JP3936785B2 - Substrate processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus that includes an electrostatic adsorption stage that induces static electricity on a surface and attracts the substrate to the surface, and performs a predetermined process on the substrate.
[0002]
[Prior art]
In the manufacture of electronic products such as LSIs (Large Scale Integrated Circuits), various surface treatments are performed on substrates. For example, in the formation process of metal wiring, a process of creating a metal thin film by sputtering a metal target made of aluminum or the like is actively performed, and in the formation process of the insulating layer, a process such as a surface oxidation process is performed. ing.
A substrate processing apparatus that performs such substrate processing often includes an electrostatic chucking stage that chucks the substrate by static electricity. FIG. 5 is a front view showing a schematic configuration of a substrate processing apparatus including a conventional electrostatic adsorption stage. In FIG. 5, an example of a sputtering apparatus is shown as an example of a substrate processing apparatus.
[0003]
The substrate processing apparatus shown in FIG. 5 is provided with a processing chamber 1 having an exhaust system 11, an electrostatic adsorption stage 2 disposed in the processing chamber 1, and a surface to be sputtered exposed in the processing chamber 1. Main target 3, gas introduction means 4 for introducing a predetermined gas into the treatment chamber 1, and a sputter power source 5 for sputtering the target 3 by causing sputter discharge in the introduced gas. Yes.
[0004]
The sputtering power supply 5 is configured to apply a predetermined negative high voltage to the target 3, for example. On the other hand, the wall of the processing chamber 1 is maintained at the ground potential, and an electric field is set between the target 3 and the target wall 3. Sputter discharge is generated by this electric field, and the target 3 is sputtered. The material of the sputtered target 3 reaches the surface of the substrate 9 and deposits a predetermined thin film.
[0005]
A magnet mechanism 6 for magnetron sputtering is provided behind the target 3. The magnet mechanism 6 includes a central magnet 61 and a circumferential peripheral magnet 62 that surrounds the central magnet 61. As shown in FIG. 5, an arch-shaped magnetic force line 63 that penetrates the target 3 is set by the magnet mechanism 6. Electrons are confined in a closed space formed by the magnetic force lines 63 and the surface of the target 3, and sputter discharge is maintained with high efficiency. For this reason, sputtering is performed at a high film formation rate.
[0006]
On the other hand, the electrostatic adsorption stage 2 includes a metal stage main body 21, a dielectric block 22 on which static electricity is induced on the surface and the substrate 9 is adsorbed, and a pair of adsorption electrodes 23 provided in the dielectric block 22. And a suction power source 24 for applying a DC voltage between the pair of suction electrodes 23, a fixture 25 for fixing the dielectric block 22 to the stage main body 21, and a heater 26 provided in the stage main body 21. It is configured. When a DC voltage is applied to the pair of adsorption electrodes 24 by the adsorption power source 23, dielectric polarization occurs in the dielectric block 22, and static electricity is induced on the surface of the dielectric block 22. The substrate 9 is adsorbed by this static electricity. More specifically, the substrate 9 is attracted to the dielectric block 22 by a Coulomb force due to static electricity or a Johnson-Rahbek force caused by the concentration of an electric field in a minute space between the substrate 9 and the dielectric block.
[0007]
The heater 26 heats the substrate 9 via the stage main body 21 and the dielectric block 22. The heater 26 is provided with a control mechanism (not shown), and can heat the substrate 9 to a predetermined temperature and maintain the temperature. In many substrate processes such as sputtering, heating the substrate 9 to room temperature or more often improves the efficiency and quality of the process. For this reason, the substrate 9 is heated and controlled by such a heater 26. .
[0008]
The fixture 25 for fixing the dielectric block 22 to the stage body 21 is a ring having a substantially L-shaped cross section as shown in FIG. One end of the fixture 25 is fixed to the stage main body 21 with screws, and the other end is locked to the periphery of the dielectric block 22.
[0009]
[Problems to be solved by the invention]
In the conventional electrostatic attraction stage according to the above configuration, the dielectric block is often made of ceramics such as alumina, and the stage body is made of metal such as stainless steel. In this case, there is a problem that the dielectric block breaks due to a difference in thermal expansion coefficient between the dielectric block and the stage body.
