JP2010129837A - Method for removing resist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove resist in which a cured layer is formed without any damage to a base layer. <P>SOLUTION: A method for removing resist includes an irradiation step of irradiating ion-implanted resist with ultraviolet light to an extent such that the cured layer of the resist formed by implanting ions becomes alkali-soluble, and a removing step of bringing the resist into contact with an alkali solution to peel the resist from a silicon substrate. Ions are implanted in the resist by 1×10<SP>14</SP>to 5×10<SP>15</SP>pieces/cm<SP>2</SP>, the irradiation amount of the ultraviolet light in the irradiation step is at least 1,800 mJ/cm<SP>2</SP>, and the alkali solution heated up to ≥60°C is used for the removing step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resist removal method.

  Conventionally, as disclosed in Patent Documents 1 to 3 below, various methods for removing a resist patterned on a base layer such as a semiconductor layer are known. In the removal method disclosed in Patent Document 1, when removing a resist that is no longer needed after the resist is exposed, the resist is washed away by dissolving in a developer.

  Patent Document 2 discloses a gas treatment process in which ozone gas is brought into contact with a substrate resist to decompose the resist components, and an ultraviolet treatment process in which the resist components are irradiated with ultraviolet rays to make the resist components soluble in an alkaline aqueous solution. And a resist removal method including an alkali treatment step of removing the resist with an alkaline aqueous solution.

In Patent Document 3, for the purpose of quickly removing the resist formed on the surface of the substrate on which high-dose ion implantation has been performed, after irradiating the substrate surface with ultraviolet rays, sulfuric acid anhydride and peroxide are used. A method of stripping a resist with a resist stripping solution containing hydrogen water is disclosed.
JP 2000-206707 A JP 2002-231696 A JP 2006-286830 A

  In the method of Patent Document 1, since the resist is removed using a developer after the resist is exposed, the manufacturing cost can be reduced. However, the process goes through an impurity element diffusion process, an ion implantation process, and the like. Then, it becomes difficult to remove the resist.

  Further, in the method of Patent Document 2, it can be expected that the resist can be removed at a high speed, but since it is processed with ozone gas, a very expensive and large-scale apparatus is required. Moreover, as Comparative Example 7, it is shown that the resist after the source / drain wiring is formed, that is, the resist that has been ion-implanted at a high concentration cannot be removed.

  Further, in the method of Patent Document 3, it is possible to remove a resist in which ions are implanted at a high concentration. However, in this method, since the treatment is performed with an acidic resist remover, the substrate is oxidized. As a result, the substrate may be damaged.

  Accordingly, an object of the present invention is to provide a method for removing a resist having a hardened layer formed so as not to damage a base layer.

  In order to achieve the above object, the present invention provides a method for removing a resist from a base layer to which a resist is applied, and curing a resist formed by ion implantation into a resist into which ions are implanted. It is a resist removal method including an irradiation step of irradiating the layer with ultraviolet light that causes alkali solubility in the layer, and a removal step of bringing the resist into contact with an alkaline solution to peel the resist from the base layer.

  In the present invention, in the irradiation step, the resist is irradiated with ultraviolet light at an irradiation amount so that the cured layer of the resist becomes alkali-soluble. The resist can be peeled off, and the resist can be removed with an alkaline solution in the removing step. That is, in the present invention, the cured layer of the resist is alkali-soluble by irradiation with ultraviolet light. For this reason, plasma ashing treatment and ozone gas treatment are unnecessary, and a large-scale apparatus is unnecessary. In addition, since the resist is peeled off from the base layer by bringing an alkaline solution into contact with the resist, the base layer is not oxidized. As a result, the resist can be removed without damaging the base layer.

The resist may be implanted with ions of 1 × 10 ¹⁴ to 1 × 10 ¹⁷ ions / cm ² .

Further, in the case where ions of 1 × 10 ^{14 to} 5 × 10 ¹⁵ ions / cm ² are implanted into the resist, an irradiation amount of ultraviolet light in the irradiation step is set to at least 1800 mJ / cm ² , and the removal step Then, you may make it use the said alkaline solution heated at 60 degreeC or more. In this aspect, even if the resist is implanted with ions of 5 × 10 ¹⁵ ions / cm ² , the resist can be peeled off from the base layer in almost the entire region.

