JPH11288922A - Ashing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely remove resist by ashing the resist at a high ashing rate and to prevent ions from being made incident on a processed wafer at plasma firing. SOLUTION: This ashing device equipped with a cylindrical plasma generation chamber 3 which has a ceiling part 3a and a process chamber 4 connected to the lower side of the plasma generation chamber 3 and communicates with the plasma generation chamber 3 through a nearly circular irradiation hole (opening) 4 provided at the lower end of the plasma generation chamber 3 and ashes the processed wafer 30 held in the process chamber 4 through irradiation with plasma generated in the plasma generation part 4 from the irradiation hole 3b is characterized in that the irradiation hole 3b is formed to nearly the same diameter as with the processed wafer 20. Furthermore, the side above the irradiation port 3b of the plasma generation chamber 3 is formed which has an area for its planar section larger than the area of the irradiation hole 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ashing apparatus used for removing a resist formed on a wafer to be processed in a photolithography process for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art As a conventional ashing device, for example, a down-flow type as shown in FIG. 5 is known. That is, this ashing device 51 is an ICP (Indu
It is of a ctively-coupled plasma type, and includes a chamber 52 for ashing the wafer 20 to be processed using reactive species (radicals) in the plasma 30 and a transfer chamber 53 connected to the chamber 52.

The chamber 52 includes a plasma generation chamber 54 as a plasma source, and a processing chamber 55 formed below the plasma generation chamber 54 so as to communicate with the plasma generation chamber 54 and ashing the wafer 20 to be processed. Have. The plasma generation chamber 54 is, for example, a cylindrical one having a ceiling portion 54a, and an opening 54b at the lower end is an irradiation port for irradiating radicals in the plasma 30 toward the processing chamber 55 (hereinafter, the irradiation of the opening 54b is performed). Mouth 54b). Here, the radical irradiation port 54b is formed to have the same diameter as the plasma generation chamber 54, and therefore, the area of the irradiation port 54b is substantially equal to the area of the plane cross section of the plasma generation chamber 54. The irradiation port 54b is connected to the wafer 2 to be processed.
A diameter substantially equal to the diameter of 0, that is, the area of the irradiation port 54b is substantially equal to the area of the upper surface which is the processing surface of the processing target wafer 20.

A ceiling 54a of the plasma generation chamber 54 has
A processing gas introduction pipe 56 used for the ashing process is connected. Further, around the side wall of the plasma generation chamber 54,
A coil 57 as an electric field supply source is provided so as to wind around the side wall.

[0005] In the processing chamber 55, a heater 58, which also serves as a stage for holding the wafer 20 to be processed, is provided almost immediately below the irradiation port 54 b of the plasma generation chamber 54.
The heater 58 is for heating the processing target wafer 20 in order to enhance the reaction between radicals in the plasma 30 and the resist on the processing target wafer 20. Further, a vacuum pump 59 for maintaining the entire inside of the chamber 52 at a predetermined vacuum state is connected to the processing chamber 55.

On the other hand, the transfer chamber 53 is connected to the processing chamber 55 of the chamber 52 via a gate valve 60, and communicates with the chamber 52 with the gate valve 60 opened. The inside of the transfer chamber 53 contains the wafer 2 to be processed.
0 and a wafer 61 to be processed.
And a transfer arm 62 for transferring the wafer to be processed 20 by the transfer arm 62.
From the heater 58 into the processing chamber 55 and from the heater 58 to the carrier 61.

In such an ashing apparatus 51, when performing the ashing process, first, the gate valve 60 is opened, and the wafer 20 to be processed stored in the carrier 61 is opened.
Is disposed on the heater 58 of the processing chamber 55 by the transfer arm 62 and is held. The heater 58 is heated in advance, and the wafer to be processed 20 is heated to a predetermined temperature by the heater 58. Next, the gate valve 60 is closed, and the inside of the chamber 52 is brought into a predetermined vacuum state. Then, a processing gas is introduced into the plasma generation chamber 54 while maintaining this vacuum state, and then a high frequency (RF) current is passed through the coil 57 to generate the plasma 30 in the plasma generation chamber 54 (ignition).
Then, the radicals in the plasma 30 are caused to flow down to the processing chamber 55 to ashing the resist on the processing target wafer 20.

