JP6067210B2 - Plasma processing equipment - Google Patents

Description

Embodiments of the present invention relates flop plasma processing apparatus.

  An electrostatic chuck is used to hold a substrate such as a semiconductor substrate, LCD glass, or printed circuit board on a sample table or to control the temperature. Since the electrostatic chuck is electrically attracted and fixed from the back surface without mechanically pressing against a part of the substrate, the entire surface of the substrate can be fixed uniformly. In recent years, it is also common to incorporate temperature adjusting means such as a heater or a cooling water channel in the electrostatic chuck and use it as temperature adjusting means for the substrate.

  However, there are several problems when using an electrostatic chuck for plasma processing.

  For example, since the back surface of the substrate and the electrostatic chuck are in direct contact with each other, scratches are generated on the back surface of the substrate, which is a contact portion, or particles generated from the electrostatic chuck adhere to the back surface of the substrate.

  In addition, due to chipping which is a minute chip of the substrate or warping of the substrate itself, the holding by the electrostatic adsorption force does not work normally, and the substrate itself may be cracked or damaged. This phenomenon appears more prominently with thin substrates.

  Therefore, conventionally, a technique for preventing scratches on the back surface of the substrate, adhesion of particles, and loss of holding power of the substrate has been performed by providing a film serving as a buffer layer on the surface of the electrostatic chuck.

  For example, Patent Document 1 discloses a method in which a process is performed by sandwiching a protective layer such as a particle capturing sheet called an anti-adhesion sheet between a suction surface of an electrostatic chuck and a substrate.

JP 2003-45949 A

  The adhesion-preventing sheet of Patent Document 1 is simply held on the chuck body by being placed on the chuck body or partially adhered by an adhesive. However, on the surface of the electrostatic chuck on which the substrate to be processed is repeatedly placed and transported, when the deposition sheet is merely placed on the surface of the electrostatic chuck, when the substrate is transported from the electrostatic chuck or the like, There is a possibility that the position of the deposition preventing sheet needs to be adjusted again. Further, when the adhesion-preventing sheet is bonded, the displacement can be suppressed, but the replacement work becomes difficult.

Therefore, in the embodiment of the present invention, to prevent misalignment provides flop plasma processing apparatus having a protective layer which can be easily carried out replacement work.

The plasma processing apparatus of this embodiment is
A treatment container capable of maintaining an atmosphere depressurized from atmospheric pressure;
A decompression section for decompressing the inside of the processing container to a predetermined pressure;
A mounting table provided inside the processing container for mounting a workpiece;
A plasma generating section for generating plasma inside the processing vessel;
By providing the mounting surface of the mounting table on the mounting surface on which the object to be processed is mounted, the adhesive force to the mounting surface of the surface facing the mounting surface is irradiated with ultraviolet light. With a protective layer that changes,
During the processing of the workpiece, the protective layer is placed on the protective layer so that the ultraviolet light is shielded by the workpiece and faces the placement surface. The adhesive strength to the mounting surface of the side surface does not change,
When the object to be processed is not placed on the mounting table, the protective layer is exposed to the irradiation of the ultraviolet light, so that the mounting surface of the surface on the side facing the mounting surface is described above. The adhesive force with respect to is smaller than the adhesive force during the treatment.

In an embodiment of the present invention, to prevent misalignment provides flop plasma processing apparatus having a protective layer which can be easily carried out replacement work.

Schematic diagram for illustrating the plasma processing apparatus according to the present embodiment Schematic diagram for illustrating the mounting table according to the present embodiment

  Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

  FIG. 1 is a schematic diagram for illustrating a plasma processing apparatus according to the present embodiment, and FIG. 2 is a schematic diagram for illustrating a mounting table according to the present embodiment.

  As shown in FIG. 1, the plasma processing apparatus 100 is provided with a processing container 1, a plasma generation unit 8, a decompression unit 105, a gate valve (not shown), and the like.

  The plasma generator 8 is composed of a lower electrode and an upper electrode.

  Here, the mounting table 10 in this embodiment is illustrated with reference to FIG.

  The mounting table 10 of this embodiment shall be comprised by the electrode main body 2 and the protective layer 3 used as a lower electrode.

  As shown in FIG. 2, the electrode body 2 further includes an electrode plate 7, a metal electrode 6, a dielectric plate 5, and a mounting surface 4.

