JP2007288103A - Etching treating device and etching treating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an etching treating device capable of preventing a chemical replacement cost from increasing and a treated waste liquid from increasing and stabilizing an etched amount. <P>SOLUTION: The etching treating device including an etching means for etching a material formed on a semiconductor substrate with the chemical liquid that is an aqueous solution containing hydrofluoric acid and/or ammonium fluoride, and a water washing means for washing the etched semiconductor substrate with a purified water, wherein the etching means is provided with a chemical liquid cooling function that controls the chemical liquid that is allowed to contact the material formed on the semiconductor substrate at a temperature in a scope that the chemical liquid is not frozen at a temperature of 20°C or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an etching processing apparatus and an etching processing method for performing etching or cleaning using a chemical solution containing hydrofluoric acid or ammonium fluoride.

Conventional wet etching of a Si oxide film (SiO ₂ ) in the manufacture of a semiconductor device is performed using a batch processing apparatus or a chemical solution of diluted hydrofluoric acid (hereinafter referred to as DHF) or buffered hydrofluoric acid (hereinafter referred to as BHF). It is performed by a single wafer processing apparatus. As a batch type processing apparatus, a dip type processing apparatus that immerses 25 or 50 wafers in a processing tank, and a batch spray process that sprays a chemical solution while rotating 25 or 50 wafers in a sealed chamber. The device is common. However, since it is necessary to precisely control the etching amount of the Si oxide film in the advanced device, a single-wafer processing apparatus with high controllability is increasingly used. A single wafer processing apparatus generally has a structure in which a wafer is horizontally held and rotated in a cleaning cup, and a chemical solution is discharged from the upper or lower portion to the entire surface of the wafer for cleaning.

  In any of these apparatuses, exhaust is performed during the chemical treatment to prevent the chemical atmosphere (chemical mist) from scattering. The temperature of the chemical solution is set to the same temperature as that of a normal clean room (room temperature in the range of 20 to 25 ° C., usually around 23 ° C.). In addition, these apparatuses are usually provided with a chemical solution circulation line, and particle removal (filtration) and chemical solution temperature control by a filter and electronic cold are performed. Since the etching rate of the chemical solution fluctuates as the wafer processing is repeated or with time, the chemical solution is exchanged at a certain frequency.

  In addition, with the miniaturization of semiconductor devices, improvement in the controllability of the etching amount is required in the etching of Si oxide films using DHF or BHF. In particular, in SoC (System on a Chip), in the STI (Shallow Trench Isolation) formation process, there is a difference in the amount of wet etching of an oxide film between a P-channel field effect transistor and an N-channel field effect transistor. It has been confirmed that a so-called depression is formed, causing deterioration of device characteristics (see, for example, Patent Document 1). Therefore, it is common to use BHF with a small difference in the etching amount between the P channel and the N channel, and it is required to perform a very small amount of etching with an etching amount of 10 nm or less with good controllability.

JP 2001-257258 A

By the way, the etching rate of DHF tends to increase with time due to evaporation of moisture. Also in the case of BHF, the etching rate increases due to the evaporation of ammonia as the wafer processing is repeated. In particular, an increase in the etching rate due to evaporation of ammonia is remarkable in BHF (HF concentration: 0.5% or less) diluted with NH ₄ F (40%): HF (50%) = 100: 1. For example, when about 100 wafers are processed using 200: 1 BHF (HF concentration: 0.25%, 1200 BHF) in a single wafer processing apparatus, an increase in etching rate of 5% or more has been confirmed. On the other hand, in the case of a chemical solution having a high HF concentration of 1% or more, such as 50: 1 BHF (150 BHF), such an increase in the etching rate is gradual and does not cause a substantial problem. Advanced devices require a small amount of oxide film etching and high controllability, so chemicals with a low etching rate such as 1200 BHF are used. However, fluctuations in the etching rate cause device characteristics to deteriorate. There was a problem that it was. In addition, if the chemical solution is frequently exchanged to stabilize the etching amount, there has been a problem in that it causes an increase in cost and an increase in drainage treatment (increase in environmental load).

