the gas supply pipe 194 at a desired flow rate. The gas supply pipe 190 communicates with the upper peripheral shower head 168a, and an on-off valve 192 is provided on the way. Further, the processing gas supply source 188 sends a dilution gas to the gas supply pipes 194a and 194b at a desired flow rate. One gas supply branch 194 a leads to the upper central shower head 166 a and the other gas supply branch 194 b leads to the side shower head 208. An MFC (mass flow controller; flow control device) 196 and an on-off valve 198 are provided in the middle of the gas supply pipe 194a. An MFC 200 and an opening / closing valve 202 are also provided in the middle of the gas supply pipe 194b.

  According to the gas introduction mechanism having such a configuration, the upper central shower head 166a and the side shower head are simultaneously discharged (introduced) from the upper peripheral shower head 168a toward the plasma generation space PS in the chamber 110. A diluted gas is discharged (introduced) from 208, and an etchant gas and a diluted gas are mixed in the plasma generation space PS to generate a mixed gas plasma.

  The gas control unit 206 can arbitrarily control the flow rate and flow rate ratio of the dilution gas in the upper central shower head 166a and the side shower head 208 through the control of the MFC 196, 200. The gas control unit 206 also controls a flow rate adjusting unit in the processing gas supply source 188.

  In order to perform etching in this plasma etching apparatus, first, a gate valve (not shown) is opened, and a semiconductor wafer W to be processed is loaded into the vacuum chamber 110 from a loading / unloading port (not shown) on the side wall of the chamber. Place on susceptor 116. Next, a DC voltage is applied from the DC power source 122 to the electrode 120 of the electrostatic chuck 118 to fix the semiconductor wafer W to the susceptor 116.

Gases for etching are respectively supplied from the three showerheads 166a, 168a, 208 to the plasma generation space PS between the upper electrode 134 (136, 138) and the susceptor (lower electrode) 116 by the gas introduction mechanism as described above. Introduce at a predetermined flow rate. That is, the upper central shower head 166a is supplied with a dilution gas containing an additive gas, the upper peripheral shower head 168a is supplied with an etchant gas, and the side shower head 208 is supplied with a dilution gas containing an additive gas. Introduced at a flow rate of. Three systems of gas introduced into the plasma generation space PS are mixed with each other to become a mixed gas. On the other hand, the total pressure in the vacuum chamber 110 is reduced to a set value (for example, 10 ⁻¹ Pa to 10 ² Pa) by the vacuum pump 178 and the APC 175 of the exhaust mechanism. Furthermore, a high frequency (60 MHz) for plasma generation is applied to the upper electrode 134 (136, 138) with a predetermined power from the first high frequency power supply 154, and a high frequency (2 MHz) is applied with a predetermined power from the second high frequency power supply 182. And applied to the susceptor 116.

  By supplying various powers as described above, in the vacuum chamber 110, the etching gas is turned into plasma by glow discharge between the upper electrode 134 (136, 138) and the susceptor 116 (lower electrode), and radicals generated by this plasma and The surface to be processed of the semiconductor wafer W is etched by the ions.

  In this plasma etching apparatus, the trap 38 reduces the above-described depressurization of depositing substances (mainly reaction products) in the exhaust gas flowing from the vacuum chamber 110 through the exhaust pipe 176 when the above-described plasma etching is performed. Collection is performed by exactly the same action as in the case of the CVD apparatus.

It is a figure which shows the structure of the low pressure CVD apparatus which concerns on one Embodiment of this invention. It is a top view which shows the structure of the trap apparatus of embodiment used for the vacuum processing apparatus of FIG. It is a longitudinal cross-sectional view which shows the structure of the trap apparatus in embodiment. It is a figure which shows one Example regarding the arrangement configuration of the trap apparatus by embodiment. It is a figure which shows another Example regarding the arrangement configuration of the trap apparatus in embodiment. It is a figure which shows the other Example regarding the arrangement configuration of the trap apparatus in embodiment. It is a longitudinal cross-sectional view which shows one modification of the structure of the trap apparatus in embodiment. It is a longitudinal cross-sectional view which shows another modification of the structure of the trap apparatus in embodiment. It is a figure which shows the structure of the etching apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vacuum processing chamber 24 Exhaust line 30 Dry pump 32 Drag pump 34 Main exhaust path 38 Trap 40 Tape heater 42 Main body 42a Inner wall 44 Exhaust gas introduction part 46 Deposit storage part 48 Trap exhaust pipe 52 Cooling jacket 54 Spiral groove part 56 Guide plate 110 Vacuum Chamber 176 Exhaust pipe 178 Vacuum pump

