JP2015088603A - Etching method, etching device and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an amount of an etchant.SOLUTION: An etching method includes: an initial preparation step for filling the etchant into an etching processing unit; and an etching step for etching a workpiece. The initial preparation step includes a liquid supply step using a new etchant having high Si concentration. The etching step includes a partial liquid exchange step using a new etching liquid having low Si concentration.

Description

  The present invention relates to an etching method, an etching apparatus, and a storage medium, and more particularly to an etching method, an etching apparatus, and a storage medium for performing an etching process on an object to be processed such as a semiconductor wafer with an etching solution.

Conventionally, in a wet etching method for an object to be processed such as a semiconductor wafer, an etching process is performed on a nitride film-oxide film using phosphoric acid as an etchant. For example, an etching solution made of phosphoric acid aqueous solution (H ₃ PO ₄ ) or the like is stored in a treatment tank and heated to a predetermined temperature, for example, 160 to 180 ° C., and is connected to a circulation line and a circulation line connected to the treatment tank. An object to be processed, for example, a semiconductor wafer (hereinafter referred to as a wafer) is etched while circulating and supplying an etching solution having a predetermined temperature via a circulating pump and a temperature controller provided (see Japanese Patent Publication No. 3-20895). .

    In the above etching method, since the ability of the etching solution (etching rate) depends on the silicon concentration in the etching solution, the silicon (Si) concentration in the etching solution is kept within a certain concentration range for good processing of the wafer. There is a need to. However, if the etching process is repeated, the silicon (Si) component of the wafer elutes into the etching solution, the silicon (Si) concentration in the etching solution increases, and the semiconductor wafer is accurately etched. Can not be. For this reason, conventionally, the entire liquid of the etching solution in the processing tank has been periodically replaced.

  Conventionally, when etching is performed using only a new etching solution having a low Si concentration (Si concentration is zero), the etching solution is supplied to the processing tank in preparation for the etching process, or etching is periodically performed in the processing tank. When all of the solution is replaced, a method (seasoning) is performed in which the dummy wafer on which the silicon nitride film is formed is etched to increase the Si concentration in the etching solution to an appropriate range. In this case, the liquid adjustment becomes complicated and the processing time becomes long, so that the throughput of the etching process decreases. However, since the Si concentration in the etching solution increases during the etching process, the Si concentration in the etching solution is lowered when the etching solution is partially replaced to keep the Si concentration in the etching solution within a predetermined range. The amount of etching solution discharged and the amount of replenishing new etching solution are small.

  On the other hand, when etching is performed using only a new etching solution having a high silicon concentration (a silicon concentration within a predetermined range in order to accurately etch a semiconductor wafer), etching into the processing tank is performed in preparation for the etching process. In the case of supplying the solution or periodically replacing the entire etching solution in the treatment tank, it is not necessary to perform seasoning, and the seasoning time can be shortened. However, since the Si concentration in the etching solution increases during the etching process, when the etching solution is partially replaced, a large amount of etching solution is discharged and a large amount of new etching solution is required.

Japanese Patent Publication No. 3-20895

  The present invention has been made in consideration of the above points, and an etching method and an etching apparatus that can increase the throughput in the etching process and can reduce the amount of the etching solution used in the etching process. And a storage medium.

  The present invention includes an initial preparation step of filling an etching solution in an etching processing unit, and an etching step of performing an etching process using an etching solution on an object to be processed housed in the etching processing unit. The process includes a liquid supply process performed using a new etching liquid having a first Si concentration, and the etching process is performed by partially replacing the etching liquid in the etching processing unit performed using the new etching liquid having a second Si concentration. An etching method including a partial liquid exchange step.

  The present invention relates to an etching apparatus that performs an etching process on an object to be processed, an etching processing unit that stores the object to be processed and performs the etching process with an etching solution, and an etching solution that is subjected to the etching process in the etching processing unit A supply unit that supplies a new etching solution to the etching processing unit, a controller that drives and controls the etching processing unit, the discharge unit, and the supply unit. Has a first supply part for supplying a new etchant with a first Si concentration and a second supply part for supplying a new etchant with a second Si concentration, and the control device fills the etchant with the etchant. An initial preparation step and an etching process for etching an object to be processed contained in the etching processing section using an etching solution. The initial preparation step includes a liquid supply step performed using a new etching solution having a first Si concentration supplied from the first supply unit, and the etching step includes the second supply unit. An etching apparatus comprising: a partial liquid exchange for partially exchanging the etching liquid in the etching processing section, which is performed by using a new etching liquid having a second Si concentration supplied from the above.

