Patent Application
20150165458
This application is based upon and claims the benefit of priority from Japanese patent application No. 2013-257033 filed on Dec. 12, 2013, the entire contents of which are incorporated herein by reference.
The present invention relates to a liquid supplying apparatus for supplying a processing liquid to a process object.
A series of steps for manufacturing semiconductor devices include a step of supplying a processing liquid, such as a thinner, a resist liquid, a polyimide or an adhesive, to a semiconductor wafer (hereinafter simply referred to as “wafer”) as a substrate (process object). Higher viscosity of the processing liquid makes it more difficult to eject the processing liquid. As the wafer diameter increases, the amount of the processing liquid required for coating the whole surface of the wafer increases. In order to suppress the throughput reduction, the processing liquid is required to be ejected in a short time.
However, if a pump having a larger capacity is employed to increase the processing liquid-ejecting rate, the processing apparatus including such a pump becomes more expensive. If processing liquid-feeding pipes having a larger internal diameter are employed to increase the processing liquid-ejecting rate, routing of the pipe becomes difficult and the layout of the apparatus and the workability of the operators are restricted.
After a pump discharges the processing liquid to the nozzle, a new processing liquid is drawn into the pump from a processing liquid container for the next discharging. It is impossible to set the charging rate, at which the processing liquid is drawn into the pump, to be so high, because a high charging rate results in generation of bubbles in the processing liquid. Under the circumstances, the preparation of the processing liquid ejection is required to be performed within as short a time as possible. As the viscosity of the processing liquid becomes higher, the pressure loss upon drawing of the processing liquid becomes greater so that generation of bubbles in the processing liquid is more likely to occur. Thus, particularly in a process using a highly viscous processing liquid, the preparation of the processing liquid ejection is required to be performed as rapidly as possible.
Japanese Patent No. JP4227171B2 describes a method of coating a wafer with a resist liquid by using a plurality of syringes. In this method, an arm picks up one of the syringes placed on a tray, the resist liquid is ejected from the one syringe held by the arm, and the one syringe is returned to the tray. JP2004-172201A describes a coating method in which a container storing a chemical liquid is held by a holding mechanism, and is moved to a position above a wafer, and the chemical liquid is ejected from the container directly to the wafer. Neither Citation 1 nor 2 considers problems associated with a highly viscous processing liquid to be ejected.
The object of the present invention is to provide a liquid supplying apparatus that can shorten the time required for ejecting a processing liquid toward a process object, without complicating the structure of the apparatus.
The liquid processing apparatus of the present invention is a liquid supplying apparatus for supplying a processing liquid to a process object, which includes: a processing liquid cartridge including: a reservoir chamber for storing the processing liquid; an ejecting port for ejecting the processing liquid stored in the reservoir chamber; a pusher unit for pushing the processing liquid stored in the reservoir chamber outward through the ejecting port; and a replenishing port for replenishing the processing liquid into the reservoir chamber; a standby unit having a standby area where the processing liquid cartridge is standing-by; a transport mechanism that transports the processing liquid cartridge between the standby unit and a location where the processing liquid cartridge supplies the processing liquid to the process object; and an actuating mechanism provided in the transport mechanism that drives the pusher unit to push the processing liquid stored in the reservoir chamber.
The standby unit may have a processing liquid replenishing passage for replenishing the processing liquid to the processing liquid cartridge, and the liquid supplying apparatus may further comprises a replenishing mechanism that replenishes the processing liquid to the reservoir chamber of the processing liquid cartridge through the replenishing port. In this case, the replenishing mechanism is provided in the standby unit. The pusher unit may include a bellows body having a proximal opened end portion, and the reservoir chamber has an opened end portion to which the proximal opened end portion of bellows body is joined; and the actuating mechanism may be configured to expand the bellows body to reduce a volume of the reservoir chamber, thereby to eject the processing liquid from the ejecting port.
The liquid supplying apparatus may further comprises a replenishing mechanism that replenishes the processing liquid to the reservoir chamber of the processing liquid cartridge located in the standby unit through the replenishing port, wherein the replenishing mechanism is configured to compress the bellows body to increase the volume of the reservoir chamber, thereby to suction the processing liquid through the replenishing port. The pusher unit may have a driving rod having a distal end connected to a distal end of the bellows body and a proximal end extending outward from the reservoir chamber; and the actuating mechanism may include a forward driving unit that drives the driving rod forward to expand the bellows body.
The liquid supplying apparatus may further comprise a replenishing mechanism that replenishes the processing liquid to the reservoir chamber of the processing liquid cartridge located in the standby unit through the replenishing port, wherein the pusher unit may have a driving rod having a distal end connected to a distal end of the bellows body and a proximal end extend outward from the reservoir chamber, and the actuating mechanism may include a backward driving unit that drives the driving rod backward to compress the bellows body. The actuating mechanism may include a gas supply unit that supplies a gas into an interior of the bellows body through the opened end portion of the bellows body, thereby to expand the bellows body. The liquid supplying apparatus may further comprise a replenishing mechanism that replenishes the processing liquid to the reservoir chamber of the processing liquid cartridge located in the standby unit through the replenishing port, wherein the replenishing mechanism includes a suction mechanism that suctions the processing liquid in the bellows body through the opened end portion of the bellows body, thereby to compress the bellows body.
The processing liquid cartridge may have a memory in which a type of the processing liquid stored in the processing liquid cartridge is stored. In this case, it is preferable that the standby unit has a plurality of standby areas, and a reading unit that reads the type of the processing liquid stored in the processing liquid cartridge stored in the memory, and that the liquid supplying apparatus further comprises a control unit configured to output a control signal instructing to select one from a plurality of processing liquid cartridges suitable for a coating process to be performed to a process object, based on data read out by the reading unit.
The processing liquid cartridge may have a locking mechanism that locks the pusher unit at a position remote from the ejecting port; and the transport mechanism may be provided with a release mechanism that releases locking of the pusher unit by the locking mechanism. The processing liquid cartridge may include a first back-flow prevention mechanism for preventing a backflow of the processing liquid into the reservoir chamber through the ejecting port, and a second back-flow prevention mechanism for preventing a backflow of the processing liquid from the reservoir chamber through the replenishing port; and a drip prevention mechanism may be provided between the first back-flow prevention mechanism and the ejecting port to suction the processing liquid existing near the ejecting port upward toward the reservoir chamber, after ejection of the processing liquid. A viscosity of the processing liquid may be within a range of 1000 cP to 4000 cP.