In the ashing process using the ashing device 51 described above, as shown in FIG.
When the processed wafer 20 having the resist 21 formed on the upper surface is heated by the heater 58 at a temperature of, for example, about 250 ° C.,
As shown in FIG. 6B, a phenomenon called popping occurs, in which vapor is generated from the resist 21 and exploded by vapor to peel off the resist 21. In FIG. 6B, reference numeral 21a denotes a resist flying by a steam explosion.
b denotes a resist that rises like a mountain due to a steam explosion.

When observing the wafer 20 after the vapor explosion due to the popping, a moon crater having a radius of about several μm to several mm is confirmed. Also resist 2
In FIG. 1, a portion 21b that is raised like a mountain (popped portion) 21b is formed by gathering the resists 21 between the exploded portions, as shown in FIG.
Even if the initial thickness t of the resist 21 is about 1 μm, the thickness T is about several μm to several tens μm. Normally, the ashing process is performed on the wafer 20 to be processed in the popped state.

[0010]

However, since the conventional ashing apparatus 51 shown in FIG. 5 has a low ashing rate, a resist having a large difference in thickness between the popped portion and the non-popped portion as described above is used. ,
When the ashing process is performed based on the non-popped portion, the popped portion 2 as shown in FIG.
1b is not sufficiently ashed and remains as a columnar residue. If an ashing process is performed so as not to generate the residue, a long time is required for the ashing process, which causes a problem that the throughput is reduced.

Moreover, the columnar residue cannot be necessarily removed by the ashing process for a long time, and there is also a problem that the hardened layer having a very poor releasability at the time of ashing becomes difficult to remove. This is due to the fact that when the radicals in the plasma are irradiated toward the wafer to be processed, the radicals contain ions, and the ions in the plasma react with the resist that rises like a mountain. It changes to a substance that is difficult to be ashed.

As described above, in the conventional ashing apparatus, the heater is provided almost immediately below the radical irradiation port, and plasma is generated (ignited) above the wafer to be processed disposed on the heater. It has become.
Therefore, irradiation of ions to the wafer to be processed at the time of plasma ignition is inevitable. Further, even if the plasma generation chamber is a plasma source that generates a small amount of ions, irradiation of ions to the wafer to be processed during plasma ignition is an unavoidable problem.

As a solution to this problem, it is conceivable to provide a shutter mechanism between the plasma generation chamber and the wafer reaction chamber. However, the provision of the shutter causes deterioration of ashing process uniformity in the wafer surface due to opening and closing of the shutter and a problem of generation of particles due to the existence of the shutter itself. It is the current situation.

Further, when ashing is performed in a state where the upper side of the popped portion of the resist is hardly ashed, as shown in FIGS. 8 (a) to 8 (e), the portion which reacts easily, that is, the popped portion The ashing process proceeds so as to go under the lower side of 21b. as a result,
In some cases, the upper side of the popped portion 21b, which is difficult to be ashed, is separated into a powder form. Occurs.

[0015]

In order to solve the above problems, an ashing apparatus according to the present invention is connected to a cylindrical plasma generation chamber having a ceiling and a lower side of the plasma generation chamber. And a processing chamber that communicates with the plasma generation chamber through a substantially circular opening provided at a lower end of the plasma generation chamber, and is held in the processing chamber by irradiation of the plasma generated in the plasma generation chamber from the opening. In the ashing apparatus for ashing a wafer to be processed, the opening is formed to have a diameter substantially equal to the diameter of the wafer to be processed held in the processing chamber, and the area above the opening of the plasma generation chamber has a plane cross-sectional area. The configuration is such that it is formed to be larger than the area of the opening.

