JP3035451B2 - Substrate surface treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing process, a liquid crystal display manufacturing process, an electronic component-related manufacturing process, and the like, for cleaning various substrates such as silicon wafers, glass substrates, and electronic components using a chemical solution. The present invention relates to a substrate surface treatment apparatus used for performing a surface treatment such as the above.

[0002]

2. Description of the Related Art When a substrate is subjected to a surface treatment, for example, a cleaning treatment using a chemical in a treatment tank, in a conventional cleaning treatment apparatus, a part of the chemical is circulated for effective use of the chemical. In order to obtain a high cleaning level, a fresh chemical solution is always supplied to the treatment tank and the used chemical solution is discharged as it is, or one of the methods has been adopted. A conventional apparatus configuration will be described below with reference to FIG.

A substrate cleaning apparatus schematically shown in FIG. 6A stores a cleaning solution 10 and stores the cleaning solution 10 therein.
The processing tank 12 includes an immersion processing section 14 in which the substrate W is immersed in the immersion processing section 10 and an overflow storage section 18 for storing a used chemical solution 16 overflowing from the immersion processing section 14. Processing tank 12
The prepared chemical solution 122 obtained by diluting the chemical solution 1 to an appropriate concentration with pure water is measured and supplied from the first quantitative tank 120 to the immersion processing unit 14, and the chemical solution 2 is supplied from the second quantitative tank 124. The prepared chemical solution 126 diluted to an appropriate concentration with pure water is measured and supplied. A part of the used chemical liquid 16 flowing out of the overflow storage part 18 of the treatment tank 12 is discharged through a drain pipe 128, and the remaining used chemical liquid is supplied to a pump 132 and a filter 134. It is configured to be returned to the immersion processing section 14 of the processing tank 12 through the inserted circulation pipeline 130. Reference numeral 136 in the figure is an opening / closing control valve.

[0006] Next, the substrate cleaning apparatus shown in FIG. 6B has a processing tank 12 similar to the apparatus shown in FIG. The supply of the cleaning chemical solution 10 to the section 14 is performed through an in-line mixer 138. In other words, a supply line for the chemical solution 1 which is connected to the first chemical solution tank 140 storing the chemical solution 1 and in which the pump 144, the filter 146, and the opening / closing control valve 148 are inserted.
142, a flow path connected to a second chemical liquid tank 150 in which the chemical liquid 2 is stored, a pump 154, a filter 156, and a supply pipe line 152 for the chemical liquid 2 interposed with an opening / closing control valve 158, and flowing to a pure water supply source. Pure water supply line 1 connected to the channel and inserted with the on-off control valve 162
Each of the mixers 138 is connected to the mixer 138, and the mixer 138 is configured to supply the cleaning chemical prepared by mixing the chemical 1, the chemical 2, and the pure water to the immersion processing unit 14 of the processing tank 12. ing. The used chemical liquid flowing out of the overflow storage section 18 of the processing tank 12 is entirely discharged as it is through the drain pipe 164.

The substrate cleaning apparatus shown in FIG. 6C has a substrate cleaning port 166 and a substrate output port 168. The substrate holding table 170 holding the posture, and the spray nozzles 172, 172 opposed to the upper and lower surfaces of the substrate W held by the substrate holding table 170, respectively, are disposed, and the substrate holding table 170 is rotated about a vertical axis. A drive mechanism 174 for rotationally driving is provided. Then, the spray nozzles 172, 172 in the processing tank 164 are provided by the cleaning chemical liquid supply system having the same configuration as that of FIG.
The cleaning liquid is supplied to the substrate W and the upper and lower surfaces of the substrate W are sprayed from the spray nozzles 172, 172 to clean the surface of the substrate W.
The used chemical liquid sprayed from the spray nozzle 172 onto the surface of the substrate W and used for cleaning the substrate W, and then flows down from the surface of the substrate W, as in the apparatus shown in FIG.
It is discharged as it is through the exhaust pipe 176.