[0010]
In addition, since the fixture for fixing the dielectric block to the stage main body is in contact with both the stage main body and the dielectric block, it also serves as a heat transfer path from the heater to the substrate. In this case, in a substrate processing apparatus that performs processing using discharge such as sputtering, the fixture is also used as a shield that suppresses discharge around the substrate.
In addition, a product generated by discharge, such as a material released from the target by sputtering, may adhere to such a fixture over time. When such product adheres more and accumulates to a predetermined thickness, it peels off due to internal stress and becomes particles. When the particles reach the substrate, the substrate becomes dirty. For this reason, in many cases, after the process is repeated a predetermined number of times, the fixture is replaced with a new one.
[0011]
However, since the new fixture has nothing attached to the surface, the thermal conditions such as heat capacity are different from those used so far. In the conventional configuration in which the fixture is a heat transfer path, the heat transfer condition changes when the fixture is renewed. For this reason, the ultimate temperature and temperature distribution of the substrate to be heated also change, and the reproducibility of the temperature conditions has been insufficient.
[0012]
The present invention has been made to solve the above problems. That is, the present invention is as no breakage of the dielectric block, and reproducibility of the temperature of the substrate during processing and to provide a substrate processing apparatus is sufficient.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 is directed to an electrostatic adsorption stage that induces static electricity on the surface and attracts the substrate to the surface, and discharges to a space facing the substrate adsorbed on the electrostatic adsorption stage. A substrate processing apparatus that performs a predetermined process on the surface of the substrate while adsorbing the substrate to the electrostatic adsorption stage.
The electrostatic adsorption stage has a metal stage main body, a dielectric block in which static electricity is induced on the surface and the substrate is adsorbed, and a fixing tool for fixing the dielectric block to the stage main body. and we have a resilient deformed by the difference in thermal expansion coefficient between the dielectric block and the main stage,
Furthermore, a shield is provided so as to cover the fixture, and the shield prevents a product due to discharge from adhering to the fixture .
In order to solve the above problem, the invention according to claim 2 is the configuration according to claim 1, wherein one end of the fixture is fixed to the stage body and the other end is locked to the edge of the dielectric block. It is a flat spring.
In order to solve the above problem, the invention according to claim 3 is provided with a heater for heating the substrate by transferring heat through the stage body and the dielectric block in the configuration of claim 1 or 2. ing.
In order to solve the above problem, according to a fourth aspect of the present invention, in the configuration of the third aspect, the shield is provided apart from the dielectric block .
In order to solve the above problems, the invention of claim 5, wherein, in the structure of the fourth aspect, the stage main body is electrically grounded, the shield ones inhibit the discharge around the substrate It is .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 is a schematic plan view of an electrostatic attraction stage according to the embodiment, and FIG. 2 is a schematic plan view of the electrostatic attraction stage shown in FIG. 1 with a shield removed. 3 is a schematic view partially showing a cross section taken along line XX shown in FIG. 1, and FIG. 4 is a schematic view showing a partial cross section taken along line YY shown in FIG. is there.
The electrostatic attraction stage of the present embodiment includes a metal stage main body 21, a dielectric block 22 on which static electricity is induced on the surface and the substrate is adsorbed, and a fixture 27 that fixes the dielectric block 22 to the stage main body 21. And have.
[0015]
The stage main body 21 is made of a metal such as stainless steel and has a disk shape with a diameter larger than that of the substrate 9 to be adsorbed. The dielectric block 22 is made of ceramics such as alumina. The dielectric block 22 is also disk-shaped, and the diameter of the upper surface that adsorbs the substrate 9 is slightly smaller than that of the substrate 9. An adsorption electrode (not shown) is embedded in the dielectric block 22, and a DC voltage is applied to the adsorption electrode by an adsorption power source (not shown).
[0016]
A buffer material 29 is provided between the stage main body 21 and the dielectric block 22. The buffer material 29 absorbs the difference in thermal expansion coefficient between the stage main body 21 and the dielectric block 22. As the buffer material 29, for example, a thin carbon sheet is employed.
The stage main body 21 is provided with a heater (not shown). As the heater, for example, a heater that generates Joule heat by energization can be used.
