JP2008227506A - Substrate treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment method which can readily adjust the temperature condition of a wafer, and can ensure the temperature uniformity of the wafer. <P>SOLUTION: The substrate loaded into a treatment chamber is laid on a supporting plate. Hereafter, the treatment chamber is shielded from the outside, and pressure in the treatment chamber is increased to already-set pressure. The temperature of the substrate is stabilized to a fixed temperature by the already-set pressure, and the pressure within the treatment chamber is decompressed to treatment pressure. When treatment for the substrate is completed in the treatment chamber, the substrate is unloaded to the outside of the treatment chamber. Methods of increasing the pressure in the treatment chamber include a method of supplying a purge gas, and a method of supplying a treatment gas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate processing method, and more particularly, to a substrate processing method placed on a plate.

  The thin film deposited on the wafer surface is selectively removed by etching, and a desired pattern is formed on the wafer surface. Such a process is repeatedly performed in the semiconductor manufacturing process. Also, not only the deposited film, but also the silicon substrate itself can be etched to create a trench. The thin film may include a different thin film such as a photoresist or a silicon oxide film or a silicon nitride film. Oxide films or nitride films provide better etching conditions than photoresists.

  A general plasma etching apparatus will be described. When the process gas is supplied into the chamber and an electric field is formed between the two electrodes, a part of the gas atoms is ionized to be free from positive ions. Electrons are generated to form a plasma. In a plasma etching apparatus, energy is supplied by a high frequency generator (RF generator) operating at 13.56 MHz.

Two main factors related to plasma etching are free radicals and ions. Free radicals have incomplete bonding and are electrically neutral. Thus, free radicals have very high reactivity due to insufficient bonding, and process through substances on the wafer and mainly chemical action. However, since ions have a charge, they are accelerated in a certain direction by a potential difference, and the process is performed mainly through physical action with the substance on the wafer.
On the other hand, the wafer is loaded into the chamber and placed on a chuck provided in the chamber. Thereafter, the wafer temperature condition is adjusted to suit the process, and if the temperature condition is satisfied, the process is started. However, there are some problems with the general apparatus as described above.

  In order to increase the precision of the process, it is necessary to adjust the process conditions accurately, and among them, the temperature condition of the wafer is very important. Here, in a state where the wafer is separated from the chuck, the gas molecules supplied into the chamber function as a temperature transfer medium between the wafer and the chuck. Therefore, it is very difficult to control the temperature of the wafer, and particularly when the process is performed in a high vacuum state, such a problem can be further serious because there are very few gas molecules in the chamber. .

  In order to solve this problem, helium gas may be sprayed to the rear surface of the wafer. In this case, a separate apparatus for fixing the wafer is required. Conventionally, a mechanical clamp or an electrostatic chuck (ESC) has been used. However, the mechanical clamp cannot apply a uniform force to the wafer, and has the disadvantage of generating particles. is there. In addition, when the electrostatic chuck is applied, the structure of the apparatus becomes complicated, the production cost increases, and a chucking / dechucking process is required when the process proceeds.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a substrate processing method capable of easily adjusting the temperature condition of a wafer.
Another object of the present invention is to provide a substrate processing method capable of ensuring temperature uniformity of a wafer.
Other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

  In order to achieve the above object, a substrate processing method according to the present invention includes a step of loading a substrate into a process chamber, supplying a process gas for processing the substrate to the process chamber, and reducing the pressure in the process chamber. Increasing the pressure to a preset pressure to stabilize the temperature of the substrate; reducing the pressure in the process chamber to a process pressure to perform a process on the substrate; and Unloading to the outside.

The process gas may include an etching gas or a cleaning gas.
In the step of performing a process on the substrate, the process gas is supplied into the process chamber in a state where an electric field is formed in the process chamber, plasma is generated, and the substrate is processed using the generated plasma. Steps may be included.
The step of performing the process on the substrate may include heating the substrate to remove a process byproduct formed on the upper surface of the substrate.