  The present invention has been made in view of the above, and it is an object of the present invention to provide an etching processing apparatus and an etching processing method capable of preventing an increase in the cost of chemical replacement and an increase in drainage treatment and stabilizing the etching amount. .

  In order to achieve the above object, an etching processing apparatus according to the present invention comprises etching means for etching a material formed on a semiconductor substrate using a chemical solution that is an aqueous solution containing hydrofluoric acid and / or ammonium fluoride. And an rinsing means for rinsing the etched semiconductor substrate with pure water, wherein the etching means causes the chemical solution contacting the material formed on the semiconductor substrate to have a temperature of 20 ° C. or lower. And a chemical solution cooling function for adjusting the temperature so that the chemical solution does not freeze.

  According to this invention, since the temperature of the chemical solution for performing the etching process is lower than the room temperature of 20 ° C., evaporation of moisture and ammonia contained in the chemical solution can be suppressed, and fluctuations in the etching rate can also be suppressed. As a result, it is possible to reduce the frequency of replacement of the chemical solution, and it is possible to realize a reduction in the chemical solution cost and a reduction in drainage treatment (reduction in environmental load). Furthermore, since the etching rate is lower than that at room temperature, a chemical solution having a high HF concentration, for example, BHF having an HF concentration of 1% or more, which has a high etching rate at room temperature but has a small variation in etching rate due to evaporation of components (time-dependent change). It is also possible to perform etching with good controllability.

  Exemplary embodiments of an etching processing apparatus and an etching processing method according to the present invention will be explained below in detail with reference to the accompanying drawings. However, in the following, the outline of the present invention will be described first, and then embodiments will be described. Note that the present invention is not limited to these embodiments.

The present invention uses an aqueous solution containing HF such as hydrofluoric acid (HF) or ammonium fluoride (NH ₄ F) as a chemical solution when performing etching treatment of a predetermined material such as a Si oxide film of a semiconductor device. Etching is performed by controlling the temperature to a temperature lower than room temperature (20 ° C. or lower). Thereby, the evaporation of the chemical solution is suppressed and the etching rate is suppressed as compared with the case of room temperature.

  Moreover, when performing an etching process, you may set the temperature of the atmosphere (gas) which contacts a chemical | medical solution to the temperature same as the temperature of a chemical | medical solution, or lower than the temperature of a chemical | medical solution. Thereby, the evaporation of the chemical during the etching process is suppressed.

  Further, when cleaning the etched semiconductor device with pure water, the semiconductor device may be cleaned by controlling the pure water at a temperature lower than room temperature (20 ° C. or lower). Thereby, the etching which arises when the chemical | medical solution which remained on the surface of the semiconductor device by the previous etching process ionizes in a pure water is suppressed.

Embodiment 1 FIG.
FIG. 1 is a diagram schematically showing the configuration of the first embodiment of the etching processing apparatus according to the present invention. FIG. 1 shows a case where the present invention is applied to a batch type immersion processing apparatus (Dip type processing apparatus) as an etching processing apparatus. In this figure, only main parts constituting the apparatus are shown in a simplified manner, and illustration of the wafer transfer mechanism and other constituent parts is omitted.

  The batch type immersion treatment apparatus 1 includes a chemical solution treatment unit 20, a water washing treatment unit 30, and a drying treatment unit 40 that are blocked from outside air. The chemical solution processing unit 20 is a portion that etches an object such as a semiconductor device using an etching solution, and is connected to a chemical solution treatment tank 21 and a chemical solution circulation line connected to the liquid discharge port 22 of the chemical solution treatment tank 21. 24, a heat exchanger 25, and a filter 26 are provided. The chemical treatment unit 20 includes an air filter unit 27, an air conditioner 28, and an exhaust port 29. In the chemical treatment unit 20, as described above, the temperature of the chemical is set to a temperature below room temperature (20 ° C. or less). Further, the temperature of the gas atmosphere in the chemical solution processing unit 20 is set to the same temperature as the chemical solution or about 10 ° C. lower than this temperature. The chemical processing unit 20 corresponds to the etching means in the claims.