In this embodiment, the ultraviolet light is preferably irradiated with an irradiation amount of 1800 mJ / cm ² over 3 minutes. In this aspect, since the ultraviolet light irradiation is performed for 3 minutes or more, the temperature of the resist is increased, thereby making the cured layer easily soluble in alkali.

On the other hand, when ions of 1 × 10 ¹⁴ ions / cm ² or less are implanted into the resist, the irradiation amount of ultraviolet light in the irradiation step is at least 1800 mJ / cm ^2, and in the removal step, 40 ° C. It is preferable to use the alkali solution heated as described above. In this aspect, even if the resist is implanted with ions of 1 × 10 ¹⁴ ions / cm ² , the resist can be peeled off from the base layer in almost the entire region.

In this aspect, the ultraviolet light is preferably irradiated with an irradiation amount of 1800 mJ / cm ² or more over 3 minutes or more. In this aspect, since the ultraviolet light irradiation is performed for 3 minutes or more, the temperature of the resist is increased, thereby making the cured layer easily soluble in alkali.

In addition, when ions of 1 × 10 ^{14 to} 5 × 10 ¹⁵ ions / cm ² are implanted into the resist, the irradiation amount of ultraviolet light in the irradiation step is set to at least 4200 mJ / cm ² , and the removal step Then, the said alkaline solution heated at 40 degreeC or more can also be used. In this aspect, even if the resist is implanted with ions of 5 × 10 ¹⁵ ions / cm ² , the resist can be peeled off from the base layer in almost the entire region.

In this embodiment, the ultraviolet light is preferably irradiated with an irradiation amount of 4200 mJ / cm ² or more over 7 minutes or more. In this aspect, since the ultraviolet light irradiation is performed for 7 minutes or longer, the temperature of the resist is increased, thereby making the cured layer easily soluble in alkali.

  The irradiation step and the removal step may be repeated.

In this case, ions of 1 × 10 ¹⁴ to 1 × 10 ¹⁷ ions / cm ² may be implanted into the resist.

And the irradiation amount of the ultraviolet light in the said irradiation process shall be at least 6000 mJ / cm < ² >, and you may make it use the said alkaline solution heated at 70 degreeC or more in the said removal process. In this aspect, even if the resist is implanted with ions of 1 × 10 ¹⁷ ions / cm ² , the resist can be peeled from the base layer in almost the entire region.

In this aspect, the ultraviolet light is preferably irradiated with an irradiation amount of 6000 mJ / cm ² or more over 10 minutes. In this aspect, since the ultraviolet light irradiation is performed for 10 minutes or longer, the temperature of the resist is increased, thereby making the cured layer easily soluble in alkali.

The irradiation intensity of the ultraviolet light may be 3 mW / cm ² or more.

  The resist may contain PAG.

  The alkaline solution may be a tetramethylammonium hydroxide aqueous solution or a trimethyl 2-hydroxyethylammonium hydroxide aqueous solution.

  The base layer may be any one of a semiconductor layer, a silicon oxide layer, a silicon nitride layer, and a metal layer.

  In the removing step, the alkali solution and a chemical solution that suppresses a neutralization reaction between the alkali solution and the supercritical carbon dioxide are injected into supercritical carbon dioxide so that the resist is peeled off from the base layer. It may be.

  In this aspect, the chemical solution that can peel the resist without damaging the fine pattern due to supercritical carbon dioxide without surface tension, and suppresses salt precipitation due to the neutralization reaction between the supercritical carbon dioxide and the alkaline solution. Can also be prevented from reacting with the supercritical carbon dioxide and the alkali solution to precipitate the salt.

  As described above, according to the present invention, the resist on which the hardened layer is formed can be removed without damaging the base layer.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a resist removal apparatus 10 capable of performing a resist removal method according to an embodiment of the present invention. The resist removing apparatus 10 is an apparatus for removing the resist from the semiconductor substrate W.

