JPH11102887A - Substrate processing vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a processing solution from flowing downward from its level and to improve nonuniformity in flow velocity distribution. SOLUTION: A processing solution is supplied from processing solution supply sections 9 provided on both sides of the bottom of a vessel body 1, so that the solution flows into the lower side of the center of a substrate 2 that is arranged in a vertical position within the body 1. Streams of the supplied solution are caused to join at the lower side of the center of the substrate 2, and then flow upwards to thereby immerse the substrate 2 in the processing solution, or flow upwards along the substrate immersed in the processing solution. Processing solution discharge pipes 14, each of which extends along the length of the vessel body 1, are provided on both sides of the upper portion of the body 1, and a slit 15 for sucking the processing solution is formed in each pipe 14. A processing solution discharge pipeline 16 having a second pump 17 is connected to the pipes 14, and the processing solution in the body 1 is forcibly discharged while causing a controller 21 to effect such a control that the amount of processing solution supplied to the body 1 matches with the amount of processing solution discharged, thereby preventing the processing solution from returning towards the substrate 2, moreover suppressing flow velocity differences between above and below the substrate 2, making the flow velocity distribution uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer, a glass substrate for liquid crystal, a substrate for manufacturing electronic parts such as a mask and a photomask, and the like. And a substrate processing tank for processing the substrate by immersing the substrate in a processing liquid.

[0002]

2. Description of the Related Art This type of substrate processing tank is conventionally generally constructed as shown in a cross-sectional view of FIG. That is, the processing liquid supply pipes 02 are provided on both sides of the bottom of the tank main body 01, and the processing liquid is supplied toward the center side of the tank main body 01, such as downward, at a predetermined interval in the longitudinal direction of the processing liquid supply pipe 02. A supply slit 03 is provided, a processing liquid is supplied into the tank main body 01, and the substrate 04 stored in a vertical posture is immersed in the processing liquid for processing.

The processing liquid supplied from both sides of the bottom into the tank body 01 joins below the center of the substrate 04 and rises along the plate surface of the substrate 04 from there.
The liquid overflows toward the upper outer peripheral edge of the tank body 01 at the liquid level, flows into the overflow tank 05, and is discharged.

[0004]

However, in the case of the prior art, some of the processing liquid that has reached the upper outer peripheral edge of the tank main body 01 at the liquid level does not overflow, but rather remains on the inner peripheral surface of the vertical wall of the tank main body 01. There was a problem of flowing downward along. As a result, there are drawbacks in that particles separated from the substrate 04 are mixed in, the gas is dissolved at the liquid surface portion, or the processing liquid containing the bubbles and particles acts on the substrate 04, thereby causing contamination of the substrate 04.

[0005] Further, the viscous resistance received from the substrate 04 is large at the portion flowing along the substrate 04, and the flow resistance at the portion flowing along the substrate 04 is determined by the edge of the substrate 04 and the tank body 01.
Therefore, the processing liquid that rises from the lower side of the center of the substrate 04 becomes a flow branched to the vertical wall side of the tank body 01 having low resistance. The flow rate of the processing liquid at a location flowing along the substrate 04 decreases. As a result, a difference in flow velocity occurs between the upper side and the lower side of the substrate 04, and the flow velocity distribution of the processing liquid over the entire substrate 04 becomes non-uniform.
When changing the type, such as chemical to pure water or pure water to chemical, or when transferring and processing substrates from a chemical tank to a pure water rinsing tank or a pure water rinsing tank to the chemical tank, the replacement time is reduced. As a result, the amount of the chemical solution or pure water used increases, which is uneconomical.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to prevent a processing liquid from flowing downward from a liquid level and to improve non-uniformity of flow velocity distribution. .