  According to another embodiment of the present invention, there is provided a substrate processing method comprising: loading a substrate into a first chamber; supplying a process gas for processing the substrate to the first chamber; Increasing the pressure to a preset pressure to stabilize the temperature of the substrate, reducing the pressure in the first chamber to a process pressure, and performing a first step on the substrate; and Unloading the outside of the first chamber and loading it into the second chamber; and increasing the pressure in the second chamber to a preset pressure to stabilize the temperature of the substrate; Reducing the pressure in the second chamber to a process pressure and performing a second step on the substrate; and unloading the substrate to the outside of the second chamber. Including and up, the.

The step of performing the first process on the substrate in the first chamber is generated by supplying the process gas into the first chamber and generating plasma in a state where an electric field is formed in the first chamber. Processing the substrate using a plasma may be included.
The performing the second process on the substrate in the second chamber may include heating the substrate to remove process by-products formed on the upper surface of the substrate.
The process gas may include an etching gas or a cleaning gas.

  According to the present invention, the gas can be supplied into the chamber to increase the internal pressure of the chamber and the density of gas molecules, and the temperature adjustment of the wafer W can be facilitated by the gas molecules. Further, the temperature deviation of each region of the wafer W can be reduced. In particular, the temperature of the wafer W can be easily adjusted using a purge gas or a process gas.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. This embodiment is provided to explain the present invention in more detail to those who have ordinary knowledge in the technical field to which the invention pertains. Accordingly, the shape of each element in the drawings may be exaggerated to emphasize a clearer description.

  On the other hand, hereinafter, the wafer W will be described as an example of the substrate, but the technical idea and scope of the present invention are not limited thereto. In the following, a plasma etching apparatus will be described as an example for explaining the present invention. However, the present invention can be applied to various semiconductor manufacturing apparatuses that perform processes while a wafer is placed on a plate. In the following, an inductively coupled plasma (ICP) type plasma apparatus will be described as an example. However, the plasma apparatus is applied to various plasma apparatuses including an electron cyclotron resonance (ECR) type. be able to.

FIG. 1 is a diagram schematically showing a semiconductor manufacturing facility 1 including process modules 10a and 10b according to the present invention.
Referring to FIG. 1, a semiconductor manufacturing facility 1 includes a process facility 2, an equipment front end module (EFEM) 3, and an interface wall 4.

  The equipment front end module 3 is mounted in front of the process equipment 2 and transfers the wafer W between a container (not shown) containing the wafer W and the process equipment 2. The equipment front end module 3 has a plurality of load ports 60 and a frame 50. The frame 50 is located between the load port 60 and the process equipment 2. A container for storing the wafer W is placed on the load port 60 by a transfer means (not shown) such as an overhead transfer, an overhead conveyor, or an automatic guided vehicle. The As the container, a sealed container such as a front open unified pod (FOUP) can be used. In the frame 50, a frame robot 70 for transferring the wafer W between the container placed on the load port 60 and the process equipment 2 is provided. An opener (not shown) that automatically opens and closes the door of the container can be provided in the frame 50. The frame 50 is provided with a fan filter unit (FFU: Fan Filter Unit, not shown) that supplies clean air into the frame 50 so that the clean air flows from the upper part to the lower part in the frame 50. Can do.

  A predetermined process is performed on the wafer W in the process facility 2. The process equipment 2 includes a loadlock chamber 20, a transfer chamber 30, and first and second process modules 10a and 10b. The transfer chamber 30 has a substantially polygonal cross section. On the surface of the transfer chamber 30, the load lock chamber 20 or the process modules 10a and 10b are located. The load lock chamber 20 is located on the side of the transfer chamber 30 adjacent to the equipment front end module 3, and the process modules 10a and 10b are located on the other side. The load lock chamber 20 includes a loading chamber 20a in which a wafer W loaded into the process facility 2 temporarily waits for the progress of the process, and a wafer W that is unloaded from the process facility 2 after the process is completed. And an unloading chamber 20b. The inside of the transfer chamber 30 and the process modules 10a and 10b is maintained in vacuum, and the inside of the load lock chamber 20 is switched to vacuum and atmospheric pressure. The load lock chamber 20 prevents external contaminants from flowing into the transfer chamber 30 and the process modules 10a and 10b. Gate valves (not shown) are provided between the load lock chamber 20 and the transfer chamber 30 and between the load lock chamber 20 and the equipment front end module 3. When the wafer W moves between the equipment front end module 3 and the load lock chamber 20, the gate valve provided between the load lock chamber 20 and the transfer chamber 30 is closed, and the load lock chamber 20 and the transfer chamber 30 When the wafer W moves between them, the gate valve provided between the load lock chamber 20 and the equipment front end module 3 is closed.