  The resist removing apparatus 10 includes an apparatus main body 12 and a substrate cassette 14 for supplying a semiconductor substrate W to the apparatus main body 12. The apparatus main body 12 includes a mounting table 18, an ultraviolet irradiation unit 20, an alkaline aqueous solution supply unit 22, a pure water supply unit 24, an ultrasonic unit 26, a transfer device 28, and the like as main components. The mounting table 18 is a table for mounting the semiconductor substrate W from which the resist is to be removed, and has a built-in motor (not shown) for rotating the semiconductor substrate W. The semiconductor substrate W is held by the rotating plate 18a and rotates.

The ultraviolet irradiation unit 20 includes an irradiation unit 20 a that can irradiate the semiconductor substrate W on the mounting table 18 with ultraviolet rays, and a control unit (not shown). The control unit is configured to be able to control the wavelength, irradiation intensity, irradiation time, irradiation distance, and the like of the ultraviolet rays irradiated from the irradiation unit 20a. The irradiation unit 20a includes ultraviolet light having a wavelength centered at 222 nm (KrCl excimer light), ultraviolet light having a wavelength centered at 248 nm (KrF excimer light), and ultraviolet light having a wavelength centered at 193 nm. (ArF excimer light), ultraviolet light (Xe excimer light) having a wavelength centered at 172 nm can be emitted. The wavelength of the irradiated ultraviolet light can be selected according to the resist type. Moreover, the irradiation intensity of the ultraviolet light irradiated from the irradiation part 20a can be set in the range of at least 3 mW / cm ² or more. Moreover, the irradiation part 20a is supported by the stand 30 so that a vertical movement is possible, and the distance with the semiconductor substrate W can be adjusted in the range of several mm-several hundred mm. The irradiation unit 20a has a corrugated reflection plate, and can irradiate the semiconductor substrate W with ultraviolet light irregularly reflected by the reflection plate. This makes it easier to irradiate the resist side surface with ultraviolet light.

  The alkaline aqueous solution supply unit 22 is for supplying an alkaline aqueous solution to the surface of the semiconductor substrate W after irradiating the semiconductor substrate W with ultraviolet light, and includes a first nozzle 22a and a temperature controller (not shown). The temperature controller adjusts the temperature of the alkaline aqueous solution ejected from the first nozzle 22a to a desired temperature. For example, the alkaline aqueous solution can be discharged at room temperature without being heated, but is heated to 40 ° C to 70 ° C. As the alkaline aqueous solution, a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) is used. An aqueous choline solution (trimethyl 2-hydroxyethylammonium hydroxide aqueous solution) may be used as the alkaline aqueous solution.

  The pure water supply unit 24 is for rinsing the surface of the semiconductor substrate W, and has a second nozzle 24a. The second nozzle 24a ejects ultrapure water. The first nozzle 22 a and the second nozzle 24 a are supported by the stand 32 so as to be movable in the vertical direction, and are rotatable about the axis of the stand 32. Therefore, the first nozzle 22a and the second nozzle 24a can easily change the relative positional relationship with the semiconductor substrate W.

  The ultrasonic unit 26 is used at the time of alkaline aqueous solution treatment and rinsing, and vibrates so that the peeled resist does not reattach to the semiconductor substrate W.

  The transport device 28 transports the semiconductor substrate W between the substrate cassette 14 and the mounting table 18.

  Next, a resist removal method using the resist removal apparatus 10 will be described. Here, a case where the resist is removed from the semiconductor substrate W on which the source and drain are formed in the manufacturing process of the semiconductor substrate W will be described. For example, as shown in FIG. 2, the semiconductor substrate W is a silicon substrate on which a p-well region 51, an n-well region 52, an element isolation layer 53, a source electrode 54, and a drain electrode 55 are formed. 56. The silicon substrate 56 forms a base layer to which the resist 60 is deposited, and a gate electrode 62 is formed on the silicon substrate 56 via an oxide film. The semiconductor substrate W has a p-MOS transistor portion 64 and an n-MOS transistor portion 66, and a resist 60 used for ion implantation or the like remains in the p-MOS transistor portion 64. A hardened layer 60a is formed on the surface of the resist 60 by ion implantation. The hardened layer 60a is obtained by altering (hardening) the surface of the resist 60 by high dose ion implantation. The implanted ions are, for example, arsenic (As). The resist 60 is a chemically amplified photoresist 60 containing PAG (Photo Acid Generator). The resist removing apparatus 10 can be used to remove the resist 60 from the silicon substrate 56.