  In a storage medium storing a computer program for causing a computer to execute an etching method, an etching method includes an initial preparation step of filling an etching solution in an etching processing unit, and an object to be processed housed in the etching processing unit. And an etching process for performing an etching process using an etchant, wherein the initial preparation process includes a liquid supply process performed using a new etchant having a first Si concentration, and the etch process includes a new etch having a second Si concentration A storage medium comprising a partial liquid exchange step of partially exchanging an etching liquid in the etching processing section performed using a liquid.

  As described above, according to the present invention, the throughput can be increased in the etching process, and the amount of the etchant used for the etching process can be reduced.

FIG. 1 is a schematic view showing an etching apparatus according to an embodiment of the present invention. 2A, 2B, and 2C are views showing an etching method of the present invention. FIG. 3 is a diagram showing control of phosphoric acid concentration in the etching method of the present invention. 4A, 4B, and 4C are views showing an etching method as a comparative example.

Embodiment An embodiment of the present invention will be described with reference to FIGS.

First, a process for selectively removing a silicon nitride film from a silicon oxide film (SiO ₂ ) and a silicon nitride film (Si ₄ N ₃ ) formed on an object to be processed, such as a wafer W, is required. The silicon nitride film is etched by being immersed in an etching solution at a high temperature, for example, 100 to 180 ° C., or an aqueous phosphoric acid solution (H ₃ PO ₄ ). In this etching method, it is important to etch the silicon nitride film and suppress the etching rate of the silicon oxide film.

  First, an etching apparatus for performing an etching method will be described.

As shown in FIG. 1, the etching apparatus accommodates a wafer W whose surface is vertically held by a wafer boat (not shown) and receives an etching liquid overflowing from the inner tank 10a and an inner tank 10a for storing the etching liquid. A semiconductor wafer W (hereinafter referred to as a wafer W), which is an object to be processed, is stored in the inner tank 10a, and an etching solution E (for example, phosphoric acid aqueous solution (H ₃ PO ₄ )) is stored in the inner tank 10a. The etching tank E is extracted from the processing tank (etching processing unit) 10 and the outer tank 10b, and the etching line E is circulated and supplied to the inner tank 10a, and the etching in the processing tank 10 is connected to the circulation line 20. A first discharge part (discharge line) 30 for discharging the liquid E and a supply part 15 for supplying a new etching liquid E into the processing tank 10 are provided. ing.

  A panel heater 11 is attached to the side and bottom of the inner tank 10a configured as described above, and the etching solution E in the processing tank 10 is set to a predetermined temperature, for example, 100 to 180 ° C. Yes. Further, a nozzle 12 connected to the circulation line 20 is provided on the bottom side in the inner tank 10a, and the etching solution E circulated and supplied from the circulation line 20 is sent uniformly into the inner tank 10a by the nozzle 12. It has become.

  The circulation line 20 is connected to a lower portion of the outer tank 10b and a nozzle 12 provided in the inner tank 10a. The circulation line 20 includes a circulation pump 21, a temperature controller 22, And a filter 23 are sequentially provided. Among these, the temperature controller 22 includes a heater for heating the etching solution E.

Next, the supply unit 15 will be described. The supply unit 15 includes two etching solution tanks 15A and 15B that store and supply a phosphoric acid aqueous solution (H ₃ PO ₄ aqueous solution). Of these, the etching solution tank 15A contains an aqueous solution of phosphoric acid having a high Si concentration (a silicon concentration in a predetermined range in order to accurately etch a semiconductor wafer: a first Si concentration), and includes a heater 15h. It is out. The etching solution tank 15B stores a phosphoric acid aqueous solution having a low Si concentration (Si concentration is zero or lower than the high Si concentration range: second Si concentration), and includes a heater 15i.

  The etching solution tank 15A serves as a first supply unit that stores and supplies a high Si concentration phosphoric acid aqueous solution, and the etching solution tank 15B serves as a second supply unit that stores and supplies a low Si concentration phosphoric acid aqueous solution.

