AUTOMATED THERMAL SLIDE DEBONDER
An improved apparatus for debonding temporary bonded wafers includes a debonder, a cleaning module and a taping module. A vacuum chuck is used in the debonder for holding the debonded thinned wafer and remains with the thinned debonded wafer during the follow up processes steps of cleaning and mounting onto a dicing tape. In one embodiment the debonded thinned wafer remains onto the vacuum chuck and is moved with the vacuum chuck into the cleaning module and then the taping module. In another embodiment the debonded thinned wafer remains onto the vacuum chuck and first the cleaning module moves over the thinned wafer to clean the wafer and then the taping module moves over the thinned wafer to mount a dicing tape onto the wafer.
Latest SUSS MICROTEC INC Patents:
This application claims the benefit of U.S. provisional application Ser. No. 61/289,634 filed Dec. 23, 2009 and entitled “AUTOMATED THERMAL SLIDE DEBONDER”, the contents of which are expressly incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates to an apparatus for temporary semiconductor wafer bonding and debonding, and more particularly to an industrial-scale apparatus for temporary wafer bonding and debonding that comprises an automated thermal slide debonder.
BACKGROUND OF THE INVENTIONSeveral semiconductor wafer processes include wafer thinning steps. In some applications the wafers are thinned down to a thickness of less than 100 micrometers for the fabrication of integrated circuit (IC) devices. Thin wafers have the advantages of improved heat removal and better electrical operation of the fabricated IC devices. In one example, GaAs wafers are thinned down to 25 micrometers to fabricate power CMOS devices with improved heat removal. Wafer thinning also contributes to a reduction of the device capacitance and to an increase of its impedance, both of which result in an overall size reduction of the fabricated device. In other applications, wafer thinning is used for 3D-Integration bonding and for fabricating through wafer vias.
Wafer thinning is usually performed via back-grinding and/or chemical mechanical polishing (CMP). CMP involves bringing the wafer surface into contact with a hard and flat rotating horizontal platter in the presence of a liquid slurry. The slurry usually contains abrasive powders, such as diamond or silicon carbide, along with chemical etchants such as ammonia, fluoride, or combinations thereof. The abrasives cause substrate thinning, while the etchants polish the substrate surface at the submicron level. The wafer is maintained in contact with the abrasives until a certain amount of substrate has been removed in order to achieve a targeted thickness.
For wafer thicknesses of over 200 micrometers, the wafer is usually held in place with a fixture that utilizes a vacuum chuck or some other means of mechanical attachment. However, for wafer thicknesses of less than 200 micrometer and especially for wafers of less than 100 micrometers, it becomes increasingly difficult to mechanically hold the wafers and to maintain control of the planarity and integrity of the wafers during thinning. In these cases, it is actually common for wafers to develop microfractures and to break during CMP.
An alternative to mechanical holding of the wafers during thinning involves attaching a first surface of the device wafer (i.e., wafer processed into a device) onto a carrier wafer and thinning down the exposed opposite device wafer surface. The bond between the carrier wafer and the device wafer is temporary and is removed (i.e., debonded) upon completion of the thinning processing steps.
Several temporary bonding techniques have been suggested including using of adhesive compounds that are chemically dissolved after processing or using of adhesive tapes or layers that are thermally or via radiation decomposed after processing. Most of these adhesive-based temporary bonding techniques are followed by a thermal slide debonding process where the device wafer and the carrier wafer are held by vacuum chucks while heat is applied to the bonded wafer pair and the wafers slide apart from each other. In the current thermal slide debonding process the separated thinned device wafer is held via a secondary support mechanism for further processing. This secondary support mechanism usually adds cost and complications to the processing equipment. It is desirable to reduce the added cost and complications.
SUMMARY OF THE INVENTIONAn improved apparatus for temporary wafer bonding and debonding 100 includes a temporary bonder 110, a wafer thinning station 120, a debonder 150, a cleaning module 170 and a taping module 180, as shown in
In general, in one aspect, the invention features an apparatus for processing a temporary bonded wafer pair comprising a device wafer and a carrier wafer. The apparatus includes a debonder for debonding the device wafer from the carrier wafer after it has been thinned, a cleaning module for cleaning the debonded thinned device wafer, a taping module for applying a tape onto the debonded thinned device wafer and a vacuum chuck. The vacuum chuck is used in the debonder and includes means for holding the debonded thinned device wafer. The apparatus also includes means for moving the vacuum chuck with the debonded thinned device wafer into and out of the cleaning module and into and out of the taping module.
