Collection chamber apparatus to separate multiple fluids during the semiconductor wafer processing cycle

The collection chamber apparatus acts to separate multiple fluids during the wafer processing cycle. Round, fluid collection trays surround the round wafer to collect each individual fluid, recycling them for later reuse. The trays move up and down by use of air cylinders and stack into each other to prevent cross contamination of the other fluids. Two opposing pistons (air cylinders) lift the trays in pairs to form fluid collection chambers. Each collection chamber has a unique drain which enters a separation manifold, flowing into separate tanks for later reuse.

TECHNICAL FIELD

The present invention is generally directed to wafer processing equipment and more particularly, to a collection chamber apparatus that provides a means to separate and collect multiple different fluids for reuse during wafer processing.

BACKGROUND

This invention relates particularly to silicon wafer processing where multiple fluids are used during a process to clean, etch or do other wet process operations. The fluids are often expensive and it is desirable to reuse them to exhaustion.

Normal wafer processing employs one collection chamber to separate a special fluid from the waste drain and enable recirculation of the fluid.

The object of this invention is to have multiple, independent collection chambers, with the ability to separate multiple different fluids for recirculation and reuse.

SUMMARY

According to the present invention, a collection chamber apparatus (fluid collecting device) is composed of multiple (n+1) round collection trays which stack and seal into each other when not in use and form multiple (n) unique collection chambers and drain systems, as required. The specific example shown has four (4) collection trays for three (3) unique collection chambers.

The collection trays move into the designated position by way of an opposing pair of vertical air cylinders.

The tops of the air cylinders have a stepped shoulder designed to separate and vertically position two trays at one time.

The two trays form a collection chamber centered on the wafer's edge. The other trays stack into each other in all positions to prevent fluid cross contamination.

As the motor spins the wafer, centrifugal force propels the fluid outward. The fluid leaves the wafers outside edge, striking the angled wall of the upper tray, which deflects the fluid into the lower tray. The lower tray has a drain spout which directs the fluid into a manifold separator. The manifold separator directs each fluid into a discrete tank (not shown) for further reuse.

For the rinse process, the trays are closed to eliminate the possibility of water being incorporated into the fluid streams.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

FIG. 1is an overview of a collection chamber apparatus100of the present invention showing collection trays130,140,150,160in a stacked, load wafer position33(seeFIGS. 2 and 2Afor additional clarity), in which a wafer115can be added or removed. The four trays surround the wafer115. It will be understood that the proceeding discussion is merely exemplary of one implementation of the present invention and not limiting of the scope of the present invention since other implementations, as discussed below, are possible.

A first fluid separating position will follow as an example of the typical description of operation, for each of the three fluids. Referring toFIGS. 3 and 6and according to one mode of operation, a pair of pistons300(e.g., air cylinders) lift the collection trays130,140forming a first collection chamber identified by the legend34(i.e., the gap (distance) between the plates).FIG. 6shows in more detail the unique piston design which both lifts trays130,140into vertical level38, and forms the desired collection chamber gap34by way of shoulders307and308. In particular, when the pistons300are actuated, a first region thereof passes through all of the aligned openings134,144,154,164formed in the collection trays; a second region thereof passes only through the openings144,154,164and a third region thereof only passes through the openings154,164. When the pistons300complete their extended stroke, the underside of the collection tray130seats on shoulder307and the underside of the collection tray140seats on shoulder308. The gap34(collection chamber) can be controlled and defined by the distance between the shoulders307,308and the thickness of the trays and further, as discussed below, the gap distance can be controlled and defined by pin28

Next, referring back toFIG. 3A, a motor112rotates a wafer115located on the spin chuck110, a dispense arm120then centers over the wafer115and dispenses the first fluid in the process. The motor112increases RPM's to spread fluid over the wafers surface, excess fluid22is slung by centrifugal force off the peripheral edge of the spin chuck110and onto the underside of the slopped wall of tray130, refer toFIG. 3B. Per fluid path22, gravity drops the fluid into the collection tray140(e.g., into the collection track thereof), where it flows into the outlet port146and the fluid conduit member147and finally into a manifold200. From there the fluid flows into the drain tube210and ends up in a discrete tank (not shown) for storage and reuse, where it is dispensed during the next wafer cycle.

