Wafer handling system with bernoulli pick-up

• US 5,324,155 A
• Filed: 01/09/1992
• Issued: 06/28/1994
• Est. Priority Date: 05/11/1987
• Status: Expired due to Term

• Current Assignee: ASM America Incorporated (ASM International NV)
• Original Assignee: Advanced Semiconductor Materials America Incorporated
• Inventors: Goodwin, Dennis L., Crabb, Richard, Robinson, McDonald, Ferro, Armand P.
• Primary Examiner(s): Huppert, Michael S.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US07/819,098
• Time in Patent Office: 901 Days
• Field of Search: 414/676, 414/729, 414/737, 414/751, 414/744.2-744.5, 414/744.8, 414/225, 414/222, 294/64.3
• US Class Current: 414/744.5
• CPC Class Codes: B25J 15/0616 with vacuum
• CPC Class Codes: B25J 9/107 of the froglegs type
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber
• CPC Class Codes: Y10S 414/141 includes means for gripping wafer

Abstract

An improved wafer handling system including a pair of robot arms each having a drive apparatus operatively coupled to its rear end portion for extending, retracting, and rotatably positioning the robot arms. The opposite end of the robot arms are operatively connected to a pick-up wand. The pick-up wand includes a top plate and a bottom plate. The lower surface of the top plate has a plurality of commonly-connected grooves ground therein and a reservoir for supplying gas to said grooves from the forward end portion of the robot arms. A plurality of gas outlets are provided in the bottom plate, and the bottom surface of the top plate is positioned securely over and flush against the top surface of the bottom plate such that at least one of the grooves are over each of the plurality of gas outlets for delivering gas thereto. The outlets are slanted for substantially radially outwardly directing a flow of gas away from the pattern and over the top surface of the water for creating an area of relatively low pressure between the bottom surface of the lower pick-up plate and the top surface of the wafer (with respect to the pressure existing beneath the wafer) for picking up or lifting the wafer without physical contact between the wafer and the wand in the actual pick-up by utilizing Bernoulli'"'"'s Principle.

Claims

1. A wafer handling system for picking up a wafer at a first location and delivering the wafer to a second location, which wafer includes a top surface, a bottom surface and a perimeter, said wafer handling system comprising in combination:

a) an enclosure in communication with the first and second locations;

b) a source of gas;

c) a pair of articulated robot arms in fluid communication with said source of gas for conveying a flow of gas therethrough, each of said pair of arms having a first end portion and a second end portion;

d) a pick-up wand assembly supported by said second end portion of each arm of said pair of robot arms, said wand assembly including means for receiving a flow of gas from said pair of robot arms and for picking of the wafer from above the top surface of the wafer without physically contacting the top or bottom surfaces of the wafer with said wand assembly;

e) said wand assembly comprising;

i) a plate having a generally planer lower surface;

ii) at least one first outlet disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

iii) a plurality of second outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

iv) a plurality of third outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

v) one of said plurality of second and third outlets including at least one outlet oriented generally toward said pair of robot arms and one of said plurality of second and third outlets including at least one outlet oriented generally away from said pair of robot arms;

vi) means disposed within said wand assembly for channeling the flow of gas in said receiving means through said at least one first outlet, said second plurality of outlets and said third plurality of outlets; and

vii) means on said wand assembly for limiting the movement of a retained wafer past said limiting means;

f) means for mounting said first end portion of said robot arms to impart motion to said pair of robot arms; and

g) drive means coupled to said mounting means for retracting, extending and rotating said pair of robot arms to pick up and deliver the wafer from the first location to the second location.