  A workpiece W can be placed on the electrode body 2, and a delivery means (not shown) for the workpiece W such as a lift pin is incorporated therein. Specific examples of the workpiece W include a wafer for a semiconductor device and a glass substrate for a liquid crystal display device, but are not limited thereto, and include any workpiece to be subjected to plasma processing.

  The electrode plate 7 is formed of a metal member such as an aluminum alloy, and is surrounded by an insulating ring (not shown). A blocking capacitor 101 and a high-frequency power source 102 are sequentially connected to the electrode plate 7 via a first potential supply line 104a. The high-frequency power source 102 applies high-frequency power of about 100 KHz to 100 MHz to the electrode plate 7.

A dielectric plate 5 having a metal electrode 6 therein is provided on the upper side of the electrode plate 7. In order for the metal electrode 6 to maintain potential insulation in the electrode body 2, the dielectric plate 5 is formed of an insulating material. As the insulating material, for example, a resin such as polyimide or a ceramic such as alumina can be used. The metal electrode 6 is connected to the DC power supply 103 via the second potential supply line 104b, and adsorbs the substrate by an electrostatic force such as a Coulomb force generated by applying a DC voltage. In the present embodiment, the surface of the dielectric plate 5 (strictly, through the protective layer 3) is used as the placement surface 4 of the workpiece W.

  The surface 4 of the dielectric plate 5 on which the workpiece W is placed can be coated with, for example, Teflon (registered trademark) to prevent etching.

  Further, the mounting surface 4 can be provided with a groove so that a gas hole to which a heat conduction gas G2 to be described later is supplied is opened and the back surface of the workpiece W can be filled with the heat conduction gas G2.

  A protective layer 3 is provided on the mounting surface 4. The protective layer 3 is made of a material whose adhesive force with respect to the mounting surface 4 changes when irradiated with ultraviolet light, and the adhesive force is reduced by irradiating with ultraviolet light, and the protective layer 3 is easily peeled off from the mounting surface 4. be able to. Examples of the material for the protective layer 3 include a UV film. Even if it is not a UV film, the protective layer 3 has an adhesive force (holding force) to such an extent that the workpiece W does not shift even when it is repeatedly placed on the placement surface 4. In the form, it can be a material having resistance to plasma etching.

  A heat conduction gas supply source (not shown) is connected to the bottom of the electrode body 2, and the surface of the electrode body 2 is connected to the electrode plate 7 through the heat conduction gas pipe and the heat conduction gas hole communicating with the inside of the dielectric plate 5. That is, the heat conduction gas G2 is supplied to the back surface of the workpiece W. Therefore, the protective layer 3 has one or more holes corresponding to the gas holes for ejecting the heat conduction gas.

  In order to cool or adjust the temperature of the electrode plate 7, this heat conduction gas pipe circulates only the electrode plate 7 without communicating the dielectric plate 5, adjusts the temperature of the electrode plate 7, and moves the object W to be processed. Indirect cooling and temperature control may be used. In this case, since the heat conduction gas holes are not opened in the mounting surface 4, it is not necessary to open the gas holes in the protective layer 3.

  Further, the heat conduction gas may be an inert gas such as He or N 2.

  Next, the plasma processing apparatus 100 using the mounting table 10 of the present embodiment will be illustrated.

  A plasma processing apparatus 100 illustrated in FIG. 1 is a capacitively coupled plasma (CCP) processing apparatus generally called a “parallel plate type RIE (Reactive Ion Etching) apparatus”. That is, it is an example of a plasma processing apparatus 100 that generates a plasma product from the process gas G using plasma generated by applying high-frequency power to parallel plate electrodes and processes the workpiece W.

  The plasma processing apparatus 100 includes a processing container 1 formed of a conductive material such as aluminum and capable of maintaining a reduced pressure atmosphere.

An upper gas nozzle 107 for introducing the processing gas G is provided in the ceiling portion of the processing container 1. The processing gas G is supplied from the processing gas supply means into the processing container 1 through the gas introduction hole 108 of the upper gas nozzle 107 while the flow rate is adjusted by a processing gas flow rate adjusting means (not shown). Specific examples of the processing gas G include CF 4, NF 3, and O 2, but are not limited to this, and are appropriately selected according to processing operations such as etching and thin film deposition.

