JP7236583B2 - Resist removing method and resist removing apparatus - Google Patents

Description

The present invention relates to a resist removing method and a resist removing apparatus.

2. Description of the Related Art Conventionally, in the manufacturing process of semiconductor substrates (hereinafter simply referred to as "substrates"), ion implantation has been performed in which ions are implanted into the material of the substrate surface to change the properties of the material. In ion implantation, a pattern of photoresist (hereinafter simply referred to as "resist"), which is a photosensitive material, is formed on the surface of the substrate as a mask in order to prevent ions from being implanted into unnecessary portions. After the ion implantation, the resist pattern is removed by a resist removal process using a resist remover.

In recent years, the dose of ions in ion implantation has increased. When ion implantation is performed at a high dose (for example, 10 ¹⁵ ions/cm ² or more), an altered layer (hardened layer) that takes time to remove with a resist stripper is formed on the surface of the resist. Therefore, in Patent Document 1, a method of irradiating the surface of the substrate with ultraviolet rays to break the bond between carbon and hydrogen in the resist, and then supplying a resist stripping solution to the surface of the substrate to quickly remove the resist. is proposed.

Note that Patent Document 2 discloses an apparatus for removing a resist on a substrate with ozone under heating. In this apparatus, a support table is provided in a reaction chamber that can be sealed, and a substrate is placed on the support table. A CO ₂ concentration measuring device is provided between the reaction chamber and the downstream ozone decomposer. In removing the resist, the support table is heated and ozone is flowed into the reaction chamber. Also, the CO ₂ concentration is measured by a CO ₂ concentration measuring instrument, and when the CO ₂ concentration falls below a predetermined value, it is determined that the resist has been completely decomposed and removed.

JP 2006-286830 A JP-A-1-186619

By the way, when removing the resist by supplying ozone gas and heating the substrate, as in Patent Document 2, on a substrate implanted with a high dose of ions, the inside ( A phenomenon in which the denatured layer ruptures may occur due to the expansion of the inner portion of the denatured layer). This phenomenon is called popping, and the popping causes the pattern on the substrate to collapse, and scattered fragments of the degraded layer to adhere to the surface of the substrate and the inside of the device. Popping may be prevented by lowering the heating temperature of the substrate, but this will lengthen the time required to remove the resist.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to appropriately detect the end point of removal of a degraded layer and efficiently remove the resist on the substrate.

The invention according to claim 1 is a resist removing method for removing the resist of a substrate having a resist pattern formed on the surface with a degraded layer formed on the main surface, comprising: a step of removing the altered layer by supplying ozone gas to the main surface while arranging the substrate and a hot plate heated to a predetermined temperature; and B) in parallel with the step A). C) detecting the end point of removal of the altered layer by measuring the concentration of ozone gas in the gas discharged from the processing space; and C) supplying ozone gas to the main surface after step A). and removing the resist by removing the resist.

The invention according to claim 2 is the resist removing method according to claim 1, wherein in the step B), the end point of removal of the deteriorated layer is detected based on the rate of change in the concentration of the ozone gas.

The invention according to claim 3 is the resist removing method according to claim 1 or 2, wherein the concentration of a predetermined component in the gas discharged from the processing space is measured in parallel with the step C). detecting the end point of removal of the resist.

The invention according to claim 4 is the resist removing method according to any one of claims 1 to 3, wherein in the step A), the substrate is placed in a first position with a gap with respect to the hot plate. The substrate is placed at a processing position to remove the deteriorated layer, and in step C), the substrate is placed at a second processing position where the gap is smaller than that of the first processing position, and the resist is removed.

The invention according to claim 5 is the resist removing method according to claim 4, wherein the processing space is openable and closable, and when the processing space is opened, the hot plate is positioned above the first processing position. The substrate is transferred from a holding unit that holds the substrate to an external transport mechanism in a state where the substrate is placed at a position away from the substrate.

The invention according to claim 6 is the resist removing method according to any one of claims 1 to 5, wherein in a processing space forming part forming the processing space, a heating is performed around the supply port of the ozone gas. Department is provided.

The invention according to claim 7 is the resist removing method according to any one of claims 1 to 6, wherein the predetermined temperature of the hot plate is set in the resist on which the deteriorated layer is formed, The temperature is equal to or higher than the temperature at which the denatured layer bursts due to internal expansion.

According to an eighth aspect of the present invention, there is provided a resist removing apparatus, comprising: a processing space forming section that forms a processing space that is isolated from the outside; a hot plate that is arranged in the processing space and heated to a predetermined temperature; an ozone gas supply unit configured to supply an ozone gas to the main surface; and a control unit for detecting the end point of removal of the degraded layer based on the measurement value of the concentration measuring unit and then removing the resist with ozone gas.