2. A wafer handling system for use in a semiconductor wafer processing system including at least a first enclosure for at least temporarily housing a plurality of wafers to be processed, a second enclosure for processing the wafers, a third enclosure for at least temporarily receiving the processed wafers, and a fourth enclosure for housing at least a portion of said wafer handling system, the fourth enclosure being in communication with the first, second, and third enclosures, said wafer handling system being operatively positioned within the fourth enclosure for picking up one of the wafers from of the first, second and third enclosures and for transporting and depositing the wafer in a different one of the first, second and third enclosures, said wafer handling system comprising in combination:

a) a pair of robot arms, each arms of said pair of robot arms having a rear end portion, a front end portion and an elongated intermediate portion therebetween, each arm of said pair of robot arms including means for forming a continuous gas passage there through;

b) means for mounting said rear end portions of said pair of robot arms to longitudinally extend, retract and rotate said pair of robot arms;

c) a source of gas;

d) means for supplying a flow of gas from said source of gas to said rear end portion of said pair of robot arms and into said continuous gas passage;

e) a wand assembly including a relatively flat pick-up wand unit, means for removably mounting said wand unit to said front end portion of said pair of robot arms, said wand assembly further including means for supplying a flow of gas from said continuous gas passage to said wand unit; and

f) said wand unit including;

i) a plate having a generally planar lower surface;

ii) at least one first outlet disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

iii) a plurality of second outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

iv) a plurality of third outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

v) one of said plurality of second and third outlets including at least one outlet oriented generally toward said pair of robot arms and one of said plurality of second and third outlets including at least one outlet oriented generally away from said pair of robot arms;

vi) means disposed within said plate for channeling the flow of gas in said wand unit through said at least one first outlet, said second outlets and said third outlets; and

vii) means on said wand unit for limiting the movement of a retained wafer past said limiting means.

3. In a semiconductor wafer processing system including at least a first enclosure for temporarily storing at least one wafer to be processed, a second enclosure for processing a wafer, a third enclosure communicating with the first and second enclosures, a pair of elongated robot arms having a rear end portion and a front end portion and operatively disposed within the third enclosure, means operatively coupled to the rear end portion of each arm of the pair of robot arms for extending and retracting the pair of robot arms and for rotating the pair of robot arms to reposition the wafer from the first enclosure to the second enclosure and a pick-up wand operatively mounted on the front end portion of the pair of robot arms for picking up and carrying the wafer, the improvement comprising in combination:

a) a source of gas under pressure;

b) a hollow conduit extending from the rear end portion to the front end portion and longitudinally through each arm of the pair of robot arms;

c) means for operatively coupling said source of gas with each of said hollow conduits adjacent the rear end portions of the pair of robot arms;

d) means for supplying gas from each of said hollow conduits at the front end portion of the pair of robot arms to the pick-up wand;

e) means for mounting the pick-up wand on the front end portion of the pair of robot arms;

f) the pick-up wand comprising;

i) a plate having a generally planar lower surface;

ii) at least one first outlet disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

iii) a plurality of second outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

iv) a plurality of third of outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

v) one of said plurality of second and third outlets including at least one outlet oriented generally toward said pair of robot arms and one of said plurality of second and third outlets including at least one outlet oriented generally away from said pair of robot arms;

vi) means disposed within said plate for channeling the gas supplied to the pick-up wand through said at least one first outlet, said second outlets and said third outlets; and

vii) means on the pick-up wand for limiting the movement of a retained wafer past said limiting means.

4. In a semiconductor processing system including a first enclosure means for at least temporarily storing a plurality of wafers to be processed, each of which wafers includes a perimeter, a second enclosure means for forming at least one process step on a wafer, a third enclosure means for at least temporarily storing a plurality of processed wafers, a fourth enclosure means in communication with the first, second and third enclosure means, a pair of robot arms having front end portions and having rear end portions mounted for movement within the fourth enclosure means, drive means for extending, retracting and rotatably positioning the pair of robot arms between the respective front end portion and the rear end portion and a pick-up wand supported by the front end portion of the pair of robot arms, a method comprising the steps of:

a) supplying gas under pressure to the rear end portions of the pair of robot arms;

b) conducting the supplied gas through the hollow interior of each arm of the pair of robot arms;

c) feeding the conducted gas from the front end portions of the pair of robot arms to the pick-up wand;

d) defining a generally planar lower surface with a plate of the pick-up wand;

e) distributing the gas through interior passages of the pick-up wand;

f) establishing an omnidirectional flow of gas across the wafer upon retention of the wafer with at least one first outlet oriented essentially normal to the surface of the plate;

g) further establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer through a plurality of second outlets disposed in the surface of the plate and channeling the gas flow from the at least one first outlet intermediate the plurality of streams of gas flow from the second outlets;