In the present invention for supplying a processing liquid to a process object, the reservoir chamber of storing the processing liquid and the ejecting port for ejecting the processing liquid are integrated with each other as the processing liquid cartridge. The processing liquid cartridge is transported toward the process object from the standby unit where the processing liquid cartridge is standing-by, and the processing liquid is ejected from the processing liquid cartridge to the process object. Thus, the ejecting port and the pusher unit for pushing the processing liquid stored in the reservoir chamber can be close to each other. As a result, as compared with a structure in which the ejecting port is located on one end of a long pipe and the processing liquid is pushed out by a pump located on the other end of the pipe, a length along which the processing liquid flows can be reduced. Therefore, since there is a less pressure loss, the processing liquid can be promptly ejected, without complicating the apparatus. In addition, since the replenishing port for replenishing the processing liquid into the reservoir chamber of the processing liquid cartridge is provided separately from the ejecting port, the ejecting port can be prevented from being contaminated when the processing liquid is replenished to the reservoir chamber.
A liquid supplying apparatus in one embodiment of the present invention, and a resist coating apparatus into which the liquid supplying apparatus is incorporated, will be explained below with reference to
As shown in
As shown in
Next, the cartridge 12 placed on the standby unit 13 is described in detail. As shown in
A nozzle 21 and a positioning member 12c are disposed on a lower surface of the cartridge 12 on one end portion thereof with respect to the longitudinal direction thereof. The nozzle 21 has an ejecting port (a discharging port) for ejecting the resist liquid. The positioning member 12c is provided to locate the cartridge 12 in place. In detail, as also shown in
A shaft 22 extends in the longitudinal direction of the cartridge 12 from a side surface on the other end portion of the cartridge 12. The shaft 22 serves as a pusher unit (driving rod) that pushes the resist liquid out of the cartridge 12 toward the nozzle 21. As shown in
An inner wall surface of the reservoir chamber 23 on the side of the shaft 22 is referred to as a wall surface part 25. The wall surface part 25 can be separated from the top surface, the bottom surface and the other side surfaces of the reservoir chamber 23. The wall surface part 25 is connected to the distal end of the shaft 22 so as to be moved forward and backward by the shaft 22. A bellows body 26 extends in the longitudinal direction of the shaft 22 to surround the outer circumferential surface of the shaft 22. The bellows body 26 is sealingly connected to the rear surface (i.e., the surface to which the shaft 22 is connected) of the wall surface part 25 and the inner wall surface of the reservoir chamber 23 surrounding an opening 22c serving as a shaft insertion hole. In other words, the portion of the reservoir chamber 23 around the opening 22c and the open end portion of the bellows body 26 are joined to each other. Thus, when the shaft 22 is moved forward toward the nozzle 21, the volume surrounded by the bellows body 26 increases in the reservoir chamber 23, so that the resist liquid in the reservoir chamber 23 is pushed out toward the nozzle 21.
A plurality of (e.g., two) latches 27, serving as a locking mechanism, are provided on the outer circumferential surface of the shaft 22 near the distal end thereof. The latches 27 can retract and project into and from the outer circumferential surface of the shaft 22. The latches 27 are arranged so as not to interfere with the bellows body 26 in the reservoir chamber 23. In addition, the latches 27 are arranged such that, when the latches 27 go out from the reservoir chamber 23 according to the backward movement of the shaft 22, the latches 27 are engaged with the periphery of the opening 22c (the wall of reservoir chamber 23 around the opening 22) so as to lock the position of the wall surface part 25.
A disc-shaped, hollow engagement member 22a is disposed on the distal end of the shaft 22. An elongated hole 22b is formed in a side wall, remote from the shaft 22, of the engagement member 22a. The hole 22b is configured to be engaged with a below-described replenishing mechanism 46 (an engagement part 46e, in detail). The structure for moving the shaft 22 forward and backward will be described later, together with the replenishing mechanism 46.
A replenishing port 28 for replenishing the resist liquid into the reservoir chamber 23 is formed in the bottom wall of the reservoir chamber 23. A check valve 29, which serves as a back-flow prevention mechanism for preventing backflow of the resist liquid, is disposed in a passage extending from the replenishing port 28. The check valve 29 allows inflow of the resist liquid from the replenishing port 28 into the reservoir chamber 23, but prevents backflow (outflow) of the resist liquid from the reservoir chamber 23 toward the replenishing port 28.
The liquid passage 24 is provided with a shutoff valve 24a for opening and closing the liquid passage 24 serving as the back-flow prevention mechanism, and a suck-back valve 24b serving as a drip prevention mechanism to draw the liquid upward from the tip end portion of the nozzle 21, which are arranged in this order from the reservoir chamber 23 to the nozzle 21. The shutoff valve 24a and the suck-back valve 24b are each configured as a diaphragm valve that operates upon supplying (or evacuating) a space behind the valve element. When a gas is supplied to the space behind the shutoff valve (valve element) 24a, the shutoff valve 24a closes the liquid passage 24. On the other hand, when the space behind the shutoff valve 24a is suctioned so that a negative pressure prevails therein, the shutoff valve 24a allows the resist liquid to flow through the liquid passage 24.
When a gas is supplied to the space behind the suck-back valve 24b, the suck-back valve 24b is positioned along the inner surface of the liquid passage 24. On the other hand, when the space behind the suck-back valve 24b is suctioned, the suck-back valve 24b is retracted from the liquid passage 24 so that the resist liquid in the liquid passage 24 is drawn into the suck-back valve 24b. Gas passages through which a gas is supplied to or discharged from the shutoff valve 24a and the suck-back valve 24b are disposed in or on the arm unit 53. These gas passages of the arm unit 53 are connected to or disconnected from the corresponding gas passage of the cartridge 12, upon attachment or detachment of the cartridge 12 to and from the arm unit 53. The detailed explanation of the connection of the gas passages are omitted herein.