  The chemical solution processing tank 21 is filled with a chemical solution 23 such as DHF or BHF, and etches the wafer 51 that has been transferred by the transfer mechanism. Note that, as described above, a transport mechanism that transports the wafer 51 to the chemical treatment tank 21 and immerses the chemical in the chemical 23 is omitted.

  The pump 24 is connected to a liquid discharge port 22 provided in the chemical liquid processing tank 21, sucks the chemical liquid 23 from the liquid discharge port 22, and sends it out to the chemical liquid processing tank 21 again. Thereby, the chemical | medical solution in the chemical | medical solution processing tank 21 is always circulated. The filter 26 removes foreign substances contained in the chemical solution 23 circulated by the pump 24.

  The heat exchanger 25 is disposed on the output side of the pump 24 and has a function of bringing the chemical solution 23 sent out from the pump 24 to a predetermined temperature. Although the temperature of the chemical solution 23 is set to an optimum range depending on the type of the chemical solution 23, in the first embodiment, the temperature of the DHF or BHF as the chemical solution 23 is set at the chemical solution component in the contact portion with the air of the chemical treatment tank 21. In order to reduce evaporation, the temperature is controlled to a low temperature (20 ° C. or lower) below room temperature. Specifically, in the case of DHF, the range of 0 to 20 ° C. is good, and it is particularly preferable to control the range to 5 to 15 ° C. Moreover, in the case of BHF, the range of -10-20 degreeC is good, and it is preferable to control to the range of 0-10 degreeC especially. When the set temperature of the chemical solution 23 is higher than the above set range, the chemical solution components evaporate quickly, and as explained in the background art, the etching rate varies greatly depending on the type of the chemical solution, and the chemical solution is frequently replaced. I will have to. On the other hand, if the temperature of the chemical solution is too low, the chemical solution is frozen or precipitates such as crystals are generated in the chemical solution, causing problems such as fluctuations in etching rate and particle adhesion. The heat exchanger 25 corresponds to the chemical liquid cooling function in the claims.

  The air filter unit 27 is installed in the upper part of the chemical | medical solution processing part 20, for example. An air conditioner 28 is connected to the air filter unit 27. The air conditioner 28 is installed outside the chemical treatment unit 20 and supplies gas (air) having a predetermined temperature into the chemical treatment unit 20 via the air filter unit 27. In the first embodiment, the air conditioner 28 is kept at the same temperature as or lower than the temperature of the chemical solution 23 in the chemical treatment tank 21. In this way, by setting the temperature of the atmosphere in the chemical solution processing unit 20 to a low temperature of 20 ° C. or less, the evaporation of the chemical component at the contact portion with the air of the chemical solution processing tank 21 can be reduced. However, if the temperature is too low and the difference from the chemical temperature becomes large, it becomes difficult to control the chemical temperature. If the temperature is extremely low, problems such as freezing of the chemical 23 and precipitation of crystals occur. It is necessary to set the temperature to such a level that no precipitation of substances occurs. The exhaust port 29 is an exhaust (not shown) in order to prevent evaporating components such as mist, hydrogen fluoride and ammonia evaporated from the chemical treatment tank 21 in the chemical treatment unit 20 from leaking outside the main body of the batch type immersion treatment apparatus 1. Connected to the processing facility, a predetermined amount of exhaust is performed. These air filter unit 27 and air conditioner 28 correspond to the atmospheric gas cooling function in the claims.

  The washing unit 30 is a part for washing the object etched by the chemical treatment unit 20, and includes a washing tank 31, a pure water supply unit 33, a pure water heat exchanger 34, an air filter unit 35, and an air conditioner 36. Is provided. In this water washing process part 30, the temperature of internal gas is controlled to the low temperature of 20 degrees C or less, It is characterized by the above-mentioned. This washing unit 30 corresponds to the washing means in the claims.

  The washing tank 31 is filled with pure water 32 and cleans the wafer 51 that has been transported by the transport mechanism. Note that, as described above, a transport mechanism that transports the wafer 51 to the washing tank 31 and immerses it in the pure water 32 is not shown.

