WO2024096543A1

WO2024096543A1 - Substrate etching method and substrate etching apparatus

Info

Publication number: WO2024096543A1
Application number: PCT/KR2023/017182
Authority: WO
Inventors: 이승훈; 모성원; 이양호; 한흥수; 배정현; 기범수
Original assignee: 주식회사 제우스
Priority date: 2022-11-03
Filing date: 2023-11-01
Publication date: 2024-05-10
Also published as: KR20240065582A

Abstract

A substrate etching method according to the present invention comprises: a high-temperature etching step of exposing a substrate on which a silicon oxide film and a silicon nitride film are stacked to an etchant at a first temperature and etching the substrate; and a low-temperature etching step of exposing the substrate to an etchant at a second temperature lower than the first temperature and etching the substrate with higher etching selectivity of the silicon nitride film to the silicon oxide film than in the high-temperature etching step.

Description

Substrate etching method and substrate etching device

The present invention relates to a substrate etching method and a substrate etching device for etching and removing a silicon nitride film laminated on a substrate used in semiconductor manufacturing.

The semiconductor manufacturing process includes, for example, a process of stacking a silicon nitride film on a substrate such as a silicon wafer, and a process of removing at least a portion of the stacked silicon nitride film by etching. The silicon nitride film can be removed by dry etching or wet etching. To date, wet etching is mainly applied among dry etching and wet etching to reduce the operating cost of etching work and increase productivity.

On the substrate, the silicon nitride film is laminated on a silicon oxide film. During the wet etching process, it is desirable for the silicon oxide film to remain as much as possible rather than be removed along with the silicon nitride film. In addition, it is desirable for the cycle time of the substrate etching operation to be as short as possible.

The background technology of the present invention is disclosed in Republic of Korea Patent Publication No. 10-0691479 (registered on February 28, 2007, title of invention: Large-area etching device).

The present invention provides a substrate etching method and a substrate etching device that improve the quality and speed of etching work by sequentially exposing the substrate to etchants of different properties during etching.

A method of etching a substrate according to the present invention: a high-temperature etching step of etching a substrate on which a silicon oxide film and a silicon nitride film are stacked by exposing it to an etchant at a first temperature; and a low-temperature etching step of exposing the substrate to an etchant of a second temperature lower than the first temperature to etch the etch selectivity of the silicon nitride film to the silicon oxide film to be higher than that of the high-temperature etching step.

The high-temperature etching step may include a first temperature etchant supply step of injecting an etchant of the first temperature into an etching chamber in which the substrate is accommodated so that the substrate is wetted with the etchant of the first temperature; and a first temperature etchant discharge step of discharging the etchant at the first temperature to the outside of the etching chamber.

The first temperature etchant supply step and the first temperature etchant discharge step may be performed simultaneously or with time differences.

The low-temperature etching step may include a second temperature etchant supply step of introducing an etchant of the second temperature into the etching chamber so that the substrate is wetted with the etchant of the second temperature; and a second temperature etchant discharge step of discharging the etchant at the second temperature to the outside of the etching chamber.

The second temperature etchant supply step and the second temperature etchant discharge step may be performed simultaneously or with time differences.

A substrate etching method according to the present invention: a low-concentration etching step of etching a substrate on which a silicon oxide film and a silicon nitride film are stacked by exposing it to a first concentration etchant containing a first concentration of Si (silicon); and a high-concentration etching step of exposing the substrate to a second concentration etchant containing a second concentration of Si higher than the first concentration to etch the etch selectivity of the silicon nitride film to the silicon oxide film to a higher etch selectivity than the low-concentration etching step. may include.

The low-concentration etching step includes: supplying the first concentration etchant into an etching chamber in which the substrate is accommodated so that the substrate is wetted with the first concentration etchant; and a first concentration etchant discharging step of discharging the first concentration etchant to the outside of the etching chamber.

The step of supplying the first concentration etchant and discharging the first concentration etchant may be performed simultaneously or with a time difference.

The high-concentration etching step may include supplying a second concentration etchant into the etching chamber so that the substrate is wetted with the second concentration etchant; and a second concentration etchant discharging step of discharging the second concentration etchant to the outside of the etching chamber.

The second concentration etchant supply step and the second concentration etchant discharge step may be performed simultaneously or with time differences.

A substrate etching apparatus according to the present invention: an etching chamber into which a substrate is inserted and received; a first etchant supply unit supplying an etchant at a first temperature to the etching chamber; a first etchant recovery unit that recovers the etchant of the first temperature that etched the substrate from the etching chamber to the first etchant supply unit; a second etchant supply unit supplying an etchant of a second temperature lower than the first temperature to the etching chamber from which the etchant of the first temperature is discharged; and a second etchant recovery unit that recovers the etchant of the second temperature that etched the substrate from the etching chamber to the second etchant supply unit.

The substrate etching apparatus of the present invention includes a rinse solution supply unit that supplies a rinse solution to the etching chamber to clean the substrate after the substrate is etched; and a cleaning solution supply unit supplying a cleaning solution to the etching chamber to remove the rinsing solution remaining on the substrate.

A substrate etching apparatus according to the present invention: an etching chamber into which a substrate is inserted and received; a first etchant supply unit supplying an etchant containing a first concentration of Si (silicon) to the etching chamber; a first etchant recovery unit that recovers the first concentration etchant that etched the substrate from the etching chamber to the first etchant supply unit; a second etchant supply unit supplying a second concentration etchant containing Si of a second concentration higher than the first concentration to the etching chamber from which the first concentration etchant is discharged; and a second etchant recovery unit that recovers the second concentration etchant that etched the substrate from the etching chamber to the second etchant supply unit.

According to the present invention, by etching the substrate with etchants of different properties, the quality of the etching work is improved, the defect rate is reduced, and the speed of the etching work is improved compared to the case of etching the substrate only with an etchant of a single property.

According to the present invention, after etching the substrate with an etchant of a first temperature, the substrate is etched with an etchant of a second temperature lower than the first temperature, or after etching the substrate with an etchant of a first concentration containing a first concentration of Si. The substrate may be etched with a second concentration etchant containing Si at a second concentration higher than the first concentration.

1 is a flow chart showing a substrate etching method according to a first embodiment of the present invention.

Figure 2 is a graph showing the etching rates of the silicon nitride film and silicon oxide film that change depending on the temperature of the etchant.

Figure 3 is a graph showing the etching selectivity of the silicon nitride film to the silicon oxide film that changes depending on the temperature of the etchant and the concentration of Si contained in the etchant.

FIG. 4 is a configuration diagram illustrating an example of a substrate etching device used to perform the substrate etching method of FIG. 1.

FIG. 5 is a configuration diagram illustrating another example of a substrate etching device used to perform the substrate etching method of FIG. 1.

Figure 6 is a flow chart showing a substrate etching method according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating an example of a substrate etching device used to perform the substrate etching method of FIG. 6.

Hereinafter, a substrate etching method and a substrate etching apparatus according to an embodiment of the present invention will be described in detail with reference to the attached drawings. The terminology used in this specification is a term used to appropriately express preferred embodiments of the present invention, and may vary depending on the intention of the user or operator or the customs of the field to which the present invention belongs. Therefore, definitions of these terms should be made based on the content throughout this specification.

