JP2012104544A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for reducing adherence of a particle generated when plasma generation starts or stops to a substrate when a film forming apparatus which uses a plasma generating device forms a film on the substrate.SOLUTION: A film forming apparatus for using a plasma which forms a thin film on a substrate 9 in a vacuum container 1 comprises a film formation region in which the plasma is used to form a film on the substrate in the vacuum container and a waiting region in which no film is formed. The film forming apparatus further comprises substrate tray moving means 11 for enabling a substrate tray 10 where the substrate was placed to move between the film formation region and the waiting region in the vacuum container and interlock means for enabling the substrate tray to move from the waiting region to the film formation region after plasma generation has started and enabling plasma generation to stop after the substrate tray has moved from the film formation region to the waiting region.

Description

  The present invention relates to a plasma processing apparatus using plasma, such as plasma CVD and etching, and a plasma processing method using the same.

  In recent years, in the manufacture of devices such as semiconductors, liquid crystal panels, organic EL panels, solar cells, etc., the device yield tends to decrease due to the miniaturization and complexity of the device, and therefore many efforts have been made to increase this yield. Is required. The biggest problem that lowers the device yield is a defect in the device pattern. As a cause of this defect, plasma processing of the substrate (deposition processing of various thin films by a general parallel plate type plasma CVD apparatus and reactive) Examples thereof include particles generated during plasma etching using an ion etching apparatus (RIE) or the like.

  Many studies have been conducted on the generation of particles and the behavior of the generated particles. For example, as shown in Non-Patent Document 1, there are two types of generation of particles: those generated in plasma during plasma generation, and electrostatic forces generated when the RF power for plasma generation is turned on / off. There are two types, one caused by peeling off what was attached to the inner wall of the chamber due to thermal stress.

As a method for reducing particles generated in plasma during plasma generation, Patent Document 1 discloses a method in which RF power generated by plasma is applied in a pulsed manner when an amorphous silicon film is formed. Further, Patent Document 2 discloses that the plasma retention amount of fine particles is reduced by reducing the flow rate ratio of the deposition gas SiH ₄ immediately before the completion of the formation of the silicon nitride film.

  However, since the film forming conditions are changed in the method described in Patent Document 1, the film quality itself changes. Furthermore, the adhesion of particles to the substrate caused by peeling from the inner wall of the chamber at the time of RF power On / Off cannot be avoided. Further, in the method described in Patent Document 2, the amount of particles staying in the plasma can be reduced. However, even in this method, the deposition of particles on the substrate that occurs when the RF power is turned on / off cannot be avoided.

JP-A-5-51753 JP-A-5-129285 J.Vac.Soc.Jpn, Vol.52.No.9,2009 P.484-490

  In the conventional plasma processing method, it is impossible to avoid deposition of particles generated when turning on / off the plasma on the substrate.

(1) The invention described in claim 1 is a plasma processing apparatus that performs a process using plasma on a substrate in a vacuum vessel, and does not perform a plasma process on a processing region for performing plasma processing on the substrate in the vacuum vessel. A substrate tray moving means that has a standby area and a substrate tray in which a substrate is placed in a vacuum vessel can move between the processing area and the standby area, and after the start of plasma generation, from the standby area of the substrate tray The plasma processing apparatus further includes an interlock unit that enables movement to the processing region and enables plasma generation to be stopped after the substrate tray is moved from the processing region to the standby region.
(2) The invention according to claim 2 is the plasma processing apparatus according to claim 1, further comprising a timer for measuring a time from the start of plasma generation, wherein the interlock means is configured to measure the plasma measured by the timer. It is characterized in that the movement of the substrate tray from the standby area to the processing area is prohibited until a predetermined time has elapsed from the start of occurrence.
(3) The invention according to claim 3 is the plasma processing apparatus according to claim 1 or 2, further comprising substrate tray position detecting means for detecting whether the position of the substrate tray is in the processing area or the standby area. In addition, the interlock means prohibits the start of plasma generation when the substrate tray position detected by the substrate tray position detection means is in the processing area, and the plasma means prevents the plasma from starting when the substrate tray position is in the processing area. It is characterized by prohibiting generation stop.
(4) The invention according to claim 4 is a plasma processing method for performing plasma processing on a substrate using the plasma processing apparatus according to any one of claims 1 to 3, wherein the plasma processing is performed on the substrate. When starting, after the plasma generation starts, the substrate tray on which the substrate is placed is moved from the standby region to the processing region, and when the plasma processing to the substrate is finished, the substrate is generated before the plasma generation is stopped. The plasma processing method is characterized in that the substrate tray on which is placed is moved from the processing region to the standby region.
(5) The invention according to claim 5 is the plasma processing apparatus according to any one of claims 1 to 3, wherein the plasma processing is film formation on a substrate.
(6) The invention according to claim 6 is the plasma processing apparatus according to claim 5, wherein the film formation is performed using plasma CVD.
(7) The invention described in claim 7 is the plasma processing apparatus according to claim 6, wherein the film formation is performed by sputtering.
(8) The invention described in claim 8 is the plasma processing apparatus according to claim 6, wherein the plasma processing apparatus is a surface wave plasma CVD apparatus.

