JP2001308079A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus and a plasma processing method which can process a substrate uniformly over the entire substrate with a reduced variation of the quality among processed substrates, if processing a plurality of substrates continuously. SOLUTION: A correction ring 31 disposed, so as to surround the peripheral edge of a wafer W on a susceptor 30 has a structure dividable concentrically into a first inner correction ring member 32 and a second outer correction ring member. The first ring member 32 has a width about 1-3 times as wide as the mean free path of a process gas component, so that heat hardly transfers to and from the susceptor 30 or the second ring member 33. The bottom of the second ring member 33 closely contacts the upside of the susceptor 30 through a heat conductive silicone rubber layer 34 to form a structure easy to cool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus and a processing method for processing a substrate such as a semiconductor wafer, and more particularly, to a plasma processing apparatus and a plasma processing for processing a substrate using plasma. About the method.

[0002]

2. Description of the Related Art Conventionally, in a processing apparatus for performing processing on a substrate to be processed such as a semiconductor wafer, for example, a plasma processing apparatus such as a plasma etching apparatus, a correction ring as an annular member is mounted on a susceptor on which a wafer W is mounted. It is done to arrange. The correction ring is a ring arranged around the wafer to correct the characteristics of the plasma generated in the processing chamber.For example, the electric field is concentrated on the wafer by the impedance of the ring, and the plasma is concentrated on the wafer. The distribution is used to concentrate the plasma on the wafer placed on the susceptor.

FIG. 14 is a vertical sectional view schematically showing the inside of a processing chamber of a typical plasma processing apparatus.

[0004] As shown in FIG.
An annular correction ring 103 is provided on the susceptor 102
The correction ring 103 is configured as a single disc-shaped member. As shown in FIG. 14, the correction ring 103 surrounds the outer periphery of the wafer W mounted on the susceptor 102, and is exposed to plasma during processing. Therefore, a plurality of wafers W
, The temperature of the correction ring 103 becomes high. When the temperature of the correction ring 103 rises, the spatial distribution of radicals is affected. For example, in the etching process, a decrease in the etching rate of the photoresist at the peripheral portion of the wafer W and a decrease in the removability of the contact holes are caused. In this case, the etching rate between the wafer W processed in the earlier order and the wafer W processed in the later order varies.

As a technique for eliminating the influence of a rise in temperature of a member disposed around a sample to be subjected to plasma processing on plasma processing, for example, Japanese Patent Application Laid-Open No. 7-310187.
In order to prevent the temperature of the protection plate 6 disposed around the sample 2 from becoming high, the protection plate 6 and the mounting table 8 (susceptor) are tightly bolted to each other to prevent the protection plate 6 from being heated. In order to cool the protection plate 6 by improving the thermal conductivity, or to flow gas as a heat conduction medium between the bottom surface of the protection plate 6 and the upper surface of the mounting table 8, heat of the protection plate 6 is transferred to the mounting table 8 side. A device for cooling the protection plate 6 by facilitating diffusion has been proposed.

[0006]

Generally, when the temperature of the correction ring 103 increases in the processing chamber 101 of the plasma etching apparatus 100, the etching rate tends to decrease from the center of the wafer W toward the outer periphery.
Graph 1 in FIG. 15 illustrates this state. This tendency corresponds to the distribution of oxygen radicals shown by the dotted line in FIG.

Therefore, in order to prevent the etching rate from decreasing on the outer peripheral side as shown in graph 1, it is considered that the temperature should be lowered by cooling the correction ring.

However, the etching rate of the wafer W to be plasma-etched in the processing
The shape of the curve of graph 1 shown over the surface direction of FIG. 1 is clearly different from the shape of the curve of graph 2 showing the distribution of oxygen radicals. There is no explanation.

If one changes the viewpoint and focuses on the processing gas deposit deposited on the susceptor 102 at a position relatively far from the outer peripheral edge of the wafer W, one answer can be obtained. That is, it is considered that when plasma is applied to the deposit layer formed by depositing the processing gas, highly reactive substances such as fluorine radicals are generated. Graph 3 in FIG. 15 is a graph in which the distribution of the fluorine radicals generated in this manner is plotted with the position from the center of the wafer W placed on the susceptor plotted on the horizontal axis. As shown in this graph 3, it is considered that the amount of fluorine radicals is rapidly increasing near the outer peripheral edge of the wafer W so as to correspond to the rapid rise of the graph 1 near the outer peripheral edge of the wafer W.

From the above, the portion from the left side to the center of the graph 1, that is, the portion from the center of the wafer W to the outer peripheral edge reflects the influence of oxygen radicals in the graph 2.
, That is, the periphery of the outer peripheral edge portion of the wafer W is considered to reflect the influence of the fluorine radical in the graph 3 which is considered to be generated from the deposit.

Here, judging only from the viewpoint of the temperature distribution, it is considered that the correction ring should be cooled. However, on the other hand, when the correction ring is cooled, the effect of the fluorine radicals generated by the plasma hitting the deposits in which the substances contained in the processing gas are deposited increases, and if the etching rate at the outer peripheral portion of the wafer W sharply increases, There is a conflicting problem that can be considered.