  By the way, a high Si concentration phosphoric acid aqueous solution supply source 16A for supplying a high Si concentration phosphoric acid aqueous solution is connected to the etching solution tank 15A via a connection line 16a, and a low Si concentration phosphoric acid aqueous solution is connected to the etching solution tank 15B. A low Si concentration phosphoric acid aqueous solution supply source 16B to be supplied is connected via a connection line 16b.

An Si solution tank 18 for storing the Si solution is installed, and an Si solution supply source 19 is connected to the Si solution tank 18 via a connection line 19a.
Furthermore the Si solution tank 18 is connected to the connection line 18a having a valve _{V 10,} the connection line 18a is connected to the connection line 16b.

The etching solution of the etchant for tank 15A is supplied into the inner tank 10a via the connection line 15a having a valve V _1. Etchant an etchant for tank 15B is supplied to the outer tub 10b via the connection line 15b having a valve _{V 4} and the valve _{V 5.} A flow rate control mechanism 39 is attached to the connection line 15b of the etching solution tank 15B. Furthermore, the etching solution tank 15A, the connection line 15c is connected to join to the connection line 15b of the etchant tank 15B, the valve _{V 2} and valve _{V 3} is provided in the connecting line 15c. Furthermore, the etching solution tank 15B, the connection line 15d is connected to join to the connection line 15a of the etching liquid tank 15A, the valve V ₉ is provided in the connecting line 15d.

  Moreover, the branch line 31 is connected to the downstream side of the filter 23 of the circulation line 20, and the branch line 31 is connected to the outer tank 10b. In this case, the branch line 31 is sequentially provided with a concentration measuring unit 27 and an elution component measuring unit 26.

Among these, the elution component measuring unit 26 measures the concentration of the silicon elution component in the etching solution E subjected to the etching process by using the refractive index of light, and the concentration measuring unit 27 is used for the etching solution E. The concentration, specifically, the concentration of the phosphoric acid aqueous solution is measured using the refractive index of light.
Also in the bottom of the inner tank 10a of the processing bath 10, the second discharge portion having a valve V ₈ (discharge line) 33 is connected.

  Moreover, as shown in FIG. 1, the DIW supply source 40 which supplies pure water (DIW) is provided, and this DIW supply source 40 is connected to the outer tank 10b of the processing tank 10 via the connection line 40a.

Furthermore, a discharge line 30 is connected to the circulation line 20, and the etching solution drawn from the circulation line 20 is discharged from the discharge line 30 to the outside. Further, the discharge line 30 is provided with a valve V ₆ , a valve V ₇ and a flow rate control mechanism 41.

Incidentally, the elution component measuring unit 26 and the concentration measuring unit 27 are connected to the control device 100.
Then, by the control device 100, the above-described functional components, for example, the circulation pump 21 and the temperature controller 22 of the circulation line 20, etching tanks 15A and 15B, a high Si concentration phosphoric acid aqueous solution supply source 16A, a low Si concentration phosphoric acid aqueous solution supply source 16B, flow control mechanism 39 and 41, the panel heater 11 and each of the valves _V 1 ~V _7, it is driven and controlled. The control device 100 can be realized as hardware, for example, by a general-purpose computer and a program (device control program, processing recipe, etc.) for operating the computer as software. The software is stored in a storage medium such as a hard disk drive fixedly provided in the computer, or is stored in a storage medium that is detachably set in the computer such as a CDROM, DVD, or flash memory. Such a storage medium is indicated by reference numeral 100a. The processor 100b calls and executes a predetermined processing recipe from the storage medium 100a based on an instruction from a user interface (not shown) as necessary, and thereby each functional component of the etching apparatus operates under the control of the control apparatus 100. Then, a predetermined process is performed.

  Next, an etching method performed by the control apparatus 100 using the etching apparatus will be described with reference to FIGS.

  2A is a diagram showing the Si concentration in the etching solution, FIG. 2B is a diagram showing the concentration of the phosphoric acid aqueous solution in the etching solution, and FIG. 2C is the temperature of the etching solution. FIG. FIG. 3 is a diagram showing control of phosphoric acid concentration.

  First, a high Si concentration phosphoric acid aqueous solution 16A is supplied in advance to the etching solution tank 15A from the high Si concentration phosphoric acid aqueous solution supply source 16A, and a low Si concentration phosphoric acid aqueous solution (Si concentration is zero) from the low Si concentration phosphoric acid aqueous solution supply source 16B. Supplied to the tank 15B.