In the resist removing apparatus 10, the transport device 28 takes out the semiconductor substrate W from the substrate cassette 14 and transports it to the mounting table 18. Then, the transfer device 28 places the semiconductor substrate W on the rotating plate 18a of the mounting table 18, and when the semiconductor substrate W is set on the rotating plate 18a, the ultraviolet irradiation unit 20 applies ultraviolet light to the semiconductor substrate W. Irradiate (irradiation process). In this irradiation step, the distance between the irradiation unit 20a and the semiconductor substrate W is set to, for example, 155 mm, and the irradiation unit 20a irradiates the semiconductor substrate W with ultraviolet light with an irradiation intensity of 10 mW / cm ² .

The irradiation time is set according to the amount of ions implanted into the resist 60. That is, since the type or the like of the semiconductor substrate W carried into the resist removing apparatus 10 is known in advance, the irradiation time may be set according to the type. For example, for a resist 60 having an ion dose of 1 × 10 ¹⁴ pieces / cm ² , the irradiation time is set to 3 minutes, and for a resist 60 having an ion dose of 5 × 10 ¹⁵ pieces / cm ^2. In this case, the irradiation time is set to 7 minutes. In other words, for a resist 60 with a dose amount of 1 × 10 ¹⁴ pieces / cm ² , an irradiation amount of 1800 mJ / cm ² is set, and with respect to a resist 60 with a dose amount of 5 × 10 ¹⁵ pieces / cm ^2. Is set to an irradiation amount of 4200 mJ / cm ² . By irradiating the ultraviolet light over the above time, the temperature of the resist 60 is raised, and it is assumed that the cured layer 60a on the resist surface easily becomes alkali-soluble.

  When the irradiation step is completed, the alkaline aqueous solution is supplied from the alkaline aqueous solution supply unit 22 (removal step). The alkaline aqueous solution is applied to the semiconductor substrate W from the first nozzle 22a. For this reason, in the removing step, the resist 60 on the surface of the semiconductor substrate comes into contact with the alkaline aqueous solution. At this time, since the rotating plate 18a rotates, the alkaline aqueous solution flows on the surface of the semiconductor substrate W. For this reason, the alkaline aqueous solution can be spread evenly over the entire surface of the semiconductor substrate, and a fresh alkaline aqueous solution can always be brought into contact with the resist 60. When the alkali-soluble resist 60 comes into contact with the aqueous alkali solution, the resist 60 is peeled off from the silicon substrate 56. At this time, ultrasonic waves are generated from the ultrasonic unit 26 as necessary. Thereby, the resist 60 peeled from the silicon substrate 56 can be prevented from adhering to the silicon substrate 56 again.

  When the alkaline aqueous solution is supplied for a predetermined time, rinsing is subsequently performed. In the rinsing step, ultrapure water is applied to the surface of the semiconductor substrate, whereby the alkaline aqueous solution remaining on the surface of the semiconductor substrate is removed. Also at this time, ultrasonic waves are generated from the ultrasonic unit 26. After rinsing for a predetermined time, the semiconductor substrate W is dried and unloaded by the transfer device 28, and a series of resist removal steps is completed.

  As described above, according to the present embodiment, in the irradiation process, the resist 60 is irradiated with an irradiation amount to such an extent that the cured layer 60a of the resist 60 becomes alkali-soluble. Even if the resist 60 is present, the resist 60 can be removed, and the resist 60 can be removed with an alkaline solution in the removing step. That is, since the hardened layer 60a of the resist 60 is made alkali-soluble by irradiation with ultraviolet light, plasma ashing processing and ozone gas processing are unnecessary, and a large-scale apparatus is not required. Moreover, since the resist 60 is peeled from the silicon substrate 56 by bringing the alkaline solution into contact with the resist 60, the silicon substrate 56 is not oxidized. As a result, the resist 60 can be removed without damaging the silicon substrate 56.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, as shown in FIG. 3, it is also possible to carry out with a resist removing apparatus 70 for removing the resist provided on the liquid crystal glass substrate W1. In the liquid crystal glass substrate W1, for example, an electrode or the like is formed, and a resist is deposited on the electrode or the like. Therefore, the resist removing apparatus 70 is used to remove the resist.