The invention according to claim 9 is the resist removal apparatus according to claim 8, wherein the control unit detects the end point of removal of the degraded layer based on the change rate of the concentration of the ozone gas.

A tenth aspect of the present invention is the resist removing apparatus according to the eighth or ninth aspect of the present invention, wherein the control section detects the end point of removal of the resist based on the measured value of the density measuring section.

The invention according to claim 11 is the resist removing apparatus according to any one of claims 8 to 10, further comprising a moving mechanism for moving the holding part relative to the hot plate, The control unit arranges the substrate at a first processing position spaced from the hot plate, removes the altered layer with the ozone gas, and then controls the moving mechanism to control the The substrate is placed at a second processing position where the gap is smaller than that of the first processing position, and the resist is removed by the ozone gas.

The invention according to claim 12 is the resist removing apparatus according to claim 11, further comprising an opening/closing mechanism for opening and closing the processing space, wherein when the processing space is opened, the control unit The substrate is placed at a position farther from the hot plate than one processing position, and the substrate is transferred from the holding section to an external transport mechanism.

The invention according to claim 13 is the resist removing apparatus according to any one of claims 8 to 12, wherein a heating part is provided around the supply port of the ozone gas in the processing space forming part.

The invention according to claim 14 is the resist removing apparatus according to any one of claims 8 to 13, wherein the predetermined temperature of the hot plate is set in the resist on which the deteriorated layer is formed, The temperature is equal to or higher than the temperature at which the denatured layer bursts due to internal expansion.

According to the present invention, it is possible to appropriately detect the end point of removal of the degraded layer and efficiently remove the resist on the substrate.

It is a figure which shows the structure of a resist removal apparatus. FIG. 4 is a diagram showing the resist removing apparatus with the processing space open; FIG. 4 is a cross-sectional view showing a resist; It is a figure which shows the flow of a resist removal process. FIG. 4 is a diagram showing the resist removing apparatus with the substrate placed at the first processing position; It is a figure which shows the change of the ozone concentration in exhaust gas. It is a figure which shows the change of the carbon dioxide concentration in exhaust gas. FIG. 10 is a diagram showing another example of a resist removing apparatus;

FIG. 1 is a diagram showing the configuration of a resist removing apparatus 1 according to one embodiment of the present invention. The resist removing apparatus 1 is an apparatus for removing resist from a substrate having a resist pattern on its main surface. The resist removing apparatus 1 includes a chamber 2, a lid lifting mechanism 31, a hot plate 4, a plurality of lift pins 51, a pin lifting mechanism 32, an ozone gas supply unit 6, a gas discharge unit 71, and a concentration measurement unit 72. and a control unit 10 . The control unit 10 is responsible for overall control of the resist removing apparatus 1 .

The chamber 2 includes a chamber main body 21 and a chamber lid portion 22 . The chamber body 21 includes a disk-shaped bottom plate portion 211 and a cylindrical body side portion 212 . The bottom plate portion 211 extends horizontally, and the body side portion 212 extends upward from the outer edge portion of the bottom plate portion 211 . The chamber lid portion 22 includes a disk-shaped top plate portion 221 and a cylindrical lid side portion 222 . The top plate portion 221 extends horizontally, and the lid side portion 222 extends downward from the outer edge portion of the top plate portion 221 . A horizontally extending shower plate 223 is fixed to the lower surface of the top plate portion 221 via a plate support portion 224 . Shower plate 223 is arranged between top plate portion 221 and hot plate 4 . A large number of through holes are formed in the shower plate 223 . The lower end surface of the lid side portion 222 vertically faces the upper end surface of the main body side portion 212 over the entire circumference. An annular recess is provided in the upper end surface of the body side portion 212, and an O-ring 23 is provided in the annular recess. The chamber main body 21 and the chamber lid 22 (including the shower plate 223) are made of stainless steel, for example.