In the above-mentioned invention, the opening at the lower end of the cylindrical plasma generation chamber is formed to have a diameter substantially equal to the diameter of the wafer to be processed held in the processing chamber, and has the same size as the conventional one. Moreover, the upper side of the opening of the plasma generation chamber is formed such that the area of the plane cross section is larger than the area of the opening. For this reason, if the height of the plasma generation chamber is made almost equal to the height of the conventional plasma generation chamber,
The volume of the plasma generation chamber is larger than that of the conventional plasma generation chamber. Therefore, a large amount of plasma is generated in the plasma generation chamber as compared with the related art, so that a large amount of plasma (radical) is irradiated into the processing chamber from the opening of the plasma generation chamber, and the processing target wafer held in the processing chamber is removed. Ashing can be performed at a very high ashing rate.

According to a second aspect of the present invention, there is provided an ashing apparatus, comprising: a plasma generation chamber connected to a lower side of the plasma generation chamber; A processing chamber communicating with the generation chamber, wherein the irradiation of the plasma generated in the plasma generation chamber from the opening, the ashing apparatus for ashing a wafer to be processed held in the processing chamber, the opening of the plasma generation chamber, The area is formed so as to be smaller than the upper surface of the wafer to be processed held in the processing chamber, and the plasma from the opening is applied to the opening so as to scan over the wafer to be processed held in the processing chamber. The apparatus has a moving means for relatively moving the processing wafer.

In the present invention, since the opening of the plasma generation chamber is formed so that the area of the opening is smaller than the upper surface of the wafer to be processed held in the processing chamber, the volume of the plasma generation chamber is the same as the conventional one. Then, compared with the related art in which the area of the opening is substantially equal to the upper surface of the wafer to be processed, the processing chamber is irradiated with the plasma at a higher density from the opening. Therefore, it becomes possible to ashing the wafer to be processed held in the processing chamber at a very high ashing rate.
In addition, if the density of radicals irradiated from the opening is slightly higher than before, it is possible to reduce the amount of plasma generated by an increase in the remaining radical density,
The size of the plasma generation chamber can be reduced. Further, since the moving means for moving the processing target wafer relative to the opening is provided so that the plasma (radical) from the opening scans over the processing target wafer held in the processing chamber, After the plasma is ignited, the entire surface of the wafer to be processed is ashed with good in-plane uniformity even when the wafer to be processed is positioned immediately below the opening when the plasma potential stabilizes and only radicals are irradiated from the opening. It becomes possible to do. Therefore, by starting ashing in this manner, irradiation of ions to the wafer to be processed during plasma ignition is prevented.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ashing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing an ashing apparatus according to the first embodiment, and is a diagram showing a chamber portion for performing an ashing process using radicals in plasma.

The ashing device 1 is of a downflow type, and the difference from the conventional downflow type ashing device 51 shown in FIG. 5 lies in the shape of the plasma generation chamber. That is, the ashing device 1 is, as in the prior art,
The chamber 2 includes a chamber 2 and a transfer chamber (not shown) connected to the chamber 2. The chamber 2 includes a plasma generation chamber 3 as a plasma source, and a plasma generation chamber 3 below the plasma generation chamber 3. The processing chamber 4 is connected in a communicating state and performs an ashing process on the wafer 20 to be processed.

The plasma generation chamber 3 is, for example, a substantially cylindrical one having a ceiling 3a, and an opening 3b provided at the lower end.
Are irradiation ports for irradiating the processing chamber 22 with radicals in the plasma 30 (hereinafter, the opening 3b is referred to as the irradiation port 3b). Then, the plasma generation chamber 3 and the processing chamber 4 are in communication with each other via the irradiation port 3b. In addition,
The arrow A in FIG. 1 indicates the flow of radicals flowing down from the plasma 30 toward the irradiation port 3b.

The irradiation port 3b has a substantially circular shape, for example.
The diameter of the processing target wafer 20 held in the processing chamber 4 is substantially equal to the diameter of the processing target wafer 20, that is, the area of the processing target wafer 20 is substantially equal to the area of the upper surface of the processing target wafer 20. Further, the upper side of the irradiation port 3b of the plasma generation chamber 3 is formed such that the area of its plane cross section is larger than the area of the irradiation port 3b. That is, the plasma generation chamber 3 has a shape in which the upper side is formed as a cylinder having a diameter larger than the diameter of the irradiation port 3b, and the lower side is reduced in diameter toward the irradiation port 3b.