[0017]
An embodiment of the invention of a substrate processing apparatus will be described. An example of a sputtering apparatus can be adopted as an embodiment of a substrate processing apparatus as in the prior art. Then, instead of the electrostatic adsorption stage shown in FIG. 5, the electrostatic adsorption stage shown in FIGS. 1 to 4 is adopted. Other configurations can be the same as those of the conventional apparatus.
[0018]
As the fixture 27 that constitutes a major feature of the electrostatic attraction stage of the present embodiment, one having elasticity that deforms due to the difference in thermal expansion coefficient between the dielectric block 22 and the stage main body 21 is employed. Specifically, the fixture 27 is a leaf spring having one end fixed to the stage body 21 and the other end locked to the edge of the dielectric block 22.
As shown in FIG. 3, one end of the fixture 27 is bent into a U-shaped cross section and screwed to the stage body 21. The other end of the fixture 27 extends toward the central axis of the electrostatic adsorption stage and rests on the periphery of the dielectric block 22. As shown in FIG. 3, the fixture 27 is slightly inclined downward from the bent portion.
[0019]
The fixture 27 in the free state is in a state where the other end is located slightly below the periphery of the dielectric block 22. The dielectric block 22 is arranged with the other end slightly lifted. For this reason, the restoring force of the fixture 27 acts to push the dielectric block 22 downward. As a result, the dielectric block 22 is fixed to the stage main body 21 by the fixture 27. More specifically, the fixture 27 is formed of a material such as Inconel, and is configured to push down the dielectric block 22 with a force of about 20 kgf per piece.
[0020]
As shown in FIG. 3, an opening 270 is provided at a position slightly beyond the other end from the bent portion of the fixture 27. A screw 271 inserted through the opening 270 fastens one end of the fixture 27 to the stage main body 21. In addition, as shown in FIG. 2, for example, eight fixtures 27 are provided around the dielectric block 22 at regular intervals. The stage body 21 is at ground potential, and therefore the fixture 27 is also at ground potential.
[0021]
As can be seen from the above description, the fixture 27 is deformed by the difference in coefficient of thermal expansion between the dielectric block 22 and the stage body 21. For example, when the coefficient of thermal expansion of the dielectric block 22 is larger than the stage main body 21, the other end of the fixture 27 is displaced slightly upward. For this reason, the dielectric block 22 is prevented from being damaged due to the difference in thermal expansion coefficient.
[0022]
On the other hand, the shield 28 is also provided in the electrostatic adsorption stage of this embodiment. The shield 28 is an annular member having a cross section as shown in FIGS. 3 and 4. The material of the shield 28 is, for example, stainless steel such as SUS304. As shown in FIG. 1, the shield 28 is disposed so as to surround the periphery of the dielectric block 22. As shown in FIG. 4, the shield 28 is screwed to the stage main body 21 with screws 281. As shown in FIG. 1, the positions of screwing are about four places. The shield 28 is short-circuited to the stage body 21 and is at the ground potential.
[0023]
As shown in FIGS. 3 and 4, the shield 28 is not in contact with the dielectric block 22 and is separated. For this reason, heat is not conducted from the shield 28 to the dielectric block 22. Therefore, when the product accumulates on the shield 28 and is exchanged, the heat transfer state is not greatly changed by the exchange of the shield 28. Of course, heat may be transmitted from the shield 28 to the dielectric block 22 by radiation or convection, but the radiation is much smaller than heat transfer by contact, and transmission by convection is less in a vacuum state. The heat transfer by radiation or convection hardly changes depending on the replacement of the shield 28, if any.
For this reason, in the substrate processing apparatus of this embodiment, even when the shield 28 is replaced, the heating state of the substrate 9 does not change, and the substrate 9 can be processed with sufficient reproducibility of the temperature conditions. it can.
[0024]
Further, as shown in FIG. 3, the fixture 27 is covered with the shield 28, and the product due to the discharge is prevented from adhering to the fixture 27. For this reason, even if it uses an electrostatic attraction stage for a long period of time, the necessity to replace the fixture 27 does not arise. If the product adheres to the fixture 27, the fixture 27 needs to be replaced after a predetermined period. In this case, there is a risk of causing the same problem as in the conventional case.
