JPH06104224A - Resist removal apparatus and its application method - Google Patents

Abstract

PURPOSE:To efficiently remove a resist into which ions have been implanted and which has been hardened by a method wherein a means which supplies a high-frequency voltage across a sample stand and a partition wall is arranged and installed and high-frequency electric power is applied to the sample stand. CONSTITUTION:First, a sample S in which ions have been implanted into a resist is placed on a sample stand 26, the inside of a reactor 11 is heated to a prescribed temperature and a treatment chamber 25 is set to a required vacuum degree. Then, a reaction gas is supplied from a gas supply pipe 13, a high-frequency power supply 17 is turned on, high-frequency electric power is applied across the sample stand 26 and a partition wall 23, and a plasma is generated inside the treatment chamber 25. A resist into which ions are accelerated and implanted and which has been denatured and hardened is sputtered and removed. Then, micorwaves are introduced into a dielectric path 12, and an electric field is generated at the lower part of the dielectric line 12. The generated electric field generates a plasma inside a plasma generation chamber 24, only neutral particles such as radicals or the like are guided mainly to the periphery of the sample S inside the treatment chamber 25 by way of holes 27, and the resist remained on the sample S is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist removing apparatus and a method of using the same, and more particularly, to a resist formed mainly in a semiconductor wafer processing step, which is hardened by ion implantation using plasma. TECHNICAL FIELD The present invention relates to a resist removing apparatus suitable for ashing and removing, and a method of using the same.

[0002]

2. Description of the Related Art An etching process in a manufacturing process of semiconductor products such as semiconductor integrated circuits is performed using a patterned resist as a mask. After the etching process is completed, the resist used as the mask is removed from the wafer surface. There is a need. In recent years, there are measures against pollution problems,
The resist removal method is shifting from a wet process to a dry process, and a method of removing ashes of a resist using plasma is widely used.

As a resist removing apparatus, the present applicants proposed the plasma apparatus disclosed in Japanese Patent Application Laid-Open No. 62-99481 and Japanese Patent Application Laid-Open No. 62-5600, and removed the resist (K. Komachi). , S. Kobayashi, J. Microwave
power, 25, P.236 (1990)).

FIG. 4 shows this type of downflow type resist removing apparatus. Reference numeral 11 in the figure denotes a hollow rectangular parallelepiped-shaped reactor. The entire reactor 11 except for the upper wall is made of metal such as stainless steel, and its surrounding wall has a double structure, and the inside is A flow chamber 21 is formed to allow the cooling water to flow therethrough. A plasma generation chamber 24 and a processing chamber 25 are formed inside the flow chamber 21. The plasma generation chamber 24 and the processing chamber 25 are partitioned by a partition wall 23 having a hole 27, and the upper part of the plasma generation chamber 24 has a microwave transmission property such as quartz glass and Al ₂ O ₃ and has a dielectric loss. The heat resistant plate 22 having a small size is hermetically sealed. Inside the processing chamber 25, a sample table 26 for mounting the sample S is arranged at a position facing the partition wall 23. An exhaust port 14 connected to an exhaust device (not shown) is formed in the lower wall of the processing chamber 25, and a gas for supplying a required reaction gas into the reactor 11 is provided on one sidewall of the plasma generation chamber 24. The supply pipe 13 is connected.

On the other hand, the dielectric line 1 is provided above the reactor 11.
2 is provided, and the upper part of the dielectric line 12 is an Al plate 1
2a, and the dielectric layer 12b is formed on the lower surface of the Al plate 12a.
Is attached. The dielectric layer 12b is made of fluororesin, polyethylene, polystyrene or the like, which has a small dielectric loss. The dielectric waveguide 12 has a waveguide 1
5, a microwave oscillator 16 is further connected to the waveguide 15, microwaves from the microwave oscillator 16 are introduced into the dielectric line 12, and the reactor 1
An electric field necessary for plasma generation is formed in the inside 1.

In the case of removing the resist by using the resist removing apparatus constructed as described above, first, the sample S is placed on the sample table 26, and then the cooling water is flown into the flow chamber 21. At the same time, the gas is exhausted from the exhaust port 14, and the processing chamber 25
To the required vacuum level. Next, the reaction gas is supplied from the gas supply pipe 13. Then, microwaves are introduced into the dielectric line 12 from the microwave oscillator 16 via the waveguide 15, and an electric field is formed below the dielectric line 12. The formed electric field passes through the heat resistant plate 22 and the plasma generation chamber 24.
Inside, plasma is generated, charged particles in the generated plasma are captured by the partition wall 23, and mainly neutral particles such as radicals are guided to the periphery of the sample S in the processing chamber 25 through the holes 27, The resist on the sample S is removed by ashing.