An inlet pipe 5 for a processing gas used for ashing is connected to the ceiling 3b of the plasma generation chamber 3 having such a shape. A coil 6 as a supply source is provided so as to wind around the side wall. An RF power supply (not shown) for supplying an RF current is connected to the coil 6.

On the other hand, the processing chamber 4 and the transfer chamber have the same configuration as the conventional ashing device 51 shown in FIG. For example, in the processing chamber 4, a heater 7 serving also as a stage for holding a wafer to be processed is provided almost immediately below the irradiation port 3 b in the processing chamber 4. Is connected to a vacuum pump 8 for maintaining a predetermined vacuum state. Further, the transfer chamber is connected to the processing chamber 4 in a state where the transfer chamber communicates with the processing chamber 4 via a gate valve, and the carrier for storing the processing target wafer 20 therein and the processing target wafer 20 are loaded into the processing chamber 4. Further, a transfer arm for unloading the processing target wafer 20 from the processing chamber 4 is provided.

In the ashing apparatus 1 described above, when ashing the resist formed on the wafer 20 to be processed, the gate valve is first opened, and the wafer to be processed stored in the carrier is moved by the transfer arm into the processing chamber 4. It is arranged and held on the heater 7. The heater 7 is heated in advance, and the wafer 7 to be processed is heated to a predetermined temperature by the heater 7. Next, the gate valve is closed, and the inside of the chamber 2 is brought into a predetermined vacuum state, and then the processing gas is introduced into the plasma generation chamber 3. And coil 6
When an RF current is passed through the plasma generation chamber 3, plasma 30 is generated (ignited) in the plasma generation chamber 3, and radicals in the plasma 30 flow down to the processing chamber 4 as shown by an arrow A to Ash the resist.

In the ashing apparatus 1 of the first embodiment, the irradiation port 3b of the plasma generation chamber 3 is
The plasma generation chamber 3 is formed to have a diameter substantially equal to the diameter of the processing target wafer 20 held therein, and the upper side of the irradiation port 3b of the plasma generation chamber 3 is formed to have a diameter larger than the irradiation port 3b. Therefore, if the height of the plasma generation chamber 3 is substantially equal to the height of the conventional plasma generation chamber, the volume of the plasma generation chamber 3 is larger than that of the conventional plasma generation chamber. As a result, a large amount of plasma 30 can be generated in the plasma generation chamber 3 as compared with the related art, so that the irradiation port 3 b
And a large amount of radicals can be irradiated to the processing chamber 4 at high density.

Therefore, the processing target wafer 20 held in the processing chamber 4 can be ashed at a very high ashing rate, so that the portion of the resist on the processing target wafer 20 that is popped by the heater 7 is thick. Even if formed, the resist can be reliably removed without leaving the popped portion as a residue. Further, since the resist can be reliably removed without requiring a long time, a decrease in throughput can be suppressed.

Further, since the ashing process can be performed at a very high ashing rate, even when the plasma 30 is ignited, a portion which is difficult to be ashed due to the irradiation of the ions in the plasma 30 occurs. It can be removed without re-adhering as particles on the wafer 20 to be processed.
Therefore, the ashing apparatus 1 of this embodiment can always keep the processing surface of the wafer 20 to be processed after the ashing process in a clean state, thereby improving the manufacturing yield and the electrical reliability of the semiconductor device. It is very effective.

In the above embodiment, the plasma generation chamber has a cylindrical shape, for example, but has a cylindrical shape with a ceiling surface.
In addition, if the plasma generation chamber is formed such that the area of the plane section on the upper side thereof is larger than the area of the irradiation port, the plane section may be, for example, substantially rectangular or polygonal.

Next, the second embodiment of the ashing apparatus according to the present invention will be described.
An embodiment will be described with reference to FIGS. Note that FIG.
FIG. 3 is a schematic configuration diagram illustrating an ashing device according to a second embodiment, and FIG. 3 is a cross-sectional view of a main part of the ashing device according to the second embodiment. FIG. 4 is a perspective view of the ashing device according to the second embodiment. 2 to 4, the same components as those in the first embodiment are denoted by the same reference numerals, and the description in this embodiment is omitted.