  The pure water supply unit 33 supplies pure water 32 to the washing tank 31. The pure water heat exchanger 34 has a function of sending pure water 32 sent from the pure water supply unit 33 to the washing tank 31 at a predetermined temperature. Specifically, the temperature of the pure water 32 is controlled to a low temperature (20 ° C. or lower) below room temperature and supplied to the water washing tank 31. In addition, as a temperature of the pure water 32, the range of 0-20 degreeC is good, and 0-10 degreeC is especially preferable. When the temperature of the pure water 32 is higher than 20 ° C., the progress of the etching of the oxide film in the rinsing tank 31 by the HF ions in the chemical liquid attached to the wafer 51 by the processing in the chemical processing section 20 is suppressed. This is because the pure water 32 freezes at a temperature lower than 0 ° C. and cannot be set.

Conventionally, it has been confirmed that a Si oxide film is etched during washing with water after treatment with a chemical solution containing HF or NH ₄ F. In particular, since a chemical solution containing ammonium fluoride (NH ₄ F) such as BHF has a high viscosity, a large amount of the chemical solution adhering to the wafer after immersion in the chemical solution is brought into the water washing tank 31 and the replacement efficiency by water washing is poor. Therefore, NH ₄ F exists in the washing tank 31 for a long time, NH ₄ F is ionized in the pure water 32, and etching of the oxide film by the ionized HF ions (H ⁺ , HF ₂ ⁻ ) proceeds. As a result, there has been a problem that the uniformity in the wafer surface of the etching amount of the Si oxide film is deteriorated. However, in the first embodiment, the pure water 32 controlled to 20 ° C. or less by the pure water heat exchanger 34 is supplied to the washing tank 31 to reduce the reaction rate of HF ions during washing. it can. The pure water heat exchanger 34 corresponds to the pure water cooling function in the claims.

  The air filter unit 35 is installed in the upper part of the water washing process part 30, for example. An air conditioner 36 is connected to the air filter unit 35. The air conditioner 36 is installed outside the washing unit 30 and supplies gas (air) having a predetermined temperature into the washing unit 30 via the air filter unit 35. In the first embodiment, the air conditioner 36 keeps the gas (air) in the washing unit 30 at the same temperature as or lower than the temperature of the pure water 32 in the washing unit 31.

  The drying processing unit 40 is for drying the wafer 51 cleaned by the rinsing processing unit 30. As the drying process, for example, spin drying that rotates the wafer 51 at high speed, IPA vapor drying using IPA (isopropyl alcohol), or IPA direct substitution drying (commonly called Marangoni drying) can be used.

  Next, the operation process of such a batch type immersion treatment apparatus 1 will be described. First, the wafer 51 is placed on a cassette on which a predetermined number (for example, a maximum of 25 or 50) of wafers 51 can be placed. It is transported into one chemical treatment unit 20 and immersed in the chemical treatment tank 21 for a predetermined time. At this time, the temperature of the chemical solution is set to a temperature below room temperature (20 ° C. or less), and the temperature in the chemical solution processing unit 20 is set to the same temperature as the chemical solution or lower. After being immersed in the chemical treatment tank 21 for a predetermined time, the wafer 51 (cassette) is pulled up from the chemical treatment tank 21, transported from the chemical treatment section 20 into the water washing treatment section 30 by the transport mechanism, and immersed in the water washing tank 12. In general, during washing, a large amount of pure water 32 is supplied from the pure water supply unit 33 to the washing tank 31 via the pure water heat exchanger 34, and the washing tank 31 overflows to adhere to the wafer 51. Is replaced and removed. At this time, the temperature of pure water is set to a temperature equal to or lower than room temperature (20 ° C. or lower). After the wafer 51 (cassette) is immersed in the rinsing tank 31 for a predetermined time, the wafer 51 (cassette) is pulled up from the rinsing tank 31 and transferred from the rinsing processing unit 30 into the drying processing unit 40 by the transfer mechanism. Then, the wafer 51 is dried by the drying processing unit 40, and the etching of the wafer 51 and the water washing process are completed.