[0007]

In recent years, it has become more frequent to locally implant impurities on the surface of a substrate by using a resist film coated on the substrate as a mask. In this case, the surface layer portion of the resist used as the mask, which has been irradiated with the ion beam, is altered and hardened.

However, in the resist removing method using the conventional resist removing apparatus, only the radicals of the plasma generated in the plasma generating chamber 24 are extracted into the processing chamber 25 by the partition wall 23 to remove the resist. Therefore, it takes a long time to remove the resist that has been surface-altered and hardened by ion implantation, and since the vapor pressure of the implanted ion oxide is generally low, it remains as a residue and must be completely removed. There was a problem that it was difficult.

The present invention has been made in view of the above problems, and even when removing a resist on which an altered hardened layer is formed by ion implantation, the wafer is efficiently damaged and not damaged. An object of the present invention is to provide a resist removing device that can remove the resist and a method of using the same.

[0010]

In order to achieve the above object, a resist removing apparatus according to the present invention comprises a waveguide for transmitting microwaves, a dielectric line connected to the waveguide, and a dielectric line. A reactor having a microwave introduction window disposed opposite to the body line, and a plasma generation chamber for generating plasma by microwaves in the reactor and a processing chamber in which a sample stage for mounting a sample is disposed. In a resist removing apparatus in which a partition wall having a plurality of holes for communicating the plasma generation chamber and the processing chamber together with the partition is installed in the reactor, high-frequency power is supplied between the sample stage and the partition wall. It is characterized in that an electric power supply means is provided.

In order to achieve the above object, the method of using the resist removing apparatus according to the present invention is such that, when the ion-implanted resist is removed, a high frequency power is supplied between the sample stage and the partition wall. Plasma is generated to remove the deteriorated hardened layer portion on the surface, and then only microwave power is supplied between the sample stage and the partition wall to remove the remaining resist portion without supplying high frequency power. Is characterized by.

[0012]

[Operation] During the ion implantation process in the LSI manufacturing process,
Thousands of Å from the resist surface due to the implanted ions
The surface layer portion of the is deteriorated and hardened. When an ordinary downflow type resist removing device is used, it is very difficult to remove the resist which has been deteriorated and hardened. Because
This is because the resist is carbonized by the heat at the time of ion implantation, and it becomes difficult to vaporize CO, CO ₂ , H ₂ O, etc. by O ₂ radicals, and the time required for removal becomes long. Further, it is because the vapor pressure of the oxide of the implanted species (P ⁺ , As ⁺ , B ⁺ etc.) is low, and easily becomes a residue.

In order to remove the resist hardened in a short time, it is a good method to remove the resist by sputtering by ion bombardment.

When the resist is sputter-removed by ion bombardment, it may be carried out in plasma, but if all the resist is removed in plasma, damage to the device becomes a problem. Therefore, only the resist-hardened resist portion that is difficult to remove the resist is removed by ion bombardment in plasma, and the remaining resist portion is removed by damage-free downflow type radicals. As a result, damage to the device is minimized, and the resist can be removed in a short time without a residue.

In order to realize the above process, it is considered that the partition wall separating the plasma and the wafer should be attached and detached, but it is very difficult to perform it during the process, and the cost is increased. Invite.

According to the above-mentioned apparatus, since the power supply means for supplying high frequency power is arranged between the sample stage and the partition wall, plasma can be generated around the sample without removing the partition wall. It is possible to generate.

According to the above-mentioned method, plasma is generated around the sample by applying high-frequency power between the sample table and the partition wall to remove the alteration-hardened resist portion on the surface, After removing the hardened resist, the supply of high frequency power is stopped, only microwave power is supplied to the dielectric line to generate plasma only in the plasma generation chamber, and the resist is removed by downflow type radicals. It becomes possible to do it.

Therefore, as described above, the damage to the device is reduced, and the ion-implanted resist can be removed in a short time without any residue.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a resist removing apparatus and a method of using the same according to the present invention will be described below with reference to the drawings. In addition,
Components having the same functions as those of the conventional example are designated by the same reference numerals. FIG. 1 is a schematic sectional view showing an embodiment of a downflow type resist removing apparatus according to the present invention. In the figure, 11 indicates a hollow rectangular parallelepiped reactor,
The entire reactor 11 except for the upper wall is made of metal such as stainless steel, and its peripheral wall has a double structure, and a flow chamber 21 for allowing cooling water to flow therein is formed therein. . A plasma generation chamber 24 and a processing chamber 25 are formed inside the flow chamber 21. The plasma generation chamber 24 and the processing chamber 25 have holes 27 at positions substantially facing the sample S.
The partition wall 23 is formed of a microwave shielding material, for example, a metal plate such as aluminum. Further, a heat-resistant plate 22 having a microwave transmission property and a small dielectric loss such as quartz glass or Al ₂ O ₃ is hermetically sealed in the upper part of the plasma generation chamber 24. Inside the processing chamber 25, at a position facing the partition wall 23,
A sample table 26 for mounting the sample S is provided,
An electrode 18 capable of applying a high frequency is provided inside the sample table 26, and a high frequency power source 17 is connected to the electrode 18. Further, the sample table 26 is provided with a pipe (not shown) through which a high-temperature solvent passes so that the sample S can be heated,
The pipe is connected to a heating circulation tank (not shown). An exhaust port 14 connected to an exhaust device (not shown) is formed in the lower wall of the processing chamber 25, and a gas for supplying a required reaction gas into the reactor 11 is provided on one sidewall of the plasma generation chamber 24. The supply pipe 13 is connected.