A transfer robot 40 is mounted in the transfer chamber 30. The transfer robot 40 loads the wafer W onto the process modules 10a and 10b or unloads the wafer W from the process modules 10a and 10b. Further, the transfer robot 40 transfers the wafer W between the process modules 10 a and 10 b and the load lock chamber 20.
The process modules 10a and 10b perform predetermined processes on the wafer W, for example, processes such as etching, cleaning, and ashing. The process modules 10a and 10b constitute one group and perform processes on the wafer W continuously.

FIG. 2 is a view schematically showing the first process module 10a of FIG.
The first process module 10 a includes a first process chamber 120, a first plate 140, a first exhaust line 160, a coil 170, and a first supply line 180.
The first process chamber 120 provides an internal space in which an etching process is performed. When the process proceeds, the internal space of the first process chamber 120 is blocked from the outside. A passage 122 through which the wafer W enters and exits is formed on one side of the first process chamber 120. The passage 122 is opened and closed by an opening / closing member such as a slit door (not shown). A first supply hole 126 is formed on the other side of the first process chamber 120. A gas supplied through a first supply line 180 described later flows into the first process chamber 120 through the first supply hole 126. A first exhaust hole 124 for discharging the gas in the first process chamber 120 is formed in the bottom wall of the first process chamber 120. The first exhaust hole 124 is formed around a first plate 140 described later, and a first exhaust line 160 described later is formed in the first exhaust hole 124.

  A first plate 140 is provided in the internal space of the first process chamber 120. The first plate 140 is supported by the support shaft 142. The wafer W is placed on the upper surface of the first plate 140. The first plate 140 is grounded, and forms an electric field in the first process chamber 120 together with a coil 170 described later. A plurality of support protrusions 140a are provided on the first plate 140, and the back surface of the wafer W is supported by the plurality of support protrusions 140a. Accordingly, the wafer W is maintained in a state of being separated from the upper surface of the first plate 140 by a certain distance.

  The first exhaust line 160 is connected to the first exhaust hole 124 and adjusts the pressure inside the first process chamber 120 and exhausts the internal air. A separate pump (not shown) for forced exhaust may be installed on the first exhaust line 160. Therefore, the internal pressure of the first process chamber 120 can be forcibly reduced using a pump.

  A coil 170 is provided on the first process chamber 120, and a high frequency generator (not shown) is connected to the coil 170. When the high frequency generator connected to the coil 170 is operated, high frequency energy is generated from the coil 170, and the generated energy is transmitted to the inside of the first process chamber 120 through the upper wall of the first process chamber 120. An electric field is formed inside the process chamber 120. Meanwhile, in the present embodiment, it is described that the coil 170 is provided on the first process chamber 120, but the position of the coil 170 may be variously modified.

  The first supply line 180 branches into a process gas line 182 and a purge gas line 184. A process gas flows inside the process gas line 182, and a purge gas flows inside the purge gas line 184. Accordingly, the process gas and the purge gas are supplied into the first process chamber 120 through the first supply line 180. On the other hand, a valve 182 a for opening and closing the process gas line 182 is installed on the process gas line 182, and a valve 184 a for opening and closing the purge gas line 184 is installed on the purge gas line 184.

  Since the process gas is determined by a process performed in the first process chamber 120, when the etching process is performed in the first process chamber 120, the process gas is an etching gas. When the cleaning process is performed, the process gas is Cleaning gas. The purge gas is supplied to the inside of the first process chamber 120 in order to discharge the internal toxic gas to the outside during maintenance and repair of the first process chamber 120. The purge gas includes an inert gas such as nitrogen (N2).