[0006]

As shown in FIG. 6 (A), in a device for circulating and using a cleaning chemical, even if a filter 134 is inserted in a circulation line 130, the chemical in the chemical is not removed. Metal ions cannot be removed by filtration. For this reason, when substrates are sequentially processed in a batch system,
Metal ions and the like gradually accumulate in the cleaning chemical solution 10 in the processing tank 12, and as shown in FIG. 7A, (the contamination level of the substrate surface and the contamination level of the chemical solution differ in content and unit. Here, as the contamination level of the substrate surface, the contamination level of the substrate surface after immersing the substrate in the chemical solution for an infinite time when the contamination level of the chemical solution is a certain value is on the same vertical axis as the contamination level of the chemical solution. The same applies to FIGS. 7B and 7C, which will be described below, and FIG. 5. The time on the horizontal axis in the figures differs in scale between the figures.) Then, the degree of contamination of the cleaning solution 10 increases, and accordingly, the degree of contamination of the substrate surface also increases. As described above, there is a problem that a high cleaning level cannot be obtained with an apparatus that uses a cleaning chemical solution in a circulating manner. Then, before the cleaning level of the substrate after the cleaning processing becomes equal to or lower than the required level, in the illustrated example, at the time when the third batch is completed, all the cleaning chemicals 10 in the processing tank 12 must be replaced with fresh chemicals. .

On the other hand, as shown in FIGS. 6 (B) and 6 (C), in a device which discharges used chemical liquid as it is, the surface of the substrate always comes in contact with fresh chemical liquid.
As shown in FIG. 7B, the cleaning level is the same between the batches, and as shown in FIG. 7C, the cleaning level is the same between the substrates, so that a high cleaning level is always obtained. However, the apparatus shown in FIGS. 6B and 6C has a problem that a larger amount of chemical solution is consumed than the apparatus shown in FIG. 6A. Further, in the immersion type processing apparatus as shown in FIG. 6B, the contaminants removed from the surface of the substrate W in the processing tank 12 and diffused in the cleaning chemical solution 10 adhere to the surface of the substrate W again. In order to prevent this, it is effective to increase the flow rate of the cleaning chemical solution 10 flowing in the liquid surface direction along the surface of the substrate W. However, in such a case, the consumption of the chemical solution is further increased, and therefore, the flow rate (supply flow rate) of the cleaning chemical solution cannot be easily increased.

The present invention has been made in view of the above circumstances, and when a chemical solution is brought into contact with a substrate to perform a surface treatment such as a cleaning process on the substrate, the consumption of the chemical solution is suppressed, and It is an object of the present invention to provide a substrate surface treatment apparatus capable of obtaining high processing quality.

[0009]

[0010]

[0011]

In the apparatus for treating a surface of a substrate according to the first aspect of the present invention, two chemical liquid collecting means and two collected chemical liquid supplying means are provided. And
The supply switching means supplies fresh chemical liquid to the processing tank by the new liquid supply means, supplies the once-used recovered chemical liquid to the processing tank by the first recovered chemical liquid supply means, and performs the processing by the second recovered chemical liquid supply means In addition to alternately switching the supply of the used chemical solution to the tank twice, the discharge / collection switching means discharges the used chemical liquid by the chemical liquid discharge means and the used chemical liquid by the first chemical liquid collection means. The recovery of the used chemical liquid and the recovery of the used chemical liquid by the second chemical liquid recovery means are selectively switched, and the control means supplies the recovered chemical liquid used twice to the treatment tank by the second recovery chemical liquid supply means. The used chemical liquid is discharged by the chemical liquid discharging means, and then the first collected chemical liquid supplying means is supplied to the processing tank by the first recovered chemical liquid supplying means.
The used chemical liquid is supplied by the second chemical liquid collecting means, the used chemical liquid is supplied to the treatment tank by the new liquid supply means, and the used chemical liquid is supplied by the first chemical liquid collecting means. Is controlled to be collected.

In the apparatus for treating a surface of a substrate according to the second aspect of the present invention, n chemical liquid recovery means and n recovered chemical liquid supply means are provided. The supply switching means selectively switches between the supply of fresh chemical liquid to the processing tank by the new liquid supply means and the supply of recovered chemical liquid to the processing tank by the n recovered chemical liquid supply means. ,
The discharge / recovery switching means alternately switches between the discharge of the used chemical liquid by the chemical liquid discharge means and the collection of the used chemical liquid by the n chemical liquid recovery means, and the control means comprises n collected chemical liquid supply means. Supplying the used chemical liquid n times to the treatment tank by the nth one and discharging the used chemical liquid by the chemical liquid discharging means,
The (n-1) th collected chemical liquid supply means supplies the collected chemical liquid used (n-1) times to the treatment tank, and the used chemical liquid is collected by the nth chemical liquid collecting means, and then the used chemical liquid is collected. The (n-2) th used chemical liquid is supplied to the treatment tank by the (n-2) th collected chemical liquid supply means, and the used chemical liquid is collected by the (n-1) th chemical liquid collection means. It repeats in order, and finally controls the new chemical supply means to supply a fresh chemical liquid to the processing tank and collect the used chemical liquid used once by the first chemical liquid recovery means.