The present invention has been made to solve the above-mentioned conventional problems. That is, the present invention provides a method for processing a plurality of substrates to be processed continuously, with a small variation in quality of the processed substrates in the processing order, and a uniform processing over the entire substrate to be processed. It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method that can be performed.

[0013]

According to the present invention, there is provided a plasma processing apparatus comprising: a processing chamber for performing processing on a substrate under substantially vacuum; a processing gas supply system for supplying a processing gas to the substrate; A plasma generating means for generating plasma in the chamber, a susceptor on which the substrate to be processed is mounted, and an outer periphery of the substrate to be processed mounted on the susceptor, which is maintained at a first temperature during processing. A first ring member, surrounding the outer periphery of the first ring member, and
And a second ring member maintained at the temperature.

In the above plasma processing apparatus, for example,
The first temperature is set to a temperature higher than the second temperature.

In the above plasma processing apparatus, it is preferable that at least the upper surface of the first ring member has a width that is one to three times as large as the mean free path of the processing gas molecules.

Here, the value of the mean free path of the processing gas molecules varies depending on conditions such as the type of the processing gas and the processing temperature.
For example, at least the upper surface of the first ring member is 1
One having a width of 25 mm to 25 mm is exemplified.

Further, it is preferable that the plasma processing apparatus further includes a cooling means for cooling the second ring member.

As the cooling means, a known cooling mechanism such as a jacket or a Peltier element can be used.
A heat conductive material layer interposed between the second ring member and the susceptor may be used.

The first ring member may be provided with irregularities on the bottom surface for forming point contacts.

As an example of the combination of the first and second ring members, the first ring member has a substantially rectangular cross-sectional shape in which a rectangular notch is formed at the inner peripheral top and the outer peripheral bottom, respectively. The second ring member has a substantially rectangular cross section provided with a rectangular protrusion on the inner peripheral side bottom, and the first ring member and the second ring member are One having a shape that can be detachably fitted is used.

The plasma processing method according to the present invention is a plasma processing method for performing a plasma processing on a substrate to be processed, wherein a first annular temperature zone is formed along an outer peripheral edge of the substrate, The plasma processing is performed on the substrate to be processed in a state where the second temperature zone is formed outside the first temperature zone.

In this plasma processing method, for example,
The first temperature zone is set to a higher temperature than the second temperature zone.

In the above-mentioned plasma processing method, it is preferable that the first temperature zone is formed to have a width of 1 to 3 times the mean free path of the processing gas molecules.

More specifically, it is preferable that the width of the first temperature zone is formed to a width of 1 mm to 25 mm.

In the plasma processing apparatus according to the present invention, the ring disposed around the substrate to be processed includes the first ring member and the second ring member.
And the first ring member is maintained at a first temperature during processing, while the second ring member is maintained at a second temperature during processing. Therefore, even when a plurality of substrates to be processed are continuously processed, there is no variation in quality among the substrates to be processed, and a substrate to be processed having a stable quality can be obtained.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view showing a schematic configuration of a plasma etching apparatus according to this embodiment.

As shown in FIG. 1, this plasma etching apparatus 1 has a processing chamber 2 formed into a cylindrical shape by, for example, aluminum or stainless steel. This processing chamber 2 is grounded. A dipole ring magnet (DRM) in which a plurality of permanent magnets are arranged in a circle around the periphery of the processing chamber 2 (not shown) is provided. By rotating the DRM, a rotating magnetic field is generated by the processing chamber. It can be formed in the space inside.

The ceiling 2B of the processing chamber 2 is
The ceiling 2B is provided with a flat hollow shower head 4 facing the susceptor 30 via the ceiling 2B. The processing gas or plasma gas introduced into the shower head 4 is directed toward the processing space S, that is, the space formed between the lower surface of the shower head 4 and the upper surface of the susceptor 30 on the gas ejection surface on the lower surface of the shower head 4. Are ejected.

The shower head 4 is formed of a conductive material, for example, anodized aluminum or surface-treated stainless steel to form an upper electrode, and is grounded via a conductor 7.

A gas introduction pipe 42 is connected to the gas introduction port 41 above the shower head 4. The gas introduction pipe 42 is branched into a plurality of pieces, and A
Ar gas source 43 for storing r gas, C4 as a processing gas
Etching gas sources 44 and 45 for storing the etching gas of F8 and O2 are connected respectively. Each of these gases is supplied while its flow rate is controlled by a mass flow controller 46 and an opening / closing valve 42 provided on the way.

A part of the side wall of the processing chamber 2 has a wafer loading / unloading port 23 corresponding to the position where the susceptor 30 is lowered.
Is disposed, and a gate valve 25 for communicating with and shutting off a transfer chamber 26 configured to be evacuated is disposed here.

The back surface of the susceptor 30 and the processing chamber bottom 2
A metal bellows 24 that is configured to extend and contract with the periphery of the opening 13 of A is provided. The bellows 24 allows the susceptor 30 to move up and down while maintaining the airtightness in the processing chamber 2.