  In the removing device 70, a substrate cassette 14 in which the liquid crystal glass substrate W1 is stored is provided. Then, the transport device 28 takes out the liquid crystal glass substrate W1 from the substrate cassette 14 and sets it on the mounting table 18. Since the mounting table 18 does not have a rotating plate, the liquid crystal glass substrate W1 is set in a fixed state. The first nozzle 22 a of the alkaline aqueous solution supply unit 22 is supported so as to be movable in the horizontal direction along a rail 22 b fixed to the stand 32. The stand 32 includes a gas nozzle 72 that can eject an inert gas. The inert gas is used for drying the liquid crystal glass substrate W1. Also in this removing apparatus 70, the irradiation process and the removing process are performed in the same manner as the resist removing apparatus 10 of the above embodiment. Other configurations, operations, and the like are the same as those of the resist removal apparatus 10 of the above-described embodiment.

  In the above-described embodiment, the alkaline aqueous solution is ejected from the nozzle 22a and falls on the semiconductor substrate W. However, the present invention is not limited to this. For example, the resist may be removed by bringing an alkaline aqueous solution into contact with the semiconductor substrate W together with supercritical carbon dioxide. Specifically, as shown in FIG. 4, in addition to the ultraviolet irradiation unit 20, the resist removal apparatus 10 includes a cleaning chamber 81 and a cleaning fluid supply that supplies supercritical carbon dioxide, an alkaline solution, and a chemical solution to the cleaning chamber 81. Part 82. The mounting table 18 is configured to be able to transport the semiconductor substrate W between the ultraviolet irradiation section where the ultraviolet irradiation unit 20 is disposed and the cleaning chamber 81. The cleaning chamber 81 has a cleaning chamber 81a that can accommodate the semiconductor substrate W to be cleaned. The cleaning fluid supply unit 82 includes a circulation circuit 83 connected to the cleaning chamber 81, a supercritical fluid supply unit 84 that supplies a cleaning fluid containing supercritical carbon dioxide to the circulation circuit 83, and an alkaline solution to the circulation circuit 83. An alkaline solution supply unit 85 for supplying the chemical solution, a chemical solution supply unit 86 for supplying the chemical solution to the circulation circuit 83, and a cleaning fluid discharge unit 87 capable of discharging the cleaning fluid of the circulation circuit 83. The circulation circuit 83 is provided with a pump 83a for circulating the cleaning fluid and a filter 83b for removing foreign substances. The supercritical fluid supply unit 84 includes a supply pipe 84a connected to the circulation circuit 83 and a supply source of supercritical carbon dioxide, and a heater 84b and an on-off valve 84c provided in the supply pipe 84a. The cleaning fluid discharge part 87 includes a discharge pipe 87a and an on-off valve 87b provided in the discharge pipe 87a. The alkaline solution supply unit 85 includes a supply pipe 85a connected to the circulation circuit 83, and an alkaline solution pump 85b and an on-off valve 85c provided in the supply pipe 85a. The alkaline solution pump 85b can inject the solution even under supercritical pressure. The alkaline solution supply unit 85 may have a heater (not shown) for heating the alkaline solution. The chemical liquid supply unit 86 includes a supply pipe 86a connected to the circulation circuit 83, and a chemical liquid pump 86b and an on-off valve 86c provided in the supply pipe 86a. The chemical liquid can be injected by the chemical pump 86b even under pressure in the supercritical region. As the chemical solution, water, methanol or the like is used. This chemical solution is for suppressing salt precipitation due to a neutralization reaction between supercritical carbon dioxide and an alkaline solution. The cleaning chamber 81 is supplied with a cleaning fluid in which an alkali solution and a chemical solution are mixed with supercritical carbon dioxide, and the semiconductor substrate W is cleaned with the cleaning fluid. By injecting a chemical solution together with an alkali solution into supercritical carbon dioxide, salt precipitation due to a neutralization reaction can be suppressed.