[0013]

In the apparatus for treating a surface of a substrate according to the first aspect of the present invention, an apparatus provided with two chemical liquid collecting means and two collected chemical liquid supplying means is used. Then, when the substrate is carried into the processing tank, first, the substrate is repeatedly used twice in the cleaning process of the substrate, and the substrate is cleaned using a chemical solution containing a contaminant, and then used once in the cleaning of the substrate. The substrate is cleaned using a chemical having a smaller amount of contaminants than the chemical, and finally the substrate is cleaned using a fresh chemical containing no contaminants. In the substrate surface treating apparatus according to the second aspect of the present invention, an apparatus provided with n chemical liquid collecting means and n collected chemical liquid supplying means is used. Then, when the substrate is carried into the processing tank, first,
The substrate is washed using the chemical solution containing the most contaminants, which is repeatedly used n times for the substrate cleaning process, and thereafter, the substrate is sequentially washed using each of the collected chemical solutions in which the amount of the contaminants gradually decreases. Finally, the substrate is cleaned using a fresh chemical solution that does not contain any contaminants.

As described above, according to the first and second aspects of the present invention, since the substrate is finally cleaned with a fresh chemical solution, high cleaning processing quality can be obtained. Also,
The chemical solution is not discharged only after being used once,
Since it is collected and used several times and then discharged,
The consumption of the chemical solution is smaller than the device that discharges the used chemical solution as it is, and in the immersion treatment device,
Even if the flow rate of the chemical in the processing tank is increased to prevent the re-adhesion of the contaminant to the substrate surface or to shorten the time required for the processing by improving the effect of removing the contaminant, the consumption of the chemical may be reduced. There is no increase.

[0015]

Preferred embodiments of the present invention will be described below with reference to the drawings.

[0016]

FIG. 1 shows an embodiment of the present invention, and is a schematic configuration diagram of a batch type immersion processing type substrate cleaning apparatus. This device, similar to the device shown in FIGS. 6A and 6B, stores the cleaning chemical 10
The processing tank 12 includes an immersion processing section 14 in which the substrate W is immersed, and an overflow storage section 18 for storing a used chemical solution 16 overflowing from the immersion processing section 14.
Further, a fresh chemical solution is prepared, and the immersion treatment section 1 of the treatment tank 12 is prepared.
The new liquid supply system for supplying to No. 4 is shown in FIG.
Similarly to the device shown in FIG.
Are connected to the pump 26, the filter 28 and the supply conduit 24 of the chemical liquid 1 through which the opening / closing control valve 30 is inserted, and the second chemical liquid tank 32 in which the chemical liquid 2 is stored. Pump 36, filter 38 and on / off control valve 4
0 is connected to the mixer 20, and the supply line 34 of the chemical solution 2 in which the zero is inserted, and the pure water supply line 42 in which the flow path is connected to the pure water supply source and the opening / closing control valve 44 is inserted are connected to the mixer 20, respectively. In the mixer 20, the chemical 1, the chemical 2 and pure water are mixed, or the chemical 1 or the chemical 2 and pure water are mixed to dilute the cleaning chemical, and the cleaning chemical is removed from the mixer 20 to the treatment tank 12. It is configured to supply to. Reference numeral 46 in the figure denotes an open / close control valve.