The lid elevating mechanism 31 vertically moves the chamber lid 22 to selectively place the chamber lid 22 between the lower position shown in FIG. 1 and the upper position shown in FIG. In FIG. 2 , the chamber lid portion 22 is separated upward from the chamber main body 21 , and a large gap is formed between the lower end surface of the lid side portion 222 and the upper end surface of the main body side portion 212 . In FIG. 1 , the lower end surface of the lid side portion 222 and the upper end surface of the main body side portion 212 are substantially in contact with each other, and the upper side of the chamber main body 21 is closed by the chamber lid portion 22 . In the state shown in FIG. 1, the space between the lower end surface of the lid side portion 222 and the upper end surface of the main body side portion 212 is sealed by the O-ring 23, and the processing space 20 cut off from the outside is formed inside the chamber 2. be. The chamber 2 is a processing space forming part that forms a processing space 20 . The processing space 20 can be opened and closed, and the lid lifting mechanism 31 is an opening and closing mechanism for opening and closing the processing space 20 . A motor or an actuator other than a motor may be used in the lid lifting mechanism 31 . The opening/closing mechanism may be a mechanism that moves the chamber body 21 .

A hot plate 4 is arranged in the processing space 20 . The hot plate 4 has a thick disc shape, and the diameter of the hot plate 4 is larger than the diameter of the disc-shaped substrate 9 . The hot plate 4 is provided with a heater 40 including a heating wire. The hot plate 4 is heated to a predetermined set temperature by current supplied to the heater 40 from an external power source. The set temperature is, for example, 200° C. or higher, which is higher than the popping temperature described below at which popping occurs. The upper limit of the set temperature of the hot plate 4 in FIG. 1 is, for example, 300.degree. The hot plate 4 is fixed to the chamber main body 21 via members not shown. The disk-shaped bottom plate portion 211, top plate portion 221, and hot plate 4 have substantially the same center axis. In the following description, the circumferential direction centered on the central axis is simply referred to as "circumferential direction".

A plurality of through holes 41 are arranged in the hot plate 4 at regular angular intervals in the circumferential direction. The bottom plate portion 211 is provided with through holes 213 at positions overlapping the through holes 41 in the vertical direction. Each of the plurality of lift pins 51 is inserted into any combination of through holes 41 and through holes 213 . The number of lift pins 51 is typically three, and in this case, the lift pins 51 are arranged at intervals of 120 degrees in the circumferential direction. The number of lift pins 51 may be four or more. Lower ends of the plurality of lift pins 51 are fixed to the pin support plate 52 . Below the bottom plate portion 211 , each lift pin 51 is surrounded by a bellows 53 . The upper end of the bellows 53 is fixed to the lower surface of the bottom plate portion 211 , and the lower end of the bellows 53 is fixed to the upper surface of the pin support plate 52 . The bellows 53 and the pin support plate 52 prevent gas or liquid from passing through the through hole 213 of the bottom plate portion 211 between the inside and outside of the chamber 2 .

The pin elevating mechanism 32 includes a stepping motor, and elevates the pin support plate 52 in the vertical direction. As a result, the plurality of lift pins 51 move vertically. By driving the stepping motor, the pin support plate 52 and the plurality of lift pins 51 can be arranged at any position between, for example, the position shown in FIG. 1 and the position shown in FIG. 2 in the vertical direction. In FIG. 1 , tips (upper ends) of the plurality of lift pins 51 are arranged inside the through holes 41 of the hot plate 4 . In FIG. 2 , the tips of the plurality of lift pins 51 are arranged above the upper surface of the hot plate 4 . The tips of the plurality of lift pins 51 are hemispherical and positioned at the same height in the vertical direction. Other types of motors or actuators other than motors may be used in the pin lifting mechanism 32 .

In the resist removing apparatus 1, when the tips of the plurality of lift pins 51 are arranged inside the through holes 41, the substrate 9 is placed on the upper surface of the hot plate 4 and held in a horizontal posture. Further, when the tips of the plurality of lift pins 51 are arranged above the upper surface of the hot plate 4, the substrate 9 is supported from below by the plurality of lift pins 51 and held in a horizontal posture. As described above, in the resist removing apparatus 1 , the holding portion that holds the substrate 9 in the processing space 20 is switched between the hot plate 4 and the plurality of lift pins 51 . The pin elevating mechanism 32 is a moving mechanism that moves the holding portion relatively to the hot plate 4 when the holding portion is a plurality of lift pins 51 . A plurality of protrusions may be provided on the upper surface of the hot plate 4 . In this case, the substrate 9 is supported from below by the plurality of protrusions when the tips of the plurality of lift pins 51 are positioned below the upper surfaces of the plurality of protrusions.

The ozone gas supply unit 6 in FIG. 1 includes an ozone gas supply source 61 , a gas supply pipe 62 , a gas supply valve 63 and a gas nozzle 64 . The gas nozzle 64 is provided in the center of the top plate portion 221 and has a gas supply port 641 that opens into the processing space 20 above the hot plate 4 . The gas nozzle 64 is connected to the ozone gas supply source 61 via the gas supply pipe 62 . A gas supply valve 63 is provided on the gas supply pipe 62 . By opening the gas supply valve 63 , ozone (O ₃ ) gas is supplied from the gas nozzle 64 to the processing space 20 .