[0025]
A position where the fixture 27 is not covered by a member other than the shield 28, or the fixture 27 is configured so that it does not peel off even if the product is deposited by forming irregularities on the surface, or the product does not fly. It is also possible to adopt a configuration in which a fixing tool 27 is provided on the front.
[0026]
In the above description, a leaf spring is taken as an example of the fixture 27, but other configurations are possible. For example, an L-shaped member may be attached to the stage main body 21 and a pressing plate may be provided at the tip thereof via a coil spring so that the pressing plate presses the periphery of the dielectric block 22 from above. In this case, these are all “fixtures”.
[0027]
In the above description, the sputtering apparatus is taken as an example of the substrate processing apparatus, but the present invention can be applied to various substrate processing apparatuses such as an etching apparatus and a CVD (chemical vapor deposition) apparatus.
Furthermore, even when no heater is used, the electrostatic adsorption stage may be heated. For example, in the case of an apparatus for processing while generating a discharge or forming a plasma, the electrostatic adsorption stage is considerably heated by such a discharge or plasma. Therefore, with such an apparatus, even when no heater is used, the dielectric block 22 can be prevented from being damaged, and the reproducibility of the temperature condition of the substrate 9 can be improved.
[0028]
In addition, as an application other than the substrate processing apparatus of the electrostatic adsorption stage, for example, an inspection apparatus for inspecting the substrate 9 can be cited. Also for such an apparatus, the configuration of the electrostatic adsorption stage of the present embodiment is effective.
[0029]
【The invention's effect】
As described above, according to the substrate processing apparatus of claim 1, 2, or 3 of the present application, since both are fixed by the fixing tool having elasticity that deforms due to the difference in thermal expansion coefficient between the dielectric block and the stage body. Further, damage to the dielectric block due to the difference in thermal expansion coefficient is prevented.
According to the substrate processing apparatus of the fourth aspect, in addition to the above effect, since the shield is provided apart from the dielectric block, heat is not conducted from the shield to the dielectric block. Therefore, even when the shield is replaced, the heat transfer state does not change greatly, and the substrate processing can be performed with sufficient reproducibility of the temperature condition.
According to the invention of claim 5, in addition to the above effect, the discharge around the substrate is suppressed .
[Brief description of the drawings]
FIG. 1 is a schematic plan view of an electrostatic attraction stage according to an embodiment.
2 is a schematic plan view showing a state where a shield is removed from the electrostatic adsorption stage shown in FIG. 1; FIG.
FIG. 3 is a schematic view partially showing a cross section taken along line XX shown in FIG. 1;
4 is a schematic diagram partially showing a cross section at YY shown in FIG. 1; FIG.
FIG. 5 is a front view showing a schematic configuration of a substrate processing apparatus including a conventional electrostatic adsorption stage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Electrostatic adsorption stage 21 Stage main body 22 Dielectric block 27 Fixing tool 271 Screw 28 Shield 281 Screw

Claims (5)

An electrostatic adsorption stage that induces static electricity on the surface and attracts the substrate to the surface, and a discharge means that generates discharge in a space facing the substrate adsorbed on the electrostatic adsorption stage. A substrate processing apparatus for performing a predetermined process on the surface of the substrate while adsorbing
The electrostatic adsorption stage has a metal stage main body, a dielectric block in which static electricity is induced on the surface and the substrate is adsorbed, and a fixing tool for fixing the dielectric block to the stage main body. and we have a resilient deformed by the difference in thermal expansion coefficient between the dielectric block and the main stage,
Furthermore, the substrate processing apparatus is provided with a shield provided so as to cover the fixture, and the shield prevents a product due to discharge from adhering to the fixture . 2. The substrate processing apparatus according to claim 1, wherein the fixture is a plate spring having one end fixed to the stage body and the other end locked to the edge of the dielectric block. 3. The substrate processing apparatus according to claim 1, further comprising a heater for heating the substrate by transferring heat through the stage body and the dielectric block. The substrate processing apparatus according to claim 3, wherein the shield is provided apart from the dielectric block. The stage body is electrically grounded, the shield substrate processing apparatus according to claim 4, characterized in that suppress discharge around the substrate.

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