Figure 1 is a flow chart showing a method for etching a substrate according to a first embodiment of the present invention, Figure 2 is a graph showing the etching rate of the silicon nitride film and silicon oxide film that changes depending on the temperature of the etchant, and Figure 3 is the temperature of the etchant. and a graph showing the etching selectivity of the silicon nitride film to the silicon oxide film that changes depending on the concentration of Si contained in the etchant, and FIG. 4 shows an example of a substrate etching device used to perform the substrate etching method of FIG. 1. This is a configuration diagram, and FIG. 5 is a configuration diagram showing another example of a substrate etching device used to perform the substrate etching method of FIG. 1.

1 to 5, the substrate etching method according to the first embodiment of the present invention involves etching at least a portion of the silicon nitride film laminated on a substrate 10, such as a silicon wafer for semiconductor manufacturing. This is how to remove it. The substrate 10 before being etched may have a structure in which a plurality of silicon nitride films and a plurality of silicon oxide films are alternately stacked, or a structure in which a silicon nitride film is stacked on a silicon oxide film.

The substrate etching method according to the first embodiment of the present invention includes a substrate loading step (S110), a high temperature etching step (S120), a low temperature etching step (S130), a substrate rinsing step (S140), and a substrate cleaning step. (S150), and a substrate unloading step (S160).

Referring to FIG. 4, an example substrate etching apparatus 100 used to perform the substrate etching method according to the first embodiment of the present invention includes an etching chamber 110, a first etchant supply unit 120, and a first etchant supply unit 120. It includes an etchant recovery unit 140, a second etchant supply unit 150, a second etchant recovery unit 170, a rinse liquid supply unit 180, a cleaning liquid supply unit 185, and a wastewater discharge unit 190.

The substrate 10 is inserted and accommodated in the etching chamber 110. The etch chamber 110 includes an etch chamber pressurizing unit 115 that supplies, for example, high-pressure nitrogen (N ₂ ) gas into the etch chamber 110 so that the pressure inside the etch chamber 110 is maintained at a high pressure higher than atmospheric pressure. can be connected with

The first etchant supply unit 120 supplies an etchant of a first temperature to the etching chamber 110 . The etchant may be, for example, an aqueous phosphoric acid (H ₃ PO ₄ ) solution. The first etchant supply unit 120 includes a first etchant chamber 121, a first etchant supply passage 131, a first etchant supply pump 130, a first etchant supply passage valve 134, and a first etchant circulation passage ( 132), a first etchant circulation flow valve 135, and a first etchant chamber pressurizing unit 125.

The first etchant chamber 121 contains an etchant of a first temperature. The first etchant supply passage 131 guides the etchant at the first temperature from the first etchant chamber 121 to the etch chamber 110 . The first etchant supply pump 130 pumps the etchant of the first temperature within the first etchant supply passage 131. The first etchant supply flow path valve 134 selectively opens and closes the first etchant supply flow path 131. The first etchant circulation flow path 132 branches off from the first etchant supply flow path 131 and guides the etchant at the first temperature to return to the first etchant chamber 121. The first etchant circulation flow path valve 135 selectively opens and closes the first etchant circulation flow path 132. The first etchant chamber pressurizing unit 125 is connected to the first etchant chamber 121, and is maintained at a high pressure state higher than atmospheric pressure, for example, high-pressure nitrogen (N ₂ ) gas. Can be supplied into the first etchant chamber 121.

Although not shown, the first etchant supply unit 120 may further include a first etchant heater for heating the etchant contained in the first etchant chamber 121. The first etchant supply flow path valve 134 is closed and the first etchant circulation flow path valve 135 is opened to circulate the etchant through the first etchant circulation flow path 132 while operating the first etchant heater to create a first etchant chamber ( When the etchant contained in 121) is heated, the etchant contained in the first etchant chamber 121 can be heated more quickly and uniformly with the etchant of the first temperature.

The first etchant recovery unit 140 recovers the etchant of the first temperature that etched the substrate 10 from the etching chamber 110 to the first etchant chamber 121 of the first etchant supply unit 120. The first etchant recovery unit 140 includes a first etchant recovery passage 141 and a first etchant recovery passage valve 145. The first etchant recovery passage 141 guides the etchant at the first temperature from the etch chamber 110 to the first etchant chamber 121 . The first etchant recovery flow path valve 145 selectively opens and closes the first etchant recovery flow path 141. Although not shown, the first etchant recovery unit 140 may further include a first etchant recovery pump that pumps the etchant at the first temperature in the first etchant recovery passage 145 toward the first etchant chamber 121. there is.

The second etchant supply unit 150 is an etching chamber after the etchant of the first temperature is discharged, that is, the etchant of the first temperature is recovered into the first etchant chamber 121 through the first etchant recovery unit 140. An etchant having a second temperature lower than the first temperature is supplied to (110). The second etchant supply unit 150 includes a second etchant chamber 151, a second etchant supply passage 161, a second etchant supply pump 160, a second etchant supply passage valve 164, and a second etchant circulation passage ( 162), a second etchant circulation flow valve 165, and a second etchant chamber pressurizing unit 155.

The second etchant chamber 121 accommodates the etchant at the second temperature. The second etchant supply passage 161 guides the etchant at the second temperature from the second etchant chamber 151 to the etch chamber 110 . The second etchant supply pump 150 pumps the second etchant in the second etchant supply passage 161. The second etchant supply flow path valve 164 selectively opens and closes the second etchant supply flow path 161. The second etchant circulation flow path 162 branches off from the second etchant supply flow path 161 and guides the etchant at the second temperature to return to the second etchant chamber 151. The second etchant circulation flow path valve 165 selectively opens and closes the second etchant circulation flow path 162. The second etchant chamber pressurizing unit 155 is connected to the second etchant chamber 151, and uses, for example, high-pressure nitrogen (N ₂ ) gas to maintain the pressure inside the second etchant chamber 151 at a high pressure higher than atmospheric pressure. Can be supplied into the second etchant chamber 151.

Although not shown, the second etchant supply unit 150 may further include a second etchant heater for heating the etchant contained in the second etchant chamber 151. The second etchant supply flow path valve 164 is closed and the second etchant circulation flow path valve 165 is opened to circulate the etchant through the second etchant circulation flow path 162 while operating the second etchant heater to create a second etchant chamber ( When the etchant contained in 151) is heated, the etchant contained in the second etchant chamber 151 can be heated more quickly and uniformly with the etchant of the second temperature.

The second etchant recovery unit 170 recovers the etchant of the second temperature that etched the substrate 10 from the etching chamber 110 to the second etchant chamber 151 of the second etchant supply unit 150. The second etchant recovery unit 170 includes a second etchant recovery passage 171 and a second etchant recovery passage valve 175. The second etchant recovery passage 171 guides the etchant at the second temperature from the etch chamber 110 to the second etchant chamber 151 . The second etchant recovery flow path valve 175 selectively opens and closes the second etchant recovery flow path 171. Although not shown, the second etchant recovery unit 170 may further include a second etchant recovery pump that pumps the second etchant in the second etchant recovery passage 175 toward the second etchant chamber 151.

The etching chamber 110, the first etchant chamber 121, and the second etchant chamber ( If 151) is maintained at high pressure, the boiling point of the etchant increases, so the temperature of the etchant, that is, the first temperature and the second temperature, can be increased within the limit where the etchant does not boil. As can be seen with reference to FIG. 2, the higher the temperature of the etchant, the greater the etching rate of the silicon nitride film. In addition, even at a temperature lower than the boiling point of the etchant, vaporization of phosphoric acid contained in the etchant is suppressed and the concentration of the etchant can be maintained constant. Accordingly, the speed and productivity of etching the substrate 10 using the substrate etching apparatus 100 are improved, the defect rate is lowered, and the quality of the etching operation is improved.