As shown in
As shown in
On the other hand, as shown in
The aforementioned standby unit 13 is configured to replenish the resist liquid into the cartridge 12, configured to read the data stored in the IC chip 12b, and configured to clean the nozzle 21. In detail, the standby unit 13 has six standby areas 31 for the cartridges 12, which are arranged side by side on the upper surface of the standby unit 13. As shown in
The recess 32 has an inner diameter slightly larger than the external diameter of the nozzle 21. A supply passage 33, for supplying a cleaning liquid and a drying-preventing gas to the tip end portion of the nozzle 21, opens into the recess 32 in the inner wall surface of the recess 32. In
The projection 13a to be engaged with the positioning member 12c of the cartridge 12 is formed beside the recess 32. Thus, when the positioning member 12c and the projection 13a are engaged with each other, the cartridge 12 is fixedly positioned in the standby area 31. Thus, even when the shaft 22 is moved forward or backward, the cartridge 12 will not displace. Although plural projections 13 are formed at plural locations, illustration thereof is omitted.
The part of the standby area 31 corresponding to the check valve 29 protrudes upward to define a protrusion 40 facing the check valve 29. The processing liquid replenishing passage 41 for replenishing the resist liquid to the cartridge 12 has an open end that opens in the upper surface of the protrusion 40. The open end of the processing liquid replenishing passage 41 is positioned so as to be overlapped with the replenishing port 28, in a plan view. A sealing member 40a such as an O-ring is embedded in the protrusion 40 to surround the open end of the processing liquid replenishing passage 41. When the resist liquid is replenished or supplied to the cartridge 12, the processing liquid replenishing passage 41 and the cartridge 12 (or the check valve 29) are hermetically connected to each other via the sealing member 40a. The other end of the processing liquid replenishing passage 41 is connected, at a position below the standby unit 13, to a reservoir 43 storing the resist liquid through a feed pump 42. The feed pump 42 is configured such that the feed pump 42 does not interfere with the resist liquid passage in the feed pump 42 when the resist liquid is replenished into the cartridge 12, so that the resist liquid can freely flow through the passage. The feed pump 42 is also configured such that the feed pump 42 maintains the level (height position) of the resist liquid in the processing liquid replenishing passage 41 at the level of the upper surface of the protrusion 40 when the replenishment of the resist liquid is completed. Namely, the feed pump 42 is provided to prevent the lowering of the liquid level of the resist liquid, in order to prevent (or reduce as much as possible) bubbles from entering the cartridge 12 through the processing liquid replenishing passage 41. Alternatively, a check valve may be provided in place of the above feed pump 42 in order to prevent backflow (lowering) of the resist liquid in the processing liquid replenishing passage 41.
In addition, the standby area 31 has a reading unit 44 that reads the data stored in the IC chip 12b of the cartridge 12. The reading of the data may be performed in non-contact manner. The data read by the reading unit 44 are transmitted to a below-described control unit 71 through a not-shown signal line, which passes through the inside of the standby unit 13, for example.
The replenishing mechanism 46 is disposed beside the standby area 31 so as to face the shaft 22 of the cartridge 12 placed on the standby area 31. The replenishing mechanism 46 is configured to be movable forward and backward on a rail 45, which runs along the direction in which the shaft 22 extends. To be specific, the replenishing mechanism 46 includes a base 46a that travels along the rail 45, a support column 46b extending vertically upward from the base 46a, and a rotating mechanism 46c supported by the support column 46b. A rotating shaft (driving unit) 46d extends horizontally toward the shaft 22, from one side of the rotating mechanism 46c facing the shaft 22. The rotating shaft 46d is rotatable about a horizontal axis located at the same level (height position) as that of the shaft 22 of the cartridge 12 placed on the standby area 31.
As show in
A not-shown liquid reservoir storing a solvent is disposed in the vicinity of the standby unit 13. Since the solvent stored in the liquid reservoir volatilizes, a solvent atmosphere is formed in a space where the cartridge 12 is placed. Due to the solvent atmosphere, drying of the nozzle 21 of the cartridge 12 (in more detail, drying of the resist liquid inside the tip end portion of the nozzle 21) placed on the standby unit 13 is suppressed.
Next, the explanation is made for the transport mechanism 30 that transports the cartridge 12 between the processing unit 11 and the standby unit 13. As shown in
As shown in
An actuating mechanism 55 is disposed on the lower surface of the arm unit 53 at a position away from the holder 54 toward the beam 52. The actuating mechanism 55 drives the shaft 22 of the cartridge 12 held by the holder 54 forward to the nozzle 21. To be specific, as shown in
A release mechanism 58 for releasing the latches 27 of the shaft 22 is disposed between the actuating mechanism 55 and the holder 54. As shown in
As shown in
As shown in
The input unit 74 is a unit through which an operator inputs the type of the resist liquid stored in the cartridge 12, when the use of the cartridge 12 is started upon starting-up of the apparatus, for example. The input unit 74 may be a keyboard, a mouse or the like for a personal computer. The memory 75 stores the number of each cartridge 12 (i.e., the identification number of the IC chip 12b) and the type of the resist liquid inputted through the input unit 74 such that they are correlated to each other. In addition, the memory 75 is configured to store an amount of the resist liquid remaining in each cartridge 12 in relation to the type of the resist liquid stored therein.
When each cartridge 12 is used in a resist-liquid ejecting process, the amount of the resist liquid used in the ejecting process which corresponds to the traveling distance of the shaft 22 can be detected. The memory 75 stores the amount of the resist liquid remaining in the cartridge 12, which is obtained by subtracting the amount of the used resist liquid from the initial amount of the resist liquid (i.e., the amount of the resist liquid stored in the cartridge 12 when the use of the one cartridge 12 was started). When the resist liquid is replenished to the cartridge 12 to fully fill the cartridge 12 according to the below-described liquid replenishing program 73b, the data of the remaining amount of the resist liquid stored in the memory 75 is reset so that the remaining amount data stored in the memory 75 becomes “full”.
It is also assumed the following. Replenishment of the resist liquid to the No. 1 and No. 6 cartridges 12 have been already completed, so that the remaining amount is “full” (i.e., the used amount is zero). At this time, the No. 2 cartridge 12 is in use for the ejecting process of the resist liquid to a wafer W. Thus, the No. 2 cartridge 12 is not placed on the standby unit 13, so that the IC chip 12b cannot be read. The No. 3 and No. 4 cartridges 12 each have therein a little amount of the resist liquid, and the resist liquid is being replenished thereto in the standby unit 13. The amount of the resist liquid remaining in the No. 5 cartridge 12 is reduced to an amount that is smaller than before use (100 ml of the resist liquid remains in the No. 5 cartridge 12, for example).
