JP2010157776A - Electrostatic chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck capable of achieving uniform substrate heating with high reproducibility. <P>SOLUTION: The electrostatic chuck includes: a substrate mounting board 21 having a substrate mounting surface on which a substrate 50 is mounted; gas leading means 29, 30, 31, 34 for sending gas to the substrate mounting board 21; a heater 24 installed in the substrate mounting board 21 to transmit heat to the substrate mounting surface; a sensor 26 installed in the substrate mounting board 21 to measure the temperature of the substrate mounting surface; and a heater heating control means 28 for controlling power to be applied to the heater 24 based on the temperature obtained from the sensor 26. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic chuck.

  In the case of forming a film on a wafer using a sputtering apparatus or the like, it is known that the characteristics and etching rate of the deposited thin film greatly depend on the substrate temperature during film formation and etching. Accordingly, it is required to heat the substrate evenly in order to make the deposited thin film uniform in the substrate or to etch the object to be etched uniformly in the substrate. Further, in order to form a film with good reproducibility between substrates, it is necessary to be able to raise the temperature to a set temperature with good reproducibility.

  4 (a) and 4 (b) show the configuration of a conventional substrate mounting table with a heater that is used in a sputtering apparatus and that heats a wafer to be processed to a set temperature. 4A is a cross-sectional view showing the overall configuration, and FIG. 4B is a cross-sectional view showing a partial configuration.

  As shown in FIG. 4A, the substrate mounting table 1 with a heater is installed in a vacuum processing chamber, and a heater 4 as a heat source in the substrate mounting table 1 and a temperature detection element (thermocouple) for monitoring the temperature of the substrate 11. ) 6 is embedded. Further, the substrate mounting table 1 is formed with a flow path 9 for introducing a heating gas (such as argon) to the substrate mounting surface, and the flow path 9 includes a gas discharge port 13 opened in the substrate mounting surface. The gas introduction port 14 opened in the lower part of the substrate mounting table 1 is connected. Then, as shown in FIG. 4B, the heating gas released from the gas discharge port 13 to the substrate placement surface flows through the gap 12 between the substrate 11 and the substrate placement surface, and heat from the heater 4 Is efficiently transmitted to the substrate 11.

  Furthermore, it has a heater heating control means 8 connected to the temperature detection element 6 and the heater, and the temperature of the substrate 11 detected by the temperature detection element 6 is taken into the heater heating control means 8 so that the substrate 11 becomes a predetermined temperature. Thus, the electric power applied to the heater 4 is adjusted appropriately. Thereby, uniform heating in the substrate 11 is performed.

  Further, the substrate 11 on the substrate mounting table 1 is fixed by the clamp 2. This is to prevent the substrate 11 from coming off the fixed position by introducing the heating gas.

  However, in the above-described substrate mounting table 1 with a heater, the heating gas is poured between the back surface of the substrate 11 and the substrate mounting surface to efficiently heat the substrate. Are not performed evenly, resulting in uneven substrate heating.

  By the way, the flow rate of the heating gas that moves through the gap 12 between the back surface of the substrate 11 and the substrate mounting surface depends on the weight of the clamp 2 and the pressing position of the substrate 11. Therefore, it is difficult to move the gas uniformly over the entire substrate 11 and to move the gas with good reproducibility each time the substrate 11 is mounted.

  In addition, in order to make this gas movement more uniform, attempts have been made to provide radial or spiral grooves on the substrate mounting surface. However, the efficiency of heat exchange efficiency with respect to the substrate 11 is also reduced in the grooves and portions other than the grooves. Differences occur, and uneven temperature distribution occurs at each position on the substrate 11.

  The present invention was created in view of the problems of the above-described conventional example, and can perform uniform substrate heating, or can perform uniform and reproducible substrate heating. Is to provide.

  According to one aspect of the present invention, a substrate mounting table having a substrate mounting surface on which a substrate is mounted, gas introducing means for sending gas to the substrate mounting table, and the substrate mounting table are provided in the substrate mounting table. A heater that transfers heat to the mounting surface, a sensor that is provided in the substrate mounting table and that measures the temperature of the substrate mounting surface, and heater heating that adjusts the power applied to the heater based on the temperature from the sensor There is provided an electrostatic chuck having a control means.

  In the electrostatic chuck according to one aspect of the present invention, in addition to the gas introducing means for sending gas to the substrate mounting table and the heater for transferring heat to the substrate mounting surface, a sensor for measuring the temperature of the substrate mounting surface, and a sensor Heater heating control means for adjusting the electric power applied to the heater based on the temperature from the substrate, so that the gas can be sent to the substrate mounting surface and the temperature of the substrate can be adjusted, thereby achieving uniform substrate heating. It can be carried out.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIGS. 1A to 1C are cross-sectional views showing a substrate mounting table with a heater according to the first embodiment of the present invention.