[0007]

The present invention has the following configuration in order to achieve the above object. That is, the invention according to claim 1 includes a tank body for immersing a substrate stored in a vertical posture with a processing liquid, a processing liquid supply unit for supplying a processing liquid to the substrate stored in the tank body. In the substrate processing tank provided with, the processing liquid supply unit is provided on each of both sides of the bottom of the tank body, and along the plate surface of the substrate and toward the center of the substrate or a lower side thereof. And a forcible discharge mechanism for sucking and discharging the processing liquid supplied from the processing liquid supply unit at an upper portion of the tank main body.

[0008] The invention described in claim 2 is the first invention.
Wherein the forcible discharge mechanism comprises a processing liquid discharge section provided on both sides of the upper portion of the tank main body, and a pump connected to the processing liquid discharge section to apply a suction force. is there.

[0009] The invention described in claim 3 is the first invention.
In the substrate processing tank described in the above, a forced discharge mechanism is connected to the processing liquid discharge unit provided at an upper part of the tank main body, at a position above the center of the substrate housed in the tank main body, and the processing liquid discharge unit. And a pump for applying suction force.

[0010] Further, the invention according to claim 4 is based on claim 2.
Alternatively, in the substrate processing tank according to claim 3, a supply amount measuring unit that measures a supply amount of the processing liquid supplied from the processing liquid supply unit, and measures a discharge amount of the processing liquid discharged from the processing liquid discharge unit. Discharge amount measuring means, and discharge of the pump based on the discharge amount of the processing liquid measured by the discharge amount measuring means such that the discharge amount becomes equal to the supply amount of the processing liquid measured by the supply amount measuring means. Pump control means for controlling the amount.

The invention described in claim 5 is the same as the invention described in claim 2.
Alternatively, in the substrate processing tank according to claim 3, a supply amount measuring unit that measures a supply amount of the processing liquid supplied from the processing liquid supply unit, and measures a discharge amount of the processing liquid discharged from the processing liquid discharge unit. Discharge amount measuring means, a flow control valve provided between the processing liquid discharge section and the pump to adjust the discharge amount of the processing liquid, and based on the discharge amount of the processing liquid measured by the discharge amount measuring means, Flow rate control means for controlling the opening degree of the flow control valve so that the discharge amount is equal to the supply amount of the processing liquid measured by the supply amount measurement means.

[0012]

The operation of the present invention is as follows. That is,
According to the first aspect of the present invention, the processing liquid supplied from the processing liquid supply units provided on both sides of the bottom of the tank main body is forcibly discharged from the upper part of the tank main body by the forced discharge mechanism so as not to generate a downward flow. To prevent the processing liquid from flowing from the upper part of the tank body back to the substrate side. Also,
By forcibly discharging by the forcible discharge mechanism,
The flow velocity at the upper part of the tank body can be made faster than that by the conventional overflow, and the high velocity makes the flow velocity above the substrate faster, thereby suppressing the flow velocity difference above and below the substrate and making the flow velocity distribution uniform.

Further, according to a second aspect of the present invention, a suction force of a pump is applied to the processing liquid which is raised along the substrate to the upper part of the tank body, and the processing liquid is discharged from the processing liquid discharge portions on both sides of the upper part of the tank body. The treatment liquid is forcibly discharged to prevent the processing liquid from flowing from the upper part of the tank body back to the substrate side. In addition, the flow velocity of the processing liquid discharged from the processing liquid discharge section is increased by the flow of the processing liquid discharged from the processing liquid discharge section, so that the flow velocity difference above and below the substrate is suppressed, and the flow velocity distribution is made uniform.

According to a third aspect of the present invention, the processing liquid raised to the upper portion of the tank body along the substrate is provided with a suction force of a pump, and the upper portion of the tank body is located above the center of the substrate. The processing liquid is forcibly discharged from the processing liquid discharge section, thereby preventing the processing liquid from flowing from the upper portion of the tank body back to the substrate side. In addition, the flow velocity of the processing liquid discharged from the processing liquid discharge section is increased by the flow of the processing liquid discharged from the processing liquid discharge section, so that the flow velocity difference above and below the substrate is suppressed, and the flow velocity distribution is made uniform.