  Therefore, in this embodiment, the resist can be peeled off without damaging the fine pattern by supercritical carbon dioxide having no surface tension, and salt precipitation by neutralization reaction between the supercritical carbon dioxide and the alkali solution is possible. Since the chemical | medical solution to suppress is also inject | poured, it can suppress that a supercritical carbon dioxide and an alkali solution react and salt precipitation.

  Next, examples actually confirmed will be described.

Example 1
In Example 1, a 300 mm silicon substrate was used. As shown in FIG. 2, a resist 60 is deposited on the silicon substrate, and arsenic ions are implanted into the source electrode 54 and the drain electrode 55. The resist 60 is a chemically amplified photoresist for KrF containing PAG and has a thickness of 1200 nm. The dose of arsenic ions was 5 × 10 ¹⁵ ions / cm ² , and ions were implanted under the condition of an acceleration voltage of 50 keV. It has been confirmed by an electron micrograph that the cured layer 60a of the resist 60 after ion implantation has a thickness of about 180 nm. Using the semiconductor substrate W obtained by dividing the silicon substrate 56 into a size of 15 × 15 mm, the following processing was performed.

First, the semiconductor substrate W was irradiated with ultraviolet rays by an ultraviolet irradiation device. The irradiated ultraviolet light is KrCl excimer light, and has a wavelength centered at 222 nm. The irradiation intensity of the lamp that irradiates ultraviolet light is 10 mW / cm ² . The distance between the lamp of the ultraviolet irradiation device and the semiconductor substrate W was 155 mm, and the irradiation time was 7 minutes. Therefore, the irradiation amount of ultraviolet light is 4200 mJ / cm ² . Next, 30 ml of a 2.38% aqueous solution of TMAH was used, the temperature of this aqueous solution was stabilized at 40 ° C., and the semiconductor substrate W was immersed therein. The immersion time was 10 minutes. The semiconductor substrate W after this treatment was observed with an optical microscope.

(Example 2)
Example 2 is the same as Example 1 except that the semiconductor substrate W is irradiated with ultraviolet light for 10 minutes (irradiation amount: 6000 mJ / cm ² ).

(Comparative Example 1)
In Comparative Example 1, the same semiconductor substrate W as in Example 1 was used. Comparative Example 1 is the same as Example 1 except that the semiconductor substrate W is irradiated with ultraviolet rays for 5 minutes (amount of irradiation 3000 mJ / cm ² ).

(Comparative Example 2)
In Comparative Example 2, the same semiconductor substrate W as in Example 1 was used. Comparative Example 2 is the same as Example 1 except that the semiconductor substrate W is irradiated with ultraviolet rays for 3 minutes (irradiation amount: 1800 mJ / cm ² ).

(Example 3)
In Example 3, the same semiconductor substrate W as in Example 1 was used. Example 3 is the same as Example 1 except that the semiconductor substrate W is irradiated with ultraviolet light for 3 minutes (irradiation amount: 1800 mJ / cm ² ) and the temperature of the TMAH aqueous solution is 60 ° C.

(Comparative Example 3)
The comparative example 3 is the same as the example 3 except that the ultraviolet irradiation time to the semiconductor substrate W is 1 minute (irradiation amount 600 mJ / cm ² ).

Example 4
In Example 4, the semiconductor substrate W having a dose amount of arsenic ions of 1 × 10 ¹⁴ ions / cm ² was used. Similar to Example 1, ion implantation was performed under the condition of an acceleration voltage of 50 keV. The ultraviolet irradiation time to the semiconductor substrate W was 3 minutes (irradiation amount 1800 mJ / cm ² ), and the temperature of the TMAH aqueous solution was 40 ° C. Other conditions are the same as those in the first embodiment.

(Example 5)
Example 5 is the same as Example 4 except that the temperature of the TMAH aqueous solution was 60 ° C.

(Comparative Example 4)
Comparative Example 4 is the same as Example 4 except that the ultraviolet irradiation time was 1 minute (irradiation amount 600 mJ / cm ² ).

(Comparative Example 5)
Comparative Example 5 is the same as Comparative Example 4 except that the temperature of the TMAH aqueous solution was 60 ° C.