In general, in another aspect, the invention features an apparatus for processing a temporary bonded wafer pair comprising a device wafer and a carrier wafer. The apparatus includes a debonder for debonding the device wafer from the carrier wafer after it has been thinned, a cleaning module for cleaning the debonded thinned device wafer, a taping module, and a vacuum chuck used in the debonder and including means for holding the debonded thinned device wafer during debonding, cleaning and taping. The cleaning module includes means for moving over the debonded thinned wafer in the debonder for cleaning the debonded thinned wafer. The taping module includes means for moving over the debonded thinned wafer in the debonder for applying the tape onto the debonded thinned wafer.
Implementations of these aspects of the invention may include one or more of the following features. The debonder includes a top chuck assembly, a bottom chuck assembly, a static gantry supporting the top chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone under the top chuck assembly and from the process zone back to the loading zone, and the bottom chuck assembly includes the vacuum chuck. The top chuck assembly includes a top support chuck bolted to the static gantry, a heater support plate in contact with the bottom surface of the top support chuck, a heater being in contact with the bottom surface of the heater support plate, a top wafer plate in contact with the heater, a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer and a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate. The apparatus further includes a lift pin assembly for raising and lowering the wafer pair onto the bottom chuck assembly. The bonder further includes a base plate supporting the X-axis carriage drive and the static gantry and the base plate includes one of a honeycomb structure with vibration isolation supports or a granite plate. The apparatus further includes means for twisting the device wafer at the same time the horizontal motion is initiated. The X-axis carriage drive includes an air bearing carriage drive. The debonder further includes two parallel lateral carriage guidance tracks guiding the X-axis carriage drive in its horizontal motion along the X-axis. The carrier wafer is held by the top chuck assembly via vacuum pulling. The plate leveling system includes three guide shafts connecting the heater to the top support chuck and three pneumatically actuated split clamps. The heater includes two independently controlled concentric heating zones configured to heat wafers having a diameter of 200 or 300 millimeters, respectively. The apparatus further includes a bonder for temporary bonding the wafer pair and a wafer thinning module for thinning the device wafer of the temporarily bonded wafer pair.
In general, in another aspect, the invention features a method for debonding and processing two via an adhesive layer temporary bonded wafers. The method includes the following steps. First, providing a bonder comprising a top chuck assembly, a bottom chuck assembly, a static gantry supporting the top chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone under the top chuck assembly and from the process zone back to the loading zone. The bottom chuck assembly comprises a vacuum chuck. Next, loading a wafer pair comprising a carrier wafer bonded to a device wafer via an adhesive layer upon the bottom chuck assembly at the loading zone oriented so that the unbonded surface of the device wafer is in contact with the bottom chuck assembly. Next, driving the X-axis carriage drive and the bottom chuck assembly to the process zone under the top chuck assembly. Next, placing the unbonded surface of the carrier wafer in contact with the top chuck assembly and holding the carrier wafer by the top chuck assembly. Next, heating the carrier wafer with a heater comprised in the top chuck assembly to a temperature around or above the adhesive layer's melting point. Next, initiating horizontal motion of the X-axis carriage drive along the X-axis by the X-axis drive control while heat is applied to the carrier wafer and while the carrier wafer is held by the top chuck assembly and the device wafer is held by the bottom chuck assembly and thereby causing the device wafer to separate and slide away from the carrier wafer. Next, moving the vacuum chuck with the debonded thinned device wafer into a cleaning station and removing any residual adhesive off the device wafer and then moving the vacuum chuck with the cleaned debonded thinned device wafer into a taping module and applying a tape to a surface of the debonded thinned device wafer. Finally, removing the taped debonded device wafer from the vacuum chuck and placing it into a device wafer cassette. The residual adhesive is removed by using a solvent and applying spin cleaning techniques. The top chuck assembly further includes a top support chuck bolted to the static gantry, a heater support plate in contact with the bottom surface of the top support chuck, a heater being in contact with the bottom surface of the heater support plate, a top wafer plate in contact with the heater, a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer and a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