  According to the present invention, it is possible to greatly reduce adhesion of particles generated at the start of plasma generation and at the stop of plasma generation to the substrate.

It is a vertical sectional view explaining the outline of the plasma CVD apparatus in one embodiment of the present invention. The substrate tray on which the substrate is placed is in the standby position A. It is a vertical sectional view explaining the outline of the plasma CVD apparatus in one embodiment of the present invention. The substrate tray on which the substrate is placed has moved to position B, which is the position during film formation. It is a flowchart of the film-forming process of the silicon nitride film using the plasma CVD apparatus by one Embodiment of this invention. It is a figure which shows that the amount of particle deposition on a board | substrate is dependent on the waiting time from the start of discharge to the start of a movement to a film-forming position, and is a figure explaining the deposition reduction effect of the particle on the board | substrate by this invention. It is a figure which shows the accumulation reduction effect of the particle | grains on the board | substrate at the time of completion | finish of film-forming at the time of the completion | finish of film-forming when the plasma CVD apparatus by one Embodiment of this invention is used similarly to FIG. It is a vertical sectional view explaining the outline of the plasma CVD apparatus by another modification of one embodiment of the present invention.

An embodiment according to the present invention will be described with reference to FIGS. Here, as an example, a case where a silicon nitride film (SiN _x film) that is a sealing film for an organic EL panel is formed using a surface wave plasma CVD apparatus will be described.

<First Embodiment>
1 and 2 are schematic cross-sectional views of a surface wave plasma CVD apparatus according to an embodiment of the present invention as seen from the front. This surface wave plasma CVD apparatus includes a reaction vessel (vacuum vessel) 1, a waveguide 2 for introducing a microwave generated by a microwave power source (not shown) into the reaction vessel 1, a slot antenna 3, a dielectric. A body plate 4 is provided. The microwave output introduced into the reaction vessel 1 can be adjusted with a microwave power source.
The generation of the surface wave plasma is caused by a microwave applied to the dielectric plate 4 and a plasma in the vicinity of the dielectric plate 4 by a high frequency electric field propagating on the vacuum side (reaction vessel side) surface of the dielectric plate 4. This is caused by the ionization of the product gas.

  A plasma generation gas discharge port 5 is provided in the reaction vessel 1, and a gas for generating the surface wave plasma 6 is released on the reaction vessel side surface of the dielectric plate 4. Further, a film forming gas discharge port 7 for discharging a film forming gas for generating a film forming material by reacting with radicals contained in the surface wave plasma P is provided. The plasma generating gas discharge port 5 and the film forming gas discharge port 7 are attached to a deposition preventing plate 8 provided so as to surround the periphery of the rectangular dielectric plate 4. The film forming gas discharge port 7 is provided away from the dielectric plate 4. The plasma generation gas discharge port 7 is provided near the dielectric plate 4. A gas supply pipe (not shown) is connected to each of the plasma generation gas discharge port 5 and the film formation gas discharge port 7, and plasma generation gas or film formation gas is supplied from an external gas supply device (not shown). The gas supply device can independently adjust the composition and flow rate of each of the plasma generation gas and the film forming gas.