FIG. 3 is a diagram schematically showing the second process module 10b of FIG.
The second process module 10 b includes a second process chamber 220, a second plate 240, a second exhaust line 260, and a second supply line 280.
The second process chamber 220 provides an internal space in which an etching process is performed. When the process proceeds, the internal space of the second process chamber 220 is blocked from the outside. A passage 222 through which the wafer W enters and exits is formed on one side of the second process chamber 220. The passage 222 is opened and closed by an opening / closing member such as a slit door (not shown). A second supply hole 226 is formed on the other side of the second process chamber 220. A gas supplied through a second supply line 280 described later flows into the second process chamber 220 through the second supply hole 226. A second exhaust hole 224 for discharging the gas in the second process chamber 220 is formed in the bottom wall of the second process chamber 220. The second exhaust hole 224 is formed around a second plate 240 described later, and a second exhaust line 260 described later is formed in the second exhaust hole 224.

  A second plate 240 is provided in the internal space of the second process chamber 220. The second plate 240 is supported by the support shaft 244. The wafer W is placed on the upper surface of the second plate 240. A heater 242 is installed inside the second plate 240. The heater 242 heats the wafer W seated on the upper surface of the second plate 240 at a process temperature. A plurality of support protrusions 240a are provided on the second plate 240, and the back surface of the wafer W is supported by the plurality of support protrusions 240a. Accordingly, the wafer W is maintained in a state of being separated from the upper surface of the first plate 240 by a certain distance.

The second exhaust line 260 is connected to the second exhaust hole 224 and adjusts the pressure inside the second process chamber 220 and exhausts the internal air. A separate pump (pump, not shown) for forced exhaust can be installed on the second exhaust line 260. Therefore, the internal pressure of the second process chamber 220 can be forcibly reduced using the pump.
A purge gas flows in the second supply line 280, and the purge gas is supplied into the second process chamber 220 through the second supply line 280. On the other hand, a valve 280 a for opening and closing the second supply line 280 is installed on the second supply line 280. The purge gas is supplied to the inside of the second process chamber 220 in order to discharge the internal toxic gas to the outside during maintenance and repair of the second process chamber 220. The purge gas includes an inert gas such as nitrogen (N2).

FIG. 4 is a flowchart showing a substrate processing method according to the present invention, and FIG. 5 is a graph showing pressure changes in the first process chamber 120 of FIG. 2 and the second process chamber 220 of FIG.
Hereinafter, an etching process for the wafer W and a method for adjusting the temperature of the wafer W will be described with reference to FIGS.

  First, the wafer W is loaded into the first process chamber 120 (S10). The transfer robot 40 loads the wafer W onto the first process module 10a, and the wafer W is placed on the first plate 140 through the first passage 122 formed on one side of the first process chamber 120. Here, the pressure inside the first process chamber 120 is maintained in a vacuum state (“a” section: wafer loading section).

  Next, the pressure inside the first process chamber 120 is increased to a preset pressure while the internal space of the first process chamber 120 is blocked from the outside, and the temperature of the wafer W is stabilized (S20). Stabilizing the temperature of the wafer W means that the temperature difference between the wafer W and the first plate 140 is within a preset range, or the temperature deviation of each region of the wafer W is within a certain range. It means to do. In addition to this, it means that the temperature of the wafer W is adjusted to a preset temperature. Here, the range in which the temperature of the wafer W can be determined to be stabilized can be determined according to the operator's request.

  The internal pressure of the first process chamber 120 increases from a vacuum state (vacuum: V) to 1999.84 Pa (15 T (Torr)) or more (preferably 2666.45 Pa (20 T)) (“b” section: temperature stabilization). section). There are two methods for increasing the pressure in the first process chamber 120. The first method is to supply a process gas to the inside of the first process chamber 120, and the second method is to supply a purge gas to the inside of the first process chamber 120. The process gas or the purge gas is supplied into the first process chamber 120 through the first supply line 180. When the gas is forcibly supplied to the inside of the first process chamber 120, the pressure inside the first process chamber 12 increases.

  When the gas is forcibly supplied to the inside of the first process chamber 120, the inside of the first process chamber 120 is filled with the gas, thereby increasing the pressure and the density of gas molecules inside the first process chamber 120. The gas molecules filling the inside of the first process chamber 120 function as a temperature transfer medium between the first plate 140 and the wafer W. Accordingly, heat transfer between the first plate 140 and the wafer W can be performed smoothly.