As described above, the shower plate 223 is arranged between the top plate portion 221 and the hot plate 4 . The ozone gas passes through a large number of through-holes in the shower plate 223 and is uniformly supplied to the upper main surface 91 of the substrate 9 (hereinafter simply referred to as "upper surface 91"). A plurality of gas nozzles 64 may be dispersedly provided on the top plate portion 221 . In this case, shower plate 223 may be omitted. In this embodiment, the ozone gas is obtained by diluting ozone with a predetermined gas. Ozone gas may be mixed with other kinds of oxidizing gas or the like.

The gas discharge portion 71 includes a gas discharge port 711 and a gas discharge pipe 712 . The gas exhaust port 711 is provided in the center of the bottom plate portion 211 and connected to one end of the gas exhaust pipe 712 . The other end of the gas exhaust pipe 712 is connected to an ozone decomposing unit (not shown) such as a filter. Gas in the processing space 20 is discharged to the outside through a gas discharge port 711 and a gas discharge pipe 712 . A plurality of gas discharge ports 711 may be provided in the resist removing apparatus 1 , and the gas discharge ports 711 may be provided in the outer edge portion of the bottom plate portion 211 , the main body side portion 212 , or the like. A concentration measurement unit 72 is connected to the gas discharge pipe 712 . The concentration measuring unit 72 measures the concentration of a predetermined component in the gas discharged from the processing space 20 (hereinafter referred to as "exhaust gas"). In this embodiment, the concentration measurement unit 72 measures the concentration of ozone and the concentration of carbon dioxide (CO ₂ ) in the exhaust gas.

Next, the resist formed on the substrate 9 will be described. FIG. 3 is a diagram abstractly showing a cross section of the resist 95 formed on the upper surface 91 of the substrate 9. As shown in FIG. The substrate 9 to be processed in the resist removing apparatus 1 is subjected to ion implantation at a high dose in the preceding process, and an altered layer 96 is formed on the surface of the resist 95 . In other words, the entire unaltered portion 97 of the resist 95 inside the altered layer 96 is covered with the upper surface 91 of the substrate 9 and the altered layer 96 . The altered layer 96 is also called a hardened layer.

Here, when the substrate 9 having the resist 95 on which the altered layer 96 is formed is heated, popping occurs in which the altered layer 96 ruptures due to internal expansion (for example, filling of gas generated from the unaltered portion 97). There is Popping does not occur when the heating temperature of the substrate 9 is low. The temperature of the substrate 9 at which popping occurs frequently (for example, 50% or more) can be identified by experiments or the like as the popping temperature. A process for efficiently removing the resist 95 with the altered layer 96 formed thereon while preventing popping will be described below.

FIG. 4 is a diagram showing the flow of resist removal processing in the resist removal apparatus 1. As shown in FIG. In the resist removing process, first, the chamber lid 22 is placed in the upper position shown in FIG. Subsequently, the substrate 9 passes through the gap between the lower end surface of the lid side portion 222 and the upper end surface of the main body side portion 212 by an external transport mechanism, and is placed between the chamber lid portion 22 and the chamber main body 21 . be done. Further, the pin elevating mechanism 32 moves the plurality of lift pins 51 upward to the position shown in FIG. Then, when the transport mechanism moves the substrate 9 slightly downward, the substrate 9 is transferred from the support portion of the transport mechanism to the plurality of lift pins 51, and the substrate 9 is supported from below by the plurality of lift pins 51 (step S11). The position of the substrate 9 shown in FIG. 2 is hereinafter referred to as "transfer position". The substrate 9 may be transferred from the support portion to the lift pins 51 by moving the tips of the lift pins 51 above the support portion.

When the support portion of the transfer mechanism moves to the outside of the chamber main body 21 and the chamber lid portion 22, the plurality of lift pins 51 descend, thereby moving the substrate 9 from the delivery position to the position shown in FIG. position”) (step S12). At the first processing position, a gap of a predetermined width (for example, several millimeters) is provided between the lower surface of the substrate 9 and the upper surface of the hot plate 4 . Further, the chamber lid portion 22 is lowered by the lid portion lifting mechanism 31 and placed in the lower position shown in FIG. As a result, the processing space 20 that is shut off from the outside is formed (step S13). In other words, the processing space 20 is closed.