  According to the first embodiment, the chemical solution treatment tank 21 and the chemical solution 23 in the circulation line are controlled to a low temperature of 20 ° C. or less by the heat exchanger 25, so that evaporation of the chemical solution 23 in the chemical solution treatment tank 21 is suppressed. be able to. Further, since the air temperature in the chemical treatment unit 20 is kept at a low temperature of 20 ° C. or less by the air conditioner 28, the evaporation of the chemical component at the contact portion with the air in the chemical treatment tank 21 can be reduced. Therefore, there is an effect that fluctuation of the etching rate of the chemical solution can be suppressed, exchange of the chemical solution can be reduced, and an increase in the chemical treatment cost and an increase in the drainage treatment (an increase in environmental load) can be suppressed.

  In addition, there is an effect that a chemical solution that cannot be used at room temperature because of a high etching rate can be used because the etching rate can be lowered by lowering the chemical temperature. For example, BHF with a HF concentration of 1% or higher (for example, 150BHF or 115BHF) has a higher etching rate than BHF with a low HF concentration, but it is confirmed that there is little variation in the etching rate even when ammonia is evaporated. Has been. Conventionally, since chemicals are processed at room temperature, BHF (for example, 1100 BHF or 1200 BHF) having a low etching rate with an HF concentration of 1% or less is used in order to control a small amount of etching required for advanced devices. It was used. Since BHF having a low HF concentration of 1% or less and having a low etching rate has a large fluctuation in the etching rate due to the evaporation of ammonia, the chemical solution must be frequently exchanged as described in the problem. However, since the etching rate is lowered by lowering the chemical solution as in the first embodiment, BHF having a high etching rate with an HF concentration of 1% or more can also be used. That is, by using a chemical solution that has a high etching rate but little change in the etching rate with time, the etching rate can be lowered and the variation in the etching rate can be reduced. As a result, the number of times of exchanging the chemical solution can be reduced as compared with the conventional case, and an increase in cost can be suppressed and an increase in environmental load can be suppressed.

  Further, since the temperature of the pure water 32 is controlled to be room temperature or lower (20 ° C. or lower) in the water washing processing section 30, the chemical liquid (HF) attached to the wafer 51 in the chemical liquid processing section 20 is pure water 32. Etching of the oxide film on the wafer 51 by the HF ions formed by replacement is suppressed. As a result, the uniformity of the etching amount of the Si oxide film within the wafer surface can be improved, and a very small amount of etching can be controlled.

Embodiment 2. FIG.
FIG. 2 is a diagram schematically showing the configuration of the second embodiment of the etching apparatus according to the present invention. FIG. 2 shows a case where the present invention is applied to a single wafer processing apparatus 101 as an etching processing apparatus. In this figure, only main parts constituting the apparatus are shown in a simplified manner, and illustration of the wafer transfer mechanism and other constituent parts is omitted.

  The main body of the single wafer processing apparatus 101 includes a processing chamber 110 that is blocked from outside air, and a cleaning cup 111 is installed therein. In the cleaning cup 111, there are provided an exhaust port 113, a stage 120 that holds the wafer 51, and a liquid discharge port 112 that discharges the chemical liquid accumulated in the cleaning cup 111. A wafer holding member 121 that holds the wafer 51 is provided at a predetermined position on the periphery of the upper side of the stage 120, and is directed toward the back surface (downward) of the wafer 51 at a position near the upper central portion of the stage 120. A gas nozzle 122 for blowing out low-temperature gas is provided. The stage 120 is connected to the motor 123 so as to be able to rotate in the plane around the vertical axis at the center in the plane during processing. The drainage port 112 is connected to a chemical liquid tank 132 described later via a pipe such as a pipe. Note that the stage 120, the wafer holding member 121, and the moe 123 correspond to the substrate holding means in the claims, and the gas nozzle 122 also corresponds to the cooling gas spraying means.