As shown in FIG. 2, the ashing apparatus 10 of the second embodiment is also provided with a downflow type chamber 11. The chamber 11 includes a plasma generation chamber 12 that is a plasma source, and a processing chamber 13 that is connected to a lower part of the plasma generation chamber 12 so as to communicate with the plasma generation chamber 12 and performs an ashing process on the wafer 20 to be processed.
Although the plasma generation chamber 12 has, for example, the same shape as that of the first embodiment, the area of the radical irradiation port 12b provided at the lower end thereof is smaller than that of the first embodiment. I have.

That is, similarly to the first embodiment, the plasma generation chamber 12 has, for example, a substantially cylindrical shape having a ceiling portion 12a, and a radical irradiation port 12b is formed at the lower end. 13 is in communication. The irradiation port 12b has, for example, a substantially circular shape and is formed to have an area smaller than the area of the upper surface of the processing target wafer 20 held in the processing chamber 13. The upper side of the irradiation port 12b of the plasma generation chamber 12 is formed such that the area of its plane cross section is larger than the area of the irradiation port 12b. That is, the plasma generation chamber 12 has a shape in which the upper side is formed as a cylinder having a diameter larger than the diameter of the irradiation port 12b, and the lower side is reduced in diameter toward the irradiation port 12b and narrowed.

The plasma generation chamber 12 is provided with a measuring means (not shown) for measuring the potential (plasma potential) of the plasma 30 generated here. The measuring means is connected to a control means to be described later, and a measurement result is outputted to the control means.

On the other hand, the ashing device 10 of the second embodiment
The processing chamber 13 is also used as a transfer chamber in a conventional ashing apparatus, and has a carrier 14 for accommodating the processing target wafer 20 therein, and relatively moves the processing target wafer 20 with respect to the irradiation port 12b. A transfer arm 15 is provided as a moving means for performing the movement, and a sensor 16 for detecting an ashing amount of the wafer 20 to be processed is provided. Further, a vacuum pump 8 for maintaining the inside of the processing chamber 13 at a predetermined vacuum state is connected.

In the second embodiment, the processing chamber 13
As shown in FIGS. 2 and 4, the carrier 14 has, for example, a substantially rectangular shape in plan view, and the carrier 14 is disposed at one end in the length direction. The plasma generation chamber 12 is located above the other end in the length direction.
Is provided. A door 13a for carrying out the carrier is provided on the side surface of the processing chamber 13 near the carrier 15 so as to be openable and closable so that the carrier 15 can be transported into the processing chamber 13 and transported from the processing chamber 13 to the outside. It has become.

The transfer arm 15 holds the processing target wafer 20 in the processing chamber 13 and moves the held processing target wafer 20 to the irradiation port 12b. For example, a loading arm 15a for loading the wafer 20 to be processed from the carrier 14 substantially below the irradiation port 12b and positioning it, and an unloading arm 15b for unloading the processing wafer 20 to the carrier 14 from almost directly below the irradiation port 12b. And is provided so as to be movable between the carrier 14 and substantially immediately below the irradiation port 12b.

Further, the transfer arm 15a of the transfer arm 15 receives the plasma (radical) from the irradiation port 12b.
Has a function of moving the processing target wafer 20 with respect to the irradiation port 12b so as to scan over the processing target wafer 20. Note that, as described above, the loading arm 15a
If the transfer arm 15 is composed of the transfer arm 15 b and the transfer arm 15 b, the processing target wafer 20 is transferred to the transfer arm 1.
Since the wafer 20 to be processed next can be arranged in the irradiation port 12b by the unloading arm 15a while the wafer is moved at 5b, it is very effective in efficiently performing the ashing process.

The sensor 16 is provided with a product such as carbon monoxide (C) generated in the process of ashing the resist.
O) is detected to detect the amount of ashing, and is installed, for example, below the irradiation port 12b of the plasma generation chamber 12 and in the vicinity where the wafer 20 to be processed is held.