The above-described electrode body 2 is provided inside the processing container 1 and is connected to the high-frequency power source 102 via a matching unit (not shown). The upper gas nozzle 107 provided so as to face the electrode body 2 is grounded. That is, the electrode body 2 constitutes a lower electrode, and the upper gas nozzle 107 constitutes an upper electrode to constitute a parallel plate electrode, and plasma P is generated during this period.

  A decompression unit 105 is connected to the bottom of the processing container 1 through a pressure control unit (not shown) and an exhaust pipe 106 so as to decompress the processing container 1 to a predetermined pressure. The decompression unit 105 can be, for example, a turbo molecular pump (TMP).

  A pressure control unit (not shown) controls the decompression unit 105 so that the internal pressure of the processing container 1 becomes a predetermined pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the processing container 1. The pressure control unit can be, for example, an APC (Auto Pressure Controller).

  A loading / unloading port for the workpiece W is provided on the side wall of the processing container 1. The carry-in / out port is provided with a door (not shown) having a seal member (not shown), and the carry-in / out port is sealed by the seal member when the door is closed, and the inside of the processing container 1 is hermetically sealed. Can be maintained.

  Next, the operation of the plasma processing apparatus 100 of this embodiment will be described.

The door of the carry-in / out port is opened by a door opening / closing mechanism (not shown), and the workpiece W is carried into the processing container 1 from the carry-in / out port by a transport means (not shown). Workpiece W is placed on the electrode body 2, held by suction electrostatic Coulomb force or the like generated by applying a DC voltage to the metal electrode 6 incorporated in the dielectric plate 5 constituting the electrode body 2 described above Is done. Next, the conveying means (not shown) is retracted outside the processing container 1, the door is closed by a door opening / closing mechanism (not shown), and the inside of the processing container 1 is exhausted to a predetermined pressure.

  The process gas G is supplied to the upper gas nozzle 107 by the process gas supply unit 109. On the other hand, high frequency power of about 100 kHz to 100 MHz is applied to the electrode body 2 from the power source. Then, since the electrode body 2 and the upper electrode constitute a parallel plate electrode, a discharge occurs between the electrodes and plasma P is generated. The process gas G is excited and activated by the generated plasma P, and plasma products such as neutral active species, ions, and electrons are generated. The generated plasma product descends in the processing container 1 and reaches the surface of the workpiece W, and a desired plasma process (for example, an etching process or an ashing process) is performed.

  In this case, among the generated ions and electrons, the lighter mass electrons move faster and reach the electrode and the upper gas nozzle 107 immediately. The electrons that have reached the electrode body 2 are prevented from moving by the blocking capacitor 101 and charge the electrode body 2. The charged voltage of the electrode body 2 reaches about 400 V to 1000 V, which is called “cathode drop”. On the other hand, since the upper electrode is grounded, movement of electrons that have reached is not prevented, and the upper electrode is hardly charged.

  Then, ions move in the direction of the electrode body 2 (the object to be processed W) along a vertical electric field generated by the cathode fall, and are incident on the surface of the object to be processed W, thereby performing a physical plasma process. The neutral active species descend by gas flow, diffusion, gravity, etc. and reach the surface of the workpiece W, and chemical plasma treatment is performed. Thereby, when processing operations such as etching and thin film deposition are finished, the workpiece W is carried out of the processing container 1 by a transport means (not shown).

  When the protective layer 3 held on the mounting surface 4 is deteriorated by corrosion or particles caused by fluorine after the processing operation, the protective layer 3 is peeled off.

  As described above, the protective layer 3 is made of a material whose adhesive force changes with respect to the mounting surface 4 by ultraviolet light, and is applied to the mounting surface 4 by ultraviolet light contained in plasma light or lamp light. As a result, the adhesive force changes, and the mounting surface 4 can be peeled off.

  The peeling method will be exemplified below.

  After the workpiece W is unloaded from the mounting surface 4 of the electrode body 2 to the outside of the processing container 1, the protective layer 3 is exposed. Therefore, when the pressure in the processing container 1 is reduced, a potential is applied to the electrode body 2 and the plasma P is generated again, the adhesive force of the protective layer 3 is reduced by the ultraviolet light contained in the light of the plasma P. Can do. That is, since the holding force of the protective layer 3 with respect to the mounting surface 4 becomes small, the protective layer 3 can be easily peeled from the mounting surface 4. The irradiation time of ultraviolet light can be obtained by experiment.