According to a fourth aspect of the present invention, the discharge amount of the pump is controlled by the pump control means to control the forced discharge amount of the processing liquid from the processing liquid discharge section, and the tank body is controlled by the processing liquid supply section. The same amount of processing liquid as the processing liquid supplied to the inside is discharged from the processing liquid discharge unit.

According to a fifth aspect of the present invention, the opening degree of a flow control valve provided between the processing liquid discharge section and the pump is controlled by a flow control means so that the processing liquid from the processing liquid discharge section is controlled. The forced discharge amount is controlled, and the same amount of processing liquid as the processing liquid supplied from the processing liquid supply unit into the tank body is discharged from the processing liquid discharge unit.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of a substrate processing tank according to the present invention, and FIG. 2 is a plan view of the first embodiment. As shown in FIGS. 1 and 2, the substrate processing tank includes a tank main body 1 and a lifter 3 that stores and removes the substrate 2 in and from the tank main body 1.

The lifter 3 integrally connects three substrate holding members 5 in which substrate holding grooves 4 for holding the substrate 2 in a vertical posture are formed at a predetermined pitch in the longitudinal direction, and one longitudinal end of the substrate holding members 5. A connecting member 6 to be connected, a substrate elevating member 7 integrally connected to the other end of the substrate holding member 5 in the longitudinal direction, and an elevating device 8 installed outside the tank body 1 and connected to the substrate elevating member 7 in an interlocked manner. It is configured.

Inside the tank body 1, a processing liquid supply section 9 made of a double quartz tube is provided on both sides of the bottom thereof, and a processing liquid supply pipe 10 is connected to the processing liquid supply section 9. The first pump 11 and the first pump 11
Is provided. Although not shown, the processing liquid supply pipe 10 can selectively supply a chemical liquid such as an etching liquid or pure water as a processing liquid by a switching configuration on the upstream side. Then, when it is necessary to change the supply amount of the processing liquid into the tank body 1 according to the type of the processing liquid, the supply amount is adjusted by the first flow control valve 12.

An outer tube 9a constituting the processing liquid supply unit 9 includes:
In a plan view, a slit 13 is formed so as to supply the processing liquid downward at a predetermined pitch in the tube axis direction so as to be located between the substrates 2 arranged in parallel. As a result, the processing liquid is supplied from the processing liquid supply units 9 on both sides toward the lower side of the center of the substrate 2, and the supplied processing liquids join at the lower side of the center of the substrate 2, and then upward. The substrate 2 is immersed in the processing liquid or flows upward along the substrate immersed in the processing liquid.

A processing liquid discharge pipe 14 extending in the longitudinal direction of the tank main body 1 is provided on both sides of the upper part of the tank main body 1. The processing liquid discharge pipe 14 is located between the parallel substrates 2 in plan view. In order to discharge the processing liquid supplied from the processing liquid supply unit 9 and raised along the substrate 2, the processing liquid discharge unit is formed with slits 15 for sucking the processing liquid at a predetermined pitch in the pipe axis direction. Is configured.

The processing liquid discharge pipe 14 is connected to the processing liquid discharge pipe 16.
Is connected to the second pump 1
7 is provided, and a forced discharge mechanism is configured to forcibly discharge the processing liquid in the tank body 1.

The processing liquid supply pipe 10 is provided with a first flow meter 18 as a supply amount measuring means for measuring the supply amount of the processing liquid supplied from the processing liquid supply unit 9. Further, a second flow meter as a discharge amount measuring means for measuring a discharge amount of the processing liquid discharged from the processing liquid discharge section between the processing liquid discharge section of the processing liquid discharge pipe 16 and the second pump 17. 19,
A second flow control valve 20 is provided.