  As shown in FIG. 1A, the substrate mounting table 101 with a heater is installed in a vacuum processing chamber. In the figure, a part of the partition wall 23 of the chamber is drawn. The substrate mounting table 21 is made of aluminum, and a heater 24 that is a heat source and a temperature detection element (thermocouple) 26 that monitors the temperature of the substrate 50 are embedded in the substrate mounting table 21.

  In addition, a through-flow path 29 is formed in the central portion of the substrate mounting table 21 to guide a heating gas (inert gas such as argon) to the substrate mounting surface. The through-flow path 29 is opened to the substrate mounting surface. The gas discharge port 33 is connected to the gas introduction port 34 opened in the lower portion of the substrate mounting table 21. As shown in FIG. 1B, the heating gas released from the gas discharge port 33 to the substrate placement surface flows through the gap 32 between the substrate 50 and the substrate placement surface, and heat from the heater 24 is obtained. Is efficiently transmitted to the substrate 50.

  Furthermore, it has a heater heating control means 28 connected to the temperature detection element 26 and the heater 24, and takes the temperature of the substrate 50 from the temperature detection element 26 into the heater heating control means 28 so that the substrate 50 becomes a predetermined temperature. The electric power applied to the heater 24 is adjusted appropriately. Thereby, uniform heating in the substrate 50 is performed.

  The substrate 50 on the substrate mounting table 21 is fixed by the clamp 22. This is to prevent the substrate 50 from coming off the fixed position by introducing the heating gas.

  Furthermore, minute convex portions 32a and concave portions 32b between the convex portions 32a are formed on the entire surface of the substrate mounting surface. When the substrate 50 is placed on the substrate placement surface, the heating gas released from the flow passage 29 freely flows in all directions in the concave portions 32b between the convex portions 32a. Since the recesses 32b are formed with a uniform density by the GBB method (glass bead blasting method) or the like, the heating gas spreads uniformly over the entire substrate 50. Further, since the substrate 50 is supported by the convex portions 32a, the concave portions 32b between the convex portions 32a do not change every time the substrate 50 is mounted, and the reproducibility of substrate heating for each substrate 50 is good.

  Next, the formation method of the convex part 32a and the recessed part 32b of a substrate mounting surface is demonstrated. The case where the GBB method (glass bead blasting method) is used will be described.

  First, glass beads having a particle size of about 80 μm are prepared. Next, a polishing liquid in which glass beads are mixed with a chemical solution is applied to the polishing surface of the polishing apparatus, and a substrate mounting table is placed thereon with the substrate mounting surface facing the polishing surface. When the polishing surface and the substrate mounting table are rotated in the same direction, the substrate mounting surface is polished by the glass beads sandwiched between the substrate mounting surface and the polishing surface. Convex portions 32a having a diameter of about 80 μm are formed in an island shape on the substrate mounting surface, and concave portions 32b are formed between the convex portions 32a.

  As described above, in the first embodiment, minute concave portions 32b and convex portions 32a are formed on the entire surface of the substrate placement surface of the substrate placement table 21.

  Therefore, when the substrate 50 is placed on the substrate placement surface, the heating gas released from the gas discharge port 33 on the substrate placement surface freely flows in the recesses 32b between the projections 32a. Since the recesses 32b are formed with a uniform density by the GBB method or the like, the heating gas spreads uniformly throughout the substrate 50. Thereby, uniform substrate heating can be performed.

  Further, since the substrate 50 is supported by the convex portions 32a, the concave portions 32b between the convex portions 32a do not change every time the substrate 50 is mounted, and the reproducibility of substrate heating for each substrate is good.

(Second Embodiment)
FIG. 2A is a top view showing a substrate mounting table 101a with a heater according to the second embodiment.

  In the substrate mounting table 101a with a heater according to the second embodiment, a radial groove 41a centered on the gas discharge port 33 for the heating gas is further formed on the substrate mounting surface of the substrate mounting table 21a in FIG. It is provided. The radial groove 41a is connected to the gas discharge port 33, and the heating gas discharged from the gas discharge port 33 flows along the radial groove 41a and freely flows in the concave portions 32b between the convex portions 32a.

  In addition, what is shown with the same code | symbol as Fig.1 (a)-(c) in a figure shows the same thing as Fig.1 (a)-(c).

(Third embodiment)
FIG. 2B is a top view showing a substrate mounting table 101b with a heater according to the third embodiment.

  This is because a plurality of concentric grooves 41b around the gas discharge port 33 for the heating gas are further provided in the radial grooves 41a of FIG. The concentric grooves 41b are connected to the radial grooves 41a at the intersections with the radial grooves 41a, and the heating gas discharged from the gas discharge port 33 flows along the radial grooves 41a and the concentric grooves 41b. It flows freely in the concave portions 32b between the convex portions 32a.

  In addition, what is shown with the same code | symbol as Fig.2 (a) in the figure shows the same thing as Fig.2 (a).

(Fourth embodiment)
FIG. 2C is a top view showing a substrate mounting table 101c with a heater according to the fourth embodiment.