  Thereafter, the protective layer 3 is peeled off from the mounting surface 4 manually or by a robot. The replacement operation of the protective layer 3 can be completed by washing the mounting surface 4 after the protective layer 3 has been peeled off with an organic solvent or the like, and then reattaching the new protective layer 3.

  Here, while the workpiece W is placed on the placement surface 4, the ultraviolet light is blocked by the workpiece W even if the plasma treatment is performed, so that the adhesive force of the protective layer 3 is not substantially changed.

  However, when the workpiece W is transported out of the processing container 1 and nothing is placed on the placement surface 4, the protective layer 3 is exposed, so that protection is provided when ultraviolet light is incident. The adhesive strength of layer 3 changes. That is, while the workpiece W is plasma-treated, the protective layer 3 has a holding force with respect to the placement surface 4, but the protective layer is generated by generating plasma while the workpiece W is not placed. When ultraviolet light is incident on 3, the holding force with respect to the mounting surface 4 becomes small and can be easily peeled off.

  The light source used for the peeling operation of the protective layer 3 may be plasma light in the processing container 1 as described above, or a light source such as a lamp may be provided separately.

  When the plasma light in the processing container 1 is used, it is not necessary to change the configuration of the apparatus, so that the peeling operation can be easily performed. Furthermore, if the plasma light used at the time of plasma cleaning is used, the peeling operation can be performed without using gas, power, or discharge time for generating plasma only for peeling the protective layer 3 from the mounting surface 4. Reduces man-hours.

  When a separate light source for irradiating ultraviolet light such as ultraviolet light is provided, a transmission window is provided on the side wall of the processing container 1, and the mounting surface 4 can be irradiated from the outside of the processing container 1 with light such as a lamp. In that case, the lamp can be provided at a position where the entire mounting surface 4 can be irradiated as much as possible. For example, when the mounting table 10 of the present embodiment is used in a processing apparatus configured to prevent plasma light from entering the processing container 1 like a remote plasma etching apparatus, a light source can be provided on the side wall of the processing container 1 or the like. .

  As described above, the protective layer 3 provided on the mounting surface 4 of the mounting table 10 of the present embodiment has an adhesive force to the mounting surface 4 during the plasma processing, but is mounted by irradiating ultraviolet light. It changes to the state where it is easy to peel off from the mounting surface 4. Thereby, the protective layer 3 can be easily peeled from the mounting surface 4 as necessary.

  The embodiment has been illustrated above. However, the present invention is not limited to these descriptions. Regarding the above-described embodiments, those in which those skilled in the art appropriately added, deleted, or changed the design of the components are also included in the scope of the present invention as long as they have the features of the present invention. For example, the shape, size, material, arrangement, number, and the like of each element included in the plasma processing apparatus 100 are not limited to those illustrated, but can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Processing container, 2 Electrode main body, 3 Protection layer, 4 Mounting surface, 5 Dielectric plate, 6 Metal electrode, 7 Electrode plate, 8 Plasma production | generation part, 10 Mounting stand, 100 Plasma processing apparatus, 101 Blocking capacitor, 102 High frequency Power supply, 103 DC power supply,
104a First potential supply line, 104b Second potential supply line, 105 Depressurization section, 106 Exhaust piping, 107 Upper gas nozzle, 108 Gas introduction hole, 109 Process gas supply section G Process gas, P plasma, W Workpiece

Claims (2)

A treatment container capable of maintaining an atmosphere depressurized from atmospheric pressure;
A decompression section for decompressing the inside of the processing container to a predetermined pressure;
A mounting table provided inside the processing container for mounting a workpiece;
A plasma generating section for generating plasma inside the processing vessel;
By providing the mounting surface of the mounting table on the mounting surface on which the object to be processed is mounted, the adhesive force to the mounting surface of the surface facing the mounting surface is irradiated with ultraviolet light. With a protective layer that changes,
During the processing of the workpiece, the protective layer is placed on the protective layer so that the ultraviolet light is shielded by the workpiece and faces the placement surface. The adhesive strength to the mounting surface of the side surface does not change,
When the object to be processed is not placed on the mounting table, the protective layer is exposed to the irradiation of the ultraviolet light, so that the mounting surface of the surface on the side facing the mounting surface is described above. adhesion against a plasma processing apparatus characterized by comprising less than the adhesive strength in the process. The plasma processing apparatus according to claim 1, further comprising a light lamp that irradiates the protective layer with ultraviolet light.

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