The first and second flow meters 18 and 19 are connected to a controller 21 as flow control means, and the controller 21 and the second flow control valve 20 are connected.

In the controller 21, the first flow meter 18
Is compared with the discharge amount of the processing liquid measured by the second flow meter 19, and the second flow rate is set so that the discharge amount of the processing liquid becomes equal to the supply amount of the processing liquid. Regulating valve 20
The opening degree is controlled.

With the above arrangement, the suction force of the second pump 17 is applied to the substrate 2 while the supply amount of the processing liquid into the tank body 1 and the discharge amount of the processing liquid from the tank body 1 are matched. The processing liquid raised along the upper part of the tank body 1 is forcibly discharged from the processing liquid discharge pipes 14 on both sides of the upper part of the tank body 1,
The processing liquid is prevented from flowing from the upper part of the tank body 1 back to the substrate 2 side. Also, forcibly discharge the processing liquid,
The flow velocity difference between the upper and lower surfaces of the substrate 2 is suppressed, the flow velocity distribution is made uniform, and the processing time of the processing liquid is shortened.

FIG. 3 is a cross-sectional view showing a second embodiment of the substrate processing tank according to the present invention. The difference from the first embodiment is as follows.

That is, a processing liquid discharge pipe 31 is provided at an upper portion of the tank main body 1 above the center of the substrate 2 accommodated in the tank main body 1 over the entire length of the tank main body 1 in the longitudinal direction. On both sides of the pipe 31 facing in the horizontal direction, slits 32 for sucking the processing liquid are formed at a predetermined pitch in the pipe axis direction so as to be located between the parallel substrates 2 in plan view. The processing liquid discharging unit is configured to discharge the processing liquid supplied from the unit 9 and raised along the substrate 2. The other configuration is the same as that of the first embodiment, and the description is omitted by attaching the same figure number.

Although not shown, the processing liquid discharge pipe 31
As in the embodiment, a processing liquid discharge pipe is connected, and a pump is provided in the processing liquid discharge pipe.
A forcible discharge mechanism is configured to forcibly discharge the processing liquid therein. Further, a flow rate control means similar to that of the first embodiment is provided, and the discharge amount of the processing liquid from the inside of the tank body 1 is controlled so as to be equal to the supply amount of the processing liquid into the tank body 1. ing.

According to the configuration of the second embodiment, since the suction force is applied to the processing liquid at a position above the center of the substrate 2, the resistance which rises along the center of the substrate 2 and a position near the center thereof is most affected. The flow can be discharged so as to be drawn in, the flow velocity difference between the top and bottom of the substrate can be effectively reduced, and the flow velocity distribution can be made uniform.

FIG. 4 is a cross-sectional view showing a third embodiment of the substrate processing tank according to the present invention. As in the second embodiment, the substrate processing tank is placed in the tank main body 1 above the tank main body 1. A first processing liquid discharge pipe 41 is provided above the center of the substrate 2 over the entire length of the tank body 1 in the longitudinal direction, and both sides of the first processing liquid discharge pipe 41 facing in the horizontal direction are viewed in plan. In the first slit 42, the processing liquid is sucked at a predetermined pitch in the tube axis direction so as to be located between the substrates 2 arranged in parallel.
Are formed.

In addition to the above configuration, a second processing liquid discharge pipe 43 is provided at each of the upper portions of the vertical walls on both sides of the tank main body 1 over the entire length of the tank main body 1 in the longitudinal direction. On each side of the discharge pipe 43 facing the horizontal direction,
In a plan view, the second processing liquid is sucked at a predetermined pitch in the tube axis direction so as to be located between the substrates 2 arranged in parallel.
Is formed.

Further, a third processing liquid discharge pipe 45 is provided at each of the uppermost portions of the vertical walls on both sides of the tank main body 1 over the entire length in the longitudinal direction of the tank main body 1. Third slits 46 for sucking the processing liquid at predetermined pitches in the tube axis direction so as to be located between the substrates 2 arranged in parallel in plan view on both sides facing in the horizontal direction.
Are formed.

