JP5630319B2 - Parts for plasma processing apparatus and marking method for identification display - Google Patents

Description

  The present invention relates to a component such as a focus ring or an electrode plate with an identification display used in a plasma processing apparatus, and a method for marking the identification display on the component.

  A plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus used in a semiconductor device manufacturing process has, for example, an upper electrode and a lower electrode connected to a high-frequency power source disposed in a chamber facing each other in the vertical direction, In a state where the substrate to be processed is arranged on the electrode, plasma is generated by applying a high-frequency voltage while flowing an etching gas or the like from the air hole formed in the upper electrode toward the substrate to be processed, and the substrate is processed. It is set as the structure which performs processes, such as an etching (patent document 1).

  And for parts such as focus rings and electrode plates used in such a plasma processing apparatus, in order to be able to determine the replacement timing of parts and to follow up the manufacturing process of parts, etc. The identification is attached. The identification display is formed by, for example, marking by a laser marking method. The parts with these identification marks may be cracked starting from the identification marks due to exposure to high temperatures during plasma processing.

  Patent Document 2 proposes a method for forming an identification display by arranging a plurality of dot holes having a substantially U-shaped longitudinal section. The diameter of the dot hole is 0.1 mm or less (preferably 0.05 mm or less). This dot hole is narrower than the sheath thickness during plasma processing, and the shortest distance between the center axes of the dot holes is the diameter. 3 times or more (for example, 0.15 mm or more). By using the identification display constituted by such dot holes, it is said that the influence of thermal stress is alleviated and the generation of cracks starting from the identification display is suppressed.

JP 2002-184664 A Japanese Patent No. 4,409,459

However, when the identification display is engraved with a dot hole as in Patent Document 2, there is a problem that visibility is inferior. In addition, when engraving the dot hole, the laser beam with high light condensing ability is concentrated on one point. Therefore, when processing to the extent that it can be visually recognized, the dot hole is easy to be engraved deeply, and the U-shape It is difficult to obtain a shape, and a conical bottomed dot hole is often formed. Then, when heat is locally applied to the dot holes due to abnormal discharge and stress is concentrated on an acute-angled shape with a sharp bottom, there is a risk of causing cracks in the component.
In addition, when forming the identification display, a smoothing operation is performed to polish the surface through a subsequent etching process after engraving characters and the like. Even in this smoothing operation, polishing dust that has entered the dot holes is completely removed. There are problems such as being unable to remove.

  The present invention has been made in view of such circumstances, and does not hinder the visibility of identification notation, and can prevent adverse effects such as cracks that originate from the identification display during plasma processing. Provided are parts for a plasma processing apparatus and a marking method for identification display.

The component for a plasma processing apparatus of the present invention is a component disposed in the plasma processing apparatus, and has an identification formed on the surface of the component by a concave groove having a U-shaped cross section and not a dot hole. The concave groove is characterized in that the ratio of the width to the depth is 0.3 or more and 2.0 or less, and the bottom of the groove is formed with a radius of curvature of 30 μm or more. To do.

  Since the identification display is provided by the concave groove, the visibility is not hindered as in the case where the identification display is given by the dot hole. Moreover, since the identification display is formed by a U-shaped groove having a cross-sectional shape, it is possible to easily remove the polishing dust generated at the time of marking the identification display. In addition, the gentle U-shaped shape of the bottom of the groove can alleviate stress concentration during plasma processing and prevent adverse effects such as cracks occurring in the part.

  Further, the identification marking method according to the present invention is a method for forming a concave groove on the surface of a component arranged in the plasma processing apparatus and marking the identification marking on the surface of the component by laser irradiation processing. At least two rows of small groove portions are formed in parallel with a part of adjacent small groove portions overlapped, and the concave groove is formed by laser irradiation processing while shifting the focus position so as to remove the space between these small groove portions. And an identification display is imprinted.

  After machining a plurality of small grooves, the focus position of the laser beam is shifted and laser irradiation processing is performed on the entire small grooves, thereby smoothing the surface of the grooves and forming a groove having a wide width and a shallow depth. be able to. Therefore, the visibility of the identification display is not hindered, and adverse effects such as cracking of parts that occur during plasma processing can be prevented.

  According to the present invention, the groove for forming the identification display can be formed with a wide width and a shallow depth, and the surface of the groove can be smoothed, so that the visibility of the identification display is hindered. In the plasma processing, it is possible to prevent a bad effect such as a crack generated from the identification display as a starting point.

It is a schematic block diagram which shows the example of a plasma processing apparatus. It is a rear view of the electrode plate which shows one Embodiment of this invention. It is a figure explaining a ditch | groove. It is a figure explaining the formation method of an identification display, (a) is formation of a small groove part, (b) is formation of the small groove part of several rows, (c) is a figure explaining smoothing of the groove surface.