  A chemical solution discharge nozzle 131 and a pure water discharge nozzle 141 are provided above the cleaning cup 111. The chemical solution circulation line connected to the chemical solution discharge nozzle 131 includes a pump 133 for sending the chemical solution from the chemical solution tank 132, a heat exchanger 134 for setting the temperature of the chemical solution to a predetermined temperature, and a filter for removing impurities in the chemical solution. 135 is connected to a chemical tank 132 for storing a chemical liquid to be supplied to the wafer 51, and the chemical tank is connected to the drain 112 of the cleaning cup 111. Further, in the second embodiment, the chemical solution tank 132 → the heat exchanger 134 → the pump 133 → the filter 135 → the chemical solution discharge nozzle 131 → the drain port 112 of the cleaning cup 111 → the wafer in which the chemical solution is circulated with the chemical solution tank 132. A pipe between the filter 135 and the chemical solution discharge nozzle 131 in order to switch the operation mode and the chemical solution tank 132 → the heat exchanger 134 → the pump 133 → the filter 135 → the chemical solution tank 132 and the standby operation mode in which the chemical solution circulates. A switching valve 136 is provided on the road. The pump 133 is always in a driving state, and the chemical solution is circulated in either the above wafer processing or standby state. The chemical solution discharge nozzle 131, the chemical solution tank 132, the pump 133, the heat exchanger 134, and the filter 135 correspond to the etching means in the claims, and the chemical solution discharge nozzle 131 and the pump 133 also correspond to the chemical solution discharge means. The heat exchanger 134 also corresponds to the chemical solution cooling means.

  The second embodiment is also characterized in that the chemical temperature is controlled to a predetermined temperature by the heat exchanger 134. The temperature of the chemical solution is set to an optimum range depending on the type of the chemical solution, but also in the second embodiment, when DHF or BHF is used as the chemical solution, the temperature is controlled to a low temperature (20 ° C. or lower) below room temperature. Specifically, in the case of DHF, the range of 0 to 20 ° C. is good, and it is particularly preferable to control the range to 5 to 15 ° C. Moreover, in the case of BHF, the range of -10-20 degreeC is good, and it is preferable to control to the range of 0-10 degreeC especially.

  A pure water heat exchanger 143 is connected to the pure water discharge nozzle 141, and low-temperature pure water is supplied to the pure water discharge nozzle 141. The pure water heat exchanger 143 has a function of sending pure water sent from the pure water supply unit 142 to the pure water discharge nozzle 141 at a predetermined temperature. Specifically, the temperature of pure water is controlled to a low temperature (20 ° C. or lower) below room temperature and supplied to the pure water discharge nozzle 141. In addition, as a temperature of pure water, the range of 0-20 degreeC is good, and 0-10 degreeC is especially preferable. This is because when the temperature of pure water is higher than 20 ° C., the progress of the etching of the oxide film due to the HF ions attached to the wafer by the chemical treatment at the chemical solution discharge nozzle 131 cannot be suppressed. This is because pure water freezes at lower temperatures and cannot be set. The pure water discharge nozzle 141, the pure water supply unit 142, and the pure water heat exchanger 143 correspond to the washing means in the claims, and the pure water heat exchanger 143 has the same pure water cooling function. It corresponds to.

  An air filter unit 151 and an air conditioner 152 that is connected to the processing chamber 110 and supplies a low-temperature gas (air) are provided in the upper portion of the processing chamber 110. The air conditioner 152 is installed outside the processing chamber 110 and supplies gas (air) having a predetermined temperature into the processing chamber 110 via the air filter unit 151. Also in the second embodiment, as in the first embodiment, the air conditioner 152 is kept at the same temperature as or lower than the temperature of the chemical solution in the processing chamber 110. The exhaust port 113 is connected to an exhaust treatment facility (not shown) in order to prevent evaporation components such as mist, hydrogen fluoride, and ammonia evaporated from the inside of the processing chamber 110 from leaking to the outside of the main body of the single wafer processing apparatus 101. Then, a predetermined amount of exhaust is performed. The air filter unit 151 and the air conditioner 152 correspond to the atmospheric gas cooling function in the claims.

  Next, an operation process of the single wafer processing apparatus 101 will be described. First, the single-wafer processing apparatus 101 is in a standby state, and a chemical solution is circulated by the switching valve 136 in the order of the chemical solution tank 132 → the heat exchanger 134 → the pump 133 → the filter 135 → the chemical solution tank 132. Thereafter, the wafer 51 is transferred into the processing chamber 110 by a transfer mechanism (not shown). Next, the wafer 51 is fixed on the stage 120 by the wafer holding member 121 with the wafer surface facing upward, and then the stage 120 is rotated in the in-plane direction by the motor 123.