(Example 6)
In Example 6, the semiconductor substrate W having a dose amount of arsenic ions of 1 × 10 ¹⁷ ions / cm ² was used. Similar to Example 1, ion implantation was performed under the condition of an acceleration voltage of 50 keV. The ultraviolet irradiation time for the semiconductor substrate W was 10 minutes (irradiation amount: 6000 mJ / cm ² ), and the temperature of the TMAH aqueous solution was 70 ° C. The immersion time in the TMAH aqueous solution was 30 seconds. Then, irradiation with ultraviolet rays and immersion in an aqueous TMAH solution were repeated three times. At this time, the peeling state of the resist 60 was observed with an optical microscope every time the ultraviolet irradiation and the immersion in the TMAH aqueous solution were performed (every cycle).

(Example 7)
In Example 7, the semiconductor substrate W into which boron (B) ions were implanted was used. The dose amount of implanted ions is 1 × 10 ¹⁷ ions / cm ² . The other conditions are the same as in Example 6.

  Tables 1 and 2 show the results of observing the resist peeling state using Examples 1 to 7 and Comparative Examples 1 to 5 using an optical microscope. “◯” in Table 1 indicates a case where the resist 60 is removed almost all over, and “x” indicates the other cases. Moreover, the numerical value in Table 2 has shown the ratio of the area where the resist 60 peeled.

As shown in Table 1, when the TMAH aqueous solution temperature is 40 ° C. with respect to the semiconductor substrate W having an ion dose of 5 × 10 ¹⁵ ions / cm ² , the ultraviolet irradiation amount is at least 4200 mJ / cm ² (irradiation time) 7 minutes), the resist 60 is removed (Example 1). If the TMAH aqueous solution temperature is 60 ° C., the resist 60 is removed if the ultraviolet ray irradiation amount is at least 1800 mJ / cm ² (irradiation time 3 minutes) (Example 3).

On the other hand, for a semiconductor substrate W having an ion dose of 1 × 10 ¹⁴ ions / cm ² , the ultraviolet irradiation dose is at least 1800 mJ, regardless of whether the TMAH aqueous solution temperature is 40 ° C. or 60 ° C. If it is / cm ² (irradiation time 3 minutes), the resist 60 is removed (Examples 4 and 5).

As shown in Table 2, it can be seen that the amount of peeling of the resist 60 increases by repeating the irradiation with ultraviolet rays and the immersion in the TMAH aqueous solution. Then, for the semiconductor substrate W having an ion dose of 1 × 10 ¹⁷ ions / cm ² , the resist 60 can be removed in almost the entire region by repeating three times (Examples 6 and 7).

  In each example and comparative example, the distance between the lamp and the semiconductor substrate W is 155 mm, but the present invention is not limited to this. The experiment was conducted with the distance between the lamp and the semiconductor substrate W being 25 mm, and similar results were obtained.

In Example 4, the semiconductor substrate W having an ion dose of 1 × 10 ¹⁴ ions / cm ² was used. For example, for a semiconductor substrate W having an ion dose of about 1 × 10 ¹² ions / cm ² . Even when processing is performed under the same conditions as in Example 4, it is clear that the resist 60 is peeled off.

  Further, in each of the examples and comparative examples, the semiconductor substrate W is immersed in the TMAH aqueous solution. However, as shown in the above embodiment, even if the TMAH aqueous solution is sprayed on the semiconductor substrate W, there is a difference in processing time. Make sure there is no.

It is a figure which shows roughly the resist removal apparatus which can implement the resist removal method as embodiment of this invention. It is a figure which shows roughly the semiconductor substrate to which the resist removal method by this embodiment can be applied. It is a figure which shows roughly the resist removal apparatus which can implement the resist removal method as other embodiment of this invention. It is a figure which shows roughly the resist removal apparatus which can implement the resist removal method as other embodiment of this invention.