  FIG. 6 is a graph showing the temperature change of the wafer W measured by the first process module 10a of FIG. 2, and the temperature of the wafer W was measured in various regions. The left graph in FIG. 6 shows the temperature change of the wafer W when the inside of the first process chamber 120 is in a vacuum state, and the right graph in FIG. 6 is when the inside of the first process chamber 120 is in a high pressure state. The temperature change of the wafer W is shown. In FIG. 6, “1” represents a time point when the wafer W is placed on the first plate 140.

  The wafer W is loaded into the first process chamber 120 by the transfer robot 40, and the temperature of the wafer W is higher than the temperature of the first plate 140. After the wafer W is placed on the first plate 140, heat transfer is performed between the wafer W and the first plate 140, and the wafer W is gradually cooled.

  Here, the wafer W shown in the left graph of FIG. 6 has a large temperature deviation depending on the region, and is gradually cooled. On the other hand, the wafer W shown in the right graph of FIG. 6 initially has a large temperature deviation depending on the region. However, the temperature of the wafer W increases as the internal pressure of the first process chamber 120 increases (“H” time point). You can see that it is converged. This is because, when the internal pressure of the first process chamber 120 is high, heat transfer is smoothly performed by gas molecules. That is, when the internal pressure is high, the temperature of the wafer W can be quickly adjusted by gas molecules. For the same reason, the temperature deviation of each region of the wafer W can be reduced.

  Next, when the temperature of the wafer W is stabilized, the internal pressure of the first process chamber 120 is reduced to the process pressure, and the first process for the wafer W is performed (S30). The internal pressure of the first process chamber 120 decreases from 2666.45 Pa (20 T) to 666.61 Pa (5 T) or less (preferably 133.32 Pa (1 T)). That is, the process pressure of the first process module 10a is 133.32 Pa (1T) (“c” section: process section).

  When the internal pressure of the first process chamber 120 reaches the process pressure, the process gas is supplied into the first process chamber 120. The process gas is supplied through the process gas line 182 and the first supply line 180. When an electric field is formed in the first process chamber 120, plasma is generated from the process gas, and the generated plasma etches the surface of the wafer W. The process gas depends on the film to be etched.

  Next, when the first step is completed, the wafer W is unloaded from the first process chamber 120 ("d" section) and loaded into the second process chamber 220 (S40) ("a" section). The method for loading the wafer W into the second process chamber 220 is the same as the method for loading the wafer W into the first process chamber 120.

  Next, the pressure in the second process chamber 220 is increased to a preset pressure while the internal space of the second process chamber 220 is shut off from the outside, and the temperature of the wafer W is stabilized (S50). The internal pressure of the second process chamber 220 increases from a vacuum state to 1999.84 Pa (15 T (Torr)) or more (preferably 2666.45 Pa (20 T)) (“b” section). The pressure of the second process chamber 220 is increased by supplying a purge gas therein. The purge gas is supplied into the second process chamber 220 through the second supply line 280. In addition, the principle of stabilizing the temperature of the wafer W is the same as the method described above.

  FIG. 7 is a graph showing the temperature change of the wafer W measured by the second process module 10b of FIG. 3, and the temperature of the wafer W was measured in various regions. The left graph in FIG. 7 represents the temperature change of the wafer W when the inside of the second process chamber 220 is in a vacuum state, and the right graph in FIG. 7 is when the inside of the second process chamber 220 is in a high pressure state. The temperature change of the wafer W is represented.

  The wafer W is loaded into the second process chamber 220 by the transfer robot 40, and the temperature of the wafer W is lower than the temperature of the second plate 240. After the wafer W is placed on the second plate 240, heat transfer is performed between the wafer W and the second plate 240, and the wafer W is gradually heated.

  Here, the wafer W shown in the left graph of FIG. 7 has a large temperature deviation depending on the region, but the wafer W shown in the right graph of FIG. 7 has almost no temperature deviation due to the region. This is because heat transfer is smoothly performed by gas molecules when the internal pressure of the second process chamber 220 is high. That is, when the internal pressure is high, the temperature of the wafer W can be quickly adjusted by gas molecules. For the same reason, the temperature deviation for each region of the wafer W can be reduced.