As described above, the carrier 14, the transfer arm 15
And outside the processing chamber 13 in which the sensor 16 is provided,
Control means 17 is provided. The control means 17 is connected to the sensor 16 and the transfer arm 15 and has a function of controlling the moving speed of the loading arm 15a during the ashing of the processing target wafer 20 based on the detection result from the sensor 16. . For example, the control unit 17 controls the sensor 1
It is determined that the point in time when CO is no longer detected from 6 is the point in time when the resist is completely removed, and the carry-in arm 15a is moved so as to ashing the next part.

The control means 17 is connected to the above-mentioned measuring means, and based on the measurement result from the measuring means, causes the carrying arm 15a to wait at a predetermined position, and carries the carrying arm 15a so as to start the ashing process. The movement start signal is output to the arm 15a. Further, when the loading arm 15a moves the wafer to be processed 20 with respect to the irradiation port 12b, the unloading arm 15b moves the unloading arm 15b so that the unloading arm 15b unloads the processing wafer 20 from the irradiation port 12b to the carrier 14. It controls movement.

The ashing apparatus 10 configured as described above
First, prior to the ashing process of the resist formed on the wafer 20 to be processed, first, the carrier 14 in which the wafer 20 to be processed is stored is transferred into the processing chamber 13 from the outside via the carrier unloading door 13a. Then, first, the processing target wafer 20 stored in the carrier 14 is taken out by the loading arm 15a. At this time, if a standby signal is output from the control means 17 to the loading arm 15a, the loading arm 15a waits at a position where the loading arm 15a is separated from the irradiation port 12b while holding the wafer 20 to be processed. Then, the plasma 30 is ignited in the plasma generation chamber 12 in the same manner as in the first embodiment.

After the ignition of the plasma 30, it is measured by the measuring means that the plasma 30 has stabilized and the plasma potential has become almost 0 V.
When the ions in 0 are cancelled and almost only radicals are present in the plasma 30, a signal to start movement is output from the control means 17 to the loading arm 15a, and the loading arm 15a 20 is moved so as to be located immediately below the irradiation port 12b. Further, as shown by arrow A, the loading arm 15a moves down from the plasma generation chamber 12 to the processing chamber 13 and moves so that radicals emitted from the irradiation port 12b scan over the wafer 20 to be processed. As a result, over the entire surface of the wafer 20 to be processed,
The resist on the processing target wafer 20 is ashed.

In this embodiment, when the carry-in arm 15a moves so that the radical scans the wafer 20 to be processed, the control means 17 calculates the moving speed based on the ashing amount detected by the sensor 16. Then, the moving speed of the loading arm 15a is controlled so that the obtained moving speed is obtained. When the ashing is performed on the entire surface of the processing target wafer 20, the processing target wafer 20 is transferred back to the unloading arm 15 b and stored in the carrier 14. On the other hand, the loading arm 15a starts transporting the wafer 20 to be processed in the next process.

As described above, in the ashing apparatus 10 of the second embodiment, the irradiation port 12 b of the plasma generation chamber 12 is set so that its area is smaller than the upper surface of the processing target wafer 20 held in the processing chamber 13. Since the lower side is formed in a narrowed shape, if the volume of the plasma generation chamber 12 is the same as that of the conventional one, the area of the irradiation port is reduced.
In comparison with the related art, the irradiation port 12b can irradiate the processing chamber 13 with high-density radicals as compared with the related art.

As a result, the wafer 2 to be processed in the processing chamber 13
0 can be ashed at a very high ashing rate. For example, if the area of the irradiation port 12b is reduced to half the area of the conventional one, the density of the radical irradiated to the processing chamber 13 can be doubled, and the ashing can be performed at almost twice the ashing rate. Also, the average ashing rate of the conventional ashing apparatus is 3 to 7 μm.
A very high ashing rate of about several tens μm / min to several hundred μm / min can be realized with respect to about m / min. Therefore, the reaction between the resist and the radicals can proceed with good reactivity without heating the wafer 20 to be processed, so that the resist can be surely peeled off without generating a residue, and the processing can be performed at high throughput. It becomes possible to do.

Further, since the ashing process can be performed at a very high ashing rate, even if the resist becomes powdery during the ashing process, it can be removed without re-adhering as particles on the wafer 20 to be processed.