  Further, a deposition region D is defined by the deposition preventing plate 8, and deposition on the substrate 9 such as an organic EL panel is performed by placing the substrate 9 in this deposition region D. The film formation region corresponds to a “processing region” in each claim.

  The substrate 9 is placed on the substrate tray 10, and the substrate tray 10 is carried together from a carry-in port (not shown) provided on the side wall of the reaction chamber 1. The reaction chamber 1 is further provided with a metal conveyor belt 11 for moving the substrate tray 10 in the reaction chamber.

  An exhaust port 12 is provided at the bottom of the reaction chamber 1, and the inside of the reaction chamber 1 is evacuated by an evacuation system (not shown) including a vacuum pump or the like connected thereto.

  A substrate tray position confirmation sensor (not shown) for confirming the position of the substrate tray 10 is provided in the reaction chamber 1 so that the position of the substrate tray 10 can be detected. Various sensors can be used as the sensor used for the substrate tray position confirmation sensor. For example, a contact sensor using a mechanical switch may be used, or a non-contact sensor such as a magnetic proximity sensor or an optical sensor may be used. Depending on the type of sensor, an apparatus configuration for confirming the position of the substrate tray 10 with one or a plurality of sensors is possible, but such description is omitted.

  In FIG. 1, the substrate tray 10 on which the substrate 9 is placed is at the position A, and in FIG. The position A is a standby position of the substrate tray 10 before film formation on the substrate 9, and is outside from the position immediately below the film formation region D surrounded by the deposition preventing plate, that is, outside the region surrounded by the deposition preventing plate. In the area. During film formation, the substrate tray 10 on which the substrate 9 is placed moves to a position B, which is a film formation position immediately below the film formation region D, to form a film.

<Silicon Nitride Film Formation Process Flow According to the Present Invention>
Here, with reference to FIG. 3, the operation of the surface wave plasma CVD apparatus according to an embodiment of the present invention will be described by taking as an example the case where an antireflection film of a silicon nitride film (SiN _x film) is formed on the substrate 9. To do. The process until the substrate 9 is carried into the reaction vessel together with the substrate tray 10, that is, the substrate 9 is first carried into the load lock chamber, and the load lock chamber is evacuated and then carried into the reaction chamber 1 in a vacuum state. This is omitted in FIG.

In step S <b> 1, the substrate 9 placed on the substrate tray 10 is carried into the reaction chamber 1, and then waits on the metal belt conveyor 11 at a standby position A away from the film formation region. Next, in step S2 after evacuation, a gas supply device (not shown) is adjusted to release 350 sccm of Ar gas as plasma generation gas from the plasma generation gas discharge port 5. Further, a mixed gas of SiH ₄ gas 70 sccm and NH ₃ gas 500 sccm is released from the film forming gas discharge port 7. At this time, the conductance of the exhaust port 12 is adjusted so that the pressure in the reaction chamber 1 is kept almost constant at about 10 Pa. The conductance adjustment is performed, for example, by providing a conductance adjustment valve or the like (not shown) between the exhaust port 12 and the vacuum exhaust system and adjusting the conductance adjustment valve.

In step S3, 1 kW of microwave power is supplied to the dielectric plate 4 through the waveguide 2 and the slot antenna 3 in this state, and a discharge occurs on the surface of the dielectric plate 4 on the reaction chamber 1 side. A wave plasma 6 is generated.
The surface wave plasma 6 generated as described above contains radicals and ions, which diffuse downward in the reaction vessel 1 and from a film forming gas discharge port 7 provided away from the dielectric plate 4. A film-forming substance is generated by reacting with the released film-forming gas.