  Subsequently, the switching valve 136 is switched so that the state of waiting for the chemical liquid is changed from the standby state to the state in which the wafer is being processed, and the chemical liquid is sent to the chemical liquid tank 132 → the heat exchanger 134 → the pump 133 → the filter 135 → the chemical liquid discharge nozzle 131 The chemical liquid is discharged from the chemical liquid discharge nozzle 131 for a predetermined time. Thereby, etching of the Si oxide film on the wafer surface is performed. At this time, the chemical liquid accumulated in the cleaning cup 111 returns from the liquid discharge port 112 to the chemical liquid tank 132. Further, in order to uniformly etch the entire wafer surface, the chemical solution discharge nozzle 131 is preferably configured to be movable in the lateral direction from the wafer center to the periphery as indicated by an arrow A in the drawing. Further, at least during the discharge of the chemical solution, a low temperature gas may be ejected from the gas nozzle 122 to the back surface of the wafer to cool the temperature of the wafer 51 to the same level as the temperature of the chemical solution.

  After the discharge of the chemical liquid on the surface of the wafer 51 for a predetermined time, the switching valve 136 is switched to bring the chemical liquid into a standby state again. Thereafter, the pure water is supplied from the pure water supply unit 142, is brought to a temperature of room temperature or lower (20 ° C. or lower) by the pure water heat exchanger 143, and low temperature pure water is discharged from the pure water discharge nozzle 141, so A water washing treatment is performed to replace or remove the water. After the rinsing process is completed, the supply of pure water is stopped, and finally the wafer 51 is rotated at high speed by the motor 123 to dry the wafer surface. In addition, since a watermark is easily formed in drying by high-speed rotation (spin drying), a method using drying using IPA (commonly referred to as rotagoni drying) may be used. This completes the wafer etching process.

  In the above description, the low temperature pure water is discharged onto the wafer 51 after the chemical liquid is discharged. However, the low temperature pure water is discharged onto the wafer 51 and then the chemical liquid is discharged onto the wafer 51 before the chemical liquid is discharged. And low temperature pure water may be discharged. Thus, by preliminarily discharging low temperature pure water onto the wafer 51 and keeping the temperature of the wafer 51 at the same low temperature as the chemical solution, the etching amount at the initial stage of the chemical solution discharge can be suppressed and the in-plane uniformity of etching can be improved. Is more preferable.

  According to the second embodiment, since the chemical liquid in the chemical liquid tank 132 and the circulation line is controlled to a low temperature (20 ° C. or lower) below room temperature by the heat exchanger 134, the evaporation of the chemical liquid components at the time of the chemical liquid discharge is suppressed. be able to. Further, since the inside of the processing chamber 110 is maintained at the same temperature as or lower than that of the chemical solution by the air conditioner 152, the evaporation of the chemical component due to contact with air during the discharge of the chemical solution can be further reduced. Here, in the case of a single wafer processing apparatus, the chemical solution covers the entire surface of the wafer and scatters in the form of water droplets from the outer periphery of the wafer. It has been confirmed that the chemical processing component is more apt to evaporate in the case of the type processing apparatus. However, in the second embodiment, even in such a single wafer processing apparatus, it is possible to suppress the evaporation of the chemical component.

  Furthermore, since pure water controlled to room temperature or lower (20 ° C. or lower) by the pure water heat exchanger 143 is used, even in the case of single wafer processing, the reaction rate of HF ions during washing is reduced. In addition, there is an effect that it is possible to suppress a slight amount of etching of the Si oxide film during the water washing (discharge of pure water) after the chemical liquid is discharged.

  Further, since the low temperature pure water is discharged before the chemical solution is discharged, the temperature of the wafer 51 as a whole is almost the same as the discharged chemical solution, and the etching controllability can be improved. When the temperature of the wafer 51 is room temperature before the chemical solution is discharged, the in-plane uniformity of etching deteriorates due to a temperature difference between a wetted portion and a non-wet portion on the wafer surface. By discharging the wafer 51 and cooling the wafer 51 over the entire surface, it becomes possible to suppress the etching unevenness at the initial stage of the chemical solution discharge and improve the in-plane uniformity.