On the other hand, above the reactor 11, the dielectric line 1
2 is provided, and the upper part of the dielectric line 12 is an Al plate 1
2a, and the dielectric layer 12b is formed on the lower surface of the Al plate 12a.
Is attached. The dielectric layer 12b is made of fluororesin, polyethylene, polystyrene or the like, which has a small dielectric loss. The dielectric waveguide 12 has a waveguide 1
5, a microwave oscillator 16 is further connected to the waveguide 15, microwaves from the microwave oscillator 16 are introduced into the dielectric line 12, and the reactor 1
An electric field necessary for plasma generation is formed in the inside 1. Further, an emission spectroscopic analysis device (not shown) is provided for detecting the resist removal condition such as whether or not the alteration-cured resist has been removed.

When removing the ion-implanted resist by using the resist removing apparatus having the above-described structure, first, the sample S ion-implanted into the resist is placed on the sample table 26 of the resist removing apparatus shown in FIG. Then, the cooling water is allowed to flow into the flow chamber 21, and at the same time, the cooling water is exhausted from the exhaust port 14 to heat the inside of the reactor 11 to a predetermined temperature.
Set 5 to the required degree of vacuum. Next, the reaction gas is supplied from the gas supply pipe 13. First, the high frequency power supply 17 is turned on to apply high frequency power between the sample stage 26 and the partition wall 23 to generate plasma in the processing chamber 25. Then, ions are accelerated and poured toward the sample table 26 that is negatively charged by the high frequency, and the resist hardened by alteration is removed by sputtering. After it is confirmed by the emission spectroscopic analyzer that the removal of the altered and hardened resist is completed, the power supply from the high frequency power source 17 is stopped. Then, microwaves are introduced into the dielectric line 12 from the microwave oscillator 16 via the waveguide 15, and an electric field is formed below the dielectric line 12. The formed electric field passes through the heat resistant plate 22 and reaches the inside of the plasma generation chamber 24 to generate plasma. The charged particles in the generated plasma are captured by the partition wall 23, and mainly neutral particles such as radicals are mainly contained. The resist introduced into the periphery of the sample S in the processing chamber 25 through the hole 27 and remaining on the sample S is removed.

Using the resist removing apparatus of this embodiment, P ⁺
Is a sample S having a resist layer ion-implanted under the conditions of an accelerating voltage of 50 kV and a dose amount of 1 × 10 ¹⁶ cm ^{-2. As} a ashing gas, O ₂ is 900 sccm, and N ₂ is 100 s.
The resist was removed by supplying ccm.

The timing of switching from the high frequency to the microwave was determined by utilizing the emission spectral analysis of plasma. At this time, the emission intensity at the spectral wavelength of CO of 309 nm was used. Figure 2 shows the monitoring results of emission spectroscopy during the resist removal was conducted by using the resist removing apparatus according to the embodiment, the case of FIG. 2, the sample stage high frequency 13.56MH _Z from the high frequency power source 17 at the beginning 1 in 26
It is supplied at an intensity of 50 W, plasma is generated in the processing chamber 25 to remove the property-hardened resist portion, and the point at which the emission intensity starts to increase sharply is judged to be the time point at which the surface-hardened resist has been removed. The high frequency power supply 17 was stopped.
Then a microwave of 2.45 GHz _Z fed at an intensity of 1.5 kW, plasma was generated in the plasma generation chamber 24, subjected to the remaining resist is removed on the sample in the down flow type to draw only radicals to the processing chamber 25 It was At this time,
The high-frequency supply time, that is, the time required to remove the alteration-cured resist surface layer is 30 seconds, the time required to switch from the high-frequency wave to the microwave is 5 seconds, and the microwave supply time, that is, the remaining resist The time required to remove the resist was 90 seconds, and the time required to remove the entire resist was 125 seconds.

[0024] As contrast 3 Comparative Example, without supplying high frequency to the sample stage 26, the microwave of 2.45 GHz _Z 1.5
It shows a case where the plasma is generated in the plasma generation chamber 24 by supplying with the intensity of kW and the resist of the sample is removed by only the downflow type radicals. The low ridges in the first half show the removal treatment process of the surface alteration hardened layer of the resist, and the high ridges in the latter half show the removal treatment process of the remaining resist. At this time, the time required to remove the entire resist was 240 seconds. That is, according to the method of the example, it was possible to reduce the total processing time by 115 seconds as compared with the case of the method of the comparative example.