The hot plate 4 is heated to a constant set temperature, and in the state shown in FIG. be. In practice, the set temperature and the width of the gap are determined by experiments or the like so that the temperature of the substrate 9 is lower than the popping temperature described above.

Subsequently, the gas supply valve 63 in the ozone gas supply unit 6 is opened, and ozone gas is jetted out from the gas supply port 641 into the processing space 20 at a predetermined supply flow rate. That is, the supply of ozone gas to the upper surface 91 of the substrate 9 is started (step S14). The supply of ozone gas is continuously performed in parallel with the heating of the substrate 9 by the hot plate 4 . Actually, a discharge valve (not shown) provided in the gas discharge pipe 712 shown in FIG. In the vicinity of the upper surface 91 of the substrate 9, the ozone gas is heated and decomposed to generate oxygen radicals and the like. Oxygen radicals and the like gradually decompose the deteriorated layer 96 that is the outermost surface of the resist 95 . The concentration measurement unit 72 constantly measures the ozone concentration and the carbon dioxide concentration in the exhaust gas, and outputs the measured values to the control unit 10 .

FIG. 6 is a diagram showing changes in ozone concentration (O ₃ concentration) in exhaust gas, and FIG. 7 is a diagram showing changes in carbon dioxide concentration (CO ₂ concentration) in exhaust gas. In FIGS. 6 and 7, changes in ozone concentration and carbon dioxide concentration in exhaust gas are indicated by solid lines L1 and L2. In FIG. 6, for comparison, the change in ozone concentration obtained when the substrate 9 is not placed in the processing space 20 is indicated by a dashed line L3. A change in ozone concentration obtained in this case is indicated by a dashed-dotted line L4. 6 and 7 also show the open/closed state of the chamber lid 22 and the open/closed state of the ozone gas (gas supply valve 63). 6 and 7, supply of ozone gas to the upper surface 91 of the substrate 9 is started at time T1.

The air in the processing space 20 is gradually replaced with ozone gas. As indicated by the solid line L1 in FIG. 6, the ozone concentration in the exhaust gas gradually increases from the start of supply of the ozone gas. At this time, part of the ozone gas is used to remove the resist 95 on the substrate 9, more precisely, to decompose the altered layer 96. FIG. Therefore, the ozone concentration at each time is smaller than the change in ozone concentration (broken line L3) when the substrate 9 is not arranged in the processing space 20 . Further, as indicated by the solid line L2 in FIG. 7, the decomposition of the altered layer 96 gradually increases the carbon dioxide concentration. At the initial stage of resist removal, most of the removed resist 95 is the degraded layer 96, and in the following description, such a period is referred to as "degraded layer removal period". If the resist 95 on the substrate 9 does not have the altered layer 96 (in this case, the substrate 9 is placed at the position shown in FIG. 1), more ozone gas will decompose the resist 95. Therefore, the ozone concentration (chain line L4) at each time is smaller than that of the solid line L1.

As the decomposition of the degraded layer 96 progresses due to the supply of the ozone gas, part of the undegraded portion 97 is exposed in the resist 95 . Since the unaltered portion 97 is more easily decomposed than the altered layer 96, more ozone gas is consumed than during the altered layer removal period, and the rate of change in ozone concentration becomes smaller. The control unit 10 constantly obtains the rate of change of the ozone concentration during resist removal. When the change rate of the ozone concentration becomes equal to or less than the predetermined threshold value, it is determined that most of the degraded layer 96 has been removed (step S15). Thus, the end point of removal of the degraded layer 96 is detected based on the change rate of the ozone concentration. In FIGS. 6 and 7, removal of the altered layer 96 is almost completed at time T2.

When the end point of removal of the degraded layer 96 is detected, or when a predetermined time elapses after detection of the end point, the plurality of lift pins 51 are lowered to move the substrate 9 from the first processing position to the position shown in FIG. (hereinafter referred to as "second processing position") (step S16). In the second processing position, the substrate 9 is placed on the upper surface of the hotplate 4 and no gap is provided between the lower surface of the substrate 9 and the upper surface of the hotplate 4 . In other words, the width of the gap is zero. The temperature of the substrate 9 placed at the second processing position is higher than when placed at the first processing position. Actually, the temperature of the substrate 9 rises to near the set temperature of the hot plate 4 . Therefore, decomposition of the ozone gas in the vicinity of the upper surface 91 of the substrate 9 is accelerated more than during the deteriorated layer removal period in which the substrate 9 is placed at the first processing position. As a result, the decomposition of the remaining resist 95 (mainly the unaltered portion 97) is also promoted. In the resist removing apparatus 1, if the gap between the substrate 9 placed at the second processing position and the hot plate 4 is smaller than the gap at the first processing position, the substrate 9 at the second processing position may be separated from the hot plate 4.