The rinse agent supply unit 180 supplies a rinse agent to the etching chamber 110 to clean the substrate 10 after the substrate 10 is etched. The rinse solution dissolves the etchant and contaminants remaining or attached to the surface of the etched substrate 10 and removes them from the surface of the substrate 10. The rinse solution may be, for example, DHF (Diluted Hydrogen Fluoride), IPA (Isopropyl Alcohol), or SC1 solution.

The rinse liquid supply unit 180 includes a rinse liquid chamber 181, a rinse liquid supply passage 183, and a rinse liquid supply passage valve 184. The rinse liquid chamber 181 accommodates the rinse liquid. The rinse liquid supply passage 183 guides the rinse liquid from the rinse liquid chamber 181 to the etching chamber 110. The rinse fluid supply flow path valve 184 selectively opens and closes the rinse fluid supply flow path 183. Although not shown, the rinse liquid supply unit 180 may further include a rinse liquid supply pump that pumps the rinse liquid from the rinse liquid chamber 181 to the etching chamber 110 through the rinse liquid supply passage 183. .

The cleaning liquid supply unit 185 supplies cleaning liquid to the etching chamber 110 to wash away and remove the rinsing liquid remaining on the substrate 10 after cleaning the substrate 10 using the rinsing liquid. The cleaning liquid may be, for example, deionized water (DIW).

The cleaning liquid supply unit 185 includes a cleaning liquid chamber 186, a cleaning liquid supply passage 187, and a cleaning liquid supply passage valve 188. The cleaning liquid chamber 186 accommodates the cleaning liquid. The cleaning liquid supply passage 187 guides the cleaning liquid from the cleaning liquid chamber 186 to the etching chamber 110. The cleaning fluid supply flow path valve 188 selectively opens and closes the cleaning fluid supply flow path 187. Although not shown, the cleaning liquid supply unit 185 may further include a cleaning liquid supply pump that pumps the cleaning liquid from the cleaning liquid chamber 186 toward the etching chamber 110 through the cleaning liquid supply passage 187.

The wastewater discharge unit 190 discharges the rinse liquid and cleaning liquid to the outside. The wastewater discharge unit 190 includes a wastewater tank 191, a wastewater discharge passage 195, a wastewater discharge passage valve 197, and a wastewater tank pressurizing portion 193. The wastewater tank 191 receives the rinse and cleaning solutions contaminated through the rinsing and cleaning processes of the substrate 10 after being discharged from the etching chamber 110 . The waste water tank pressurizing unit 193 is connected to the waste water tank 191, and, for example, pumps high-pressure nitrogen (N ₂ ) gas into the waste water tank 190 so that the pressure inside the waste water tank 191 is maintained at a high pressure higher than atmospheric pressure. It can be supplied internally.

The wastewater discharge flow path 195 guides the contaminated rinse and cleaning fluids from the etching chamber 110 to the wastewater tank 191. The wastewater discharge flow path valve 197 selectively opens and closes the wastewater discharge flow path 195. Although not shown, the wastewater discharge unit 190 may further include a wastewater discharge pump that pumps the contaminated rinse and cleaning liquid in the wastewater discharge passage 195 toward the wastewater tank 190.

In the substrate etching method according to the first embodiment of the present invention, the substrate loading step (S110) is a step of inserting the substrate 10 on which a silicon oxide film and a silicon nitride film are stacked into the etching chamber 110. Preferably, the substrates 10 may be inserted into the etching chamber 110 one by one.

The high temperature etching step (S120) is a step of etching the substrate 10 inserted and placed in the etching chamber 110 by exposing it to an etchant at a first temperature. The high-temperature etching step (S120) includes a first temperature etchant supply step (S121) and a first temperature etchant discharge step (S122). Referring to FIG. 4 , the first temperature etchant supply step (S121) is a step of introducing an etchant of a first temperature into the etching chamber 110, and may be performed by the first etchant supply unit 120.

As described above, when the etchant contained in the first etchant chamber 121 is heated by operating the first etchant heater while circulating through the first etchant circulation passage 132, the etchant contained in the first etchant chamber 121 is heated more quickly and It can be uniformly heated with an etchant of the first temperature. The etchant at the first temperature heated in this way may be introduced into the etch chamber 110 from the first etchant chamber 121 through the first etchant supply passage 131.

The etchant of the first temperature introduced into the etching chamber 110 flows to the substrate 10, and the substrate 10 is wetted with the etchant of the first temperature and thus etched. The etchant at the first temperature is supplied to the etching chamber 110 for a predetermined time so that the substrate 10 can be properly etched.

The first temperature etchant discharging step ( S122 ) is a step of discharging the etchant of the first temperature introduced into the etching chamber 110 to the outside of the etching chamber 110 . The first temperature etchant supply step (S121) and the first temperature etchant discharge step (S122) may be performed simultaneously. In other words, the etchant at the first temperature supplied into the etching chamber 110 may pass through the substrate 10 and be immediately discharged from the etching chamber 110 . Alternatively, the first temperature etchant supply step (S121) and the first temperature etchant discharge step (S122) may be performed with time differences. In other words, the first temperature etchant supply step (S121) may be performed first, and then the first temperature etchant discharge step (S122) may be performed after a certain period of time.

The etchant of the first temperature discharged from the etching chamber 110 may not be discharged to the outside of the substrate etching apparatus 100 but may be recovered into the first etchant chamber 121 through the first etchant recovery unit 140 . The etchant recovered in the first etchant chamber 121 may be heated again to the first temperature by the first etchant heater for the next etching operation of the substrate 10.

The low-temperature etching step (S130) is a step of etching the substrate 10 inserted into the etching chamber 110 by exposing it to an etchant of a second temperature lower than the first temperature. The low-temperature etching step (S130) etches the substrate 10 at a slower etching rate than the high-temperature etching step (S120) and increases the etching selectivity of the silicon nitride film to the silicon oxide film. In other words, the etching rate in the low-temperature etching step (S130) is slower than the etching rate in the high-temperature etching step (S120), and the etch selectivity in the low-temperature etching step (S130) is the etch selectivity in the high-temperature etching step (S120). higher than

As shown in FIG. 2, the etching rate by the etchant increases as the temperature of the etchant increases in both the case of the silicon nitride film and the silicon oxide film. Meanwhile, as shown in FIG. 3, the etch selectivity, which is the etch rate of the silicon nitride film relative to the etch rate of the silicon oxide film, decreases as the temperature increases. A decrease in the etch selectivity means that the amount of the silicon oxide film removed when the silicon nitride film is removed by etching increases. The trend of decreasing etching selectivity as the temperature of the etchant increases is common regardless of the concentration of Si (silicon) contained in the etchant.

If etching is performed with a high-temperature etchant at the start of etching, the etching rate is large and the etching speed is fast, thereby reducing the total time required to etch the substrate 10. However, if etching continues with a high-temperature etchant until the etching is completed, it is difficult to finely control the degree of etching of the silicon nitride film and silicon oxide film, so the quality of the etching work deteriorates and the defect rate increases, such as when too much of the silicon oxide film is etched. Escalating problems may occur. Therefore, for a predetermined period of time from the start of etching, the substrate 10 is first etched with an etchant of a relatively high first temperature, and then the substrate 10 is etched with an etchant of a relatively low temperature of the second temperature. In addition to improving the speed of the etching process, the quality of the etching process can also be improved as etching of silicon oxide is minimized. Etching the substrate 10 by adding an etchant at a first temperature can be called high-speed, low-selectivity etching, and etching the substrate 10 by adding an etchant at a second temperature can be called low-speed, high-selectivity etching.