The susceptor 30 is controlled by the high frequency power supply 10
A high frequency voltage of, for example, 13.56 MHz can be applied via the feeder line 12 and the elevating shaft 14 with the matching circuit 11 interposed therebetween.

An exhaust port 20 is provided on a side wall opposite to the wafer loading / unloading port 23, and a vacuum pipe 21 is connected to the exhaust port 20. The vacuum pipe 21 is provided with a vacuum pump 22.
By actuating, the air in the processing chamber 2 is exhausted, whereby the inside of the processing chamber 2 can be made substantially vacuum.

A substantially disk-shaped susceptor 30 made of a conductive material such as aluminum or stainless steel is provided inside the processing chamber 2 as a lower electrode. The susceptor 30 is supported and fixed to the upper end of an elevating shaft 14 inserted through an opening 13 at the center of the processing chamber bottom 2A, and is arranged to be able to elevate and lower by an elevating mechanism (not shown). During operation of the plasma etching apparatus 1, etching is performed with the wafer W placed on the upper surface of the susceptor 30.

A cooling jacket 15 in the form of a passage is provided inside the susceptor 30. By flowing a coolant through the jacket 15, the susceptor 30, and thus the wafer W mounted thereon, can be maintained at a desired temperature. It has become. Further, a plurality of lifter holes 16, 16,... Are formed in predetermined positions of the susceptor 30 so as to penetrate in the vertical direction, and can be moved up and down in the vertical direction corresponding to the lifter holes 16, 16,. Wafer lifter pins 17 are provided. The wafer lifter pin 17 is located at the bottom 2 of the processing chamber.
A pin elevating rod 18 movably mounted up and down through the opening 13 of A, and is integrally movably mounted. At the penetrating portion of the wafer lifter pin 17, a metal telescopic bellows 19 is provided between the wafer lifter pin 17 and the back surface of the susceptor 30, so that the wafer lifter pin 17 can move up and down while maintaining airtightness. I have. The wafer W is moved up and down by moving the wafer lift pins 17 up and down while holding the susceptor 30 at the position indicated by the one-dot chain line in FIG. Usually, three such wafer lift pins 17 are provided along the periphery of the wafer W.

On the upper surface of the susceptor 30, an annular correction ring 31 is provided.

FIG. 2 is a partially enlarged vertical sectional view of the upper part of the susceptor 30 according to the present embodiment, and FIG. 3 is an exploded perspective view of the correction ring 31 according to the present embodiment.

As shown in FIGS. 2 and 3, the correction ring 31 is composed of two concentric annular members. One of these annular members is a first correction ring member 3.
2, and another annular member is a second correction ring member 33.

These two correction ring members 32 and 33 are fitted together to form one correction ring 31.

That is, as shown in FIG. 2, the first correction ring member 32 has a rectangular notch 32a at the top on the inner peripheral side in its cross section. Similarly, a rectangular notch 32b is formed at the outer peripheral bottom.

The notch 32a at the top of the inner peripheral side of the first correction ring member 32 is designed to fit the outer peripheral edge of the wafer W when set on the susceptor 30 as shown in FIG. Has become.

The bottom of the first correction ring member 32 is formed with relatively rough irregularities 32c.
Zero point contact with the upper surface. This is to prevent the upper surface of the susceptor 30 from making surface contact with the bottom surface of the first correction ring member 32. By reducing the contact area between the bottom surface of the first correction ring member 32 and the upper surface of the susceptor 30, the first correction ring member 32
The heat conductivity between the first correction ring member 32 and the susceptor 30 is reduced so that the temperature of the first correction ring member 32 that has been heated by being exposed to the plasma during the processing of the wafer W does not decrease. The formation of the unevenness 32c at the bottom can be omitted.

A cutout portion 32b having a rectangular cross section is also formed on the outer peripheral bottom of the first correction ring member 32. The notch 32b is used for a second correction ring member 3 described later.
3 for fitting.

The second correction ring member 33 has a protruding portion 33a having a rectangular cross section on the inner peripheral bottom, and the protruding portion 33a forms a flange-shaped (flange) -shaped protruding portion.

The protruding portion 33a has a shape that just meshes with the cutout portion 32b on the outer peripheral bottom surface of the first correction ring member 32 described above.
When the first correction ring member 33 and the second correction ring member 33 are set on the susceptor 30, the notch 32 b and the protrusion 33 a are fitted together, and the first correction ring member 32 and the second correction ring member 33 In addition, a correction ring 31 is formed. That is, as shown in FIG. 2, the first correction ring member 32 and the second correction ring member 33 are connected to the susceptor 30.
When set on the first correction ring member 32,
The upper surfaces of the correction ring members 33 constitute the same plane. A heat conductive material layer as a cooling means, for example, a silicon rubber layer 34 is interposed between the bottom surface of the second correction ring member 33 and the upper surface of the susceptor 30. The silicon rubber layer 34 has excellent thermal conductivity, and is in close contact with the bottom surface of the second correction ring member 33 and the upper surface of the susceptor 30 to transfer heat between the second correction ring member 33 and the susceptor 30. Is easy. Therefore, even when the temperature of the second correction ring member rises during operation of the processing apparatus, the second correction ring member 3
3 spreads heat to the susceptor 30.
The susceptor 30 is always cooled by a built-in jacket. Therefore, the second correction ring member 33 is also cooled and its temperature rise is suppressed.