The aforementioned ejecting program 73a is a program for execution of the wafer transportation and the resist liquid ejection, according to the type and the thickness of the resist film to be formed on the wafer W, based on recipes specifying various process parameters such as the type of the resist liquid to be used, the amount of the resist liquid to be ejected, the rotating speed of the wafer W and the time for maintaining the rotation of the wafer W. The liquid replenishing program 73b is configured such that, while monitoring (calculating) the remaining amount of the resist liquid in the cartridge 12 from the start of the use of the cartridge 12. When the remaining amount falls below a predetermined threshold value, the liquid replenishing program 73b performs the replenishing process in the standby unit 13. The time period required for the replenishment of the resist liquid can be known in advance through an experiment, for example. While the resist liquid is being replenished to the cartridge 12, the cartridge 12 is not available until the replenishment of the resist liquid is finished. At this time, data indicating “During Replenishment” is registered in the memory 75.
The cartridge selecting program 73c is a program for selecting one of the cartridges 12, which is used for the ejecting process of the resist liquid (the cartridge 12 is held by the arm unit 53 and transported). During execution of the resist liquid replenishment to a certain cartridge 12, this cartridge 12 is not available. In this case, when this cartridge 12 is desired to be used for a succeeding process, the arm unit 53 has to wait until the replenishment of the resist liquid is completed. However, standing-by of the arm 53 may result in reduction of the throughput of the apparatus. In addition, if the resist liquid has a higher viscosity, the flow resistance increases and thus bubbles are likely to be generated in the resist liquid, so that there is greater difficulty in the feeding of the resist liquid. As a result, the replenishment completion waiting time lengthens.
In order to cope with this situation, among the six cartridges 12, three cartridges 12 are assigned to the Resist 1 having the highest viscosity, and two cartridges 12 are assigned to the Resist 2 having the second highest viscosity. Thus, if one of the cartridges assigned to the Resist 1 (or 2) is being replenished with the Resist 1 (or 2) when the Resist 1 (or 2) needs to be ejected, an available cartridge 12 (in which the Resist 1 (or 2) remains) other than the cartridge 12 during replenishment is selected.
To be specific, a case where the Resist 2 needs to be ejected is explained. As shown in
The authenticity judging program 73d judges whether the cartridge 12 placed on the standby unit 13 is a genuine product, or an altered or imitation product. When a cartridge 12 on which the IC chip 12b is not applied is placed on the standby unit 13, the type of the resist liquid cannot be read from the cartridge 12. Thus, the operation is performed on the assumption that no cartridge 12 is placed on the standby area 31 on which such a cartridge 12 is placed.
Meanwhile, in a case where an imitated IC chip 12b is applied to a cartridge 12, the IC chip 12b does not store data showing that the cartridge 12 is a genuine product. When such a cartridge 12 is placed on the standby area 31, the authenticity judging program 73d causes the display unit 76 to display an alarm urging to stop the use of the altered or imitated cartridge 12, and issue instructions to stop the operation of the apparatus until the alarm disappears. These programs 73a to 73d respectively have steps for performing below-described operations of the apparatus. The programs 73a to 73d are installed to the control unit 71 from the storage unit 77 which is storage medium such as a hard disc, a compact disc, a magneto-optical disc, a memory card, a flexible disk, etc.
Next, the operation of the liquid supplying apparatus is explained. At the start-up of the apparatus, the operator places the cartridges 12 each filled with the resist liquid on the standby unit 13, and each reservoir 43 of the standby unit 13 is filled with the corresponding resist liquid. The shaft 22 of each cartridge 12 is immovably locked by the latches 27 at a position away from the nozzle 21. The replenishing mechanism 46 of each standby unit 13 is standing-by at a position remote from the corresponding cartridge 12. The feed pump 42 of each standby unit 13 is driven in advance such that the resist liquid level in the standby unit 13 reaches the protrusion 40, in order to prevent air from entering the cartridge 12 when the resist liquid is replenished. The operator inputs the type of the resist liquid stored in each cartridge 12 through the input unit 74. The memory 75 stores the identification number of the IC chip 12b of each cartridge 12 and the type of the corresponding resist liquid such that they are correlated to each other, and also stores data showing that each cartridge 12 is filled with the resist liquid.
Then, a wafer W is held on the spin chuck 14 by a not-shown transport arm. Depending on the type of a resist film to be formed on the wafer W, in other words, depending on the recipe, the transport mechanism 30 is moved toward one of the cartridges 12 storing the resist liquid to be used. As shown in
Thereafter, the arm unit 53 is moved upward. Thus, as shown in
Following thereto, as shown in
The wafer W coated with the resist film is unloaded from the processing unit 11 by the not-shown transport arm. Then, another unprocessed wafer W is transported to the processing unit 11. If the recipe of the unprocessed wafer W is the same as that of the preceding wafer W (when the resist liquid of the same type is to be applied), the resist liquid is applied in the same manner, with the use of the cartridge 12 which has been already held by the arm unit 53.
On the other hand, when the resist liquid of another type is used, the cartridge 12 is replaced with another one in the following manner. Namely, the shutoff valve 24a is closed, and then the arm unit 53 returns the cartridge 12 held by the arm 53 to the original standby area 31, according to the sequence reverse to the sequence for taking out this cartridge 12 from the standby area 31. In detail, the transport mechanism 30 is moved to place the cartridge 12 above the corresponding standby area 31, and lowers the cartridge 12 to place it in contact with the standby area 31. Thereafter, the engagement of shaft 22 with the actuating mechanism 55 and the engagement of the cartridge 12 with the holder 54 are released.
After that, the arm unit 53 is moved backward to a position at which the actuating mechanism 55 and the shaft 22 do not interfere with each other, and then the arm unit 53 is moved upward, leaving the cartridge 12 placed on the standby area 31. In the cartridge 12 returned to the standby area 31, since the wall surface part 25 is located near the nozzle 21, the restoring force (resilient force) of the bellows body 26 urges the wall surface part 25 toward the shaft 22 side, and such a motion of the wall surface part 25 may result in a situation where atmospheric air is drawn into the cartridge 12 via the check valve 29. However, since the projection 40 is air-tightly in contact with the lower part of the check vale 29, no or very little atmospheric air is drawn into the cartridge 12.