FIG. 3Cshows an alternate fluid path30, in which the fluid23can run down the underside of tray130and multiple drip grooves24are included to stop the flow and direct the fluid down into the intended collection tray140(which is disposed below tray130).

FIG. 3Dshows a cross-section through a lift pin28. A pair of pins28extends through openings135,145,155,165of the opposing flange sections of the collection trays. The pins28are configured to lift the bottom tray(s)150,160off of a rest29and against the collection tray140to seal them against splashes, while still maintaining the chamber gap34. The pins28are thus designed to hold the bottommost collection tray in contact with the others so as to provide a seal between the collection trays that are in contact with one another. As shown, the pin28includes a radial protrusion or the like at or near the bottom end (and also at or near the top end) which supports the bottommost tray.

FIGS. 4 and 9show the apparatus100with the trays130,140,150,160forming a second collection chamber36(gap), positioned by a pair of pistons310(second pistons) in combination with the pair of pistons300(first pistons) which are also actuated and in their fully extended states. When the pistons310are actuated and move upwardly, the stepped construction of the pistons310is such that both the collection trays130,140are supported by the first shoulder of the pistons310(resulting in the trays130,140being in sealed contact with one another) and the trays150,160seating against the second shoulder of the pistons310. As shown the pistons320are not actuated. A second discrete fluid26, flows through the chamber36, following normal path25in which the fluid flows into the outlet port156and the fluid conduit member157and finally into the manifold200. From there the fluid flows into the drain tube210and ends up in a discrete tank (not shown) for storage and reuse, where it is dispensed during the next wafer cycle.

FIGS. 5 and 10show the apparatus100with the trays130,140,150,160forming a third collection chamber37, positioned by a piston pair320(third pistons) in combination with the pair of pistons300,310(first and second pistons) which are also actuated and in their fully extended states. When the pistons320are actuated and move upward, the stepped construction of the pistons320is such that the collection trays130,140,150(the three uppermost trays) are supported by the first shoulder of the pistons310(resulting in the trays130,140,150being in sealed contact with one another) and the tray160(bottommost tray) seats against the second shoulder of the pistons320. A third discrete fluid32, flows through the collection chamber37following normal path42in which the fluid flows into the outlet port166and the fluid conduit member167and finally into the manifold200. From there the fluid flows into the drain tube210and ends up in a discrete tank (not shown) for storage and reuse, where it is dispensed during the next wafer cycle.

The distance between the two collection trays that define one specific, selected collection chamber remains the same regardless of which two collection trays130,140,150,160define such collection chamber. This is a result of the construction of the pistons (e.g., the shoulders formed therein) and controlled distance of the strokes thereof.

As shown in theFIGS. 8-10, the top end of each piston300can include a stop member321in the form of a protrusion to limit the movement of the collection tray130(the uppermost collection tray) in an upward direction. As will be understood, the most upward position of the collection tray130results in the collection tray130seating against this stop member321. The stop members321thus assist in holding the collection tray assembly together.

Additional details and advantages of the present invention include but are not limited to: (1) the collection apparatus is able to collect multiple different fluids without cross contamination of each other, and directing each fluid into a separate drain; (2) it contains multiple collection trays which are determined by the number of fluids plus one; (3) the collection trays have the ability to stack into each other, preventing other fluids from splashing into them, thus eliminating cross contamination; (4) air cylinders with shoulders designed to vertically position and set the gap between two trays, thereby forming each collection chamber; (5) multiple drip grooves are designed into the underside of each tray, to direct fluid into the intended lower tray's drain; (6) when the collection trays are stacked together a gap is left between the upper and lower tray such that space is left for fluid that has yet to drain out of the tray, thereby preventing splashing of the fluid and (7) each fluid is discharged into a unique drain.