The following materials can be used as the material of the second correction ring member 33. For example, silicon, SiO ₂ , SiC, Al ₂ O ₃ , AlN, Y ₂ O _{3 and the} like can be mentioned.

As shown in FIG. 2, the first correction ring member 3
Reference numeral 2 has a substantially rectangular or hook-shaped cross-sectional shape in which a cutout portion 32b on the outer peripheral side bottom surface and a cutout portion 32a on the inner peripheral side are formed. Therefore, the first correction ring member 32 is
Of the first correction ring member 32 in the axial direction, as shown in FIG. 3, and can be easily removed.

Therefore, when the thickness of the first correction ring member 32 itself is reduced by etching, only the first correction ring member 32 can be replaced, which is economically excellent. In addition, there is an advantage that maintenance can be performed without any trouble since the replacement is easy.

Further, as shown in FIG. 2, the first correction ring member 32 is connected to the second correction ring member 33 and the susceptor 3.
0, it is not in close contact with the entire surface of the wafer W, but has such a size and shape that a gap is formed. In a state where the inside of the processing chamber 2 is kept substantially in a vacuum as in the operation of the plasma processing apparatus, almost no gas molecules exist in these gaps, and thus these gaps function as a heat insulating layer. Therefore, the first correction ring member 32 and the second correction ring member 33 or the first correction ring member 32
During the operation of the plasma etching apparatus 1, heat transfer between the susceptor 30 and the susceptor 30 can be suppressed to almost negligible level.

As a material of the first correction ring member 32, silicon or the like is used. In addition to silicon, the following materials can be used. For example, SiO ₂ ,
SiC, Al ₂ O ₃ , AlN, Y ₂ O _{3 and the} like can be mentioned.

The upper surface 32d of the first correction ring member 32
Is a width capable of effectively scavenging reactive substances such as fluorine radicals, which are considered to be generated from the processing gas deposits deposited on the surface of the susceptor 30, that is, an unnecessary free radical, and The dimensions are set so as not to impair the uniformity of the thermal distribution in the processing chamber 2.

The value of the width D depends on the type and temperature of the processing gas,
Although it fluctuates depending on conditions such as the degree of vacuum, for example, the same level as the mean free path λ of the processing gas molecule, for example, a range of 1 to 5 times the same mean free path λ is preferable, and 1 to 5 times the same mean free path λ. The range of 2 to 3 times is more preferable.

More specific numerical values include, for example, the width D
Is set to 1 to 25 mm. This width D corresponds to the width of the first temperature zone formed in the processing chamber 2 during operation of the plasma etching apparatus.

The reason why the preferable range of the width D of the first correction ring member 32 is set to the above range is that if the width D is smaller than the above range, the first correction ring member 32 will be used during processing.
This is because the width of the first temperature zone, which is a cylindrical temperature zone formed in the vicinity of the upper surface, becomes smaller.

When the width of the first temperature zone is smaller than the lower limit of the width D, the first radical scavenges the fluorine radicals generated by the plasma hitting the deposits deposited on the upper surface of the second correction ring member 33. In this temperature zone, the capability of the scavenging is reduced, sufficient scavenging is not performed, and the remaining fluorine radicals without scavenging reach the outer peripheral edge of the wafer W and increase the etching rate with respect to the upper surface of the wafer W.

On the other hand, when the width D exceeds the above range, the width of the first temperature zone which is a cylindrical temperature zone formed near the upper surface of the first correction ring member 32 during processing becomes large.

When the width of the first temperature zone is larger than the upper limit of the width D, there is a probability that gas molecules that do not contribute to the processing, for example, gas molecules such as argon collide with the upper surface 32 d of the first correction ring member 32. Increase. If the probability that gas molecules such as argon collide with the upper surface 32d of the first correction ring member 32 increases, the uniformity of thermal distribution in the processing chamber 2 is impaired, and the uniformity of processing of the wafer W is impaired. It is.

By setting the width D of the first correction ring member in the above range, the temperature distribution can be made uniform over the entire upper surface of the susceptor including the placed wafer W. At the same time, the fluorine radicals generated when the plasma is applied to the deposits deposited on the second correction ring member 33 outside the outer peripheral edge of the wafer W are converted to the first temperature at which the fluorine radicals are formed near the upper surface of the first correction ring member. Since scavenging can be performed depending on the band, it is possible to prevent the progress of local etching near the outer peripheral portion of the wafer W due to the fluorine radicals.

Next, an etching process performed using the plasma etching apparatus configured as described above will be described.