On the other hand, an outflow pipe 48 connected to the overflow storage section 18 of the processing tank 12 is connected to an inlet of a discharge / recovery switch 50, and is connected to an inlet of the discharge / recovery switch 50. One of the outlets is connected to a drain pipe 52 through which an open / close control valve 54 is inserted. Another outlet of the discharge / collection switching device 50 is connected to a first collection tank 60 via a first collection line 56 in which an opening / closing control valve 58 is inserted. The outlet is a second recovery pipe 64 in which the opening / closing control valve 66 is inserted.
Is connected to the second collection tank 68 via the First
As will be described later, the recovery chemical solution 62 collected after being used once for the substrate cleaning process in the processing tank 12 is stored in the recovery tank 60, and the second recovery tank 68 stores
In the processing tank 12, the recovered chemical solution 70 that has been used after being repeatedly used for cleaning the substrate twice is stored.

Further, inside the first recovery tank 60,
One end of a first recovered chemical supply pipe 72 in which a pump 74 and a filter 76 are inserted is inserted. The other end of the recovered chemical supply pipe 72 is connected to a supply switch 80 via an open / close control valve 78. Is connected to one of the inlets. Further, one end of a second collected chemical supply pipe 82 in which a pump 84 and a filter 86 are interposed is inserted into the second collection tank 68, and the one end of the collected chemical supply pipe 82 is inserted into the second collected tank 68. The other end is connected to another inlet of the supply switch 80 via the open / close control valve 88.
The still another inlet of the feed switch 80 is provided with the above-described mixer.
The ends of the 20 outlet-side pipes 90 are connected to each other via an open / close control valve 92. The outlet of the supply switch 80 is connected to the immersion processing section 14 of the processing tank 12 via a liquid supply pipe 94.

The mixer 20 and the opening / closing control valves 30, 40, 44, and the supply switching unit 80 and the opening / closing control valves 78, 88, 92 are respectively constituted, for example, as shown in a sectional view in FIG. The discharge / recovery switching device 50 and the open / close control valves 54, 58, 66 are configured, for example, as shown in a sectional view in FIG. And, the respective open / close control valves 30, 40, 44, 78, 88, 92, 54, 58,
66 includes valve bodies 96, 104, 112, valve seats 98, 106, 114, diaphragms 100, 108, 116, and air cylinders 102, 110, 118.
2, 110, and 118 are configured to be controlled by a control circuit (not shown).

Next, a description will be given, with reference to FIG. 4, of an operation in a case where the substrate is cleaned by using the apparatus shown in FIG.

As shown in FIG. 4A, in the state where the recovered chemicals 62 and 70 are stored in the first recovery tank 60 and the second recovery tank 68, respectively, When a plurality of substrates W to be cleaned are carried in,
First, the open / close control valves 88 and 54 are opened and the open / close control valve 7 is opened.
4, 92, 58, and 66 are closed to allow the substrate to be cleaned in the processing tank 12 from the second recovery tank 68 to the processing tank 12, as indicated by solid arrows in FIG. Supplying the collected chemical solution 70 that has been used after being repeatedly used twice and supplying the used chemical solution that has flowed out of the processing tank 12 to an outflow line
The liquid is discharged to the outside of the device through the drain line 48 and the drain line 52. In this manner, the substrate W is cleaned using the twice-used collected chemical solution 70. Next, by opening and closing the opening and closing control valves 78 and 66 and closing the opening and closing control valves 88, 92, 54 and 58, as shown by the solid line arrow in FIG.
From 60 to the processing tank 12, the collected chemical solution 62 used only once in the processing tank 12 for the substrate cleaning process is supplied and collected, and the used chemical solution flowing out of the processing tank 12 is discharged from the processing tank 12.
48 and a second collection tank 68 through a second collection line 64.
Collect inside. In this way, the once-used collected chemical solution 62
The substrate W is subjected to a cleaning process by using. Finally, the opening / closing control valves 92, 58 are opened, and the opening / closing control valves 78, 88, 5
4 and 66, a fresh chemical solution containing no contaminants is supplied from the mixer 20 to the processing tank 12 as shown by a solid line arrow in FIG.
The used chemical liquid flowing out of the tank is recovered into the first recovery tank 60 through the outflow line 48 and the first recovery line 56. In this manner, the substrate W is cleaned using the fresh cleaning solution.

When one cleaning process is completed, the processed substrate W is unloaded from the processing bath 12 and a plurality of substrates W to be processed next are loaded into the processing bath 12. Then, the above operation is repeated.

When the cleaning process of the substrate W is performed as described above, the degree of contamination of the substrate surface gradually decreases as shown in FIG. Is performed, so that a high cleaning process quality is obtained, and a high cleaning level is equally obtained between batches. In addition, since the chemical is discharged after being used three times in the cleaning process of the substrate, the chemical is effectively used.