In particular, in the substrate 10 in which a silicon nitride film is stacked on top of a silicon oxide film, the silicon oxide film is not exposed until the silicon nitride film is removed by etching. Accordingly, the substrate 10 is first etched with an etchant at a relatively high first temperature for a predetermined period of time from the start of etching of the substrate 10 until the silicon oxide film is exposed, and then using an etchant at a relatively low temperature at the second temperature. When the substrate 10 is etched with an etchant, the productivity and quality of the etching work can be further improved.

For example, in high-speed, low-selectivity etching, the temperature of the etchant, that is, the first temperature, may be 200°C, and in low-speed, high-selectivity etching, the temperature of the etchant, that is, the second temperature, may be 180°C. At this time, the concentration of Si contained in the etchant at the first temperature and the etchant at the second temperature may be the same at 1300 ppm. As another example, in high-speed, low-selectivity etching, the temperature of the etchant, that is, the first temperature, is 160 ° C., and in low-speed, high-selectivity etching, the temperature of the etchant, that is, the second temperature, is 150 ° C. In this case, the etchant of the first temperature and The concentration of Si contained in the etchant at the second temperature may be the same at 700ppm.

The low-temperature etching step (S130) includes a second temperature etchant supply step (S131) and a second temperature etchant discharge step (S132). The second temperature etchant supply step (S131) is a step of introducing an etchant of a second temperature into the etching chamber 110, and may be performed by the second etchant supply unit 150 described with reference to FIG. 4. Similar to what was mentioned in the description of the first temperature etchant supply step (S121), the etchant contained in the second etchant chamber 151 is heated by operating the second etchant heater while circulating it through the second etchant circulation passage 162. , the etchant contained in the second etchant chamber 151 can be heated more quickly and uniformly with the etchant at the second temperature.

The etchant at the second temperature heated in this way may be introduced into the etch chamber 110 from the second etchant chamber 151 through the second etchant supply passage 161. The etchant at the second temperature introduced into the etching chamber 110 flows to the substrate 10, and the substrate 10 is wetted with the etchant at the second temperature and thus etched. The etchant at the second temperature is supplied to the etching chamber 110 for a predetermined time so that the substrate 10 can be properly etched.

The second temperature etchant discharging step ( S132 ) is a step of discharging the etchant of the second temperature introduced into the etching chamber 110 to the outside of the etching chamber 110 . The second temperature etchant supply step (S131) and the second temperature etchant discharge step (S132) may be performed simultaneously. In other words, the etchant at the second temperature supplied into the etching chamber 110 may pass through the substrate 10 and be immediately discharged from the etching chamber 110 . Alternatively, the second temperature etchant supply step (S131) and the second temperature etchant discharge step (S132) may be performed with time differences. In other words, the second temperature etchant supply step (S131) may be performed first, and the second temperature etchant discharge step (S132) may be performed after a certain period of time.

The etchant of the second temperature discharged from the etching chamber 110 may not be discharged to the outside of the substrate etching apparatus 100 but may be recovered into the second etchant chamber 151 through the second etchant recovery unit 170 . The etchant recovered in the second etchant chamber 151 may be heated again to a second temperature by the second etchant heater for the next etching operation of the substrate 10.

The substrate rinsing step (S140) includes a rinse solution supply step and a rinse solution discharge step. The rinse solution supply step is a step of supplying a rinse solution to the etching chamber 110 to clean the etched substrate 10. The rinse liquid supplied into the etching chamber 110 dissolves the etchant and contaminants remaining or attached to the surface of the etched substrate 10 and removes them from the surface of the substrate 10. The rinse liquid supply step is performed by the rinse liquid supply unit 180 described above.

The rinse liquid discharging step is a step of cleaning the substrate 10 and discharging the contaminated rinse liquid to the outside of the etching chamber 110. The rinse liquid discharged from the etching chamber 110 is stored in the wastewater tank 191. The rinse liquid discharge step is performed by the wastewater discharge unit 190 described above.

The substrate cleaning step (S150) includes a cleaning liquid supply step and a cleaning liquid discharge step. The cleaning liquid supply step is a step of supplying the cleaning liquid to the etching chamber 110. The cleaning solution supplied into the etching chamber 110 washes away and removes the rinse solution remaining on the substrate 10 after cleaning the substrate 10 using the rinse solution. The cleaning liquid supply step is performed by the cleaning liquid supply unit 185 described above.

The cleaning liquid discharge step is a step of discharging the contaminated cleaning liquid to the outside of the etching chamber 110 by washing away and removing the rinse liquid remaining on the substrate 10 . The cleaning solution discharged from the etching chamber 110 is stored in the wastewater tank 191. The cleaning liquid discharge step is performed by the wastewater discharge unit 190 described above.

The substrate unloading step (S160) is a step of removing the etched substrate 10 from the etching chamber 110 after the low-temperature etching step (S130). In the embodiment shown in Figure 1, the substrate unloading step (S160) is performed after the substrate rinsing step (S140) and the substrate cleaning step (S150), but the present invention is not necessarily limited thereto, and the low-temperature etching step ( After S130), the etched substrate 10 may be taken out of the etching chamber 110, and the substrate 10 may then be rinsed and cleaned.

Meanwhile, although not shown in FIG. 1, a step of rinsing the high-temperature etched substrate 10 may be added after the high-temperature etching step (S120) and before the low-temperature etching step (S130). Alternatively, a substrate drying step of vaporizing and removing the cleaning solution remaining on the surface of the substrate 10 may be added after the substrate cleaning step (S150) and before the substrate unloading step (S160).

Meanwhile, the substrate etching method according to the first embodiment of the present invention can also be performed by another example of the substrate etching apparatus 200 shown in FIG. 5. Referring to FIG. 5, another example of a substrate etching apparatus 200 used to perform the substrate etching method according to the first embodiment of the present invention includes an etching chamber 210, an etchant supply unit 220, and an etchant recovery unit. (240), a rinse liquid supply unit 280, a cleaning liquid supply unit 285, and a wastewater discharge unit 290. Compared to the substrate etching apparatus 100 shown in FIG. 4, the substrate etching apparatus 200 shown in FIG. 5 is provided with an etchant supply unit 220 and an etchant recovery unit 240, and the etchant supply unit 220 There is a difference in that the temperature controller 224 is installed in the etchant chamber 221. Below, we will mainly explain these differences.

The substrate 10 is inserted and accommodated in the etching chamber 210. The etch chamber 210 includes an etch chamber pressurizing unit 215 that supplies, for example, high-pressure nitrogen (N ₂ ) gas into the etch chamber 210 so that the pressure inside the etch chamber 210 is maintained at a high pressure higher than atmospheric pressure. can be connected with

The etchant supply unit 220 supplies etchant to the etching chamber 210 . The etchant may be, for example, an aqueous phosphoric acid (H ₃ PO ₄ ) solution. The etchant supply unit 120 includes an etchant chamber 221, a temperature controller 224, an etchant supply passage 231, an etchant supply pump 230, an etchant supply passage valve 234, an etchant circulation passage 232, and an etchant circulation passage. It is provided with a valve 235 and an etchant chamber pressurizing part 225.