When a cluster tool device (not shown) equipped with the plasma etching device 1 is started, the cluster tool device is placed adjacent to the processing chamber 2 of the plasma etching device 1 via a carrier cassette, a transfer arm, and a load lock chamber (not shown). Is transferred to the transfer chamber 26.

Next, the transfer arm (not shown) rotates in the transfer chamber 26 and stops facing the front of the plasma etching apparatus 1. Thereafter, the gate valve 25 in front of the plasma etching apparatus 1 is opened, and the transfer arm enters the processing chamber 2 of the plasma etching apparatus 1 while holding the unprocessed wafer W.

On the other hand, in the processing chamber 2, the susceptor 3
1 is lowered downward in the processing chamber 2 as shown by the dashed line in FIG. 1, and in this state, the unprocessed wafer W is transferred from the transfer chamber 26 through the wafer loading / unloading port 23 to the processing chamber 2.
And placed on the susceptor 30.

Next, the susceptor 30 is raised by moving the elevating shaft 14 upward, and the wafer W placed on the upper surface thereof is made to approach the lower surface of the shower head 4.

In this state, the inside of the processing chamber 2 is evacuated while a predetermined amount of plasma gas or etching gas is supplied from the shower head 4 into the processing chamber 2.
This evacuation is performed after the gate valve 25 of the wafer loading / unloading port 23 of the processing chamber is closed and the inside of the processing chamber 2 is sealed. When the gate valve 25 is lowered to close the wafer loading / unloading port 23 and the inside of the processing chamber 2 is sealed, the vacuum pump 22 is operated to evacuate.

By continuously rotating the vacuum pump 22 at this rotation speed, the inside of the processing chamber 2 is maintained at the process pressure, and at the same time, a high-frequency voltage of, for example, 13.56 MHz is applied between the lower electrode susceptor 30 and the upper electrode. Is applied to generate plasma in the processing space S, and an etching process of, for example, an oxide film formed on the surface of the wafer W is performed.

Most of the plasma generated at the start of the process hits the upper surface of the wafer W and etches the oxide film on the upper surface of the wafer W. Some of the plasma generated at the same time spreads to a wider range than the outer peripheral edge of the wafer W, and the upper surface 32d of the first correction ring member 32
And reaches the upper surface of the second correction ring member 33.

At this time, since the first correction ring member 32 is disposed at a position near the outer peripheral edge of the wafer W, the amount of plasma irradiation is large, and the temperature reaches a high temperature in a short time. Since the first correction ring member 32 is a member having a small heat capacity, the temperature rises in a relatively short time, and when it reaches a predetermined temperature, it does not rise any more, and becomes thermally stable at a high temperature.

Since the bottom surface of the first correction ring member 32 is formed with rough irregularities 32c, the contact area between the first correction ring member 32 and the upper surface of the susceptor 30 is very small. A state close to contact is formed. Therefore, the first correction ring member 32 and the susceptor 3
Although a gap is formed between the upper surface of the processing chamber 2 and the upper surface of the processing chamber 2, the inside of the processing chamber 2 is maintained at a substantially vacuum during the processing, and air molecules hardly exist in the gap. As a result, the first correction ring member 32 is in a state equivalent to being insulated from the susceptor 30 and the second correction ring member 33, and is stably maintained at a high temperature. As a result, during processing, the first temperature band H of high temperature is located near the upper surface 32d of the first correction ring member 32.
Is formed.

On the other hand, the second correction ring member 33 has a structure in which heat can be easily transferred through the susceptor 30 cooled by the jacket and the silicon rubber layer 34. Therefore, even if the plasma is applied or the surrounding heat propagates and heat is supplied to the second correction ring member 33, the second correction ring member 33 is cooled via the susceptor 30 and the silicon rubber layer 34. Therefore, the temperature of the second correction ring member 33 does not rise so much and is maintained at a lower temperature than that of the first correction ring member 32.

As a result, a relatively low temperature second temperature zone L is formed near the upper surface of the second correction ring member 33.

As described above, during processing, the first temperature zone H due to the first correction ring member 32 is formed with a narrow width D on the outer peripheral edge of the wafer W, and the second correction zone is further formed outside the first temperature zone H. A second temperature zone L resulting from the ring member 33 is formed.

During the processing, several kinds of gas molecules including the processing gas molecules are moving in the processing chamber 2. Some of them collide with the second correction ring member 33, but since the second correction ring member 33 is maintained at a relatively low temperature, it is not possible to significantly disturb the thermal distribution in the processing chamber 2. Absent. Further, a high-temperature first correction ring member 32 is disposed inside the second correction ring member 33. The width D of the first correction ring member 32 is 1 to 3 times or 1 times the mean free path λ of the processing gas molecules. Since it is as narrow as about 5 times, the number of gas molecules colliding with the upper surface 32d of the first correction ring member 32 is very small. Processing chamber 2
The effect on the processing gas atmosphere in the chamber is only negligible. Therefore, when observed over the entire processing gas atmosphere in the processing chamber 2, a uniform temperature distribution is achieved over the entire upper surface of the susceptor 30, and uniform etching is performed at the center and the outer peripheral edge of the wafer W.