Claims (15)

Provided between a vacuum processing chamber in which a predetermined vacuum processing is performed on a target object using a predetermined processing gas under reduced pressure and a vacuum pump for exhausting the vacuum processing chamber to a vacuum, from the vacuum processing chamber A trap device for collecting sedimentary substances contained in discharged exhaust gas,
An airtight body having an inverted conical or cylindrical inner wall;
An exhaust gas introduction part provided at an upper part of the main body for introducing the exhaust gas from the vacuum processing chamber into the main body;
A deposit reservoir provided at the bottom of the main body for accumulating the depositing substance that has changed from a gas phase to a solid phase while descending the main body;
A trap apparatus having an inlet disposed near a bottom of the main body and an exhaust pipe connected to the vacuum pump at an outlet.   The trap apparatus according to claim 1, wherein the exhaust gas introduction unit is configured to introduce the exhaust gas from the vacuum processing chamber obliquely downward along the inner wall surface of the main body.   The said deposit reservoir part has a cooling means for accelerating that the said depositable substance changes from a gaseous phase to a solid phase, and maintaining the solid state of the said depositable substance. The trap device described.   The trap apparatus according to claim 3, wherein the main body is made of a heat conductive material and is cooled by the cooling means of the deposit reservoir by heat conduction.   The trap apparatus according to any one of claims 1 to 4, wherein an opening is formed at a lower end of the main body, and the deposit reservoir is detachably attached to the main body so as to airtightly close the opening.   The trap device according to any one of claims 1 to 5, wherein the main body has a guide groove portion formed in a spiral shape on the inner wall surface for guiding the exhaust gas from the vacuum processing chamber. A vacuum processing chamber in which a predetermined vacuum processing is performed using a predetermined processing gas on a target object under reduced pressure;
A first vacuum pump for evacuating the vacuum processing chamber;
A trap device provided in an exhaust path between the vacuum processing chamber and the first vacuum pump in order to collect sedimentary substances contained in the exhaust gas discharged from the vacuum processing chamber;
The trap device is
An airtight body having an inverted conical or cylindrical inner wall;
An exhaust gas inlet provided in the upper part of the main body for introducing the exhaust gas from the vacuum processing chamber into the main body;
A deposit reservoir provided at the bottom of the main body for storing the depositing substance that has changed from a gas phase to a solid phase while descending the main body;
A vacuum processing apparatus comprising: an exhaust pipe having an inlet disposed near the bottom of the main body and an outlet connected to the vacuum pump.   The trap apparatus according to claim 7, wherein the exhaust gas introduction section of the trap apparatus is configured to introduce the exhaust gas from the vacuum processing chamber obliquely downward along the inner wall surface of the main body.   9. The deposit reservoir of the trap device includes cooling means for promoting the change of the depositing substance from a gas phase to a solid phase and maintaining the solid state of the depositing substance. The trap device described.   The vacuum processing apparatus according to claim 9, wherein a main body of the trap device is made of a heat conductive material and is cooled by a cooling means of the deposit reservoir by heat conduction.   The said trap apparatus WHEREIN: Opening is formed in the lower end of the said container, The said deposit reservoir part is attached to the said container so that attachment or detachment is possible so that the said opening may be sealed airtightly. Vacuum processing equipment.   The vacuum processing apparatus according to any one of claims 8 to 11, wherein a main body of the trap apparatus has a guide groove portion formed in a spiral shape on the inner wall surface for guiding exhaust gas from the vacuum processing chamber.   The vacuum processing apparatus as described in any one of Claims 8-12 which provides a 2nd vacuum pump in the exhaust path between the said trap apparatus and the said 1st vacuum pump.   The vacuum processing apparatus as described in any one of Claims 8-12 which provides a 2nd vacuum pump in the exhaust path between the said vacuum processing chamber and the said trap apparatus. The exhaust gas in the exhaust passage is heated to a predetermined temperature in order to keep the depositing substance in a gas phase in the exhaust passage from the exhaust port of the vacuum processing chamber to the exhaust gas inlet of the trap device body. The vacuum processing apparatus as described in any one of Claims 8-14 which has a heating means to do.

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