Then, the arm unit 53 is moved to a position above the cartridge 12 to be used next, and the cartridge 12 is lifted up like the prior cartridge 12. Thereafter, the resist liquid coating process is performed in the same manner as described above. In selecting a cartridge 12 to be used next, if the cartridge 12 desired to be used next is being replenished with the resist liquid so that the cartridge 12 is unavailable, the arm unit 53 is operated in the following manner.
That is, if another cartridge 12, which stores the resist liquid of the same type as that of the resist liquid to be used next, is placed on the standby unit 13 (when the resist liquid to be used next is the Resist 1 or the Resist 2), the arm unit 53 does not take the unavailable cartridge 12 but takes the available cartridge 12. On the other hand, if the cartridge 12 desired to be used next is being replenished with the resist liquid, and there is no cartridge 12 of the same type on the standby unit 13 (when the Resist 3 is used), the arm unit 53 stands-by above the standby area 31 until the replenishment of the resist 3 is completed.
In the standby unit 13 to which the used cartridge 12 is returned, a liquid thinner is supplied to the nozzle 21 to clean the nozzle 21. In addition, due to a solvent atmosphere generated by the thinner, the inside of the nozzle 21 of the cartridge 12 placed on the standby unit 13 is prevented from being dried. As has been already described in detail, in the standby unit 13, the remaining amount of the resist liquid is calculated based on the identification number of the IC chip 12b. When the remaining amount is not more than the predetermined threshold value, replenishment of the resist liquid is performed. That is, the replenishing mechanism 46 is moved forward to the cartridge 12 and is engaged with the shaft 22 as shown in
Since the check valve 29 of the cartridge 12 and the processing liquid replenishing passage 41 are air-tightly connected via the sealing member 40a while the shutoff valve 24a is closed, the resist liquid is suctioned upward from the processing liquid replenishing passage 41, as shown in
In this manner, the liquid supplying apparatus performs resist film coating processes to wafers W according to the corresponding recipes for the respective wafers W, while changing the resist liquid to be used and while replenishing the resist liquid into the cartridge 12 as needed basis. During the operation in which one of the cartridge 12 storing the Resist 1 (or 2) held by the arm unit 53 ejects the Resist 1 (or 2) to a plurality of wafers W successively, when the amount of the resist liquid remaining in the cartridge 12 becomes insufficient, the cartridge 12 is replaced with another one in the same manner as mentioned above. In detail, the arm unit 53 returns the used cartridge 12 to the original standby area 31, then the arm unit 53 picks up another cartridge 12 of the same type so as to process a succeeding wafer W. Then, the resist liquid is replenished to the vacant cartridge 12 in the same manner as describe above.
In the aforementioned embodiment, the reservoir chamber 23 storing the resist liquid and the nozzle 21 for ejecting the resist liquid are integrated with each other as the cartridge 12. In addition, the cartridge 12 is transported from the standby unit 13 to a position right above a wafer W, and the resist liquid is ejected from the cartridge 12. Moreover, the replenish port 28 for replenishing the resist liquid to the cartridge 12 is provided separately from the nozzle 21 for ejecting the resist liquid. Thus, when the resist liquid is replenished to the cartridge 12, contamination of the nozzle 21 can be suppressed. Namely, when a highly viscous processing liquid (resist liquid) adheres to an outer surface of the nozzle 21, it is difficult to remove such a processing liquid only by spraying a solvent such as a thinner to the nozzle 21. Thus, if a highly viscous processing liquid is replenished through the nozzle 21, in other words, if a port is commonly used for ejecting the resist liquid and for replenishing the resist liquid, an extra operation such as a wiping operation by the operator is needed after the replenishing process, and thus the number of process steps increases and the throughput of the apparatus decreases. On the other hand, in the foregoing embodiment, since the replenishing port 28 is provided separately from the ejecting port (nozzle 21) for ejecting the resist liquid, contamination of the nozzle 21 can be prevented, avoiding the reduction of throughput.
In addition, in the foregoing embodiment, the actuating mechanism 55 for pushing the processing liquid (resist liquid) is not disposed on the end portion of a long pile extending from the nozzle 21, but is disposed near the nozzle 21. Namely, in operation, the actuating mechanism 55 integrated with the arm unit 53 is disposed near the nozzle 21. Thus, in the foregoing embodiment, since the resist liquid can be ejected without using any pipeline, even if the mechanism for driving the resist liquid (actuating mechanism 55) do not have a high performance, the resist liquid can be ejected at a high ejecting rate. To be more specific, in a case where the viscosity of the resist liquid is 10000 cP, the ejecting rate of the resist liquid is 2 ml/s, the internal diameter of the nozzle 21 is φ4.5 mm, and the length of the nozzle 21 is 50 mm, the pressure loss occurred when the resist liquid is ejected from the nozzle 21 is 0.1 MPa, which is significantly smaller than the pressure loss occurred in a case where the resist liquid is supplied to the nozzle through a long pipe. Thus, even when a wafer W having a diameter as large as 400 mm is processed and/or even when a resist liquid (processing liquid) having a viscosity as high as 1000 cP or more (e.g., 1000 cP to 4000 cP), the resist liquid can be ejected smoothly. It is not necessary to complicate the structure of the apparatus to achieve the above-described performance.
In addition, unlike conventional structures in which different pipes and different pumps are provided for different types of resist liquids, in the foregoing embodiment, one pumping mechanism (actuating mechanism 55) is shared by a plurality of cartridges 12 for ejecting different types of resist liquid, the apparatus can be manufactured at a lower cost. Further, since the apparatus substantially do not have any pipes, a higher degree of freedom in layout of the apparatus component member is achieved, and leakage of resist liquid from the joint of piping can be avoided.