On the other hand, some of the substances constituting the processing gas adhere to and accumulate on the surface of the second correction ring member 33, and when the deposits are exposed to plasma, reactive substances such as highly corrosive fluorine radicals are produced. Is considered to be generated. Such a reactive substance diffuses and the second correction ring member 3
When the wafer W is to be moved from the upper second temperature zone L to the position where the wafer W is mounted, the temperature between the second temperature zone L and the wafer W is high due to the first correction ring member 32. Must pass through the first temperature zone H.

At this time, since the first temperature zone H is maintained at a sufficiently high temperature, the reaction of fluorine radicals and the like diffused from the second temperature zone L before passing through the first temperature zone H is completed. The reactive substance is converted into another substance by reacting on the surface of the first correction ring member 32, that is, the first temperature zone H, and the reactivity disappears.
It is considered that the reactive substance diffusing from the substrate W to the wafer W side is substantially removed, so that the influence on the wafer W is prevented beforehand.

When the intended etching process is completed after performing the etching process for a predetermined time, the degree of vacuum in the processing chamber 2 is reduced to a degree slightly higher than the degree of vacuum in the transfer chamber 26. Processing chamber 2 in reverse order
The processed wafer W is taken out from the inside. Then, similarly, the wafer W is transferred into the subsequent processing chamber, and predetermined processing is performed in the processing chamber. After a series of processing is completed, the processed wafer W is taken out from the last processing chamber into the transfer chamber 26, and is further stored in the carrier cassette from the transfer chamber 26 via the load lock chamber, and the processing is performed. Complete.

As described above, in the plasma processing apparatus 1 according to the present embodiment, the heat transfer is limited just outside the wafer W mounting portion of the susceptor 30 with the same width as the mean free path of the processing gas. A first correction ring member 32 is provided, and a second correction ring member 33 is provided immediately outside the first correction ring member 32. The second correction ring member 33 is made of silicon rubber. Since the heat is easily released to the susceptor 30 side by using the layer 34, the first
, A high-temperature first temperature zone H is formed around the correction ring member, and a relatively low-temperature second temperature zone formed by the second correction ring member 33 outside the first temperature zone H. L is formed.

As a result, the temperature distribution on the susceptor 30 is high near the center and low around the second correction ring member 33 on the outer periphery. Processing is performed.

On the other hand, the wafer W placed on the susceptor 30
A first correction ring member 32 having a narrow width, that is, the same width as the mean free path of the processing gas molecules, is inserted in the vicinity of the outer peripheral edge of the first correction ring member 32. Will be maintained. Therefore, the first correction ring member 3
A high temperature first temperature zone H is formed in the vicinity of the upper surface of 2. The corrosive substance such as fluorine radicals generated around the second correction ring member 33 is scavenged by the action of the first temperature zone H, so that the corrosive substance such as fluorine radicals is To prevent the etching from locally progressing.

The present invention is not limited to the contents described in the above embodiment. For example, in the above-described embodiment, a plasma etching apparatus for a silicon wafer has been described as an example, but the present invention can also be used for other reactive gas processing apparatuses, for example, CVD.

Further, it goes without saying that the present invention can be applied to a processing apparatus for processing an LCD glass substrate as well as a silicon wafer.

In the above embodiment, a rotating magnetic field type processing apparatus using a so-called dipole ring magnet (DRM) for rotating a plurality of cylindrical permanent magnets around a processing chamber has been described as an example. The present invention is also applicable to a processing device not equipped with a ring magnet (DRM).

(Example) Hereinafter, the wafer W was etched using various types of correction rings by using the plasma etching apparatus 1 of the type described in the above embodiment.

FIGS. 4 to 9 show the relationship between the distance from the center of the wafer and the etching rate.

FIG. 4 is a graph showing the result when a single thin annular correction ring of the conventional type is used without cooling and the silicon oxide film formed on the surface of the wafer is subjected to plasma etching. FIG. 5 is a graph showing the result when plasma etching of a silicon oxide film is performed using one conventional thin annular correction ring in a cooled state, and FIG. Correction ring member and second
FIG. 9 is a graph showing a result when plasma etching of a silicon oxide film is performed in a state where a second correction ring member is cooled using a correction ring that can be divided concentrically with the correction ring member of FIG.

In each graph, continuous curves show data for one wafer, and the measurement was performed on three wafers at 30, 60, and 120 seconds after the start of measurement.

When FIG. 4 is compared with FIG. 6, the graph of FIG.
The variation between wafers is small at a position outside mm, the time dependency of the etching rate near the outer peripheral edge is small, and the etching rate is stable.

Next, comparing FIG. 5 with FIG. 6, the graph of FIG. 6 shows that the slope of the curve is smaller at a portion outside 60 mm from the center of the wafer to the left and right, and the variation of the etching rate at this portion is small. This shows that the difference between the etching rates in the wafer surface is small.