The first processing liquid discharge pipe 41 is connected to a first processing liquid discharge pipe 48 provided with a third flow control valve 47, and the second processing liquid discharge pipe 43 is connected to a first processing liquid discharge pipe 43. The fourth processing liquid discharge pipe 50 provided with the fourth flow control valve 49 is connected to the third processing liquid discharge pipe 45, and the third processing liquid discharge pipe 45 provided with the fifth flow control valve 51 is connected to the third processing liquid discharge pipe 45. A pipe 52 is connected. First, second and third processing liquid discharge pipes 4
8, 50 and 52 are connected to the processing liquid discharge pipe 16 provided with the second pump 17.

The third, fourth and fifth flow control valves 47,
49 and 51 are set so that the opening degree becomes smaller in that order, and apply the largest suction force to the first treatment liquid discharge pipe 41 and the smallest suction force to the third treatment liquid discharge pipe 45. It has become. In the third embodiment, the third
May be omitted.

The processing liquid supply section 9 is formed by the first, second and third processing liquid discharge pipes 41, 43 and 45 and the first, second and third slits 42, 44 and 46 described above.
A processing liquid discharge unit configured to discharge the processing liquid supplied along with the substrate 2 and rising along the substrate 2 is configured.

The first, second and third processing liquid discharge pipes 48, 50 and 52, the processing liquid discharge pipe 16,
In addition, a forced discharge mechanism for forcibly discharging the processing liquid in the tank body 1 by the second pump 17 is configured.

The processing liquid supply pipe 10 is provided with a first flow meter 18 as a supply amount measuring means for measuring the supply amount of the processing liquid supplied from the processing liquid supply section 9. Further, the connection point of the processing liquid discharge pipe 16 with the first, second, and third processing liquid discharge pipes 48, 50, 52 and the second pump 17.
A second flow meter 19 is provided as a discharge amount measuring means for measuring the discharge amount of the processing liquid discharged from the processing liquid discharge section.

The first and second flow meters 18 and 19 are connected to a controller 21 as flow control means, and the controller 21 and the third, fourth and fifth flow regulating valves 47, 49 and 51 are connected to each other. It is connected.

In the controller 21, the first flow meter 18
Is compared with the discharge amount of the processing liquid measured by the second flow meter 19, and the third and the third are set so that the discharge amount of the processing liquid becomes equal to the supply amount of the processing liquid. 4th and 5th
Of the flow control valves 47, 49, and 51 are proportionally controlled. The other configuration is the same as that of the second embodiment, and the description thereof will be omitted by retaining the same reference numerals.

With the above structure, the suction force of the second pump 17 is applied to the substrate 2 while the supply amount of the processing liquid into the tank body 1 and the discharge amount of the processing liquid from the inside of the tank body 1 are matched. The processing liquid raised along the upper portion of the tank body 1 along the tank body 1
The first and second processing liquid discharge pipes 43 and 45 are also arranged around the first processing liquid discharge pipe 41 above the center of the substrate 2 accommodated in the tank main body 1 at the top. The processing liquid is forcibly discharged to prevent the processing liquid from flowing from the upper part of the tank body 1 back to the substrate 2 side. In addition, the processing liquid is forcibly discharged to suppress the flow velocity difference between the upper and lower surfaces of the substrate 2 and to make the flow velocity distribution uniform, thereby shortening the processing time for replacing the processing liquid.

Instead of the flow control means in the above embodiment, for example, a variable discharge type pump is used as the second pump 17, based on the discharge amount of the processing liquid measured by the second flow meter 19. A pump control means configured to control the discharge amount of the pump so that the discharge amount is equal to the supply amount of the processing liquid measured by the first flow meter 18 may be used.