In general, in another aspect, the invention features a method for debonding and processing two via an adhesive layer temporary bonded wafers. The method includes the following steps. First, providing a chamber comprising a top chuck assembly, a bottom chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone and from the process zone back to the loading zone. Next, loading a wafer pair comprising a carrier wafer bonded to a device wafer via an adhesive layer upon the bottom chuck assembly at the loading zone oriented so that the unbonded surface of the device wafer is in contact with the bottom chuck assembly. Next, driving the X-axis carriage drive and the bottom chuck assembly to the process zone and placing the top chuck assembly on top of the bottom chuck assembly. Next, placing the unbonded surface of the carrier wafer in contact with the top chuck assembly and holding the carrier wafer by the top chuck assembly. Next, heating the carrier wafer with a heater comprised in the top chuck assembly to a temperature around or above the adhesive layer's melting point. Next, initiating horizontal motion of the X-axis carriage drive along the X-axis by the X-axis drive control while heat is applied to the carrier wafer and while the carrier wafer is held by the top chuck assembly and the device wafer is held by the bottom chuck assembly and thereby causing the device wafer to debond and slide away from the carrier wafer. Next, moving the top chuck assembly with the debonded carrier wafer away from the process zone. Next, moving a cleaning station module into the chamber over the debonded device wafer and removing any residual adhesive off the device wafer. Next, moving the cleaning station module out of the chamber after any residual adhesive is removed off the device wafer. Next, moving a taping module into the chamber over the debonded and cleaned device wafer and applying a tape to a surface of the debonded device wafer and then removing the taped debonded device wafer from the bottom chuck assembly and placing it into a device wafer cassette. The residual adhesive is removed by using a solvent and applying spin cleaning techniques. The top chuck assembly further includes a top support chuck bolted to the static gantry, a heater support plate in contact with the bottom surface of the top support chuck, a heater being in contact with the bottom surface of the heater support plate, a top wafer plate in contact with the heater, a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer and a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
Referring to the figures, wherein like numerals represent like parts throughout the several views:
Referring to
Referring to
The temporary bonding (68) of the carrier wafer 30 to the device wafer 20 takes place in temporary bonder module, 210. Referring to
The debond process 60b is a thermal slide debond process and includes the following steps, shown in
In cases where the thinned device wafer is thicker than about 100 micrometers usually no additional support is needed for moving the thinned wafer 20 from the thermal slide debonder 150 to the further processing stations 170, 180. However, in cases where the thinned device wafer 20 is thinner than 100 micrometers a secondary support mechanism is required to prevent breaking or cracking of the thinned device wafer. Currently, the secondary support mechanism includes an electrostatic carrier or a carrier comprising a Gelpak™ acrylic film on a specially constructed wafer. As was mentioned above, these secondary support mechanism add complications and cost to the process.
The present invention eliminates the need for a secondary carrier by allowing a vacuum chuck 152 used in the thermal slide debonder 150 to remain with the thinned wafer 20 during the follow up processes steps of cleaning (52) and mounting onto a dicing tape (53). In one embodiment the thinned wafer 20 remains onto the vacuum chuck 152 and is moved with the vacuum chuck into the various process stations. In another embodiment the thinned wafer 20 remains onto the vacuum chuck 152 and the various process stations 170, 180 move over the thinned wafer 20 to perform the various process steps.
Referring to
Referring to
Referring to
Referring to
Referring to
The loading and pre-alignment of the wafers is facilitated with the mechanical centering device 460, shown in
Referring to
Referring to
Referring to
Referring to
Several embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
Claims
1. An apparatus for processing a temporary bonded wafer pair comprising a device wafer and a carrier wafer, said apparatus comprising:
- a debonder for debonding the device wafer from the carrier wafer;
- a cleaning module for cleaning the debonded device wafer;
- a taping module for applying a tape onto the debonded device wafer;
- a vacuum chuck wherein said vacuum chuck is used in the debonder during the debonding for holding the device wafer and comprises means for holding the debonded device wafer; and
- means for moving the vacuum chuck with the debonded device wafer into and out of the cleaning module and into and out of the taping module.
2. The apparatus of claim 1 wherein said debonder comprises a top chuck assembly, a bottom chuck assembly, a static gantry supporting the top chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone under the top chuck assembly and from the process zone back to the loading zone, and wherein said bottom chuck assembly comprises said vacuum chuck.
3. The apparatus of claim 2 wherein said top chuck assembly comprises:
- a top support chuck bolted to the static gantry;
- a heater support plate in contact with the bottom surface of the top support chuck;
- said heater being in contact with the bottom surface of the heater support plate;
- a top wafer plate in contact with the heater;
- a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer; and
- a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
4. The apparatus of claim 2 further comprising a lift pin assembly for raising and lowering said wafer pair onto the bottom chuck assembly.
5. The apparatus of claim 2 wherein said bonder further comprises a base plate supporting the X-axis carriage drive and the static gantry and wherein said base plate comprises one of a honeycomb structure with vibration isolation supports or a granite plate.
6. The apparatus of claim 2 further comprising means for twisting the device wafer at the same time said horizontal motion is initiated.
7. The apparatus of claim 2 wherein said X-axis carriage drive comprises an air bearing carriage drive.
8. The apparatus of claim 2 wherein said debonder further comprises two parallel lateral carriage guidance tracks guiding said X-axis carriage drive in its horizontal motion along the X-axis.
9. The apparatus of claim 2 wherein said carrier wafer is held by said top chuck assembly via vacuum pulling.
10. The apparatus of claim 3, wherein said plate leveling system comprises three guide shafts connecting said heater to said top support chuck and three pneumatically actuated split clamps.