In the processing chamber 13, the transfer arm 15 for moving the processing target wafer 20 with respect to the irradiation port 12 b causes the transfer port 15 to move the processing target wafer 20 to the irradiation port 12 b so that the radicals from the irradiation port 12 b scan over the processing target wafer 20. The target wafer 20 can be moved with respect to the target wafer 20.
Can be ashed with good in-plane uniformity. Moreover, since the scanning method is employed, the wafer 2 to be processed
It is not necessary to simultaneously irradiate the entire surface of 0 with radicals. Therefore, the amount of processing gas used can be reduced and the RF current supplied to the coil 6 can be reduced as compared with the conventional ashing device. Further, it is possible to reduce the size of the plasma generation chamber while maintaining a higher ashing rate than before.

Since the ashing device 10 employs a scanning system, as described above, after the plasma 30 is ignited, when the plasma potential stabilizes and only radicals are irradiated from the irradiation port 12b. The wafer 20 to be processed can be positioned directly below the irradiation port 12b by the transfer arm 15. As a result, irradiation of ions to the processing target wafer 20 when the plasma 30 is ignited can be prevented, so that the resist can be prevented from being changed to a substance which is hardly ashed due to ion irradiation.

Therefore, also by this, the resist can be surely peeled off, the processing can be performed at a high throughput, and the effect of preventing the resist changed into a substance which is hardly ashed from being re-adhered to the processing target wafer 20 can be obtained. According to the ashing apparatus 10 of the second embodiment, the manufacturing yield and the electrical reliability of the semiconductor device can be further improved.

In the second embodiment, an example has been described in which the ashing process is performed without heating the wafer to be processed without heating the wafer to be processed, but the wafer to be processed is heated before the ashing. A means for heating may be provided. For example, in the ashing apparatus 10 of the second embodiment, the loading arm 15a is configured to include a unit for heating the processing target wafer 20 held by the loading arm 15a, so that the processing target wafer 20 can be heated. . Further, even if a thickly popped portion is formed in the resist on the processing target wafer 20 by the heating of the processing target wafer 20 at this time, ashing can be performed at a high ashing rate. Needless to say, it can be peeled off.

In the second embodiment, an example has been described in which the control means automatically starts the movement of the carry-in arm to the irradiation port and controls the moving speed of the carry-in arm at the time of ashing. The movement of the loading arm to the irradiation port may be started by the operator by monitoring the measurement result of the plasma potential from the means. In addition, it is possible to perform the ashing while keeping the moving speed of the loading arm constant during the ashing without providing a sensor for detecting the ashing amount in the processing chamber.

Further, in the second embodiment, an example has been described in which the moving means in the present invention comprises a transfer arm. However, any means may be used as long as it moves the wafer to be processed relative to the irradiation port. The chamber may be moved with respect to the wafer to be processed held at a predetermined position in the processing chamber. Alternatively, the position of a holding unit such as a stage for holding the plasma generation chamber and the wafer to be processed is fixed, and the lower end of the plasma generation chamber is configured so that the direction of the irradiation port of the plasma generation chamber can be freely changed.
The moving means may change the direction of the irradiation port so that the irradiation port scans on the wafer to be processed.

When the lower end of the plasma generation chamber is formed so that the direction of the irradiation port can be freely changed, for example, the lower end of the plasma generation chamber is formed in a nozzle shape, and the lower end of the nozzle is connected to the irradiation port. And Also, at the connection between the upper end of the nozzle and the plasma generation chamber above the nozzle, the upper end of the nozzle is formed in a hemispherical shape, and the plasma generation chamber side is slidably supported by receiving the upper end of the nozzle. Form. An ashing apparatus is provided by providing a moving unit that changes the direction of the irradiation port by changing the angle of the nozzle with respect to the plasma generation chamber above the nozzle. With this configuration, it is only necessary to change the direction of the irradiation port, which is very effective for miniaturization of the apparatus.