(Initial preparation process)
Next, as shown in FIGS. 2A to 2C, an initial preparation step is performed. Supplying a new etching solution E (high Si concentration of phosphoric acid aqueous solution _(H 3 _PO 4)) Open the valve _{V 1} from the etching liquid tank 15A to the inner tank 10a is first. Thereafter, the etching solution in the inner tank 10a is overflowed and sent to the outer tank 10b. Next, the circulation pump 21 is driven to circulate the etching solution E overflowed to the outer tank 10 b so as to return to the inner tank 10 a through the circulation line 20. In this way, the etching solution E is filled in the processing tank 10. Close the valve V ₁ After filling of the etchant E to the processing tank 10 is completed to stop the supply of the etching liquid E. Next, the temperature controller 22 heats the etching solution E to a predetermined temperature (100 to 180 ° C.) to bring it into a boiling state.

  After the temperature of the etchant E rises to a boiling state, the amount of heat given to the etchant E in the circulation line 20 is adjusted by the temperature controller 22, so that the etchant E in the inner tank 10a maintains the boiling state. Is maintained at a predetermined temperature.

  In addition, in order to perform etching at a desired etching rate, it is necessary to maintain the etching solution E at a predetermined concentration, and the temperature of the etching solution E is maintained at the boiling temperature unique to the etching solution E having the predetermined concentration. In this way, a state in which the wafer W can be etched in the processing bath 10 is prepared (initial preparation step).

  As described above, since the new etching solution has a high Si concentration in the initial preparation step, the conventional seasoning time can be eliminated or shortened.

(Etching process)
In this state, the wafer W held vertically by a wafer boat (not shown) is accommodated in the inner tank 10a. The wafer W is immersed in the etching solution E in the inner tank 10a for a predetermined time and etched. Thereafter, the wafer W is taken out from the processing tank 10. Thereafter, a new wafer W is accommodated in the inner tank 10a and processed. The etching process is repeated. The etching method includes a plurality of etching processes including a first etching process, a second etching process, a third etching process,... And an interval process between these etching processes (FIGS. 2A and 2B). ) (C)).

  Here, the etching process means that the wafer W is immersed in the etching solution E in the inner tank 10a, and the interval process between the etching processes means that the wafer W is in the etching solution E in the inner tank 10a. If not immersed, that is, the n-th etching process is completed and the wafer W for one etching process unit is taken out from the inner tank 10a, and the next one processing unit unit is started to start the n + 1-th etching process. This is the period until the wafer W is immersed in the inner tank 10a. In the plurality of etching steps, the etching solution E is continuously circulated through the circulation line 20.

  By performing the etching process, silicon (Si) is eluted from the wafer W into the etching solution E in the inner tank 10a.

  When such an etching process is repeated, silicon (Si) content is eluted from the wafer W into the etching solution E, and if the concentration of the eluted component (Si concentration or silicon concentration) in the etching solution becomes too high, the etching solution Properties deteriorate.

  In the present invention, the following control is performed to cope with such a case.

That is, first in the etching step, the control device 100 is driven valves V ₆ and valve V _7, have been subjected etchant E to the etching process in the inner tank 10a is discharged line from the circulation line 20 by a first set amount It is discharged to the 30 side and then discharged outward from the discharge line 30.

At the same time, the control device 100 drives the valves V ₄ and V ₅ and the flow rate control mechanism 39 so that the low Si concentration phosphoric acid aqueous solution (Si concentration is zero) is passed through the connection line 15b from the etching solution tank 15B by the second set amount. It is supplied into the outer tank 10b of the processing tank 10.

  In this way, the etching solution E subjected to the etching process in the processing tank 10 is discharged by the first set amount, and the new etching solution is supplied to the processing tank 10 by the second set amount. The etching solution E can be partially replaced. In this case, the etchant E is discharged by the first set amount, and at the same time, the new etchant E is supplied by the second set amount, whereby the liquid level of the etchant in the processing bath 10 can be kept substantially constant.

  In FIG. 2A, in the first etching step, the second etching step, and the third etching step, the etching solution is discharged by the first set amount and supplied by the second set amount. The Si concentration is shown.

  Specifically, during each etching step, the etching solution in the processing tank 10 subjected to the etching process is discharged by 0.05 L / min (first set amount), and 0.05 L of a new etching solution is supplied to the processing tank 10. / Min (second set amount) is supplied.