As the resist 95 remaining on the substrate 9 decreases, the carbon dioxide concentration in the exhaust gas decreases. After that, the ozone concentration becomes saturated at a certain constant value, and the carbon dioxide concentration becomes almost zero. The control unit 10 determines that the removal of the unaltered portion 97 has been completed when the carbon dioxide concentration becomes equal to or less than a predetermined threshold value (step S17). By measuring the carbon dioxide concentration in this way, the end point of the removal of the resist 95 is detected. In the resist removing apparatus 1, by placing the substrate 9 at the second processing position after removing the altered layer 96, the resist 95 is reduced compared to the case where the processing is continued with the substrate 9 temporarily placed at the first processing position. can be completed in a short period of time.

When the end point of removal of the resist 95 is detected at time T3, the gas supply valve 63 is closed at time T4 after a predetermined time has elapsed from time T3, and the supply of ozone gas is stopped (step S18). This completes the treatment of the substrate 9 with the ozone gas. The time from time T3 to time T4 is a time (over-etching time) set to more reliably remove the resist 95 on the substrate 9 . Actually, a discharge valve (not shown) provided in the gas discharge pipe 712 is closed, and the gas discharge operation within the processing space 20 is also stopped. After stopping the supply of ozone gas, nitrogen gas or the like may be supplied to the processing space 20 to replace the ozone gas in the processing space 20 with the nitrogen gas.

Subsequently, the chamber lid portion 22 is lifted by the lid lifting mechanism 31 and placed at the upper position shown in FIG. Thereby, the processing space 20 is opened (step S19). Further, the substrate 9 moves upward from the second processing position to the delivery position shown in FIG. 2 by raising the plurality of lift pins 51 (step S20). Furthermore, the support of the transport mechanism is arranged between the substrate 9 and the hot plate 4 . Then, the substrate 9 is transferred from the plurality of lift pins 51 to the support portion by moving the support portion upward (step S21). In the resist removing apparatus 1, the substrate 9 is moved from the plurality of lift pins 51 holding the substrate 9 to the transport mechanism in a state where the substrate 9 is placed at a position farther from the hot plate 4 than the first processing position shown in FIG. Passed. After that, the substrate 9 passes through the gap between the lower end surface of the lid side portion 222 and the upper end surface of the main body side portion 212 and is carried out of the resist removing apparatus 1 . This completes the resist removing process for the substrate 9 . If there is a substrate 9 to be processed next, the processing of steps S11 to S21 is repeated for that substrate 9 .

Here, a resist removing apparatus of a comparative example will be described. In the resist removing apparatus of the comparative example, after loading the substrate 9, the substrate 9 is placed at the second processing position shown in FIG. 1, and the resist 95 (altered layer 96 and unaltered portion 97) is removed. As described above, the set temperature of the hot plate 4 is equal to or higher than the popping temperature, which is the temperature at which the resist 95 having the altered layer 96 ruptures due to internal expansion. Therefore, popping of the resist 95 may occur in the resist removing apparatus of the comparative example. In FIG. 3, the expansion of the unaltered portion 97 is indicated by an arrow A1.

When popping occurs, the pattern on the substrate 9 collapses, and scattered fragments of the altered layer 96 adhere to the upper surface 91 of the substrate 9 and the interior of the chamber 2 . It is also conceivable to prevent popping by setting the set temperature of the hot plate 4 lower than the popping temperature. However, since the removal rate of the resist 95 is affected by the temperature of the substrate 9, the time required to remove the resist 95 is lengthened. Also, the substrate 9 may be excessively oxidized. Although it is conceivable to change the set temperature of the hot plate 4 during resist removal, it is difficult to rapidly change the temperature of the hot plate 4 .

On the other hand, in the resist removing apparatus 1, the substrate 9 is placed at the first processing position with a gap from the hot plate 4, and the degraded layer 96 is removed by ozone gas. Subsequently, by controlling the pin elevating mechanism 32, the substrate 9 is placed at a second processing position with a smaller gap from the hot plate 4 than the first processing position, and the resist 95 is removed by ozone gas. This makes it possible to efficiently (in a short time) remove the resist 95 on the substrate 9 while preventing popping using the hot plate 4 whose temperature is difficult to change rapidly. As a result, excessive oxidation of the substrate 9 can also be suppressed. Further, since the second processing position is a position where the substrate 9 is in contact with the upper surface of the hot plate 4, the substrate 9 can be efficiently heated to a high temperature.