In the above embodiment, two recovery tanks for recovering used chemicals are provided. However, only one recovery tank may be provided. After the substrate is loaded, supply the used chemical liquid once from the recovery tank to the processing tank, discharge the used chemical liquid from the processing tank, and then supply fresh chemical liquid to the processing tank. Collect used chemicals flowing out of the tank into the collection tank. Further, n or more recovery tanks may be provided. In this case, when the substrate is carried into the processing tank, first,
From the n-th recovery tank, the recovered chemical liquid repeatedly used n times for the substrate cleaning process is supplied to the processing tank, and the used chemical liquid is discharged from the processing tank. The recovery chemical used in the cleaning process of the substrate from the tank (n-1) is supplied to the processing tank, and the used chemical is recovered from the processing tank into the n-th recovery tank, and then (n-2) ) The recovery chemical solution used (n-2) times for the substrate cleaning process from the recovery tank is supplied to the processing tank, and the used chemical liquid is transferred from the processing tank into the (n-1) th recovery tank. The same operation is repeated afterwards, and finally, a fresh chemical is supplied to the treatment tank,
The used chemical liquid flowing out of the processing tank is collected into the first collection tank.

Further, in the above-described embodiment, a description has been given of the substrate cleaning processing apparatus of the batch type immersion processing method, but various types of the sheet type immersion processing method or the sheet type spray processing method as shown in FIG. The present invention can be similarly applied to the substrate surface treatment apparatus described above. Further, as a method of supplying a fresh chemical solution to the treatment tank, instead of a method using an in-line mixer as shown in the above embodiment, a quantitative tank is used as shown in FIG. A method of quantifying the chemical solution in advance may be used. Further, the means for supplying the recovered chemical liquid from the recovery tank to the processing tank may be pump pressure feeding as in the above embodiment, or may be a means for pressurizing the liquid surface of the recovered chemical liquid in the recovery tank.

[0026]

Since the present invention is constructed and operates as described above, the substrate surface treatment apparatus according to the first and second aspects of the present invention is used to bring a chemical solution into contact with the substrate. When surface treatment such as substrate cleaning is performed, the consumption of chemicals is greatly reduced compared to equipment that discharges used chemicals as it is, and it is possible to use chemicals that circulate and use chemicals. Higher processing quality can be obtained. And especially in the immersion type substrate cleaning apparatus,
Since the flow rate of the cleaning chemical flowing along the surface of the substrate in the processing tank can be increased without increasing the consumption of the chemical, the contaminants removed from the substrate surface and diffused in the cleaning chemical can be increased. Redeposition on the substrate surface can be effectively prevented, and a higher cleaning level can be obtained. On the other hand, when the same cleaning level is obtained, throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a batch type immersion processing type substrate cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a configuration of a mixer and a feed switch used in the apparatus shown in FIG.

FIG. 3 is a cross-sectional view showing an example of a configuration of a discharge / recovery switching device used in the apparatus shown in FIG.

FIG. 4 is a schematic diagram for explaining an operation when a substrate cleaning process is performed using the apparatus shown in FIG. 1;

FIG. 5 is a graph for explaining changes over time in the contamination level of the substrate surface and the contamination level of the chemical solution when the substrate is cleaned using the apparatus shown in FIG. 1;

FIG. 6 is a schematic diagram showing a configuration example of a conventional substrate cleaning apparatus.

FIG. 7 is a graph for explaining changes over time in the contamination level of the substrate surface and the contamination level of the chemical solution when the substrate is cleaned by using the conventional apparatuses shown in FIG. 6; FIG.