  Here, each etching step is a partial replacement constituted by a step of discharging the etching solution in the processing tank 10 by a first set amount and a step of supplying a new etching solution by a second set value into the processing bath 10. Includes patterns. In this partial replacement pattern, the etching solution used for the etching process is continuously discharged over the entire period during the etching process, and a new etching liquid is continuously supplied over the entire period during the etching process. .

  In FIG. 2A, a partial replacement pattern in which the Si concentration continuously increases is performed. However, for example, supply and discharge of an etchant are performed so as not to exceed a predetermined Si concentration range during the etching process. The Si concentration can also be increased stepwise and intermittently. The value of the Si concentration at the completion of the etching process can be arbitrarily changed according to the wafer W to be etched.

Next, during the interval step between the etching process, the valve V ₈ by the control device 100 is driven, is subjected to the etchant E to the etching process in the inner tank 10a is full liquid discharged through the discharge line 33.

Next, the control device 100 is driven valve _{V 1,} the etching solution tank 15A from the high Si concentration phosphoric acid solution (high Si concentration of the new etching solution) is inner tank 10a of the processing tank 10 through a connection line 15a Supplied to.

  In this way, all the etching solution E subjected to the etching process in the processing tank 10 is discharged, and a new etching liquid is supplied into the processing tank 10, so that the etching liquid E in the processing tank 10 has a high Si concentration. The entire solution can be exchanged with an aqueous phosphoric acid solution.

  By each interval step, the silicon concentration can be returned to the same value as the silicon concentration at the start of the etching step immediately before the interval step at the start of the etching step immediately after the interval step.

  By the way, in each etching process and interval process, pure water (DIW) evaporates from the processing tank 10. At this time, based on the measured value of the phosphoric acid concentration from the concentration measuring unit 27, DIW is replenished from the DIW supply source 40 to the outer tank 10b of the processing tank 10, and the phosphoric acid concentration in the processing tank 10 is kept constant. (See FIG. 3). In this case, when the etching solution (for example, phosphoric acid concentration b) used for the etching process is discharged from the processing bath 10 and a new etching solution (for example, phosphoric acid concentration a) is supplied into the processing bath 10, the phosphoric acid concentration a and the phosphoric acid concentration b are supplied. Thus, the phosphoric acid concentration in the processing tank 10 changes, and therefore, the amount of DIW supplied from the DIW supply source 40 to the outer tank 10b must also be changed.

  In the present embodiment, during each etching step, the etching solution is discharged based on the first set amount determined so that the phosphoric acid concentration in the processing bath 10 is constant, and at the same time, the phosphoric acid concentration in the processing bath 10 is increased. A new etching solution may be supplied based on the second set amount determined to be constant.

  As described above, according to the present embodiment, as shown in FIG. 2A, in the initial preparation step and the interval step, the high Si concentration phosphoric acid aqueous solution is supplied from the etching solution tank 15A to the treatment tank 10 and processed. The entire liquid in the tank 10 is exchanged, and in each etching step, the partial liquid exchange in the treatment tank 10 is performed by supplying a low Si concentration phosphoric acid aqueous solution from the etching solution tank 15B to the treatment tank 10. Thus, in the initial preparation step and the interval step, by using a high Si concentration phosphoric acid aqueous solution as a new etching solution, it is possible to save the time for adjusting the etching solution such as seasoning in the initial preparation step and the interval step, The time required for the initial preparation process and the interval process can be shortened, and the throughput of the etching process can be improved. Further, in the etching process, by using a low Si concentration phosphoric acid aqueous solution as a new etching solution, the etching solution is discharged from the processing bath 10 by a small first set amount such as 0.05 L / min, and the etching solution is supplied to the processing bath 10. Partial liquid exchange for supplying only a small second set amount such as 0.05 L / min is performed, whereby the Si concentration can be kept at 130 ppm or less. Since the first set amount and the second set amount necessary for partial liquid exchange can be kept small in this way, the concentration of the phosphoric acid aqueous solution of the etching solution E in the processing tank 10 can be kept substantially constant (FIG. 2 ( b)), and the temperature of the etching solution E in the processing bath 10 can be kept substantially constant (see FIG. 2C).