  The difference from FIG. 2A and FIG. 2B is that a lattice-like groove 41c is provided instead of the radial groove or the concentric groove. The lattice-like grooves 41c are connected to each other at the intersections. The lattice-shaped groove 41c is also connected to the gas discharge port 33 for the heating gas, and the heating gas discharged from the gas discharge port 33 flows vertically and horizontally along the lattice-shaped groove 41c, and the convex portion 32a It flows freely in the recess 32b.

  In addition, what is shown with the same code | symbol as Fig.2 (a) in the figure shows the same thing as Fig.2 (a).

  As described above, in the second to fourth embodiments, the radial grooves 41 a centered on the gas discharge ports 33, the concentric grooves 41 b, or the lattice-shaped grooves 41 c connected to the gas discharge ports 33 are provided. By providing the heating gas, the heating gas can be quickly spread to the peripheral portion of the substrate mounting surface through the grooves 41a, 41b, and 41c, and the heating gas can be made to flow evenly over the entire back surface of the substrate through the recess. Therefore, the uniformity of substrate heating is further increased.

  Furthermore, the substrate mounting tables 101, 101a to 101c with heaters of the first to fourth embodiments are used for film formation and etching under normal pressure or reduced pressure conditions such as a sputtering apparatus or a film forming apparatus such as a CVD apparatus or a dry etching apparatus. It is possible to equip with the apparatus which performs. Thus, when the film is formed on the substrate and the film on the substrate is etched, the substrate can be kept at a uniform temperature, so that a uniform film can be formed or uniform etching can be performed.

  The substrate mounting tables 101, 101a to 101c have one gas discharge port 33. However, as shown in FIG. 3, a gas flow path 29 passing through the substrate mounting tables 101, 101a to 101c is provided. The branch passages 29a to 29c may be provided by branching, and two or more gas discharge ports 33a to 33c connected to the branch passages 29a to 29c may be formed. As a result, the heating gas can be discharged directly from the plurality of gas discharge ports 33a to 33c onto the substrate mounting surface, so that the heating gas can be spread evenly over the entire wafer surface.

  Further, although the heating gas is not particularly heated in the above, the heating gas may be heated to the substrate heating temperature in advance before the heating gas heating means is provided to flow to the substrate mounting table.

  Furthermore, although the substrate 50 is fixed by the clamp 22, it can also be fixed by an electrostatic chuck, a vacuum chuck, or the like.

  In addition to argon, other inert gases may be used as the heating gas.

FIG. 1A is a cross-sectional view showing a substrate mounting table with a heater according to the first embodiment of the present invention, and FIG. 1B is a substrate mounting of the substrate mounting table with a heater in FIG. FIG. 1C is a cross-sectional view showing details of the vicinity of the placement surface, and FIG. 1C is a top view showing a convex portion formed on the substrate placement surface. 2A is a top view and a perspective view showing a substrate mounting surface of a substrate mounting table with a heater according to a second embodiment of the present invention, and FIG. 2B is a third view of the present invention. It is a top view shown about the substrate mounting surface of the substrate mounting table with a heater which concerns on this embodiment, FIG.2 (c) is a substrate mounting of the substrate mounting table with a heater which concerns on the 4th Embodiment of this invention. It is a top view shown about a surface. FIG. 3 is a sectional view showing a substrate mounting table with a heater according to another embodiment of the present invention. 4A is a cross-sectional view illustrating a conventional substrate mounting table with a heater according to a conventional example, and FIG. 4B illustrates details of the vicinity of the substrate mounting surface of the substrate mounting table with a heater in FIG. It is sectional drawing.

21, 21a substrate mounting table,
22 clamps,
23 chamber partition walls,
24 heater,
25, 27 wiring,
26 thermocouple (temperature detection means),
28 heater heating control means,
29 channels,
30 Gas piping,
31 Flow rate control means,
32 gap,
32a convex part,
32b recess,
33 Gas outlet
34 Gas inlet,
41a, 41b, 41c groove,
101, 101a, 101b, 101c A substrate mounting table with a heater.

Claims (4)

A substrate mounting table having a substrate mounting surface on which the substrate is mounted;
Gas introduction means for sending gas to the substrate mounting table;
A heater provided in the substrate mounting table, for transferring heat to the substrate mounting surface;
A sensor which is provided in the substrate mounting table and measures the temperature of the substrate mounting surface;
An electrostatic chuck comprising: heater heating control means for adjusting electric power applied to the heater based on a temperature from the sensor. The substrate mounting table is
A gas inlet for introducing the gas;
The electrostatic chuck according to claim 1, further comprising: a plurality of gas discharge ports provided on the substrate mounting surface and configured to discharge a gas introduced from the gas introduction port. The substrate mounting surface is
A plurality of grooves connected to the gas discharge port and extending radially from the gas discharge port to an end of the substrate mounting surface;
The electrostatic chuck according to claim 2, further comprising: a surface adjacent to the plurality of grooves, and the convex portion formed in an island shape.   The electrostatic chuck according to claim 1, wherein the sensor includes a thermocouple.

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