The etchant chamber 221 accommodates the etchant. The etchant supply passage 231 guides the etchant from the etchant chamber 221 to the etch chamber 210 . The etchant supply pump 230 pumps the etchant within the etchant supply passage 231 . The etchant supply flow path valve 234 selectively opens and closes the etchant supply flow path 231. The etchant circulation flow path 232 branches off from the etchant supply flow path 231 and guides the etchant to return to the etchant chamber 221. The etchant circulation flow path valve 235 selectively opens and closes the etchant circulation flow path 232. The etchant chamber pressurizing unit 225 is connected to the etchant chamber 221 and, for example, applies high-pressure nitrogen (N ₂ ) gas to the etchant chamber 221 so that the pressure inside the etchant chamber 221 is maintained at a high pressure higher than atmospheric pressure. It can be supplied internally.

The temperature controller 224 may heat or cool the etchant chamber 221 to increase or decrease the temperature of the etchant contained in the etchant chamber 221. Close the etchant supply flow path valve 234 and open the etchant circulation flow path valve 235 to circulate the etchant through the etchant circulation flow path 232 while operating the temperature controller 224 to heat the etchant contained in the etchant chamber 221. If so, the etchant contained in the etchant chamber 221 can be heated more quickly and uniformly to a specific temperature, for example, the first temperature. In addition, the etchant supply flow path valve 234 is closed, the etchant circulation flow path valve 235 is opened, the etchant is circulated through the etchant circulation flow path 232, and the temperature controller 224 is operated to operate the etchant liquid contained in the etchant chamber 221. By cooling, the etchant contained in the etchant chamber 221 can be cooled more quickly and uniformly to a specific temperature, for example, the second temperature.

The etchant recovery unit 240 recovers the etchant that etched the substrate 10 from the etching chamber 210 to the etchant chamber 221 of the etchant supply unit 220 . The etchant recovery unit 240 includes an etchant recovery passage 241 and an etchant recovery passage valve 245. The etchant recovery passage 241 guides the etchant from the etch chamber 210 to the etchant chamber 221. The etchant recovery flow path valve 245 selectively opens and closes the etchant recovery flow path 241. Although not shown, the etchant recovery unit 240 may further include an etchant recovery pump that pumps the etchant in the etchant recovery passage 245 toward the etchant chamber 221.

When the etch chamber 210 and the etchant chamber 221 are maintained at high pressure by the etch chamber pressurizing unit 215 and the etchant chamber pressurizing unit 225, the boiling point of the etchant increases, so that the etchant is maintained within the limit where the etchant does not boil. The temperature, that is, the first temperature and the second temperature, can be increased. As can be seen with reference to FIG. 2, the higher the temperature of the etchant, the greater the etch rate of the silicon nitride film. In addition, even at a temperature lower than the boiling point of the etchant, vaporization of phosphoric acid contained in the etchant is suppressed and the concentration of the etchant can be maintained constant. Accordingly, the speed and productivity of etching the substrate 10 using the substrate etching apparatus 200 are improved, the defect rate is lowered, and the quality of the etching operation is improved.

The rinse liquid supply unit 280 supplies rinse liquid to the etching chamber 210 to clean the substrate 10 after the substrate 10 is etched. The rinse solution dissolves the etchant and contaminants remaining or attached to the surface of the etched substrate 10 and removes them from the surface of the substrate 10. The rinse solution may be, for example, DHF (Diluted Hydrogen Fluoride), IPA (Isopropyl Alcohol), or SC1 solution.

The rinse liquid supply unit 280 includes a rinse liquid chamber 281, a rinse liquid supply passage 283, and a rinse liquid supply passage valve 284. The rinse liquid chamber 281 accommodates the rinse liquid. The rinse liquid supply passage 283 guides the rinse liquid from the rinse liquid chamber 281 to the etching chamber 210 . The rinse fluid supply flow path valve 284 selectively opens and closes the rinse fluid supply flow path 283. Although not shown, the rinse liquid supply unit 280 may further include a rinse liquid supply pump that pumps the rinse liquid from the rinse liquid chamber 281 to the etching chamber 210 through the rinse liquid supply passage 283. .

The cleaning liquid supply unit 285 supplies cleaning liquid to the etching chamber 210 to wash away and remove the rinsing liquid remaining on the substrate 10 after cleaning the substrate 10 using the rinsing liquid. The cleaning liquid may be, for example, deionized water (DIW).

The cleaning liquid supply unit 285 includes a cleaning liquid chamber 286, a cleaning liquid supply flow path 287, and a cleaning liquid supply flow path valve 288. The cleaning liquid chamber 286 accommodates the cleaning liquid. The cleaning fluid supply passage 287 guides the cleaning fluid from the cleaning fluid chamber 286 to the etching chamber 210 . The cleaning fluid supply flow path valve 288 selectively opens and closes the cleaning fluid supply flow path 287. Although not shown, the cleaning liquid supply unit 285 may further include a cleaning liquid supply pump that pumps the cleaning liquid from the cleaning liquid chamber 286 toward the etching chamber 210 through the cleaning liquid supply passage 287.

The wastewater discharge unit 290 discharges the rinse liquid and cleaning liquid to the outside of the etching chamber 210. The wastewater discharge unit 290 includes a wastewater tank 291, a wastewater discharge passage 295, a wastewater discharge passage valve 297, and a wastewater tank pressurizing portion 293. The wastewater tank 291 receives the rinse and cleaning solutions contaminated through the rinsing and cleaning processes of the substrate 10 after being discharged from the etching chamber 210 . The waste water tank pressurizing unit 293 is connected to the waste water tank 291, and, for example, pumps high-pressure nitrogen (N ₂ ) gas into the waste water tank 290 so that the pressure inside the waste water tank 291 is maintained at a high pressure higher than atmospheric pressure. It can be supplied internally.

The wastewater discharge flow path 295 guides the contaminated rinse and cleaning fluids from the etching chamber 210 to the wastewater tank 291. The wastewater discharge flow path valve 297 selectively opens and closes the wastewater discharge flow path 295. Although not shown, the wastewater discharge unit 290 may further include a wastewater discharge pump that pumps the contaminated rinse and cleaning liquid in the wastewater discharge flow path 295 toward the wastewater tank 290.

In the substrate etching method using the substrate etching device 200 shown in FIG. 5, the etchant contained in the etchant chamber 220 is heated by the temperature controller 224 with an etchant of a first temperature and supplied to the etch chamber 210. The etchant of the first temperature is recovered to the etchant chamber 220 through the recovery unit 240, and is cooled to the etchant of the second temperature by the temperature controller 224 to form the etchant in the etchant chamber 210. ) is supplied to the etchant and is recovered back to the etchant chamber 220 through the etchant recovery unit 240, which is different in detail from the substrate etching method using the substrate etching device 100 shown in FIG. Since everything else is the same, duplicate descriptions will be omitted.

FIG. 6 is a flowchart showing a substrate etching method according to a second embodiment of the present invention, and FIG. 7 is a configuration diagram showing an example of a substrate etching device used to perform the substrate etching method of FIG. 6. Referring to Figures 6 and 7, the substrate etching method according to the third embodiment of the present invention is a method of removing at least a portion of the silicon nitride film laminated on a substrate 10, such as a silicon wafer for semiconductor manufacturing, by etching.

The substrate etching method according to the third embodiment of the present invention includes a substrate loading step (S210), a low-concentration etching step (S220), a high-concentration etching step (S230), a substrate rinsing step (S240), a substrate cleaning step (S250), and a substrate Includes an unloading step (S260). The substrate etching apparatus 300 used to perform the substrate etching method according to the third embodiment of the present invention includes an etching chamber 310, a first etchant supply unit 320, a first etchant recovery unit 340, and a first etchant recovery unit 340. 2 It includes an etchant supply unit 350, a second etchant recovery unit 370, a rinse liquid supply unit 380, a cleaning liquid supply unit 385, and a wastewater discharge unit 390.