h) yet further establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer through a plurality of third outlets disposed in the surface of the plate and channeling the gas flow from the at least one first outlet intermediate the plurality of streams of gas flow from the third outlets;

i) conveying a flow of gas from the hollow interior of the pick-up wand to each of the at least one first outlet, the second outlets and the third outlets;

j) directing a flow of gas from at least one outlet of the plurality of second and third outlets generally toward the front end portion of the pair of robot arms;

k) further directing a flow of gas from at least one outlet of the plurality of second and third outlets generally away from the front end portion of the pair of robot arms; and

l) limiting movement of the retained wafer past a predetermined location attendant the pick-up wand.

5. In a wafer handling system including a pair of robot arms having front end portions, at least one arm of the robot arms being hollow, means for extending, retracting and rotating the pair of robot arms, and a pick-up wand having interior passages, a surface defined by a plate and carried by the pair of robot arms, a method for handling a wafer comprising the steps of:

a) supplying gas under pressure through at least one hollow arm of the pair of robot arms to the interior passages in the pick-up wand;

b) defining a generally planar lower surface with a plate of the pick-up wand;

c) establishing an omnidirectional flow of gas across the wafer upon retention of the wafer with at least one first outlet oriented essentially normal to the surface of the plate;

d) further establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer through a plurality of second second outlets disposed in the surface of the plate and channeling the gas flow from the at least one first outlet intermediate the plurality of streams of gas flow from the second outlets;

e) yet further establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer through a plurality of third outlets disposed in the surface of the plate and channeling the gas flow from the at least one first outlet intermediate the plurality of streams of gas flow from the third outlets;

f) conveying a flow of gas from the interior passages of the pick-up wand to each of the at least one first outlet, the second outlets and the third outlets;

g) directing a flow of gas from at least one outlet of the plurality of second and third outlets generally toward the front end portions of the pair of robot arms;

h) further directing a flow of gas from at least one outlet of the plurality of second and third outlets generally away from the front end portions of the pair of robot arms; and

i) limiting movement of the retained wafer past a predetermined location attendant the pick-up wand.

6. The method for handling a wafer set forth in claim 5 including the step of filtering the flow of gas to the pick-up wand for removing particles from the gas.

7. A wafer pick-up assembly comprising:

a) a pair of elongated robot arms, each arm of said pair of robot arms having a front end portion, a rear end portion and at least one arm having a continuous conduct extending from said rear end portion to said front end portion;

b) means operatively coupled to said rear end portion of each arm of said pair of robot arms for extending, retracting and rotatably positioning said pair of robot arms;

c) a pick-up wand operatively carried by said front end portion of each arm of said pair of robot arms for picking up a wafer, said pick-up wand including a gas reservoir;

d) means for supplying gas to said rear end portion of at least one arm of said pair of robot arms to channel gas through said continuous conduit;

e) means for supplying the gas from said front end portion of at least one arm of said pair of robot arms to said gas reservoir of said pick-up wand;

f) said wand assembly comprising;

i) a plate having a generally planar lower surface;

ii) at least one first outlet in fluid communication with said gas reservoir and disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

iii) a plurality of second outlets in fluid communication with said gas reservoir and disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

iv) a plurality of third outlets in fluid communication with said gas reservoir and disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the perimeter of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

v) one of said plurality of second and third outlets including at least one outlet oriented generally toward said pair of robot arms and one of said plurality of second and third outlets including at least one outlet oriented generally away from said pair of robot arms;

vi) means disposed within said plate for channeling the gas from said gas reservoir through said at least one first outlet, said second outlets and said third outlets; and

vii) means on said pick-up wand for limiting the movement of a retained wafer past said limiting means.