[Explanation of symbols]

 10 Chemical solution for cleaning 12 Treatment tank 14 Immersion treatment section of treatment tank 16 Used chemical liquid 18 Overflow storage section of treatment tank 20 Mixer 22, 32 Chemical tank 24, 34 Chemical supply line 26, 36, 74, 84 Pump 30, 40, 44, 54, 58, 66, 78, 88, 92 On-off control valve 42 Pure water supply line 48 Outflow line 50 Drain / recovery switch 52 Drainage line 56 First recovery line 60 One collection tank 62 Single-use collected chemical 64 Second collection conduit 68 Second collection tank 70 Double-used collected chemical 72 First collected chemical supply conduit 80 Supply switch 82 Second Recovery chemical supply line 94 Liquid supply line W Substrate

Continuation of the front page (56) References JP-A-62-156659 (JP, A) JP-A-2-278823 (JP, A) JP-A-3-32417 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H01L 21 / 304,21 / 306 B08B 3/00-3/14

Claims (2)

(57) [Claims] 1. A processing tank for receiving a substrate and bringing a chemical solution into contact with the substrate to perform a surface treatment on the substrate, a new liquid supply means for supplying a fresh chemical liquid to the processing tank, And a chemical solution discharging means for discharging a used chemical solution used for surface treatment and flowing out of the processing tank, wherein the chemical solution discharging means is used for surface processing of the substrate in the processing tank and flows out of the processing tank. First chemical liquid collecting means for collecting the used chemical liquid in the first recovery tank, and a first recovery chemical liquid supply for supplying the single-use recovery chemical liquid collected in the first recovery tank to the processing tank. Means for collecting used chemical liquid supplied to the processing tank by the first recovered chemical liquid supply means, used for the surface treatment of the substrate in the processing tank, and flowing out of the processing tank to the second recovery tank. 2 chemical liquid collecting means, A second recovery chemical liquid supply unit that supplies the twice-used recovered chemical liquid collected in the second recovery tank to the processing tank; and a fresh chemical liquid supply to the processing tank by the new liquid supply unit. The supply of the single-use collected chemical liquid to the processing tank by the first collected chemical liquid supply unit and the supply of the twice-used collected chemical liquid to the processing tank by the second collected chemical liquid supply unit are selectively switched. Supply switching means, discharging of used chemical liquid by the chemical liquid discharging means, and the first
Discharge / collection switching means for selectively switching between the collection of the used chemical liquid by the chemical liquid collecting means and the collection of the used chemical liquid by the second chemical liquid collecting means, and the processing tank by the second collected chemical liquid supply means And supplying the used chemical liquid to the treatment tank by the first collected chemical liquid supply means and supplying the used chemical liquid to the treatment tank by the first collected chemical liquid supply means. The used chemical liquid is collected by the chemical liquid collecting means, and finally the fresh chemical liquid is supplied to the treatment tank by the new liquid supply means and the supply switching is performed so as to collect the used chemical liquid by the first chemical liquid collecting means. And a control means for controlling the discharge / collection switching means. 2. A processing tank for accommodating a substrate and surface-treating the substrate by bringing a chemical liquid into contact with the substrate, a new liquid supply means for supplying a fresh chemical liquid to the processing tank, And a chemical solution discharging means for discharging a used chemical solution used for surface treatment and flowing out of the processing tank, wherein the chemical solution discharging means is used for surface processing of the substrate in the processing tank and flows out of the processing tank. N (n is an integer of 3 or more) chemical liquid collecting means for collecting the used chemical liquids into the respective collecting tanks for each use, and supplying the collected chemical liquids collected in the respective collecting tanks to the processing tank. n recovery chemical liquid supply means, and alternatively switching between supply of fresh chemical liquid to the processing tank by the new liquid supply means and supply of recovery chemical liquid to the processing tank by the n recovery chemical liquid supply means. Supply switcher Discharge / recovery switching means for selectively switching between the discharge of the used chemical liquid by the chemical liquid discharge means and the collection of the used chemical liquid by the n chemical liquid recovery means; and The n-th supply supplies the used chemical solution to the treatment tank n times and discharges the used chemical solution by the chemical solution discharging means. Then, the (n-1) th collected chemical solution supply means supplies (n- 1) Supply the used chemical solution once and use the above n
The used chemical liquid is collected by the nth one of the individual chemical liquid collecting means, and then the (n-2) th collected chemical liquid supply means supplies the used chemical liquid (n-2) times to the treatment tank ( The used chemical liquid is collected by the (n-1) th chemical liquid collecting means, and the above operation is repeated in order. Finally, a fresh chemical liquid is supplied to the treatment tank by the new liquid supply means and the first chemical liquid collecting means is used. A surface treatment apparatus for a substrate, further comprising control means for controlling the supply switching means and the discharge / collection switching means so as to collect used chemical liquid.