As described above, in the resist removing apparatus and the method of using the same according to the embodiment, the high frequency power source 1
Since 7 is connected to the sample table 26 and high frequency power is supplied between the sample table 26 and the partition wall 23,
When removing the surface layer of the resist hardened by the ion implantation process, high-frequency power is applied to accelerate the ions to remove the resist hardened by sputtering in a short time. Further, it is judged whether the alteration-hardened resist can be removed or not by the change in the plasma emission intensity of CO, and after the alteration-hardened resist is removed, the resist is removed by microwaves to damage the wafer. The resist can be removed so that it does not exist. Therefore, by using such a method, it is possible to increase the removal rate of the resist that has been hardened by alteration without shortening the damage to the wafer, and shorten the processing time as a whole.

In the above embodiment, the supply of the high frequency power from the high frequency power source 17 was switched to the microwave. However, the present invention is not limited to this method, and the high frequency is generated while the plasma is first generated by the microwave. Alternatively, a method may be used in which the surface-altered hardened layer of the resist is removed by supplying the sample to the sample table 26, and then only the high frequency is stopped and the entire resist is removed.

Further, in the above embodiment, the high frequency power is supplied to the sample table 26. However, when handling a device sensitive to damage, the high frequency power is supplied to the partition wall 23 and the sample table 26 is grounded. Is also good.

[0028]

As described in detail above, in the resist removing apparatus according to the present invention, a waveguide for transmitting microwaves, a dielectric line connected to the waveguide, and the dielectric line. And a reactor having a microwave introduction window disposed opposite to each other, and partitioning the inside of the reactor into a plasma generation chamber for generating plasma by microwaves and a processing chamber in which a sample stage for mounting a sample is disposed. In a resist removing device in which a partition wall having a plurality of holes for communicating the plasma generation chamber and the processing chamber is installed in the reactor, power for supplying high-frequency power between the sample stage and the partition wall. Since the supply means is provided, plasma can be generated around the sample, and the resist that has been sputter-altered and hardened by the accelerated ions can be removed in a short time.

Further, as described in detail above, in the method of using the resist removing apparatus according to the present invention, when removing the ion-implanted resist, high-frequency power is supplied between the sample table and the partition wall. After the plasma is generated in the processing chamber to remove the deteriorated hardened layer portion on the surface, microwave power is not supplied between the sample stage and the partition wall, and only microwave power is supplied to remove the remaining resist portion. Therefore, it is possible to generate plasma around the sample by applying the high-frequency power, and to remove the alteration-hardened portion of the resist surface in a short time. After removing the alteration-hardened resist, the high-frequency power is applied. Is stopped, microwave power is supplied to the dielectric line to generate plasma only in the plasma generation chamber, and resist is removed by downflow type radicals. It is possible.

Therefore, even when the resist portion which has been ion-implanted and has been altered and hardened is removed, it can be efficiently removed in a short time without damaging the wafer.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a downflow type resist removing apparatus according to the present invention.

FIG. 2 is a graph showing an emission spectral waveform when removing a resist according to an example.

FIG. 3 is a graph showing an emission spectral waveform when removing a resist by a conventional method.

FIG. 4 is a schematic sectional view showing a conventional downflow type resist removing apparatus.

[Explanation of symbols]

 11 Reactor 12 Dielectric Line 15 Waveguide 17 High Frequency Power Supply (Power Supply Means) 23 Partition Wall 24 Plasma Generation Room 25 Processing Room 26 Sample Stand 27 Holes

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H05H 1/46 9014-2G (72) Inventor Katsuyuki Ono 4-5 Kitahama, Chuo-ku, Osaka-shi, Osaka No. 33 Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. A waveguide comprising microwaves, a dielectric line connected to the waveguide, and a reactor having a microwave introduction window arranged opposite to the dielectric line, The reactor is partitioned into a plasma generation chamber for generating plasma by microwaves and a processing chamber in which a sample stage on which a sample is placed is arranged, and has a plurality of holes for communicating the plasma generation chamber with the processing chamber. A resist removing apparatus having a partition wall built in the reactor, wherein a power supply unit for supplying high-frequency power is disposed between the sample stage and the partition wall. 2. When removing the ion-implanted resist, high-frequency power is supplied between the sample stage and the partition wall to generate plasma in the processing chamber to remove the deteriorated hardened layer portion on the surface, 2. The method of using the resist removing apparatus according to claim 1, wherein the residual resist portion is removed by supplying only microwave power without supplying high frequency power between the sample stage and the partition wall.