After the microwave power supply is started, the plasma 6 is generated, and the generation of the film-forming material as described above is started. In step S4, for example, after about 10 seconds, the standby position A as shown in FIG. The substrate tray 10 having the substrate 9 placed thereon is moved to the film formation region as shown in FIG. 2 using the metal belt conveyor 11 (film formation position B). In the state moved to this position B, silicon nitride is deposited on the substrate 9 to form a film (step S5). In this state, the film forming process time is adjusted so that a SiN _x film having a desired thickness can be obtained.

  When the film formation is finished, the substrate tray 10 on which the substrate 9 is placed while the above plasma generation and film formation operation in the surface wave excitation plasma CVD apparatus is continued using the metal belt conveyor 11. The tray 10 is moved from position B to position A (step S6). After the substrate tray 10 has moved from position B to position A, the supply of microwave power, plasma generation gas, and film formation gas is stopped, and plasma generation and film formation are stopped (step S7).

When the substrate 9 is taken out from the reaction chamber 1 after the film formation, the substrate 9 is further carried out together with the substrate tray 10 to the load lock chamber after step S7, but these are omitted in FIG.
In the operation of the surface wave plasma CVD apparatus, whether the substrate tray is at the film formation position (position B) or the standby position (position A) is determined by the above-described substrate tray position confirmation sensor (not shown). (Shown).

  The effect of reducing the generation of particles in the film forming method using the plasma CVD apparatus according to the present invention described above will be described below with reference to FIGS.

<Effect of reducing particle deposition on substrate according to the present invention>
In FIG. 4, when starting the film formation, the substrate 9 is not moved to the film formation position B for a certain period of time from the start of discharge and supply of plasma generation gas and film formation gas, but is kept in the standby position A, thereby waiting for the substrate 9. It shows that the amount of particles deposited on the surface decreases. That is, this indicates that the amount of accumulated particles depends on the waiting time until the particle deposition position B is moved.

In the leftmost bar graph (a) in FIG. 4 (the waiting time from the start of discharge to the start of film formation is 0), the substrate tray 10 is moved to the film formation position B by the metal belt conveyor 11 before the start of discharge. Has been.
It has been confirmed that almost no particles are generated when the substrate tray 10 is moved by the metal belt conveyor 11. Accordingly, even if the substrate tray is moved by the metal belt conveyor 11 before the start of the discharge by the microwave power supply, the particles adhering to the substrate surface are mostly particles generated at the start of the discharge by the start of the microwave supply.

  When the substrate tray 10 is moved to the film forming position B 10 seconds after the start of discharge (bar graph (b) in the center of FIG. 4), particles adhering to the substrate 9 are greatly reduced. This decrease in particles is almost the same when the substrate tray 10 is moved to the film forming position B 30 seconds after the start of discharge (bar graph (c) on the right side of FIG. 4).

  In the example shown in FIG. 4, the waiting time for the movement of the substrate tray 10 to the film forming position B is about 10 seconds, and the amount of particles adhering to the substrate surface is minimized. The waiting time is appropriately adjusted because it varies depending on the state (such as microwave power) and the inside of the reaction vessel (such as a deposition plate and a reaction vessel wall).

FIG. 5 shows that when depositing the film, the deposition amount of particles on the substrate 9 is reduced by moving the substrate 9 to the standby position A before stopping the discharge and supply of the plasma generation gas and the deposition gas. Indicates.
(D) in FIG. 5 shows the amount of particles deposited on the substrate 9 in the film forming process so far when the substrate is moved to the standby position A before the discharge is stopped. Further, (e) in FIG. 5 shows particles deposited on the substrate 9 when the discharge and the plasma generation gas and the deposition gas supply are stopped as described above while the substrate 9 is placed at the deposition position B. Indicates the amount.

  As can be seen from FIG. 5, when the discharge is stopped, if the substrate 9 is not moved from the film formation region to the standby region, it can be seen that many particles are deposited on the substrate. Further, by moving the substrate 9 to the standby position A before stopping the discharge, the particles deposited on the substrate 9 can be greatly reduced as shown in FIG.