In addition, the replenishing mechanism 46 for replenishing the resist liquid to the cartridge 12 is provided separately from a mechanism for ejecting the resist liquid (actuating mechanism 55). Further, a plurality of cartridges 12 are prepared for a highly viscous resist liquid (Resists 1 and 2). Thus, while the resist liquid is being replenished to one of the cartridges 12, the ejecting process of the resist liquid can be performed. Thus, it is not necessary to interrupt the process until the replenishment of the resist liquid is completed. Moreover, the replenishing rate at which the resist liquid is replenished to the cartridge 12 can be set slower to such a rate that ensures that no bubbles are generated in the resist liquid. Thus, as compared with a case in which the ejection and the replenishment of the resist liquid is carried out by one pumping mechanism, the operation for removing bubbles can be omitted or shortened, whereby the throughput of the apparatus can be improved further. In addition, the amount of the resist liquid that must be discarded in the bubble removal operation can be reduced to zero or a very small amount.
Furthermore, as compared with a case in which a long pipe for feeding the resist liquid is used, it is not difficult to use a clean material, such as quartz, which rarely produces particles, for the resist liquid-contacting members arranged between the shaft 22 and the nozzle 21 (for forming spaces in which the resist liquid flows) can be formed of a clean material such as quartz which rarely produces particles. Namely, such a clean material is so expensive that it is difficult to use the clean material for a long pipe. However, due to the substantially pipe-less structure as described above, the clean material can be used at an acceptable cost. In addition, since the resist liquid-contacting area (processing liquid-contacting area) is small, the area can be easily cleaned. That is, even in a case where a processing liquid such as a polyimide which is easily solidified is used, or the cartridge 12 is left for a long period of time, the processing liquid-contacting area can be cleaned without difficulty. Thus, it is easy to restart the apparatus. Moreover, since the processing liquid-contacting area is small, the whole parts associated with the processing liquid-contacting area can be replaced at a low cost.
If a not-shown replenishing tool for replenish the resist liquid to the cartridge 12 (a tool including the processing liquid replenishing passage 41 and the replenishing mechanism 46) is prepared, the degree of freedom of the apparatus operation can be improved. For example, an evaluation of a resist liquid is performed easily and simply by charging (replenishing) the resist liquid to be evaluated into the cartridge with the use of the not-shown replenishing tool. In this case, it is not necessary to cause the resist liquid for evaluation to flow through the standby unit 13.
Next, another embodiment of the present invention is described. The arm unit 53 in this embodiment has a mechanism for driving the wall surface part 25 by using a gas, in place of the aforementioned actuating mechanism 55 that mechanically drives the shaft 22. To be specific, as shown in
The housing 81 has openings 83 in communication with the interior of the housing 81 in a side surface thereof facing the cartridge 12 and in a lower surface thereof, respectively. A sealing member 84, such as an O-ring, is provided around the circumference of the openings 83 on the side of the cartridge 12, whereby opposing outer wall surfaces of the carriage 12 and the housing 81 can be air-tightly connected to each other.
One end of a supply pipe 85, which is included in a gas supply mechanism for supplying the gas, is connected to a wall surface of the housing 81 on the side farther from the cartridge 12. The other end of the supply pipe 85 connected to a gas reservoir (gas source) 85c via a valve 85a and a flow rate regulating unit 85b. An exhaust passage 86a, which is connected to an exhaust mechanism 86 such as a vacuum pump, is connected to the opening 83 in the lower surface of the housing 81. A pressure regulating unit 86b, such as a butterfly valve, is provided in the exhaust passage 86a. Thus, when the gas is supplied from the supply pipe 85 to the space 25a, the wall surface part 25 is moved forward. On the other hand, when the space 25a is evacuated, the wall surface part 25 is moved backward. After the resist liquid has been ejected from the nozzle 21, the forward movement and the backward movement of the wall surface part 25 is stopped by balancing the force that drives the wall surface part 25 forward and the force that drives the wall surface part 25 backward by controlling the pressure in the space 25 by supplying/discharging the gas to and from the space 25a.
The standby unit 13 also has a mechanism for moving backward the wall surface part 25 by using a gas. In detail, as shown in
One end of an exhaust passage 93, which is included in a suction mechanism for exhausting the housing 91, is connected to a side surface of the housing 91 on the side farther from the cartridge 12. An exhaust mechanism 95 is connected to the other end of the exhaust passage 93 via a pressure regulating unit 94. By evacuating the housing 91 by the exhaust mechanism 95, the wall surface part 25 can be moved backward. The housing 91 is equipped with a not-shown urging mechanism formed of, e.g., a spring for urging the housing 91 away from the cartridge 12. Thus, when the negative pressure established by the exhaust mechanism 95 is released, the housing 91 moves away from the cartridge 12 by the urging force by the urging mechanism. On the other hand, when the evacuation by the exhaust mechanism 95 is started, the outside air is drawn into the housing 91, and a negative pressure is generated by the airflow between the housing 91 and the cartridge 12, whereby the housing 91 moves toward the cartridge 12 to come into air-tight contact with the cartridge 12.
In addition, although omitted in
A bellows body 104, which is expandable/contractible along the longitudinal direction of the cylindrical body 103, is received within the cylindrical body 103. The bellows body 104 is resiliently compressed in the cylindrical body 103 so that the bellows body 104 tends to expand in the longitudinal direction. One end of the bellows body 104 facing the wall surface part 25 is air-tightly fixed to the cylindrical body 103 circumferentially along the inner circumferential surface thereof. A sealing member 105 having a circular disc shape is connected to the other end of the bellows body 104 away from the wall surface part 25. The sealing member 105 moves forward and backward in conjunction with the expansion and compression of the bellows body 104. The sealing member 105 moves forward and backward between a position at which the sealing member 105 is in sealing contact with the other end of the cylindrical body 103 (i.e., a seat on which the sealing member 105 is seated) and a position remote from the contact position toward the wall surface part 25. Thus, under the condition in which no external force is applied to the bellows body 104 and the sealing member 105, the sealing member 105 and the cylindrical body 103 are in sealing contact with each other, so that the space 25a is isolated from the outside (i.e., the atmosphere outside the cartridge 12) to lock the movement of the wall surface part 25. On the other hand, when the sealing member 105 is moved away from the seat of the cylindrical body 103 toward the nozzle 21, the space 25a is communicated with the outside of the cartridge 12, so that a gas can be supplied to and discharged from the space 25a.