Referring again toFIGS. 1-10and further to the above discussion, it will be appreciated that the collection chamber apparatus100includes a number of working components that are actuatable, as described below, in order to place the collection chamber apparatus100in different operating positions and more specifically, to create a defined collection chamber and a corresponding defined fluid flow path that allows collection of a liquid used in the wafer processing.

The collection chamber apparatus100includes a wafer support member110on which a wafer115is disposed during processing thereof. The wafer support member110is in the form of a rotatable wafer spin chuck. The spin chuck110is operatively connected to a motor112which is configured to rotate the spin chuck110at a selected speed (RPM). Operation of the spin chuck110is by traditional methods.

A fluid dispensing arm120represents a means for dispensing a fluid119onto the wafer115. The fluid dispensing arm120can be any number of different types of traditional fluid dispensing members including the arm120shown in the figures. As described herein, during wafer processing, liquid is dispensed onto a surface of the wafer115and during rotation of the wafer115, the fluid is propelled radially outward and off of the wafer115by centrifugal force.

In accordance with the present invention, the collection chamber assembly of the apparatus100is disposed circumferentially about the spin chuck110and thus, is disposed circumferentially about the wafer115. As mentioned above, the collection chamber component comprises a plurality of collection trays that serve to not only collect the fluid being propelled radially outward off of the wafer115during the processing thereof but also routes the fluid to an outlet to facilitate collection of the fluid. In the illustrated embodiment, which is exemplary in nature, there are four different collection trays130,140,150,160that are arranged in a stacked configuration. However, it will be understood that less than or more than four collection trays can be used in the apparatus100. It will be appreciated that the addition of one collection tray results in a corresponding addition of a distinct collection chamber for collecting a fluid. This aspect will be readily understood from the below discussion and from the drawing figures.

The collection trays130,140,150,160can have the same or similar basic design as shown in the figures. In the illustrated embodiment, the collection tray130is generally annular shaped with a center opening131that receives the spin chuck110and the wafer115. The collection tray130has a main section that defines an annular shaped collection track132which is defined by a floor and a pair of beveled side walls that are adjacent and slope up from the floor. Alternative floor design is equally possible and the illustrated design is only exemplary in nature.

As shown inFIG. 1, the collection tray130also has a pair of outwardly extending flange sections133. The flange sections133are preferably located opposite one another (e.g., 180 degrees apart) and have a plurality of openings134formed therein. The openings134are spaced along the flange section between the side walls thereof. In the illustrated embodiment, there are three openings134that receive working pistons (e.g., ends of pneumatic (air) cylinders) as described below. There is also an additional opening135formed in each flange section133. The openings134,135can be arranged such that the two openings134are adjacent one another and the third opening134is spaced from this pair of openings134with the opening135being disposed between the pair of openings134and the spaced third opening134.

The collection tray130also includes an outlet port136which is in fluid communication with the fluid collection track132. The outlet port136can be in the form of a spout that extends radially outward from the main section between the flange sections133. In the illustrated embodiment, the outlet port136is generally V-shaped and extends outward from the main section and thus provides a trough along which the collected fluid flows. The bottom of the outlet port136is in fluid communication with the bottom (floor) of the fluid collection track132and thus fluid can flow from the fluid collection track132into the outlet port136. As will be described below, the outlet port of each collection tray is in fluid communication with the manifold structure200to route the collected fluid.

The collection tray140is similar to the collection tray130and is generally annular shaped with a center opening141that receives the spin chuck110and the wafer115. The collection tray140has a main section that defines an annular shaped collection track142which is defined by a floor and a pair of beveled side walls that are adjacent and slope up from the floor.