[0054]

As described above, according to the ashing apparatus of the first aspect, the upper side of the opening of the plasma generation chamber is formed so that the area of the plane cross section is larger than the area of the opening. Since a large amount of plasma can be generated in the plasma generation chamber, the target wafer held in the processing chamber can be ashed at a very high ashing rate. Therefore, even if a thickly popped portion is formed by heating the resist on the wafer to be processed, the resist can be reliably peeled off without leaving the popped portion as a residue, and it becomes powdery during the ashing process. The lost resist can be removed without fail. Further, since the resist can be reliably removed without requiring a long time, a decrease in throughput can be suppressed.

According to the ashing apparatus of the second aspect of the present invention, the opening is formed so that the area of the opening of the plasma generation chamber is smaller than the upper surface of the wafer to be processed held in the processing chamber. High density plasma (radical)
Is irradiated into the processing chamber, the wafer to be processed held in the processing chamber can be ashed at a very high ashing rate. Therefore, the same effect as the first aspect can be obtained. The moving means scans the wafer to be processed by the plasma (radicals) from the opening, so that the entire surface of the wafer to be processed can be ashed with good in-plane uniformity. The wafer to be processed can be positioned immediately below the opening at the time when the irradiation is started. Therefore, irradiation of ions to the wafer to be processed at the time of plasma ignition can be prevented, so that the resist can be prevented from being changed to a substance which is hardly ashed by ion irradiation, and the resist can be surely peeled off.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a first embodiment of an ashing device according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the ashing device according to the present invention.

FIG. 3 is a sectional view of a main part showing a second embodiment of an ashing device according to the present invention.

FIG. 4 is a perspective view showing a second embodiment of the ashing device according to the present invention.

FIG. 5 is a schematic configuration diagram illustrating an example of a conventional ashing device.

FIGS. 6A and 6B are diagrams for explaining how the resist is popped by heating.

FIGS. 7A and 7B are diagrams for explaining the problem of the present invention (part 1), wherein FIG. 7A is a diagram showing a wafer to be processed before ashing, and FIG. 7B is a diagram showing a wafer to be processed after ashing.

FIGS. 8A to 8E are diagrams (part 2) for describing the problem of the present invention, and are diagrams sequentially illustrating states when ashing is performed on a popped wafer to be processed;

[Explanation of symbols]

1,10 ashing device, 3,12 plasma generation chamber, 3a, 12a ceiling, 3b, 12b irradiation port,
4, 13 processing chamber, 15 transfer arm, 16 sensor
17: control means, 20: wafer to be processed, 30: plasma

Claims (4)

[Claims] The plasma generation chamber has a cylindrical plasma generation chamber having a ceiling and a substantially circular opening connected to a lower side of the plasma generation chamber and provided at a lower end of the plasma generation chamber. A processing chamber communicating with the plasma generation chamber, and irradiating plasma generated in the plasma generation chamber from the opening to ashing a wafer to be processed held in the processing chamber, wherein the opening is formed in the processing chamber. The plasma generation chamber is formed so as to have a diameter substantially equal to the diameter of the wafer to be processed, and the upper side of the opening of the plasma generation chamber is formed so that the area of its plane cross section is larger than the area of the opening. An ashing device characterized by the above-mentioned. 2. A plasma generation chamber, comprising: a plasma generation chamber; and a processing chamber connected to a lower side of the plasma generation chamber and communicating with the plasma generation chamber through an opening at a lower end of the plasma generation chamber. An ashing apparatus for ashing a wafer to be processed held in the processing chamber by irradiating the plasma generated at the opening from the opening, wherein the opening of the plasma generation chamber has an area held in the processing chamber. The processing wafer is formed to be smaller than the upper surface of the wafer, and the processing wafer is relatively moved with respect to the opening so that the plasma from the opening scans over the processing wafer held in the processing chamber. An ashing device comprising a moving means for causing the ashing. 3. The plasma generation chamber is formed in a cylindrical shape having a ceiling so that the area of a plane cross section of the plasma generation chamber above the opening is larger than the area of the opening. The ashing device according to claim 2, wherein the ashing device is formed. 4. A sensor provided in the processing chamber for detecting an ashing amount of the wafer to be processed, and a moving speed of a moving unit at the time of ashing of the wafer to be processed is controlled based on a detection result from the sensor. 3. The ashing apparatus according to claim 2, further comprising control means for performing the operation.