Hereinafter, an embodiment in which a component for a plasma processing apparatus of the present invention is applied to an electrode plate will be described with reference to the drawings.
First, a plasma etching apparatus 1 will be described as a plasma processing apparatus using this electrode plate.
As shown in the schematic cross-sectional view of FIG. 1, the plasma etching apparatus 1 is provided with an electrode plate (upper electrode) 3 in the upper part of the vacuum chamber 2 and a gantry (lower electrode) 4 that can be moved up and down in the lower part. Are provided in parallel with the electrode plate 3 at a distance from each other. In this case, the upper electrode plate 3 is supported in an insulated state with respect to the wall of the vacuum chamber 2 by an insulator 5, and an electrostatic chuck 6 and a focus ring 7 that surrounds the electrostatic chuck 6 are mounted on the mount 4. And a wafer (substrate to be processed) 8 is placed on the electrostatic chuck 6 with a peripheral edge supported by a focus ring 7. Further, an etching gas supply pipe 9 is provided in the upper part of the vacuum chamber 2, and the etching gas sent from the etching gas supply pipe 9 passes through the diffusion member 10 and then is a gas passage hole provided in the electrode plate 3. 11 is made to flow toward the wafer 8 and discharged from the discharge port 12 on the side of the vacuum chamber 2 to the outside. On the other hand, a high frequency voltage is applied between the electrode plate 3 and the gantry 4 by a high frequency power source 13.

  The electrode plate 3 is formed in a disk shape with silicon, and a cooling plate 14 made of aluminum or the like having excellent thermal conductivity is fixed to the back surface of the electrode plate 3, and the gas passing through the electrode plate 3 is also passed through the cooling plate 14. Through holes 15 are formed at the same pitch as the gas passage holes 11 so as to communicate with the holes 11. The electrode plate 3 is fixed in the plasma processing apparatus 1 by screwing or the like with the back surface in contact with the cooling plate 14. As shown in FIG. 2, the electrode plate 3 is provided with an identification display 30 such as a serial number on the back surface in contact with the cooling plate 14.

In the plasma etching apparatus 1, when an etching gas is supplied by applying a high-frequency voltage from a high-frequency power source 13, the etching gas passes through the diffusion member 10, passes through the gas passage hole 11 provided in the electrode plate 3, and is electrode plate. 3 is released into the space between the gantry 3 and the gantry 4 and becomes plasma in this space, hits the wafer 8, and the surface of the wafer 8 is etched by sputtering, ie, physical reaction, and chemical reaction of the etching gas. The
Further, for the purpose of uniformly etching the wafer 8, the generated plasma is concentrated on the central portion of the wafer 8, and is prevented from diffusing to the outer peripheral portion, thereby generating a uniform plasma between the electrode plate 3 and the wafer 8. In order to generate the plasma, the plasma generation region 16 is usually surrounded by a silicon shield ring 17.

Next, the electrode plate 3 will be described with reference to FIGS.
An identification display 30 is attached to the back surface of the electrode plate 3 at the position shown in FIG. The identification display 30 is configured by imprinting a character string in which characters, numerals, and the like are combined by the concave groove 31 shown in FIG. In this case, with respect to the electrode plate 3 having a diameter of 300 mm and a plate thickness of 10 mm, an identification display 30 is attached at a position 10 mm inside from the outer periphery of the electrode plate 3.
The electrode plate 3 is formed in a disc shape from single crystal silicon, columnar crystal silicon, or polycrystalline silicon.
The concave groove 31 is processed by a laser marker or the like, and has a U-shaped cross section as shown in FIG. The ratio of the width W to the depth H (H / W) is 0.3 or more and 2.0 or less, and the concave groove 31 is formed with a curvature radius R of the bottom 33 of 30 μm or more.

Next, a method for marking the groove 31 on the electrode plate 3 will be described.
The concave groove 31 is formed by, for example, laser irradiation processing using a laser marker or the like.
A laser marker is a device that can focus characters on a surface of a workpiece by condensing a laser beam on the workpiece and perform thermal processing. By controlling the focus position, output intensity, and scanning speed of the laser beam, processing with a desired width and depth can be performed.

In the present embodiment, laser irradiation processing is performed a plurality of times until the desired width of the concave groove 31 is obtained, and the processed groove is gradually widened.
First, as shown in FIG. 4A, a small groove 32a having a width of about 80 μm is processed at a predetermined position on the back surface of the electrode plate 3 by the first laser irradiation. Next, as shown in FIG. 4 (b), the second laser irradiation and the third laser irradiation are sequentially performed in parallel so as to partially overlap the small groove 32a, and a part of the adjacent small groove 32 is formed. The small groove portions 32b and 32c are processed in a state where the two are stacked. In this way, the laser irradiation is repeated a plurality of times until the desired width (here, about 200 μm) is obtained.