FIG. 7 is a graph showing the results when a conventional thin annular correction ring is used without cooling and the resist film formed on the surface of the wafer is subjected to plasma etching. FIG. 8 is a graph showing the result of plasma etching of a resist film using one conventional thin annular correction ring in a cooled state, and FIG. 9 is a graph showing the result of the first correction ring. FIG. 9 is a graph showing a result of performing a plasma etching of a resist film in a state where the second correction ring member is cooled, using a correction ring that can be concentrically divided into a member and a second correction ring member.

In each graph, continuous curves show data for one wafer, and the measurement was performed for three wafers at 30, 60, and 120 seconds after the start of measurement.

When comparing FIG. 7 with FIG. 9, the graph of FIG. 9 showing the result of the split type correction ring has almost the same shape of the three curves, and the variation between wafers at a portion outside the center of 60 mm from the center. That is, the time dependency of the etching rate is small, and the etching rate near the outer peripheral edge is stable.

Next, comparing FIG. 8 with FIG. 9, the graph of FIG. 9 shows that the variation of the etching rate in the portion outside the left and right 60 mm from the center is small, and the difference in the etching rate in the wafer plane is small.

From the above results, when the plasma etching process is performed using the correction ring 31 according to the present embodiment, the variation in the etching rate between wafers in different processing orders is small, and the vicinity of the center and the outer peripheral edge of the wafer is reduced. It can be seen that a uniform etching process can be performed with little change in the etching rate between.

FIGS. 10 to 12 show the relationship between the diameter of the through hole and the distance from the center of the wafer when the silicon oxide film formed on the wafer surface is etched to form the through hole. It is a graph. In each graph, a curve (STD) when a through-hole is formed by using one conventional ring-shaped correction ring without cooling, and a curve obtained by cooling and using one conventional ring-shaped correction ring are shown. Curve (Cooling) in the case of forming a through-hole by cooling, and curve (DIVIDED 1) in the case of forming a through-hole by cooling and using the second correction ring member of the two-part correction ring of the present invention. Three curves are shown. FIG. 10 shows the value of the diameter near the top of the through hole, FIG. 11 shows the value of the diameter near the center of the through hole, and FIG.
2 indicates the value of the diameter at the bottom of the through hole.

As is apparent from the results shown in FIGS. 10 to 12, the value of the diameter of any part of the through hole is
It can be seen that when formed using the correction ring of the present embodiment, a through hole having a small variation in the value of the diameter and a uniform size can be formed from the center of the wafer to the outer peripheral edge.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. In the following description, among the embodiments after this embodiment, the contents overlapping with the preceding embodiment will not be described.

In this embodiment, a correction ring 31A having a structure as shown in FIG. 13 is used.

In this correction ring 31A, a disk-shaped first correction ring member 32A having a rectangular cross-section is replaced with a substantially rectangular cross-section second correction ring member 33A having a notch. The second correction ring member 33 </ b> A is disposed on the upper surface of the susceptor 30 via the silicon rubber layer 34. On the other hand, the first correction ring member 32A is merely placed in the notch on the inner peripheral side of the second correction ring member 33A.

In the correction ring 31A according to the present embodiment,
First correction ring member 32A, second correction ring member 3
Since the shape of 3A is simple, it is easy to manufacture, and the effect of reducing the manufacturing cost can be obtained.

[0101]

According to the plasma processing apparatus of the present invention, the ring disposed around the substrate to be processed is separated into the first ring member and the second ring member, and the first ring member is Since the second ring member is maintained at the second temperature during the processing while being maintained at the first temperature during the processing, even when a plurality of substrates to be processed are continuously processed. Variations in quality between substrates to be processed are small, and uniform processing can be performed over the entire substrate to be processed.

According to the plasma processing method of the present invention,
A first temperature zone is formed in an annular shape along the outer peripheral edge of the wafer, a second temperature zone is formed outside the first temperature zone, and a plasma process is performed on the wafer in this state. Even when the substrates to be processed are continuously processed, the variation in quality among the substrates to be processed is small, and moreover, uniform processing can be performed over the entire substrate to be processed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a plasma etching apparatus according to a first embodiment.

FIG. 2 is a vertical cross-sectional view in which an upper portion of a susceptor according to the first embodiment is partially enlarged.

FIG. 3 is an exploded perspective view of the correction ring according to the first embodiment.

FIG. 4 is a graph showing the relationship between the distance from the wafer center and the etching rate of a silicon oxide film when a conventional correction ring is used without cooling.

FIG. 5 is a graph showing a relationship between a distance from a wafer center and an etching rate of a silicon oxide film when a conventional correction ring is used while being cooled.

FIG. 6 is a graph showing the relationship between the distance from the wafer center and the etching rate of the silicon oxide film when the correction ring according to the first embodiment is used.

FIG. 7 is a graph showing a relationship between a distance from a wafer center and an etching rate of a resist film when a conventional correction ring is used without cooling.

FIG. 8 is a graph showing a relationship between a distance from a wafer center and an etching rate of a resist film when a conventional correction ring is used while being cooled.