As shown in
Thus, when the housing 81 (91) approaches the cartridge 12, the sealing member 84 (92) is brought into sealing contact with the cylindrical body 103. Then, the housing 81 (91) is further moved toward the cartridge 12, the rod 112 pushes the sealing member 105 toward the nozzle 21 side with the housing 81 (91) being in sealing contact with the cartridge 12, so that the internal space of the housing 81 (91) and the space 25a are communicated with each other. Thus, supplying and evacuating of a gas via the housing 81 (91) is enabled. As is apparent from the above description, also in the embodiment of
Next, yet another embodiment of the present invention is described. In this embodiment, the apparatus is configured to adjust a thickness of a resist film to be formed on a wafer W, based on an amount of a resist liquid to be used (ejected) to the wafer W (used amount or ejection amount). To be specific, as shown in
The weight measuring unit 121 is formed by two planar bodies that are vertically opposed to each other. A plurality of resilient members, such as springs, are interposed between the planar bodies, and are distributed in the plane of the planar bodies. The vertical distance between the planar bodies can be measured by a suitable measuring device such as camera. The measured distance is transmitted to the control unit 71. The weight of the resist liquid in the cartridge 12 is calculated by subtracting total weights of the holder 54, the solvent nozzle 61 and the arm unit 53 from the weight measured by the measuring unit 121. In
Namely, as described above, the amount of the resist liquid ejected to a wafer W from the nozzle 21 can be detected by the controller 71 based on the moving distance at which the wall surface part 25 is moved forward toward the nozzle 21. However, in a process which requires precise control of the resist film thickness, it is preferable that the ejection amount of the resist liquid can be monitored by another measurement system in addition to the aforementioned distance based measurement system, and also preferable that the thickness of the resist film can be adjusted. In this embodiment, the arm unit 53 is provided with the weight measuring unit 121 that measures the weight of the resist liquid, and the thickness of the resist film can be adjusted in accordance with the below-described sequence.
Specifically, as shown in
Then, transport of a wafer W to the processing unit 11 is started (step S3). The cartridge 12 filled with the resist liquid is held by the arm unit 53 beforehand, and the weight of the cartridge 12 is measured before ejection of the resist liquid (step S4). After that, the spin chuck 14 is rotated at a low rotating speed (or is stopped) such that the resist liquid does not spread on the surface of the wafer W. Under this condition, the resist liquid is ejected from the nozzle 21 (step S5), in the manner as previously described in detail. Thereafter, the weight of the cartridge 12 is measured again (step S6). Note that, prior to the ejection of the resist liquid, the aforementioned pre-wetting process is performed (description thereof is omitted).
Then, the weight A of the resist liquid having been ejected from the nozzle 21 is calculated by subtracting the weight of the cartridge 12 after ejection of the resist, from the weight of the cartridge 12 before ejection of the resist (step S7). If the calculated weight A is not less than the value corresponding to the minimum resist ejection amount Amin (measured by weight) (Yes in step S8), it is judged that the thickness of a resist film can be adjusted and thus the program proceeds to the next step. On the other hand, if the weight A of the resist liquid is less than the value corresponding to the minimum resist ejection amount Amin (measured by weight) (No in step S8), it is judged that the resist liquid existing on the surface of the wafer W is insufficient for adjusting the thickness of the resist film. In this case, the ejection of the resist liquid and the weight measurement of the cartridge 12 before and after the resist liquid ejection are performed. Then, the steps S4 to S8 are repeated until the sum of the newly obtained weight A and the previously obtained weight(s) A becomes not less than the weight Amin (measured by weight).
Following thereto, the difference between the target film thickness Y′ and the expected film thickness Y, which is expected from the already calculated weight A, is calculated (step S9). The target film thickness Y′ is set in the recipe beforehand. As described in detail in the “Example” section later, the expected film thickness Y can be obtained by substituting X in Expression (1) (described later) with the weight A.
After the difference ΔY (ΔY=Y′−Y) has been calculated, the difference is set as a correction thickness (step S10), and a correction recipe is determined. To be specific, as will be understood from the “Examples” described later, the thickness of the resist film can be adjusted by adjusting at least one of the following parameters: the rotating speed of the wafer W and the time in which the rotation of the wafer W is maintained (hereinafter referred to as “rotating time”). As compared with the rotating time, the rotating speed of the wafer W has a larger impact on the thickness of the resist film, that is, the adjustment of the rotating speed allows a wider range of adjustment of the resist film thickness. Thus, the correction recipe is created as follows. It is judged through calculation whether the film thickness can be adjusted only by adjusting the rotating speed of the wafer W (Δx1). If it is judged that the film thickness cannot be adjusted only by adjusting the rotating speed of the wafer W, the rotating time of the wafer W (Δx2) is also adjusted in addition to the rotating speed of the wafer W.
Thereafter, the recipe is updated such that the correction recipe thus obtained according to the above is substituted for the old recipe (the recipe before updated) (step S12). To be specific, in a case where the rotating speed of the wafer W is “x1” while the rotating time of the wafer W is “x2” in the old recipe, the rotating speed of the wafer W becomes “x1″+”Δx1″ and the rotating time of the wafer W becomes “x2″+”Δx2″ in the updated recipe. By rotating the wafer W about the vertical axis according to the thus obtained recipe, the resist liquid spreads outwardly over the surface of the wafer W and the excessive amount of resist liquid is spun off, so that a resist film of the desired thickness is formed on the wafer W (step S13). Since the aforementioned steps succeeding to the step S7 are performed by the control unit 71 promptly and rapidly, there is no possibility that the resist liquid becomes dried and solidified on the surface of the wafer W.
After that, when the remaining amount of the resist liquid in the cartridge 12 becomes insufficient, the resist liquid is replenished to the cartridge 12 (step S14) in the above-described manner. The processed wafer W is unloaded from the processing unit 11, and another unprocessed wafer W is loaded into the processing unit 11 so as to be processed in accordance with the steps S3 to S14.