The substrate 10 is inserted and accommodated in the etching chamber 310. The etch chamber 310 includes an etch chamber pressurizing unit 315 that supplies, for example, high-pressure nitrogen (N ₂ ) gas into the etch chamber 310 so that the pressure inside the etch chamber 310 is maintained at a high pressure higher than atmospheric pressure. can be connected with

The first etchant supply unit 320 supplies an etchant of a first concentration containing Si (silicon) of a first concentration to the etching chamber 310 . The etchant may be, for example, an aqueous phosphoric acid (H ₃ PO ₄ ) solution. The first etchant supply unit 320 includes a first etchant chamber 321, a first etchant supply passage 331, a first etchant supply pump 330, a first etchant supply passage valve 334, and a first etchant circulation passage ( 332), a first etchant circulation flow valve 335, and a first etchant chamber pressurizing unit 325.

The first etchant chamber 321 accommodates a first concentration etchant containing Si of a first concentration. To elaborate, Si contained in the etchant may be included in the etchant in the form of Si ions. The first etchant supply passage 331 guides the first concentration etchant from the first etchant chamber 321 to the etch chamber 310 . The first etchant supply pump 330 pumps the first etchant within the first etchant supply passage 331 . The first etchant supply flow path valve 334 selectively opens and closes the first etchant supply flow path 331. The first etchant circulation flow path 332 branches off from the first etchant supply flow path 331 and guides the first concentration etchant to return to the first etchant chamber 321. The first etchant circulation flow path valve 335 selectively opens and closes the first etchant circulation flow path 332. The first etchant chamber pressurizing unit 325 is connected to the first etchant chamber 321, and is maintained at a high pressure state higher than atmospheric pressure, such as by using high-pressure nitrogen (N ₂ ) gas. Can be supplied into the first etchant chamber 321.

Although not shown, the first etchant supply unit 320 may further include a first etchant heater for heating the etchant contained in the first etchant chamber 321. The first etchant supply flow path valve 334 is closed and the first etchant circulation flow path valve 335 is opened to circulate the etchant through the first etchant circulation flow path 332 while operating the first etchant heater to create a first etchant chamber ( When the etchant contained in 321) is heated, the etchant contained in the first etchant chamber 321 can be heated more quickly and uniformly to an etchant of a specific temperature.

The first etchant recovery unit 340 recovers the first concentration etchant that etched the substrate 10 from the etching chamber 310 to the first etchant chamber 321 of the first etchant supply unit 320. The first etchant recovery unit 340 includes a first etchant recovery passage 341 and a first etchant recovery passage valve 345. The first etchant recovery passage 341 guides the first concentration etchant from the etch chamber 310 to the first etchant chamber 321 . The first etchant recovery flow path valve 345 selectively opens and closes the first etchant recovery flow path 341. Although not shown, the first etchant recovery unit 340 may further include a first etchant recovery pump that pumps the first concentration etchant in the first etchant recovery passage 345 toward the first etchant chamber 321. .

The second etchant supply unit 350 discharges the first concentration etchant, that is, the first concentration etchant is recovered into the first etchant chamber 321 through the first etchant recovery unit 340, so that the etchant is not filled. A second concentration etchant containing Si of a second concentration higher than the first concentration is supplied to the chamber 310. The second etchant supply unit 350 includes a second etchant chamber 351, a second etchant supply passage 361, a second etchant supply pump 360, a second etchant supply passage valve 364, and a second etchant circulation passage ( 362), a second etchant circulation flow valve 365, and a second etchant chamber pressurizing unit 355.

The second etchant chamber 321 accommodates the second concentration etchant. The second etchant supply passage 361 guides the etchant at the second temperature from the second etchant chamber 351 to the etch chamber 310 . The second etchant supply pump 350 pumps the second etchant in the second etchant supply passage 361. The second etchant supply flow path valve 364 selectively opens and closes the second etchant supply flow path 361. The second etchant circulation flow path 362 branches off from the second etchant supply flow path 361 and guides the etchant at the second temperature to return to the second etchant chamber 351. The second etchant circulation flow path valve 365 selectively opens and closes the second etchant circulation flow path 362. The second etchant chamber pressurizing unit 355 is connected to the second etchant chamber 351, and is maintained at a high pressure state higher than atmospheric pressure by using, for example, high-pressure nitrogen (N ₂ ) gas. Can be supplied into the second etchant chamber 351.

Although not shown, the second etchant supply unit 350 may further include a second etchant heater for heating the etchant contained in the second etchant chamber 351. The second etchant supply flow path valve 364 is closed and the second etchant circulation flow path valve 365 is opened to circulate the etchant through the second etchant circulation flow path 362 while operating the second etchant heater to create a second etchant chamber ( When the etchant contained in the etchant 351) is heated, the etchant contained in the second etchant chamber 351 can be heated more quickly and uniformly to an etchant of a specific temperature.

The second etchant recovery unit 370 recovers the second concentration etchant that etched the substrate 10 from the etching chamber 310 to the second etchant chamber 351 of the second etchant supply unit 350. The second etchant recovery unit 370 includes a second etchant recovery passage 371 and a second etchant recovery passage valve 375. The second etchant recovery passage 371 guides the second concentration etchant from the etch chamber 310 to the second etchant chamber 351. The second etchant recovery flow path valve 375 selectively opens and closes the second etchant recovery flow path 371. Although not shown, the second etchant recovery unit 370 may further include a second etchant recovery pump that pumps the second etchant in the second etchant recovery passage 375 toward the second etchant chamber 351.

The etching chamber 310, the first etchant chamber 321, and the second etchant chamber ( If 351) is maintained at high pressure, the boiling point of the etchant increases, so the temperature of the etchant can be increased within the limit where the etchant does not boil. As can be seen with reference to FIG. 2, the higher the temperature of the etchant, the greater the etch rate of the silicon nitride film. In addition, even at a temperature lower than the boiling point of the etchant, vaporization of phosphoric acid contained in the etchant is suppressed and the concentration of the etchant can be maintained constant. Accordingly, the speed and productivity of etching the substrate 10 using the substrate etching apparatus 300 are improved, the defect rate is lowered, and the quality of the etching operation is improved.

The rinse liquid supply unit 380 supplies rinse liquid to the etching chamber 310 to clean the substrate 10 after the substrate 10 is etched. The rinse solution dissolves the etchant and contaminants remaining or attached to the surface of the etched substrate 10 and removes them from the surface of the substrate 10. The rinse solution may be, for example, DHF (Diluted Hydrogen Fluoride), IPA (Isopropyl Alcohol), or SC1 solution.

The rinse liquid supply unit 380 includes a rinse liquid chamber 381, a rinse liquid supply passage 383, and a rinse liquid supply passage valve 384. The rinse liquid chamber 381 accommodates the rinse liquid. The rinse liquid supply passage 383 guides the rinse liquid from the rinse liquid chamber 381 to the etching chamber 310. The rinse fluid supply flow path valve 384 selectively opens and closes the rinse fluid supply flow path 383. Although not shown, the rinse liquid supply unit 380 may further include a rinse liquid supply pump that pumps the rinse liquid from the rinse liquid chamber 381 to the etching chamber 310 through the rinse liquid supply passage 383. .

The cleaning liquid supply unit 385 supplies cleaning liquid to the etching chamber 310 to wash away and remove the rinse liquid remaining on the substrate 10 after cleaning the substrate 10 using the rinse liquid. The cleaning liquid may be, for example, deionized water (DIW).