  Here, FIGS. 4A, 4B, and 4C describe a comparative example of the present invention. In the comparative example shown in FIGS. 4A, 4B, and 4C, in the initial preparation step and the interval step, the high Si concentration phosphoric acid aqueous solution is supplied from the etching solution tank 15A to the treatment bath 10 to remove all the inside of the treatment bath 10. In each etching process, a high Si concentration phosphoric acid aqueous solution is supplied from the etching solution tank 15A to the treatment tank 10 to exchange partial liquids in the treatment tank. In the comparative example shown in FIGS. 4A, 4B, and 4C, other configurations are substantially the same as those of the embodiment shown in FIGS.

  In the comparative example shown in FIGS. 4A, 4B, and 4C, since the high Si concentration phosphoric acid aqueous solution is used as a new etching solution during the etching process, the etching solution from the treatment tank 10 is as large as 0.5 L / min. The first set amount is discharged, and partial liquid exchange is performed to supply the etching solution to the processing tank 10 by a large second set amount such as 0.5 L / min, thereby keeping the Si concentration at 130 ppm or less. As described above, since the first set amount and the second set amount necessary for the partial liquid exchange are increased, the concentration of the phosphoric acid aqueous solution of the etching solution E in the processing tank 10 greatly varies (see FIG. 4B). ). In this case, the temperature of the etching solution E in the processing tank 10 also varies greatly (see FIG. 4C).

  On the other hand, according to the present embodiment, the first set amount and the second set amount necessary for partial replacement of the etchant during the etching process can be kept small, so that the phosphoric acid of the etchant in the processing tank 10 The aqueous solution concentration can be kept substantially constant, and the temperature of the etching solution E in the processing bath 10 can be kept substantially constant.

Modified Example Next, a modified example of the present invention will be described. In the above embodiment, in the interval step, an example in which a high Si concentration phosphoric acid aqueous solution is supplied from the etching solution tank 15A to the treatment tank 10 to exchange all the liquid in the treatment tank 10 has been shown. In the interval step, the partial liquid exchange may be performed in the processing bath 10 by supplying a low Si concentration phosphoric acid aqueous solution from the etching solution tank 15 </ b> B to the processing bath 10. Thereby, the same effect as the etching process can be obtained also in the interval process, and the next new wafer etching process can be prepared.

When the low Si concentration phosphoric acid solution via the connection line 15b from the etchant tank 15B (Si concentration is zero) is supplied to the second set amount by the processing bath 10 outer tub 10b of the valve V ₂ and valve V ₃ is driven, and the high Si concentration phosphoric acid aqueous solution may be added to the low Si concentration phosphoric acid aqueous solution via the connection line 15c. At this time, the second set amounts are the low Si concentration phosphoric acid aqueous solution and the high Si concentration phosphoric acid aqueous solution. The total value of

In the above embodiment, the low Si concentration phosphoric acid aqueous solution supply source 16B supplies the low Si concentration phosphoric acid aqueous solution (Si concentration is zero) to the etching solution tank 15B. Not limited to this, the Si solution may be supplied from the Si solution tank 18 to the etching solution tank 15B as necessary to adjust the Si concentration of the low Si concentration phosphoric acid aqueous solution. Thereby, when the weighing accuracy of the etching solution is deteriorated because the amount of liquid exchange in the partial exchange is too small, the amount of liquid exchange can be increased by increasing the Si concentration.

Pattern in which Si solution and low Si concentration phosphoric acid aqueous solution are prepared and supplied to inner tank 10a In the above embodiment, high Si concentration phosphoric acid aqueous solution (phosphoric acid aqueous solution having high Si concentration) is previously supplied from high Si concentration phosphoric acid aqueous solution supply source 16A. Although the low Si concentration phosphoric acid aqueous solution supply source 16B is supplied to the etching solution tank 15A, the low Si concentration phosphoric acid aqueous solution (phosphoric acid solution having a Si concentration of zero Si concentration) is supplied to the etching solution tank 15B. Not limited to this, a low Si concentration phosphoric acid aqueous solution supply source 16B supplies a low Si concentration phosphoric acid aqueous solution (phosphoric acid aqueous solution having zero Si concentration) to the etching solution tank 15B, and the Si solution tank 18 supplies the etching solution tank 15B. The Si solution is supplied to the Si tank so that the Si concentration of the high Si concentration phosphoric acid aqueous solution is adjusted and supplied to the inner tank 10a. The degree phosphoric acid aqueous solution supply source 16A may be Si concentration is supplied to the outer tub 10b as aqueous solution of phosphoric acid source of zero. Thereby, instead of using the high Si concentration phosphoric acid aqueous solution supplied from the outside of the apparatus, a desired high Si concentration phosphoric acid aqueous solution can be generated and used in the apparatus.