When the processed groove formed by the small groove portions 32 constituting the concave groove 31 has a desired width, the focus position of the laser beam is shifted so as to remove the saw groove portions 34 between the plurality of rows of small groove portions 32, thereby reducing the small grooves. Processing is performed so that the entire width of the processed groove formed by the groove portion 32 is traced with laser light. Thereby, as shown in FIG.4 (c), the saw groove part 34 is removed and the surface of a process groove | channel is processed into a U-shaped cross-sectional shape. Thereafter, the electrode plate 3 is etched in order to remove the heat-affected layer remaining after the laser irradiation processing. Further, the surface of the electrode plate 3 is polished to a predetermined thickness by polishing it about several tens to 100 μm.
The processed grooves formed by the small grooves 32 are processed with a depth of about 200 μm in order to ensure that the recessed grooves 31 can be visually recognized even after the surface of the electrode plate 3 is polished.

  In this way, after processing a plurality of small groove portions 32, the entire groove processed by the small groove portions 32 is subjected to laser irradiation processing by shifting the focus position of the laser beam, thereby smoothing the surface of the processed groove, A concave groove 31 having a large width W can be formed.

  By the way, at the time of the plasma etching process, the electrode plate 3 exposed to the plasma generation region is exposed to a high temperature, and thermal stress is applied to the electrode plate 3 by repeatedly expanding and contracting at each processing. However, in the electrode plate 3 of the present embodiment, the groove 31 constituting the identification display 30 attached to the back surface is formed so as to have a U-shaped cross-sectional shape, and the groove 31 The ratio of the width W to the depth H is large. Therefore, the width W of the concave groove 31 can be sufficiently secured, and the visibility of the identification display 30 is not hindered. In addition, stress concentration during plasma processing can be relaxed, and adverse effects such as cracks occurring in parts can be prevented. Further, in the identification display 30 constituted by the concave grooves 31, it is possible to easily remove the polishing dust generated at the time of marking.

Next, the Example which concerns on the components for plasma processing apparatuses of this invention is described.
As in the first embodiment, a single crystal silicon electrode plate having a diameter of 300 mm and a thickness of 10 mm was used as the sample, and the occurrence of cracks due to the difference in the groove forming the identification display was confirmed.
The identification display was engraved on one side of the electrode plate under the conditions shown in Table 1 below and by forming a concave groove having the shape shown in FIG. In addition, the identification display attached to the sample was a character string “ABC123”, a character height of 6 mm, and was stamped at a position 10 mm inside from the outer periphery of the electrode plate.
Further, 50 electrode plates as samples were prepared for each condition. Then, on the hot plate heated to 100 ° C., the electrode plate is placed with the engraved surface with the identification indication on top, and the number of electrode plates with cracks starting from the identification indication at this time is confirmed. did. In addition, the crack which started from the identification display had generate | occur | produced immediately after mounting on a hotplate.
Visibility was evaluated by observing 5 people from the vertical direction (50 cm directly above the identification display), and when all 5 people confirmed the characters correctly, “◯” was given, and even one person could not read. Cases were evaluated as “x”.

  As shown in Table 1, if the ratio (H / W) of the width W to the depth H of each groove is 0.3 or more and 2.0 or less and the radius R of the bottom of the groove is 30 μm or more, the identification display It can be seen that cracks originating from can be effectively prevented and good visibility can be obtained. Further, in order to obtain good visibility of the identification display, it is sufficient that the width W of the groove is about 200 μm. However, according to Table 1, a groove having a width W of 240 μm may be formed. Is possible.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the laser medium of the laser marker, the light source, and the like are not particularly limited as long as the parts such as the electrode plate can be stamped.
In the above-described embodiment, the Si electrode plate is used as the plasma processing apparatus component. However, in the present invention, the identification display is engraved on the surface of the component such as quartz, alumina ceramic, yttria ceramic, or SiC. Also effective.

DESCRIPTION OF SYMBOLS 1 Plasma etching apparatus 2 Vacuum chamber 3 Electrode plate (component for plasma processing apparatuses)
4 Stand 5 Insulator 6 Electrostatic Chuck 7 Focus Ring 8 Wafer 9 Etching Gas Supply Pipe 10 Diffusion Member 11 Gas Passing Hole 12 Discharge Port 13 High Frequency Power Supply 14 Cooling Plate 15 Through Hole 16 Plasma Generation Area 17 Shield Ring 30 Identification Display 31 Concave Groove 32, 32a, 32b, 32c Small groove part 33 Bottom part 34 Saw groove part

Claims (2)

A component disposed in the plasma processing apparatus, wherein the surface of the component is U-shaped in cross-section and has an identification display formed by a groove that is not a dot hole. Is a part for a plasma processing apparatus, wherein the ratio of the width to the depth is 0.3 or more and 2.0 or less, and the bottom of the groove is formed with a radius of curvature of 30 μm or more.   A method of forming a concave groove on a surface of a component disposed in a plasma processing apparatus and marking an identification display, wherein at least two rows of small groove portions are adjacent to the surface of the component by laser irradiation processing. Are formed in parallel in a state where a part of the groove is overlapped, and a concave groove is formed by shifting the focus position so as to remove the space between these small groove portions and laser processing is performed, and an identification display is imprinted. The marking method of the identification display.

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