The cleaning liquid supply unit 385 includes a cleaning liquid chamber 386, a cleaning liquid supply passage 387, and a cleaning liquid supply passage valve 388. The cleaning liquid chamber 386 accommodates the cleaning liquid. The cleaning liquid supply passage 387 guides the cleaning liquid from the cleaning liquid chamber 386 to the etching chamber 310. The cleaning fluid supply flow path valve 388 selectively opens and closes the cleaning fluid supply flow path 387. Although not shown, the cleaning liquid supply unit 385 may further include a cleaning liquid supply pump that pumps the cleaning liquid from the cleaning liquid chamber 386 toward the etching chamber 310 through the cleaning liquid supply passage 387.

The wastewater discharge unit 390 discharges the rinse liquid and cleaning liquid to the outside of the etching chamber 310. The wastewater discharge unit 390 includes a wastewater tank 391, a wastewater discharge passage 395, a wastewater discharge passage valve 397, and a wastewater tank pressurization portion 393. The wastewater tank 391 receives the rinse and cleaning solutions contaminated through the rinsing and cleaning processes of the substrate 10 after being discharged from the etching chamber 310 . The waste water tank pressurizing unit 393 is connected to the waste water tank 391, and, for example, pumps high-pressure nitrogen (N ₂ ) gas into the waste water tank 390 so that the pressure inside the waste water tank 391 is maintained at a high pressure higher than atmospheric pressure. It can be supplied internally.

The wastewater discharge flow path 395 guides the contaminated rinse and cleaning fluids from the etching chamber 310 to the wastewater tank 391. The wastewater discharge flow path valve 397 selectively opens and closes the wastewater discharge flow path 395. Although not shown, the wastewater discharge unit 390 may further include a wastewater discharge pump that pumps the contaminated rinse and cleaning liquid in the wastewater discharge passage 395 toward the wastewater tank 390.

The substrate loading step (S210) is a step of inserting the substrate 10 on which a silicon oxide film and a silicon nitride film are stacked into the etching chamber 310. Preferably, the substrates 10 may be inserted into the etching chamber 310 one by one.

The low-concentration etching step (S220) is a step of etching the substrate 10 inserted and placed in the etching chamber 310 by exposing it to a first concentration etchant. The low-concentration etching step (S220) includes a first concentration etchant supply step (S221) and a first concentration etchant discharge step (S322). The first concentration etchant supply step (S221) is a step of injecting the first concentration etchant into the etching chamber 310, and may be performed by the first etchant supply unit 320 described with reference to FIG. 7.

The first concentration etchant introduced into the etching chamber 310 flows to the substrate 10, and the substrate 10 is wetted with the first concentration etchant and thus etched. The first concentration etchant is supplied to the etching chamber 310 for a predetermined time so that the substrate 10 can be properly etched.

The first concentration etchant discharge step (S222) is a step of discharging the first concentration etchant introduced into the etching chamber 310 to the outside of the etching chamber 310. The first concentration etchant supply step (S221) and the first concentration etchant discharge step (S222) may be performed simultaneously. In other words, the first concentration etchant supplied into the etching chamber 310 may pass through the substrate 10 and be immediately discharged from the etching chamber 310. Alternatively, the first concentration etchant supply step (S221) and the first concentration etchant discharge step (S222) may be performed with time differences. In other words, the first concentration etchant supply step (S221) may be performed first, and then the first concentration etchant discharge step (S222) may be performed after a certain period of time. The first concentration etchant discharged from the etching chamber 310 may not be discharged to the outside of the substrate etching apparatus 300 but may be recovered into the first etchant chamber 321 through the first etchant recovery unit 340 .

The high-concentration etching step (S230) is a step of etching the substrate 10 inserted into the etching chamber 310 by exposing it to a second concentration etchant containing Si of a second concentration higher than the first concentration. The high-concentration etching step (S230) etches the substrate 10 at a slower etching rate than the low-concentration etching step (S220) and increases the etch selectivity of the silicon nitride film to the silicon oxide film. In other words, the etching rate in the high-concentration etching step (S230) is slower than the etching rate in the low-concentration etching step (S220), and the etch selectivity in the high-concentration etching step (S230) is the etch selectivity in the low-concentration etching step (S220). higher than

As shown in Figure 3, the etching selectivity, which is the etching rate of the silicon nitride film relative to the etching rate of the silicon oxide film, decreases as the temperature increases, and when the temperature is the same, the etching solution containing a relatively high concentration of Si is etched. The selectivity is greater than that of an etchant containing a relatively low concentration of Si. A decrease in the etch selectivity means that the amount of the silicon oxide film removed when the silicon nitride film is removed by etching increases. The trend of decreasing etching selectivity as the temperature of the etchant increases is common regardless of the concentration of Si contained in the etchant. In addition, as shown in FIG. 2, the etching rate by the etchant increases as the temperature of the etchant increases in both the case of the silicon nitride film and the silicon oxide film. Meanwhile, if the substrate 10 is etched for too long with an etchant containing a high concentration of Si, an unnecessary silicon oxide film may be abnormally generated.

Therefore, for a predetermined period of time from the start of etching, the substrate 10 is first etched with an etchant with a first concentration containing a relatively low concentration of Si, and then with an etchant with a second concentration containing a relatively high concentration of Si. When the substrate 10 is etched, etching of silicon oxide is minimized, thereby improving the quality of the etching process and improving the speed of the etching process. Etching the substrate 10 by adding an etchant of a first concentration can be called low-selectivity etching, and etching the substrate 10 by adding an etchant of a second temperature can be called high-selectivity etching.

For example, in high-speed, low-selectivity etching, the concentration of Si contained in the first concentration etchant may be 1300 ppm, and in low-speed, high-selectivity etching, the concentration of Si contained in the second concentration etchant may be 1700 ppm. At this time, the temperature of the first concentration etchant and the second concentration etchant may be the same at 200°C. As another example, in high-speed, low-selectivity etching, the concentration of Si contained in the first concentration etchant may be 700 ppm, and in low-speed, high-selectivity etching, the concentration of Si contained in the second concentration etchant may be 800 ppm. At this time, the temperature of the first concentration etchant and the second concentration etchant may be the same at 160°C.

The high concentration etching step (S230) includes a second concentration etchant supply step (S231) and a second concentration etchant discharge step (S232). The second concentration etchant supply step (S231) is a step of injecting the second concentration etchant into the etching chamber 310, and may be performed by the second etchant supply unit 350 described with reference to FIG. 7. The second concentration etchant may be introduced into the etch chamber 310 from the second etchant chamber 351 through the second etchant supply passage 361. The second concentration etchant introduced into the etching chamber 310 flows to the substrate 10, and the substrate 10 is wetted with the second concentration etchant and thus etched. The second concentration etchant is supplied to the etching chamber 310 for a predetermined time so that the substrate 10 can be properly etched.

The second concentration etchant discharge step (S232) is a step of discharging the second concentration etchant introduced into the etching chamber 310 to the outside of the etching chamber 310. The second concentration etchant supply step (S231) and the second concentration etchant discharge step (S232) may be performed simultaneously. In other words, the second concentration etchant supplied into the etching chamber 310 may pass through the substrate 10 and be immediately discharged from the etching chamber 310 . Alternatively, the second concentration etchant supply step (S231) and the second concentration etchant discharge step (S232) may be performed with time differences. In other words, the second concentration etchant supply step (S231) may be performed first, and the second concentration etchant discharge step (S232) may be performed after a certain period of time. The second concentration etchant discharged from the etching chamber 310 may not be discharged to the outside of the substrate etching apparatus 300 but may be recovered into the second etchant chamber 351 through the second etchant recovery unit 340 .