W Semiconductor wafer (object to be processed)
E Etching solution 10 Treatment vessel 10a Inner vessel 10b Outer vessel 11 Panel heater 12 Nozzle 15 Supply portion 15A Etching solution tank 15B Etching solution tank 16A High Si concentration phosphoric acid aqueous solution supply source 16B Low Si concentration phosphoric acid aqueous solution supply source 18 For Si solution Tank 19 Si solution supply source 20 Circulation line 21 Circulation pump 22 Temperature controller 23 Filter 26 Elution component measurement unit 27 Concentration measurement unit 30 Discharge line 40 DIW supply source 100 Controller 100a Storage medium

Claims (11)

An initial preparation step of filling the etching processing section with an etching solution;
An etching step of performing an etching process using an etchant on an object to be processed housed in the etching processing unit,
The initial preparation step includes a liquid supply step performed using a new etching solution having a first Si concentration,
The etching method includes a partial liquid exchanging process in which the etching liquid in the etching processing part is partially exchanged using a new etching liquid having a second Si concentration.   The new etching solution having the first Si concentration has a silicon concentration within a predetermined range in order to accurately etch the semiconductor wafer, and the new etching solution having the second Si concentration is higher than the new etching solution having the first Si concentration. 2. The etching method according to claim 1, wherein the Si concentration is low.   2. The etching according to claim 1, further comprising an interval step executed between the etching step and a next etching step of the object to be processed, wherein the interval step includes a whole liquid replacement step or a partial liquid replacement step. Method.   4. The etching method according to claim 3, wherein the whole liquid exchange step in the interval step includes a step of discharging the whole amount of the etching solution in the etching processing unit and then supplying a new etching solution into the etching processing unit. .   5. The partial liquid exchange step in the interval step includes a step of discharging the etching solution in the etching processing unit and simultaneously supplying a new etching solution into the etching processing unit. Etching method. In an etching apparatus that performs an etching process on a workpiece,
An etching processing unit that accommodates an object to be processed and performs an etching process with an etchant;
A discharge part for discharging the etching solution used in the etching process in the etching process part;
A supply unit for supplying a new etching solution to the etching processing unit;
A controller for driving and controlling the etching processing unit, the discharge unit, and the supply unit;
The supply unit includes a first supply unit that supplies a new etching solution having a first Si concentration, and a second supply unit that supplies a new etching solution having a second Si concentration,
The controller is
An initial preparation step of filling the etching processing section with an etching solution;
Performing an etching process for performing an etching process using an etchant on an object to be processed housed in the etching processing unit,
The initial preparation step includes a liquid supply step performed using a new etching solution having a first Si concentration supplied from the first supply unit,
Etching characterized in that the etching step includes a partial liquid exchange in which the etching liquid in the etching processing part is partially exchanged using a new etching liquid having a second Si concentration supplied from the second supply part. apparatus.   The new etching solution having the first Si concentration has a silicon concentration within a predetermined range in order to accurately etch the semiconductor wafer, and the new etching solution having the second Si concentration is higher than the new etching solution having the first Si concentration. The etching apparatus according to claim 6, wherein the Si concentration is low. Further comprising an interval step executed between the etching step and the etching process of the next object to be processed;
The etching apparatus according to claim 6, wherein the interval process includes a whole liquid replacement process or a partial liquid replacement process.   9. The etching according to claim 8, wherein the whole liquid exchange step in the interval step includes a step of discharging the whole amount of the etching solution in the etching processing unit and then supplying a new etching solution into the etching processing unit. apparatus.   10. The partial liquid exchange step in the interval step includes a step of discharging an etching solution in the etching processing unit and simultaneously supplying a new etching solution into the etching processing unit. Etching equipment. In a storage medium storing a computer program for causing a computer to execute an etching method,
Etching method
An initial preparation step of filling the etching processing section with an etching solution;
An etching step of performing an etching process using an etchant on an object to be processed housed in the etching processing unit,
The initial preparation step includes a liquid supply step performed using a new etching solution having a first Si concentration,
The storage medium includes a partial liquid exchanging process in which the etching liquid in the etching processing part is partially exchanged using a new etching liquid having a second Si concentration.

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