By adjusting a thickness of a resist film in the above-described manner based on the actual weight of the resist liquid ejected to a wafer W, even when there are bubbles in the resist liquid stored in the cartridge 12 or when the resist liquid is erroneously ejected from the nozzle 21, the thickness of the resist film can be adjusted to a value that is expected by the recipe. Although in the above embodiment employing the weight measuring unit 121 the correction amount is calculated while the resist liquid is being placed on the wafer W, the following operation is also possible. Namely, this wafer is processed at the rotating speed for the rotating time specified by the old (not updated) recipe, and the succeeding wafer is processed in accordance with a recipe that is updated according to the above-described manner through calculation. In this case, after a resist film has been formed on one wafer W, the difference of the expected film thickness Y which is expected from the actual weight of the resist liquid ejected to the one wafer W from the target film thickness Y′ is calculated. Then, the rotating speed and the rotating time are corrected such that the difference of thickness becomes zero, and the corrected rotating speed and rotating time are applied to the wafers W succeeding to the one wafer W.
When the resist liquid is drawn into the cartridge 12 of
In the respective embodiments, although the resist liquid is replenished to the cartridge 12 in the standby unit 13, a transport unit such as a movable cart may be provided, and an operator may replenish the resist liquid by the transport unit, for example. In addition, in the step of replenishing the resist liquid to the cartridge 12, if the cartridge 12 becomes unusable due to clogging of the replenishing port 28 for example, the cartridge 12 may be replaced with an unused new cartridge 12.
Although the processing liquid handled by the liquid supplying apparatus is a resist liquid in the foregoing embodiments, the processing liquid may be a liquid comprising a polyimide resin, or an adhesive solution which is used for adhering wafers W to each other in the thickness direction. Alternatively, the processing liquid may be a solvent such as a thinner, and a pre-wetting process may be performed to a wafer W by using the cartridge 12 filled with the solvent. When the pre-wetting process is performed by using the cartridge 12 filled with a solvent, another holder (not shown) may be disposed besides the holder 54, such that the arm unit 53 can hold the cartridge 12 for resist liquid and the cartridge 12 for solvent at the same time.
A piston-cylinder mechanism may be used instead of the aforementioned structure comprising the shaft 22 and the wall surface part 25. Namely, the outer circumferential surface of the wall surface part 25 may be in sealing contact with an inner wall surface of the reservoir chamber 23, so that the resist liquid can be pushed out by the wall surface part 25. In this case, the replenishing port 28 is positioned nearer to the nozzle than the moving range of the wall surface part 25. Alternatively, the replenishing port 28 and the nozzle 21 may be positioned nearer to the proximal end of the arm unit 53 than the movement range of the wall surface part 25, such that the resist liquid is replenished into the cartridge 12 when the shaft 22 is moving forward, while the resist liquid is ejected when the shaft 22 is moving backward. Although the replenishing port 28 and the nozzle 21 are arranged side by side in the foregoing embodiments, the replenish port 28 may be formed above the nozzle 21 to configure a so-called, vertical-type cartridge.
In the foregoing embodiments, a negative pressure (suction force) generated in the cartridge 12 by moving backward the wall surface part 25 is used to replenish the resist liquid into the cartridge 12. However, the replenishment of the resist liquid may be performed by pumping the resist liquid pressurized by the feed pump 42 into the cartridge 12. Although the shutoff valve 24 is formed as a diaphragm valve driven by air, the shutoff valve 24 may be a check valve that does not allow the resist liquid to return from the nozzle 21 to the reservoir chamber 23.
In the foregoing embodiments, the replenishing mechanism 46 (or housing 91) disposed on the standby unit 13 moves the wall surface part 25 backward to replenish the resist liquid into the cartridge 12. However, the wall surface part 25 may be moved backward by the actuating mechanism 55 (housing 81) of the arm unit 53. That is, the mechanism for pushing out the resist liquid in the cartridge 12 toward the nozzle 21 may also serve as the mechanism for replenishing the resist liquid into the cartridge 12. In this case, after the arm unit 53 has placed the used cartridge 12 on the standby unit 13, the arm unit 53 is kept engaged with the cartridge 12 and the actuating mechanism 55 (housing 81) of the arm unit 53 moves the wall surface part 25 backward so as to replenish the resist liquid into the cartridge 12. Thereafter, the arm unit 53 again transports the cartridge 12 having been filled with the resist liquid to the processing unit 11. Also in such a configuration, since the liquid passages used for ejecting the resist liquid to a wafer W are shortened, a large-sized pump and/or pipes having excellent pressure resistance is no longer needed.
Resist liquid was ejected onto wafers W having a diameter of 450 mm, while changing the ejection amount of the resist liquid. The spread area in which the resist liquid spreads (expands) on the surface of each wafer W was observed. In detail, after an amount of the resist liquid had been ejected to a central portion of the wafer W while the wafer W was rotated about the vertical axis at a rotating speed, the radius of the resist liquid (resist film) spreading in a circle on the surface of each wafer W was measured.
The result is described below. As shown in
The next experiment was conducted to examine the relationship between the resist liquid discharging pressure (i.e., the pressure applied to the space 25a to eject the resist liquid from the nozzle 21) and the amount of the resist liquid ejected from the nozzle 21, in a case where the resist liquid stored in the cartridge 12 is ejected by pressurizing the cartridge 12. The result is described below. As shown in
An experiment was conducted to examine how the ejection time of the resist liquid gave an impact on the quality of a resist film. When the resist liquid was ejected at a very slow ejection rate of 0.08 ml/second (the ejection time was about 400 seconds), the film thickness was non-uniform in a plane of the wafer W, as indicated by white squares (Experiment 3-1) in the graph of
Y=0.1X+40.95 (1)
Thus, in the previously described embodiment employing the weight measuring unit 121, the expected film thickness Y is calculated from Equation (1).
Y=−0.0402X+82.801 (2)
Thus, it can be understood that, when it is required that the expected film thickness Y is corrected by changing the rotating speed of the wafer W, the rotating speed of the wafer W should be increased (or decreased) by a value (Δx1) obtained by dividing the correction film thickness ΔY by the value of “−0.0402”.
Y=−0.366X+65.51 (3)
When it is required that the expected film thickness Y is corrected by adjusting the rotating time, the rotating time should be increased (or decreased) by a value (Δx2) obtained by dividing the correction film thickness ΔY by a value of “−0.366”. By using the rotating time as an adjusting parameter of the expected film thickness Y in addition to the rotating speed of the wafer W, the adjustment range is widened due to synergy effect.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-257033 | Dec 2013 | JP | national |