The substrate rinsing step (S240) includes a rinse solution supply step and a rinse solution discharge step. The rinse solution supply step is a step of supplying a rinse solution to the etching chamber 310 to clean the etched substrate 10. The rinse liquid supplied into the etching chamber 310 dissolves the etchant and contaminants remaining or attached to the surface of the etched substrate 10 and removes them from the surface of the substrate 10. The rinse liquid supply step is performed by the rinse liquid supply unit 380 described above.

The rinse liquid discharging step is a step of cleaning the substrate 10 and discharging the contaminated rinse liquid to the outside of the etching chamber 310 . The rinse liquid discharged from the etching chamber 310 is stored in the wastewater tank 391. The rinse liquid discharge step is performed by the wastewater discharge unit 390 described above.

The substrate cleaning step (S250) includes a cleaning liquid supply step and a cleaning liquid discharge step. The cleaning liquid supply step is a step of supplying the cleaning liquid to the etching chamber 310. The cleaning solution supplied into the etching chamber 310 washes away and removes the rinse solution remaining on the substrate 10 after cleaning the substrate 10 using the rinse solution. The cleaning liquid supply step is performed by the cleaning liquid supply unit 385 described above.

The cleaning liquid discharge step is a step of discharging the contaminated cleaning liquid to the outside of the etching chamber 310 by washing away and removing the rinse liquid remaining on the substrate 10 . The cleaning solution discharged from the etching chamber 310 is stored in the wastewater tank 391. The cleaning liquid discharge step is performed by the wastewater discharge unit 390 described above.

The substrate unloading step (S260) is a step of removing the etched substrate 10 from the etching chamber 310 after the low-temperature etching step (S230). In the embodiment shown in FIG. 6, the substrate unloading step (S260) is performed after the substrate rinsing step (S240) and the substrate cleaning step (S250), but the present invention is not necessarily limited thereto, and the high-concentration etching step ( After S230), the etched substrate 10 may be taken out of the etching chamber 310, and the substrate 10 may then be rinsed and cleaned.

Meanwhile, although not shown in FIG. 6, a step of rinsing the substrate 10 etched with the first concentration etchant after the low-concentration etching step (S220) and before the high-concentration etching step (S230) may be added. Alternatively, a substrate drying step of vaporizing and removing the cleaning solution remaining on the surface of the substrate 10 may be added after the substrate cleaning step (S250) and before the substrate unloading step (S260).

According to the substrate etching method described above, by etching the substrate 10 with etchants of different properties, the quality of the etching work is improved, the defect rate is lowered, and the quality of the etching work is reduced compared to the case of etching the substrate only with an etchant of a single property. Speed improves. As a specific example, after etching the substrate with an etchant at a first temperature and then etching the substrate with an etchant at a second temperature lower than the first temperature, or after etching the substrate with an etchant at a first concentration containing a first concentration of Si, The substrate may be etched with a second concentration etchant containing Si at a second concentration higher than the first concentration.

The present invention has been described with reference to an embodiment shown in the drawings, but this is merely illustrative, and those skilled in the art will recognize that various modifications and other equivalent embodiments are possible therefrom. You will understand. Therefore, the true scope of protection of the present invention should be determined only by the appended claims.

Claims

A high-temperature etching step of etching a substrate on which a silicon oxide film and a silicon nitride film are stacked by exposing it to an etchant at a first temperature; and

A low-temperature etching step of exposing the substrate to an etchant of a second temperature lower than the first temperature to etch the etch selectivity of the silicon nitride film to the silicon oxide film to be higher than that of the high-temperature etching step. A substrate etching method using.
According to claim 1,

The high temperature etching step is,

A first temperature etchant supply step of injecting the etchant at the first temperature into an etching chamber containing the substrate so that the substrate is wetted with the etchant at the first temperature; and

A method of etching a substrate comprising a first temperature etchant discharging step of discharging the etchant at the first temperature to the outside of the etching chamber.
According to clause 2,

A substrate etching method, wherein the first temperature etchant supply step and the first temperature etchant discharge step are performed simultaneously or with a time difference.
According to clause 2,

The low temperature etching step is,

A second temperature etchant supply step of injecting the etchant at the second temperature into the etching chamber so that the substrate is wetted with the etchant at the second temperature; and

A method of etching a substrate comprising a second temperature etchant discharging step of discharging the etchant at the second temperature to the outside of the etching chamber.
According to clause 4,

A method of etching a substrate, wherein the second temperature etchant supply step and the second temperature etchant discharge step are performed simultaneously or with a time difference.
A low-concentration etching step of etching a substrate on which a silicon oxide film and a silicon nitride film are stacked by exposing it to a first concentration etchant containing a first concentration of Si (silicon); and

A high-concentration etching step of exposing the substrate to a second concentration etchant containing a second concentration of Si higher than the first concentration to etch the etch selectivity of the silicon nitride film to the silicon oxide film to a higher etch selectivity than the low-concentration etching step; A substrate etching method comprising:
According to clause 6,

The low concentration etching step is,

A first concentration etchant supply step of injecting the first concentration etchant into an etching chamber in which the substrate is accommodated so that the substrate is wetted with the first concentration etchant; and

A method of etching a substrate, comprising: discharging the first concentration etchant to the outside of the etching chamber.
According to clause 7,

A method of etching a substrate, wherein the first concentration etchant supply step and the first concentration etchant discharge step are performed simultaneously or with a time difference.
According to clause 7,

The high concentration etching step is,

a second concentration etchant supply step of introducing the second concentration etchant into the etching chamber so that the substrate is wetted with the second concentration etchant; and

A method of etching a substrate, comprising: discharging the second concentration etchant to the outside of the etching chamber.
According to clause 9,

A method of etching a substrate, characterized in that the step of supplying the second concentration etchant and discharging the second concentration etchant are performed simultaneously or with a time difference.
an etching chamber into which a substrate is inserted and received;

a first etchant supply unit supplying an etchant at a first temperature to the etching chamber;

a first etchant recovery unit that recovers the etchant of the first temperature that etched the substrate from the etching chamber to the first etchant supply unit;

a second etchant supply unit supplying an etchant of a second temperature lower than the first temperature to the etching chamber from which the etchant of the first temperature is discharged; and

A substrate etching device comprising: a second etchant recovery unit that recovers the etchant of the second temperature that etched the substrate from the etching chamber to the second etchant supply unit.
According to clause 11,

a rinse solution supply unit that supplies a rinse solution to the etching chamber to clean the substrate after the substrate is etched; and

A substrate etching device further comprising: a cleaning solution supply unit supplying a cleaning solution to the etching chamber to remove the rinsing solution remaining on the substrate.
an etching chamber into which a substrate is inserted and received;

a first etchant supply unit supplying an etchant containing a first concentration of Si (silicon) to the etching chamber;

a first etchant recovery unit that recovers the first concentration etchant that etched the substrate from the etching chamber to the first etchant supply unit;

a second etchant supply unit supplying a second concentration etchant containing Si of a second concentration higher than the first concentration to the etching chamber from which the first concentration etchant is discharged; and

A second etchant recovery unit that recovers the second concentration etchant that etched the substrate from the etching chamber to the second etchant supply unit.
According to clause 13,

a rinse solution supply unit that supplies a rinse solution to the etching chamber to clean the substrate after the substrate is etched; and

A substrate etching device further comprising: a cleaning solution supply unit supplying a cleaning solution to the etching chamber to remove the rinsing solution remaining on the substrate.