By measuring the concentration of a predetermined component in the gas discharged from the processing space 20 in parallel with the removal of the altered layer 96 by the ozone gas, the end point of removal of the altered layer 96 can be appropriately detected for each substrate 9. . As a result, the period during which the substrate 9 is heated at a relatively low temperature (the period during which the substrate 9 is placed at the first processing position) is prevented from becoming unnecessarily long, and the resist 95 on the substrate 9 is removed. The time required can be shortened. Moreover, popping can be prevented more reliably.

By measuring the concentration of a predetermined component in the gas discharged from the processing space 20 in parallel with the removal of the resist 95 (mainly, the unaltered portion 97 ) by ozone gas, the end point of removal of the resist 95 can also be determined appropriately for each substrate 9 . can be detected. As a result, the period during which the substrate 9 is heated can be prevented from becoming unnecessarily long, and excessive oxidation of the substrate 9 can be suppressed more reliably. Also, the resist 95 can be removed more reliably.

The pin elevating mechanism 32 having a stepping motor can freely change the gap between the substrate 9 and the hot plate 4 . As a result, it is possible to easily adjust the temperature of the substrate 9 during the degraded layer removal period, and to more reliably prevent popping.

FIG. 8 is a diagram showing another example of the resist removing apparatus 1. As shown in FIG. In the resist removing apparatus 1 of FIG. 8, the heating section 24 is provided on the top plate section 221 of the chamber lid section 22 . Other configurations are the same as those of the resist removing apparatus 1 of FIG. 1, and the same configurations are denoted by the same reference numerals.

The heating portion 24 provided in the chamber lid portion 22 surrounds the gas supply port 641 for ejecting ozone gas. Therefore, when the ozone gas is supplied to the upper surface 91 of the substrate 9 , the top plate portion 221 is heated by the heating portion 24 and the ozone gas ejected from the gas supply port 641 is also heated. This raises the temperature of the ozone gas, promoting the generation of oxygen radicals and the like. As a result, the degraded layer 96 is removed from the substrate 9 placed at the first processing position and the undegraded portion 97 is removed from the substrate 9 placed at the second processing position without excessively increasing the temperature of the substrate 9. Removal can be done in a short time. Thus, the resist removal apparatus 1 of FIG. 8 can accelerate the removal of the resist 95 . Since the temperature rise of the substrate 9 caused by the heating of the top plate portion 221 by the heating portion 24 is slight, the occurrence of popping in the substrate 9 placed at the first processing position is prevented when the degraded layer 96 is removed. It is possible.

Various modifications are possible for the resist removing apparatus 1 and the resist removing method.

The holding portion that holds the substrate 9 at the first processing position may be other than the plurality of lift pins 51 . For example, a holding section having a mechanism for holding the outer edge of the substrate 9 may be employed in the resist removing apparatus 1 . In this case, depending on the design of the resist removing apparatus 1, the resist 95 may be removed with the main surface on which the resist 95 is formed facing downward or sideways. Moreover, the holding part may move relatively to the hot plate 4, and a moving mechanism for moving the hot plate 4 in the vertical direction may be employed.

The gas supply port 641 of the ozone gas supply unit 6 may be provided at a portion other than the top plate portion 221 of the chamber lid portion 22 , for example, may be provided at the lid side portion 222 .

Only one of the ozone concentration and the carbon dioxide concentration is measured by the concentration measurement unit 72, and the end point of removal of the degraded layer 96 and the end point of removal of the resist 95 are detected based on the measured value of the one concentration. may be Further, the concentration of the ions in the ion implantation performed using the pattern of the resist 95 may be detected by the concentration measuring section 72 .

If the concentration of the predetermined component in the gas discharged from the processing space 20 can be substantially measured, the concentration measurement section 72 may be provided other than the gas discharge pipe 712 . For example, the concentration measuring section 72 can be provided in the vicinity of the gas outlet 711 in the bottom plate section 211 .

Detection of the end point of removal of the degraded layer 96 by the control unit 10 may be performed by various methods based on the measurement value of the concentration measurement unit 72 . For example, a reference profile showing a typical change in ozone concentration or carbon dioxide concentration from the start to the end of removal of the altered layer 96 is prepared, and by fitting the actually obtained concentration change profile to the reference profile, the alteration The endpoint of removal of layer 96 may be detected. Similarly, detection of the end point of removal of the resist 95 (unaltered portion 97 ) by the control unit 10 may be performed by various methods based on the measurement values of the density measurement unit 72 .