FIG. 9 is a graph showing the relationship between the distance from the center of the wafer and the etching rate of the resist film when the correction ring according to the first embodiment is used.

FIG. 10 is a graph showing the relationship between the diameter of a through hole formed by etching a silicon oxide film on a wafer and the distance from the center of the wafer.

FIG. 11 is a graph showing a relationship between a diameter of a through hole formed by etching a silicon oxide film on a wafer and a distance from the center of the wafer.

FIG. 12 is a graph showing a relationship between a diameter of a through hole formed by etching a silicon oxide film on a wafer and a distance from a center of the wafer.

FIG. 13 is a vertical sectional view of a correction ring according to a second embodiment.

FIG. 14 is a vertical sectional view of a conventional plasma etching apparatus.

FIG. 15 is a graph showing the relationship between the etching rate of a resist film and the distance from the center of a wafer when a conventional plasma etching apparatus is used.

[Explanation of symbols]

1. Plasma etching apparatus (plasma processing apparatus) 2.
... processing chamber, 30 ... susceptor, 31 ... correction ring,
32: first correction ring member, 33: second correction ring member, 34: silicon rubber layer (cooling means), 32c ...
Unevenness, H: first temperature zone, L: second temperature zone, 42
... gas supply pipe (gas supply system), 21 ... exhaust pipe.

Claims (20)

[Claims] A processing chamber for performing processing on the substrate under substantially vacuum; a processing gas supply system for supplying a processing gas to the substrate; plasma generating means for generating plasma in the processing chamber; A susceptor on which the substrate to be processed is mounted; a first ring member surrounding an outer periphery of the substrate to be processed mounted on the susceptor and maintained at a first temperature during processing; and the first ring A second ring member surrounding the outer periphery of the member and maintained at a second temperature during processing. 2. The plasma processing apparatus according to claim 1, wherein the first temperature is higher than the second temperature. 3. The plasma processing apparatus according to claim 1, wherein at least an upper surface of the first ring member has a width which is 1 to 3 times a mean free path of the processing gas molecules. A plasma processing apparatus characterized by the above-mentioned. 4. The plasma processing apparatus according to claim 1, wherein at least an upper surface of said first ring member has a width of 1 mm to 25 mm. Plasma processing equipment. 5. The plasma processing apparatus according to claim 1, further comprising cooling means for cooling said second ring member. 6. The plasma processing apparatus according to claim 1, wherein said cooling means is a heat conductive material interposed between a second ring member and said susceptor. A plasma processing apparatus characterized by being a layer. 7. The plasma processing apparatus according to claim 1, wherein irregularities are formed on a bottom surface of the first ring member to form a point contact. Plasma processing apparatus. 8. The plasma processing apparatus according to claim 1, wherein the first ring member has a rectangular notch at each of an inner peripheral top and an outer peripheral bottom. The second ring member has a substantially rectangular cross section with a rectangular projection on the inner peripheral bottom, and the second ring member has a substantially rectangular cross section. A plasma processing apparatus having a shape in which the second ring member is detachably fitted. 9. The plasma processing apparatus according to claim 1, wherein the plasma processing is an etching process. 10. The plasma processing apparatus according to claim 1, wherein a cooling jacket is provided inside the susceptor. 11. The plasma processing apparatus according to claim 1, wherein an outer peripheral edge of the workpiece is fitted to an inner peripheral top of the first ring member. A plasma processing apparatus, wherein a part is formed. 12. The plasma processing apparatus according to claim 1, wherein the first ring member and the second ring member are made of silicon, SiO ₂ , SiC,
A plasma processing apparatus characterized by being formed of one material selected from the group consisting of Al ₂ O ₃ , AlN, and Y ₂ O ₃ . 13. The plasma processing apparatus according to claim 1, wherein the second ring member has a substantially rectangular cross-sectional shape, and the first ring member and the first ring member are connected to each other. A plasma processing apparatus, wherein the plasma processing apparatus is formed in a shape to be detachably fitted to a second ring member. 14. A plasma processing method for performing plasma processing on a substrate to be processed, wherein an annular first temperature zone is formed along an outer peripheral edge of the substrate to be processed, and
With a second temperature zone formed outside the temperature zone of
A plasma processing method, wherein the processing target substrate is subjected to a plasma processing. 15. The plasma processing method according to claim 14, wherein the first temperature zone is a zone having a higher temperature than the second temperature zone. 16. The plasma processing method according to claim 14, wherein the first temperature zone is formed to have a width that is 1 to 3 times a mean free path of the processing gas molecules. Plasma processing method. 17. The plasma processing method according to claim 14, wherein the width of the first temperature zone is formed to a width of 1 mm to 25 mm. Processing method. 18. The plasma processing method according to claim 14, wherein the plasma processing is an etching processing. 19. The plasma processing method according to claim 14, wherein the etching is an etching using a gas containing a fluorine atom. 20. The plasma processing method according to claim 14, wherein the gas containing a fluorine atom is a compound gas containing a fluorine atom and a carbon atom. Plasma treatment method.