In the above embodiment, the substrate 2 is stored in or taken out of the tank main body 1 by the lifter 3. However, the present invention provides, for example, a cassette in which the substrate is stored in the tank main body 1. It may be housed in a container and immersed. Also, the present invention can be applied to a case where the substrates are immersed one by one.

In the above embodiment, the processing liquid is supplied from the processing liquid supply unit 9 so as to be directed downward below the center of the substrate 2 housed in the tank body 1 in a vertical posture.
The processing liquid may be supplied so as to be directed toward the center of the processing liquid.

In the above-described embodiment, the processing liquid discharge section is formed at a predetermined pitch in the tube axis direction so as to be located between the parallel substrates 2 in plan view. Slits 15, 3 on 14, 31, 41, 43, 45
Although 2, 42, 44 and 46 are formed, they may be formed so as to extend over the entire length toward the tube axis direction to constitute the processing liquid discharge section.

[0046]

As is apparent from the above description, according to the first aspect of the present invention, the processing liquid supplied from the processing liquid supply units provided on both sides of the bottom of the tank main body is used. Since it is sucked and discharged at the upper part, particles removed from the substrate may be mixed in, the gas may be dissolved at the liquid level, or the processing liquid containing the bubbles or particles may act on the substrate to contaminate the substrate. Can avoid
Processing quality can be improved. In addition, the processing liquid is forcibly discharged by the forcible discharge mechanism to suppress the flow velocity difference between the top and bottom of the substrate and to make the flow velocity distribution uniform, so that a type of liquid such as chemical to pure water or pure water to chemical is used. When replacing with a different processing solution, or when transferring and processing a substrate from a chemical bath to a pure water rinsing bath or from a pure water rinsing bath to a chemical bath, the replacement processing time can be shortened, and the amount of processing solution used can be reduced. It is possible to reduce the cost, improve the economic efficiency, and improve the processing efficiency to increase the productivity.

According to the second aspect of the present invention, the processing liquid is forcibly discharged from the processing liquid discharge portions on both sides of the upper part of the tank body by the suction force of the pump, and the processing liquid is removed from the upper part of the tank body. It is discharged while preventing it from flowing back to the substrate side, so particles removed from the substrate may be mixed in,
It is possible to avoid the processing solution in which gas is dissolved or bubbles or particles are taken in on the liquid surface portion acting on the substrate, thereby preventing the substrate from being contaminated, thereby improving the processing quality. In addition, since the processing liquid is forcibly discharged to suppress the flow velocity difference between the top and bottom of the substrate and to make the flow velocity distribution uniform, the time required for the processing liquid replacement processing can be shortened, and the consumption of the processing liquid can be reduced. The productivity can be improved as well as the processing efficiency can be improved.

According to the third aspect of the present invention, the processing liquid is forcibly discharged from the processing liquid discharge portion above the center of the substrate on the upper portion of the tank body by the suction force of the pump. Is discharged from the upper part of the tank body to return to the substrate side, so that particles removed from the substrate may be mixed in, gas may be dissolved at the liquid level, and bubbles or particles may be trapped in the processing liquid. It is possible to prevent the substrate from being contaminated by acting on the substrate, thereby improving the processing quality. In addition, the processing liquid is forcibly discharged,
Since the flow velocity difference between the top and bottom of the substrate is suppressed and the flow velocity distribution is made uniform, the processing time for processing liquid replacement can be shortened, the amount of processing liquid used can be reduced, and economy can be improved, and processing efficiency is improved and production is improved. Can be enhanced.

According to the fourth aspect of the present invention, the discharge amount of the pump is controlled by the pump control means, and the same amount of the processing liquid as the processing liquid supplied into the tank body from the processing liquid supply unit is supplied. Since the processing liquid is discharged from the processing liquid discharge unit, even if the amount of the processing liquid supplied from the processing liquid supply unit fluctuates, the same amount of the processing liquid is reliably discharged, and the processing liquid returns to the substrate side from the upper part of the tank body. The flow can be prevented better.