8. A wafer handling apparatus for transporting a wafer having upper and lower planar surfaces from a first location to a second location, said apparatus comprising in combination:

a) a wand assembly for discharging a plurality of streams of gas to engage the wafer at the first location without contacting the upper or lower planar surfaces of the wafer and to disengage the wafer at the second location, said wand assembly including a rear end portion;

b) said wand assembly comprising;

i) a plate having a generally planar lower surface;

ii) at least one first outlet disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

iii) a plurality of second outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

iv) a plurality of third outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

v) one of said plurality of second and third outlets including at least one outlet oriented generally toward said rear end portion and one of said plurality of second and third outlets including at least one outlet oriented generally away from said rear end portion;

vi) means disposed within said plate for channeling the gas through said at least one first outlet, said second plurality of outlets and said third plurality of outlets; and

vii) means on said wand assembly for limiting the movement of a retained wafer past said limiting means;

c) means for controlling the flow of the gas through said at least one first outlet and each of said second and third outlets; and

d) means for transporting said wand assembly from the first location to the second location.

9. A wafer transport apparatus having at least one arm for transporting a wafer from one location to another and a wand assembly supported by the at least one arm for releasably retaining the wafer in response to an outflow of gas received through the at least one arm from a source of gas, said wand assembly comprising in combination:

a) a plate having a generally planar lower surface;

b) at least one first outlet disposed in the surface of said plate for establishing an omnidirectional flow of gas across the wafer upon retention of the wafer, said at least one first outlet being oriented essentially normal to the surface of said plate;

c) a plurality of second outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward one segment of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said second outlets;

d) a plurality of third outlets disposed in the surface of said plate for establishing a plurality of streams of gas flow toward another segment of the wafer upon retention of the wafer and for channeling the gas flow from said at least one first outlet intermediate the plurality of streams of gas flow from said third outlets;

e) one of said plurality of second and third outlets including at least one outlet oriented generally toward the at least one arm and one of said plurality of second and third outlets including at least one outlet oriented generally away from the at least one arm;

f) means disposed within said plate for channeling the gas received from the at least one arm through said at least one first outlet, said second outlets and said third outlets; and

g) means on said wand assembly for limiting the movement of a retained wafer past said limiting means.

10. The apparatus as set forth in claim 9 wherein each of said plurality of second and third outlets includes a greater number of outlets oriented generally toward the at least one arm than the number of outlets oriented generally away from the at least one arm.

11. The apparatus as set forth in claim 9 wherein said channeling means includes a plurality of interconnecting passageways disposed in said wand assembly for interconnecting each of said at least one first outlet and said second and third outlets with the outflow of gas from the at least one arm.

12. A wafer transport apparatus including a source of gas and operating in accordance with Bernoulli'"'"'s principle, said apparatus comprising in combination:

a) at least one arm for transporting a wafer from one location to another, said at least one arm including means for conveying a flow of gas from the source of gas;

b) a wand assembly supported upon said at least one arm for releasably retaining the wafer to be transported and for receiving a flow of gas from said at least one arm;

c) a plate attached to said wand assembly for defining a generally planar lower surface of said wand assembly;

d) a first plurality of outlets disposed in the bottom surface of said plate for exhausting the gas received by said wand assembly and for establishing a plurality of streams of gas flow toward one segment of the wafer upon retention of the wafer;

e) a second plurality of outlets disposed in the surface of said plate for exhausting the gas received by said wand assembly and for establishing a plurality of streams of gas flow toward another segment of the wafer upon retention of the wafer;

f) one of said first and said second plurality of outlets including at least one outlet oriented generally toward said at least one arm and one of said first and second plurality of outlets including at least one outlet oriented generally away from the at least one arm;

g) at least a third outlet disposed in the surface of said plate for exhausting the gas received by said wand assembly and for establishing a flow of gas intermediate the plurality of streams of gas flow emanating from said first and second plurality of outlets upon retention of the wafer; and

h) means depending below said plate surface for limiting the movement of a retained wafer past said limiting means.

13. The apparatus as set forth in claim 12 wherein at least one of said first and second plurality of outlets include a greater number of said outlets having a component of gas flow toward said limiting means than the number of said outlets having a component of gas flow away from said limiting means.

14. The apparatus as set forth in claim 12 including a plurality of interconnecting passageways disposed in said wand assembly for interconnecting each of said first and second plurality of outlets and said at least one third outlet with the outflow of gas from said at least one arm.

15. The apparatus as set forth in claim 12 wherein said limiting means extends from said plate.