In the above description, the case where the antireflection film of the silicon nitride film (SiN _x film) is formed on the substrate 9 such as an organic EL panel using the surface wave plasma CVD apparatus has been described. However, the present invention is not limited to the formation of a silicon nitride film. For example, the present invention can be applied to the case where a film other than the SiN _x film is formed by changing the film forming gas, or the case where the etching is performed while changing the plasma generation gas.

Further, in the above, a surface wave plasma generator including a microwave power source (not shown), a waveguide 2, a slot antenna 3, and a dielectric plate 4 is particularly provided as a film forming apparatus in order to generate surface wave plasma. The apparatus and method of the present invention have been described by taking a film forming apparatus using a surface wave plasma CVD apparatus as an example. However, the present invention is not limited to a surface wave plasma generation apparatus, and can be implemented in various other apparatuses that perform film formation by generating plasma between two electrodes.
For example, in the case of a parallel plate type plasma CVD apparatus (PECVD apparatus), an RF power source for applying a radio frequency (RF) and a plate type metal electrode for applying RF are used in place of the surface wave plasma generator described above. It is obvious that the metal belt conveyor 11 can be used as a GND-side electrode to generate plasma between these two electrodes, and therefore the present invention can be similarly implemented in a PECVD apparatus.
Furthermore, similarly, the present invention can be used in film formation by a sputtering apparatus using plasma generated between two electrodes.

  A major feature of the surface wave plasma CVD apparatus is that, in principle, a counter electrode is not required unlike the PECVD apparatus. Therefore, the generated plasma is one of the counter electrodes (GND side electrode) in the parallel plate type plasma CVD apparatus. That is, it is not affected by the position of the substrate tray as a part. Therefore, even if the substrate is moved during plasma generation, the density of the surface wave plasma generated near the dielectric plate 4 does not change. Since surface wave plasma is generated in the vicinity of the dielectric plate 4, if the substrate tray is located away from the dielectric plate 4 or the surface wave plasma generation region, the density of the surface wave plasma is It does not affect. Further, since the substrate tray 10 corresponding to the stage on which the substrate is placed or the metal belt conveyor 11 is not used as the GND side electrode for generating the surface wave plasma, the substrate tray 10 is simply grounded. There are no strict requirements for the connection.

The present invention is not limited to the embodiment described above, and various modifications can be made.
<Modification of Embodiment of the Present Invention>
In the above description, the substrate on which the film is formed is placed on the metal conveyor belt 11 that can reciprocate. However, any substrate can be placed on the substrate as long as it can reciprocate. It may be. However, in order to keep the pressure in the reaction chamber 1 constant, a structure that does not affect the evacuation conductance is required.
For example, instead of a metal conveyor belt, a plurality of rollers 13 (rollers having a length corresponding to the length of the depth of the substrate tray so that the substrate tray 10 can be conveyed) as shown in FIG. The tray may reciprocate between the film formation region (position B) and the standby region (position A).
In the case where the present invention is applied to a PECVD apparatus, the roller may be a metal roller, and this may be a counter electrode on the GND side.

<Other Modifications of the Present Invention>
In the above-described embodiment of the present invention, a plurality of substrate tray position confirmation sensors (not shown) are used to detect whether the substrate tray 10 is at the film forming position or at the standby position, thereby controlling plasma generation. Also good. For example, when the plasma generating gas is introduced into the reaction chamber 1 and the microwave power is further introduced to generate the plasma 6, the substrate tray 10 is not at the standby position (position A) but at the film forming position (position B). Provides an interlock device that prohibits the start of plasma generation. That is, this interlock device prevents the plasma generation gas and the microwave power from being introduced into the reaction chamber 1 when the substrate tray 10 is in the position B before the start of plasma generation.

  Similarly, this interlock device prohibits the generation of plasma 6 from being stopped if the substrate tray 10 is not moved to position A when attempting to stop the generation of plasma 6 at the end of film formation. To do. That is, when the substrate tray 10 is not moved to the position A before the plasma generation is stopped, the supply of the plasma generation gas and the microwave power to the reaction chamber 1 is not stopped.