Explanation of symbols

W Semiconductor substrate W1 Liquid crystal glass substrate 10 Resist removing device 12 Device main body 14 Substrate cassette 18 Mounting table 18a Rotating plate 20 Ultraviolet irradiation unit 20a Irradiation unit 22 Alkaline aqueous solution supply unit 22a First nozzle 22b Rail 24 Pure water supply unit 24a Second nozzle 26 Ultrasonic Unit 28 Transport Device 30 Stand 32 Stand 51 p-Well Region 52 N-Well Region 53 Element Isolation Layer 54 Source Electrode 55 Drain Electrode 56 Silicon Substrate 60 Resist 60a Hardened Layer 62 Gate Electrode 64 p-MOS Transistor Portion 66 n -MOS transistor part 70 Resist removing device 72 Gas nozzle 81 Cleaning chamber 81a Cleaning room 82 Cleaning fluid supply part 83 Circulating circuit 83a Pump 83b Filter 84 Supercritical fluid supply part 84a Supply pipe 4b heater 84c off valve 85 alkaline solution supply portion 85a supply pipe 85b alkaline solution pump 85c off valve 86 agent supplying section 86a supply pipe 86b chemical pump 86c-off valve 87 the cleaning fluid discharge portion 87a discharge pipe 87b off valve

Claims (17)

A method of peeling the resist from the base layer to which the resist is applied,
Irradiation step of irradiating the resist into which ions are implanted with ultraviolet light to an extent that causes alkali solubility in the cured layer of the resist formed by the ion implantation;
Removing the resist in contact with an alkaline solution and peeling the resist from the base layer. The resist removal method according to claim 1, wherein ions of 1 × 10 ¹⁴ to 1 × 10 ¹⁷ ions / cm ² are implanted into the resist. The resist is implanted with ions of 1 × 10 ^{14 to} 5 × 10 ¹⁵ ions / cm ² ,
The irradiation amount of ultraviolet light in the irradiation step is at least 1800 mJ / cm ² ,
The resist removal method according to claim 1, wherein the alkaline solution heated to 60 ° C. or higher is used in the removing step. The resist removal method according to claim 3, wherein the ultraviolet light is irradiated with an irradiation amount of 1800 mJ / cm ² over 3 minutes. The resist is implanted with ions of 1 × 10 ¹⁴ ions / cm ² or less,
The irradiation amount of ultraviolet light in the irradiation step is at least 1800 mJ / cm ² ,
The resist removal method according to claim 1, wherein the alkaline solution heated to 40 ° C. or higher is used in the removing step. The resist removal method according to claim 5, wherein the ultraviolet light is irradiated with an irradiation amount of 1800 mJ / cm ² or more over 3 minutes or more. The resist is implanted with ions of 1 × 10 ^{14 to} 5 × 10 ¹⁵ ions / cm ² ,
The irradiation amount of ultraviolet light in the irradiation step is at least 4200 mJ / cm ² ,
The resist removal method according to claim 1, wherein the alkaline solution heated to 40 ° C. or higher is used in the removing step. The resist removal method according to claim 7, wherein the ultraviolet light is irradiated with an irradiation amount of 4200 mJ / cm ² or more over 7 minutes or more.   The resist removal method according to claim 1, wherein the irradiation step and the removal step are repeated. The resist removal method according to claim 9, wherein ions of 1 × 10 ¹⁴ to 1 × 10 ¹⁷ ions / cm ² are implanted into the resist. The irradiation amount of ultraviolet light in the irradiation step is at least 6000 mJ / cm ² ,
The resist removal method according to claim 10, wherein the alkaline solution heated to 70 ° C. or higher is used in the removing step. The resist removal method according to claim 11, wherein the ultraviolet light is irradiated with an irradiation amount of 6000 mJ / cm ² or more over 10 minutes. The resist removal method according to claim 1, wherein the irradiation intensity of the ultraviolet light is 3 mW / cm ² or more.   The resist removal method according to claim 1, wherein the resist contains PAG.   The resist removal method according to any one of claims 1 to 12, wherein the alkaline solution is a tetramethylammonium hydroxide aqueous solution or a trimethyl 2-hydroxyethylammonium hydroxide aqueous solution.   The resist removal method according to claim 1, wherein the base layer is any one of a semiconductor layer, a silicon oxide layer, a silicon nitride layer, and a metal layer.   In the removing step, the alkali solution and a chemical solution that suppresses a neutralization reaction between the alkali solution and the supercritical carbon dioxide are injected into supercritical carbon dioxide, and the resist is peeled off from the base layer. Item 2. The resist removal method according to Item 1.

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