  Next, when the temperature of the wafer W is stabilized, the internal pressure of the second process chamber 220 is reduced to the process pressure, and the second process is performed on the wafer W (S60). The internal pressure of the second process chamber 220 decreases from 2666.45 Pa (20 T) to 666.61 Pa (5 T) or less (preferably 133.32 Pa (1 T)). That is, the process pressure of the second process module 10b is 133.32 Pa (1T) (“C” section).

  When the internal pressure of the second process chamber 220 reaches the process pressure, the second plate 240 heats the wafer W to a preset temperature. When the wafer W is heated, the substance remaining on the surface of the wafer W after the first step (etching) is vaporized and discharged to the outside through the second exhaust line 260 in a gas state.

  The above-described preferred embodiments of the present invention are disclosed for the purpose of illustration, and those having ordinary knowledge in the technical field to which the present invention pertains depart from the technical idea of the present invention. Various substitutions, modifications, and alterations are possible within the scope of not being included, and such substitutions, alterations, and the like belong to the scope of the claims.

It is a figure which shows roughly the semiconductor manufacturing equipment containing the process module by this invention. It is a figure which shows the 1st process module of FIG. 1 schematically. It is a figure which shows the 2nd process module of FIG. 1 schematically. 3 is a flowchart illustrating a substrate processing method according to the present invention. 4 is a graph showing pressure changes in the first process chamber of FIG. 2 and the second process chamber of FIG. 3. It is a graph which shows the temperature change of the wafer W measured with the 1st process module of FIG. It is a graph which shows the temperature change of the wafer W measured with the 2nd process module of FIG.

Explanation of symbols

1 Semiconductor manufacturing equipment 10a, 10b Process module 120, 220 Process chamber 140, 240 Plate 160, 260 Exhaust line 170 Coil 180, 280 Supply line

Claims (10)

Loading a substrate into the process chamber;
Supplying a process gas for processing the substrate to the process chamber, and increasing the pressure in the process chamber to a preset pressure to stabilize the temperature of the substrate;
Reducing the pressure in the process chamber to a process pressure and performing a process on the substrate;
Unloading the substrate out of the process chamber;
A substrate processing method comprising:   The substrate processing method according to claim 1, wherein the process gas includes an etching gas or a cleaning gas.   In the step of performing a process on the substrate, the process gas is supplied into the process chamber while an electric field is formed in the process chamber, plasma is generated, and the substrate is processed using the generated plasma. The substrate processing method according to claim 1, further comprising a step.   4. The substrate processing method according to claim 3, wherein the step of performing the process on the substrate includes a step of removing the process by-product formed on the upper surface of the substrate by heating the substrate.   2. The substrate processing method according to claim 1, wherein the preset pressure is 2666.45 Pa (Pascal), and the process pressure is 133.32 Pa. Loading a substrate into the first chamber;
Supplying a process gas for processing the substrate to the first chamber, and increasing the pressure in the first chamber to a preset pressure to stabilize the temperature of the substrate;
Reducing the pressure in the first chamber to a process pressure and performing a first process on the substrate;
Unloading the substrate to the outside of the first chamber and loading it into a second chamber;
Increasing the pressure in the second chamber to a preset pressure to stabilize the temperature of the substrate;
Reducing the pressure in the second chamber to a process pressure and performing a second process on the substrate;
Unloading the substrate to the outside of the second chamber;
A substrate processing method comprising:   The step of performing the first process on the substrate in the first chamber is generated by supplying the process gas into the first chamber and generating plasma in a state where an electric field is formed in the first chamber. The substrate processing method according to claim 6, further comprising: processing the substrate using plasma.   The method of claim 6, wherein performing the second process on the substrate in the second chamber includes heating the substrate to remove a process byproduct formed on an upper surface of the substrate. Substrate processing method.   The substrate processing method according to claim 6, wherein the process gas includes an etching gas or a cleaning gas.   The substrate processing method according to claim 6, wherein the preset pressure is 2666.45 Pa (Pascal), and the process pressure is 133.32 Pa.

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