  Further, since the gas set at the same temperature as the chemical solution is blown onto the wafer 51 during the discharge of the chemical solution, the temperature of the wafer 51 can be kept at the same temperature as the chemical solution on the entire surface, and the in-plane uniformity of etching can be improved. It has the effect that it can be made better.

In the first and second embodiments described above, the batch type immersion processing apparatus and the single wafer processing apparatus have been described as the etching processing apparatus, but in addition to this, the batch type spray processing apparatus and other etching processing apparatuses The idea of the invention can be applied. In addition to this, the present invention can also be applied to the case of using a polymer removal cleaning liquid containing HF or NH ₄ F.

  As described above, the etching apparatus according to the present invention is suitable for etching and cleaning processes using a chemical solution containing hydrofluoric acid or ammonium fluoride.

It is a figure which shows typically the structure of Embodiment 1 of the etching processing apparatus by this invention. It is a figure which shows typically the structure of Embodiment 2 of the etching processing apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Etching processing apparatus 20 Chemical processing part 21 Chemical processing tank 22,112 Drain outlet 23 Chemical liquid 24,133 Pump 25,134 Heat exchanger 26,135 Filter 27,35,151 Air filter unit 28,36,152 Air conditioner Conditioner 29,113 Exhaust port 30 Flushing processing unit 31 Flushing tank 32 Pure water 33,142 Pure water supply unit 34,143 Pure water heat exchanger 40 Drying processing unit 51 Wafer 110 Processing chamber 111 Cleaning cup 120 Stage 121 Wafer holding Member 122 Gas nozzle 123 Motor 131 Chemical solution discharge nozzle 132 Chemical solution tank 136 Switching valve 141 Pure water discharge nozzle

Claims (6)

Etching means for etching a material formed on a semiconductor substrate using a chemical solution that is an aqueous solution containing hydrofluoric acid and / or ammonium fluoride;
Rinsing means for rinsing the etched semiconductor substrate with pure water;
In an etching processing apparatus comprising:
The etching means has a chemical solution cooling function for adjusting a temperature of the chemical solution in contact with a material formed on the semiconductor substrate to a temperature within a range where the chemical solution does not freeze at a temperature of 20 ° C. or less. Processing equipment.   2. The etching processing apparatus according to claim 1, wherein the etching unit further includes an atmospheric gas cooling function for maintaining a temperature of a gas around a chemical solution for etching the semiconductor substrate at a temperature of 20 ° C. or less.   The etching apparatus according to claim 1, wherein the water washing means has a pure water cooling function for cooling the pure water to a temperature of 20 ° C. or less.   The chemical solution cooling function of the etching means is characterized in that when the chemical solution is an aqueous solution containing hydrofluoric acid and ammonium fluoride, the chemical solution is cooled to a temperature in the range of -10 ° C to 20 ° C. The etching processing apparatus as described in any one of 1-3. A substrate holding means for holding the semiconductor substrates one by one in the processing chamber so that the substrate surfaces thereof are horizontal, and being rotatable about a direction perpendicular to the substrate surfaces;
A chemical solution ejecting means for spraying a chemical solution which is an aqueous solution containing hydrofluoric acid or ammonium fluoride provided on the semiconductor substrate held on the substrate holding means, and formed on the surface of the semiconductor substrate;
A chemical cooling means for setting the chemical to a temperature within a range where the chemical does not freeze at a temperature of 20 ° C. or lower, and supplying the chemical to the chemical discharge means;
A cooling gas spraying means for spraying a gas of 20 ° C. or less to the back surface of the semiconductor substrate held by the substrate holding means;
An etching processing apparatus comprising: In an etching method of etching a material formed on a semiconductor substrate using a chemical solution that is an aqueous solution containing hydrofluoric acid and / or ammonium fluoride,
An etching method, wherein the chemical solution is set at a temperature within a range of 20 ° C. or less so that the chemical solution does not freeze, and is contacted with a material formed on the semiconductor substrate for etching.

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