The collection tray140also has a pair of outwardly extending flange sections143. The flange sections143are preferably located opposite one another (e.g., 180 degrees apart) and have a plurality of openings144formed therein. The openings144are spaced along the flange section between the side walls thereof. In the illustrated embodiment, there are three openings144that receive working pistons (e.g., ends of pneumatic (air) cylinders) as described below. There is also an additional opening145formed in each flange section143. The openings144,145can be arranged such that the two openings144are adjacent one another and the third opening144is spaced from this pair of openings144with the opening145being disposed between the pair of openings144and the spaced third opening144.

The collection tray140also includes an outlet port146which is in fluid communication with the fluid collection track142. The outlet port146can be in the form of a spout that extends radially outward from the main section between the flange sections143. In the illustrated embodiment, the outlet port146is generally V-shaped and extends outward from the main section and thus provides a trough along which the collected fluid flows. The bottom of the outlet port146is in fluid communication with the bottom (floor) of the fluid collection track142and thus fluid can flow from the fluid collection track142into the outlet port146.

The collection tray150is similar to the other collection trays and is generally annular shaped with a center opening151that receives the spin chuck110and the wafer115. The collection tray150has a main section that defines an annular shaped collection track152which is defined by a floor and a pair of beveled side walls that are adjacent and slope up from the floor.

The collection tray150also has a pair of outwardly extending flange sections153. The flange sections153are preferably located opposite one another (e.g., 180 degrees apart) and have a plurality of openings154formed therein. The openings154are spaced along the flange section between the side walls thereof. In the illustrated embodiment, there are three openings154that receive working pistons (e.g., ends of pneumatic (air) cylinders) as described below. There is also an additional opening155formed in each flange section153. The openings154,155can be arranged such that the two openings154are adjacent one another and the third opening154is spaced from this pair of openings154with the opening155being disposed between the pair of openings154and the spaced third opening154.

The collection tray150also includes an outlet port156which is in fluid communication with the fluid collection track152. The outlet port156can be in the form of a spout that extends radially outward from the main section between the flange sections153. In the illustrated embodiment, the outlet port156is generally V-shaped and extends outward from the main section and thus provides a trough along which the collected fluid flows. The bottom of the outlet port156is in fluid communication with the bottom (floor) of the fluid collection track152and thus fluid can flow from the fluid collection track152into the outlet port156.

The collection tray160is generally annular shaped with a center opening161that receives the spin chuck110and the wafer115. The collection tray160has a main section that defines an annular shaped collection track162which is defined by a floor and a pair of beveled side walls that are adjacent and slope up from the floor.

The collection tray160also has a pair of outwardly extending flange sections163. The flange sections163are preferably located opposite one another (e.g., 180 degrees apart) and have a plurality of openings164formed therein. The openings164are spaced along the flange section between the side walls thereof. In the illustrated embodiment, there are three openings164that receive working pistons (e.g., ends of pneumatic (air) cylinders) as described below. There is also an additional opening165formed in each flange section163. The openings164,165can be arranged such that the two openings164are adjacent one another and the third opening164is spaced from this pair of openings164with the opening165being disposed between the pair of openings164and the spaced third opening164.

The collection tray160also includes an outlet port166which is in fluid communication with the fluid collection track162. The outlet port166can be in the form of a spout that extends radially outward from the main section between the flange sections163. In the illustrated embodiment, the outlet port166is generally V-shaped and extends outward from the main section and thus provides a trough along which the collected fluid flows. The bottom of the outlet port166is in fluid communication with the bottom (floor) of the fluid collection track162and thus fluid can flow from the fluid collection track162into the outlet port166.

As mentioned above, the collection trays130,140,150,160are arranged in a stacked configuration and thus the respective flange sections are stacked on top of each other and are configured to mate with one another and the respective outlet ports are disposed on top of one another as shown.