According to the fifth aspect of the present invention, the opening degree of the flow control valve provided between the processing liquid discharge section and the pump is controlled by the flow control means, so that the processing liquid supply section can control the opening of the tank body. The same amount of processing liquid is discharged from the processing liquid discharge section as the processing liquid supplied to the inside, so even if the processing liquid supplied from the processing liquid supply section fluctuates, the same amount of processing liquid is reliably discharged. In addition, it is possible to more favorably prevent the processing liquid from flowing from the upper portion of the tank body back to the substrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a substrate processing tank according to the present invention.

FIG. 2 is a plan view of the first embodiment.

FIG. 3 is a cross-sectional view showing a second embodiment of the substrate processing tank according to the present invention.

FIG. 4 is a cross-sectional view showing a third embodiment of the substrate processing tank according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional substrate processing bath.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank main body 9 ... Processing liquid supply part 14, 31 ... Processing liquid discharge pipe 15, 32 ... Slit 16 ... Processing liquid discharge pipe 17 ... Second pump 18 ... First flow meter 19 ... Second flow meter 20 ... second flow rate adjusting valve 21 ... controller 41 ... first processing liquid discharge pipe 42 ... first slit 43 ... second processing liquid discharge pipe 44 ... second slit 45 ... third processing liquid discharge pipe 46 ... third slit 47 ... third flow control valve 48 ... first processing liquid discharge pipe 49 ... fourth flow control valve 50 ... second processing liquid discharge pipe 51 ... fifth flow control valve 52 ... second 3 treatment liquid discharge piping

Claims (5)

[Claims] 1. A substrate processing tank comprising: a tank main body for immersing a substrate stored in a vertical position with a processing liquid; and a processing liquid supply unit for supplying a processing liquid to the substrate stored in the tank main body. In the above, the processing liquid supply unit is provided on each of both sides of the bottom of the tank body, and supplies the processing liquid along the plate surface of the substrate and toward the center of the substrate or a lower side thereof, A substrate processing tank, wherein a forced discharge mechanism for sucking and discharging the processing liquid supplied from the processing liquid supply unit is provided at an upper portion of the tank main body. 2. The substrate processing tank according to claim 1, wherein the forcible discharge mechanism is provided with a processing liquid discharge section provided on both sides of an upper portion of the tank main body, and a suction force is provided by being connected to the processing liquid discharge section. And a pump for processing the substrate. 3. The substrate processing tank according to claim 1, wherein the forcible discharge mechanism comprises: a processing liquid discharge unit provided at an upper part of the tank main body and above a center of a substrate housed in the tank main body; And a pump connected to the processing liquid discharge section to apply a suction force. 4. The substrate processing tank according to claim 2, wherein a supply amount measuring unit that measures a supply amount of the processing liquid supplied from the processing liquid supply unit, and the processing liquid discharged from the processing liquid discharge unit. A discharge amount measuring means for measuring the discharge amount of the processing liquid, and a supply amount of the processing liquid whose discharge amount is measured by the supply amount measuring means based on the discharge amount of the processing liquid measured by the discharge amount measuring means. And a pump control means for controlling the discharge amount of the pump so as to be equal to each other. 5. The substrate processing tank according to claim 2, wherein a supply amount measuring unit for measuring a supply amount of the processing liquid supplied from the processing liquid supply unit, and the processing liquid discharged from the processing liquid discharge unit. A discharge amount measuring means for measuring a discharge amount of the processing liquid; a flow control valve provided between the processing liquid discharge section and the pump for adjusting a discharge amount of the processing liquid; and a discharge amount measuring means for measuring the discharge amount. A flow control means for controlling an opening degree of the flow control valve based on a discharge amount of the processing liquid so that the discharge amount becomes equal to a supply amount of the processing liquid measured by the supply amount measuring means; Processing tank.