The configurations in the above embodiment and each modified example may be combined as appropriate as long as they do not contradict each other.

REFERENCE SIGNS LIST 1 resist removing device 2 chamber 4 hot plate 6 ozone gas supply unit 9 substrate 10 control unit 20 processing space 24 heating unit 31 lid lifting mechanism 32 pin lifting mechanism 51 lift pin 72 concentration measuring unit 91 upper surface 95 resist 96 altered layer 641 gas supply port S11-S21 steps

Claims (14)

A resist removing method for removing the resist of a substrate having a resist pattern on the main surface and having an altered layer formed on the surface, comprising:
A) removing the altered layer by supplying ozone gas to the main surface while placing the substrate and a hot plate heated to a predetermined temperature in a processing space isolated from the outside;
B) in parallel with the step A), detecting the end point of removal of the altered layer by measuring the concentration of ozone gas in the gas discharged from the processing space;
C) after step A), removing the resist by supplying ozone gas to the main surface;
A method of removing a resist, comprising: The resist removal method according to claim 1,
A method of removing a resist, wherein in the step B), the end point of removal of the deteriorated layer is detected based on the change rate of the concentration of the ozone gas. The resist removal method according to claim 1 or 2,
In parallel with the step C), the resist removing method further comprises a step of detecting the end point of removal of the resist by measuring the concentration of a predetermined component in the gas discharged from the processing space. The resist removal method according to any one of claims 1 to 3,
In step A), the altered layer is removed by arranging the substrate at a first processing position with a gap from the hot plate,
In the above step C), the resist removing method is characterized in that the substrate is placed at a second processing position where the gap is smaller than that of the first processing position, and the resist is removed. The resist removal method according to claim 4,
The processing space is openable and closable,
When the processing space is opened, the substrate is placed at a position farther from the hot plate than the first processing position, and the substrate is moved from a holding unit that holds the substrate to an external transport mechanism. A method of removing a resist, characterized in that: The resist removal method according to any one of claims 1 to 5,
A resist removing method, wherein a heating section is provided around an ozone gas supply port in a processing space forming section that forms the processing space. The resist removal method according to any one of claims 1 to 6,
A method of removing a resist, wherein the predetermined temperature of the hot plate is equal to or higher than a temperature at which the degraded layer bursts due to internal expansion of the resist on which the degraded layer is formed. A resist removing device,
a processing space forming unit that forms a processing space that is isolated from the outside;
a hot plate placed in the processing space and heated to a predetermined temperature;
a holding unit that holds, in the processing space, a substrate that has a resist pattern on its main surface and that has an altered layer formed on its surface;
an ozone gas supply unit that supplies ozone gas to the main surface;
a concentration measuring unit that measures the concentration of ozone gas in the gas discharged from the processing space;
a control unit that detects the end point of removal of the degraded layer based on the measured value of the concentration measurement unit, and then removes the resist with ozone gas;
A resist removing apparatus comprising: The resist removing apparatus according to claim 8,
The resist removing apparatus, wherein the control unit detects the end point of removal of the deteriorated layer based on the change rate of the concentration of the ozone gas. The resist removing apparatus according to claim 8 or 9,
The resist removing apparatus, wherein the control unit detects the end point of removal of the resist based on the measured value of the density measuring unit. The resist removing apparatus according to any one of claims 8 to 10,
further comprising a moving mechanism for moving the holding part relative to the hot plate;
The control unit arranges the substrate at a first processing position spaced from the hot plate, removes the altered layer with the ozone gas, and then controls the moving mechanism to control the A resist removing apparatus, wherein the substrate is placed at a second processing position where the gap is smaller than that of the first processing position, and the resist is removed by the ozone gas. The resist removing apparatus according to claim 11,
further comprising an opening and closing mechanism for opening and closing the processing space,
When the processing space is opened, the control unit places the substrate at a position farther from the hot plate than the first processing position, and the substrate is transferred from the holding unit to an external transport mechanism. A resist removing apparatus characterized by: The resist removing apparatus according to any one of claims 8 to 12,
A resist removing apparatus, wherein a heating section is provided around the supply port of the ozone gas in the processing space forming section. The resist removing apparatus according to any one of claims 8 to 13,
The resist removing apparatus according to claim 1, wherein the predetermined temperature of the hot plate is equal to or higher than a temperature at which the degraded layer bursts due to internal expansion of the resist on which the degraded layer is formed.

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