The plasma CVD apparatus of the present invention may further include a timer (not shown) that measures the time from the start of plasma generation. This makes it possible to automate the film formation process so that the substrate is moved to the film formation position B after a predetermined time has elapsed since the start of plasma generation.
Further, the interlock device is operated so that the substrate tray 10 can be moved from the standby position A to the film forming position B after a predetermined time has elapsed from the start of plasma generation measured by the timer. Is also possible. With the interlock device operating as described above, it is possible to automate the film forming process so as to minimize the accumulation of particles on the substrate.

  The plasma CVD apparatus may further include a control device including a microcomputer (not shown) that controls the plasma CVD apparatus. The control device controls the start / stop of plasma generation and the movement of the substrate tray based on output signals from the substrate tray position confirmation sensor and timer and based on the operating state of the interlock device. By this, it becomes possible to further automate the film forming process of the substrate by the apparatus of the present invention described above. It is also possible to realize the above-described interlock device by controlling the plasma CVD device by software incorporated in the microcomputer.

  When the above-described interlock device is activated and plasma generation start / stop is prohibited, or when the movement of the substrate tray is prohibited, the substrate tray 10 is informed to the operator of the plasma CVD apparatus. A warning may be issued notifying that the position of is not appropriate. This warning may be performed by a sound generator provided in the surface wave plasma CVD apparatus. When the plasma CVD apparatus is remotely operated and monitored by a computer or the like, the warning signal is sent to this warning signal. You may make it display on the display of a computer.

  Although the embodiments of the present invention and examples of modifications thereof have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

1. Vacuum container (reaction chamber)
2. Microwave waveguide 3. Slot antenna 4. Dielectric plate 5. Plasma generation gas discharge port 6. Plasma 7. Deposition gas discharge port 8. Deposition plate 9. Substrate 10. Substrate tray 11. Metal conveyor belt 12 ... Exhaust port 13 ... Roller

Claims (8)

A plasma processing apparatus that performs processing using plasma on a substrate in a vacuum vessel,
The vacuum vessel includes a processing region for performing plasma processing on the substrate and a standby region for not performing plasma processing,
A substrate tray moving means for allowing a substrate tray on which the substrate is placed in the vacuum container to move between the processing region and the standby region;
After the start of the plasma generation, the substrate tray can be moved from the standby area to the processing area, and the plasma generation can be stopped after the substrate tray is moved from the processing area to the standby area. A plasma processing apparatus, further comprising: a lock unit. The plasma processing apparatus according to claim 1,
The apparatus further includes a timer for measuring a time from the start of plasma generation, and the interlock unit waits for the substrate tray until a predetermined time has elapsed from the start of plasma generation measured by the timer. A plasma processing apparatus for prohibiting movement from a region to the processing region. The plasma processing apparatus according to claim 1 or 2,
The apparatus further comprises substrate tray position detecting means for detecting whether the position of the substrate tray is in the processing area or the standby area, and the interlock means detects the substrate tray detected by the substrate tray position detecting means. The plasma processing apparatus prohibits the start of plasma generation when the position is in the processing region, and prohibits the generation stop of the plasma when the position of the substrate tray is in the processing region. A plasma processing method for performing plasma processing on a substrate using the plasma processing apparatus according to claim 1,
When starting the plasma processing on the substrate, after the generation of plasma, the substrate tray on which the substrate is placed is moved from the standby region to the processing region,
When the plasma processing on the substrate is finished, the substrate tray on which the substrate is placed is moved from the processing region to the standby region before plasma generation is stopped. The plasma processing apparatus according to any one of claims 1 to 3,
The plasma processing apparatus, wherein the plasma processing is film formation on the substrate. The plasma processing apparatus according to claim 5, wherein
The plasma processing apparatus is characterized in that the film formation is performed using plasma CVD. The plasma processing apparatus according to claim 6, wherein
The plasma processing apparatus is characterized in that the film formation is performed using sputtering. The plasma processing apparatus according to claim 6, wherein
The plasma processing apparatus is a surface wave plasma CVD apparatus.

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