The outlet ports136,146,156,166thus resemble angled troughs/spouts which permit fluid to flow downward by gravity. As best shown inFIGS. 3A and 3B, each of the outlet ports146,156, and166includes a fluid conduit member147,157,167, respectively, which descends downwardly therefrom. As shown, each of the fluid conduit members147,157,167can be in the form of a tubular structure that communicates at a top open end with the bottom of the respective outlet port. The fluid conduit members147,157,167can be vertically oriented and thus, fluid flows by gravity from the respective outlet port into the fluid conduit member to a separation manifold200. As shown inFIGS. 4 and 5, the fluid conduit members147,157,167are slidingly received within respective inlet ports201,202,203of the manifold to establish a fluid connection. The manifold200includes a drain tube210which is in fluid communication with each of the fluid conduit members and thus, fluid flowing through the fluid conduit member flows into the manifold and into the drain tube210. The drain tube210routes the fluid to a predetermined location such as a location at which a collection tank is provided for collecting the fluid.

The collection aspect of the apparatus100is based on the fact that the individual collection trays130,140,150,160can each be moved to a predetermined position so as to define a discrete collection chamber that is configured to collect the fluid that is propelled outwardly off of the wafer during processing. It will be appreciated that different means for moving the collection trays can be used and the ones described herein are merely exemplary in nature. In the illustrated embodiment, pneumatic devices are used to control the movement of the trays and in particular, pistons in the form of air cylinders are used. To move the multiple (e.g., 4) collection trays, there are multiple pistons and in particular and according to one embodiment, when the apparatus includes n number of collection trays, there are 2*(n−1) number of pistons. Further, it will be appreciated that each tray can be moved by one or more piston and thus, while the illustrated embodiment shows pistons being arranged in pairs, other variations are equally possible. For example, sets of three pistons can be used instead to move the collection trays. To provide the proper support, it is desired that there be at least two pistons for moving a respective collection tray (e.g., as mentioned, there can be three or more pistons used per collection tray).

As shown, there is a pair of first pistons300, a pair of second pistons310, and a pair of third pistons320. The pistons300,310,320are arranged below the flange sections of the collection trays and are axially aligned with select ones of the openings134,144,154,164. The openings134,144,154,164are axially aligned with one another and differ in only dimensions (i.e., diameters thereof), thereby allow at least a portion of the piston to pass through select openings. Each piston300,310,320includes a stepped construction so as to create select interference with the tray so as to effectuate a lifting of a select tray.

For the purpose of illustration and as described below, the pair of first pistons300is designed to lift the collection trays130,140; the pair of second pistons310is designed to lift the collection trays140,150and the pair of third piston320is designed to lift the collection trays150,160. In other words, each pair of pistons is designed to lift two collection trays; however, in combination with other pairs of pistons being actuated, more than two collection trays are moved.

As shown best inFIG. 6, the stepped construction of the first piston300is defined by a first shoulder307and a second shoulder308. The outer diameter of the second shoulder308is greater than the first shoulder307. The piston300thus has a variable diameter and in particular, includes a first region between the first shoulder307and top end that has a first outer diameter; a second region between the two shoulders that has a second outer diameter and a third region below the second shoulder308that a third diameter, wherein the first outer diameter<second outer diameter<third outer diameter. The openings134,144,154,164are purposely sized so that only one or more of the regions is free to pass therethrough and the shoulders307,308create lifting surface for lifting select collection trays.

As shown inFIG. 7, the collections trays are configured to include an anti-splash feature. More specifically, a fluid reservoir199is formed between adjacent closed collection trays to reduce fluid splashing when the collection trays are closed. More particularly, the underside of one collection tray and the topside of the collection tray immediately beneath it leave the fluid reservoir199between them when the two trays are collapsed. The fluid reservoir prevents fluid from being squeezed or splashed out from between the trays when the trays are closed.FIG. 7shows collections trays130,140,150in closed positions, with one fluid reservoir199being formed between the collection trays130,140and another fluid reservoir199being formed between the collection trays140,150.

While the invention has been described in connection with certain embodiments thereof, the invention is capable of being practiced in other forms and using other materials and structures. Accordingly, the invention is defined by the recitations in the claims appended hereto and equivalents thereof.