11. The apparatus of claim 3, wherein said heater comprises two independently controlled concentric heating zones configured to heat wafers having a diameter of 200 or 300 millimeters, respectively.
12. The apparatus of claim 1 further comprising:
- a bonder for temporary bonding the wafer pair; and
- a wafer thinning module for thinning the device wafer of the temporarily bonded wafer pair.
13. An apparatus for processing a temporary bonded wafer pair comprising a device wafer and a carrier wafer, said apparatus comprising;
- a debonder for debonding the device wafer from the carrier wafer;
- a cleaning module for cleaning the debonded device wafer, wherein the cleaning module comprises means for moving over the debonded wafer in the debonder for cleaning the debonded wafer;
- a taping module for applying a tape onto the debonded device wafer, wherein the taping module comprises means for moving over the debonded wafer in the debonder for applying the tape onto the debonded wafer; and
- a vacuum chuck used in the debonder and comprising means for holding the debonded device wafer during debonding, cleaning and taping.
14. The apparatus of claim 13 wherein said debonder comprises a top chuck assembly, a bottom chuck assembly, a static gantry supporting the top chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone under the top chuck assembly and from the process zone back to the loading zone, and wherein said bottom chuck assembly comprises said vacuum chuck.
15. The apparatus of claim 14 wherein said top chuck assembly comprises:
- a top support chuck bolted to the static gantry;
- a heater support plate in contact with the bottom surface of the top support chuck;
- said heater being in contact with the bottom surface of the heater support plate;
- a top wafer plate in contact with the heater;
- a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer; and
- a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
16. The apparatus of claim 14 further comprising a lift pin assembly for raising and lowering said wafer pair onto the bottom chuck assembly.
17. The apparatus of claim 14 wherein said bonder further comprises a base plate supporting the X-axis carriage drive and the static gantry and wherein said base plate comprises one of a honeycomb structure with vibration isolation supports or a granite plate.
18. The apparatus of claim 14 further comprising means for twisting the device wafer at the same time said horizontal motion is initiated.
19. The apparatus of claim 14 wherein said X-axis carriage drive comprises an air bearing carriage drive.
20. The apparatus of claim 14 wherein said debonder further comprises two parallel lateral carriage guidance tracks guiding said X-axis carriage drive in its horizontal motion along the X-axis.
21. The apparatus of claim 14 wherein said carrier wafer is held by said top chuck assembly via vacuum pulling.
22. The apparatus of claim 15, wherein said plate leveling system comprises three guide shafts connecting said heater to said top support chuck and three pneumatically actuated split clamps.
23. The apparatus of claim 15, wherein said heater comprises two independently controlled concentric heating zones configured to heat wafers having a diameter of 200 or 300 millimeters, respectively.
24. The apparatus of claim 13 further comprising:
- a bonder for temporary bonding the wafer pair; and
- a wafer thinning module for thinning the device wafer of the temporarily bonded wafer pair.
25. A method for debonding and processing two via an adhesive layer temporary bonded wafers, comprising:
- providing a debonder comprising a top chuck assembly, a bottom chuck assembly, a static gantry supporting the top chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone under the top chuck assembly and from the process zone back to the loading zone, and wherein said bottom chuck assembly comprises a vacuum chuck;
- loading a wafer pair comprising a carrier wafer bonded to a device wafer via an adhesive layer upon said bottom chuck assembly at the loading zone oriented so that the unbonded surface of the device wafer is in contact with the bottom chuck assembly;
- driving said X-axis carriage drive and said bottom chuck assembly to the process zone under the top chuck assembly;
- placing the unbonded surface of the carrier wafer in contact with the top chuck assembly and holding said carrier wafer by said top chuck assembly;
- heating said carrier wafer with a heater comprised in said top chuck assembly to a temperature around or above said adhesive layer's melting point;
- initiating horizontal motion of said X-axis carriage drive along the X-axis by said X-axis drive control while heat is applied to said carrier wafer and while said carrier wafer is held by said top chuck assembly and said device wafer is held by said bottom chuck assembly and thereby causing the device wafer to separate and slide away from the carrier wafer;
- moving said vacuum chuck with said debonded device wafer into a cleaning module and removing any residual adhesive off said device wafer;
- moving said vacuum chuck with said cleaned debonded device wafer into a taping module and applying a tape onto a surface of the debonded device wafer; and
- removing the taped debonded device wafer from the vacuum chuck and placing it into a device wafer cassette.
26. The method of claim 25 wherein said residual adhesive is removed by using a solvent and applying spin cleaning techniques.
27. The method of claim 25, wherein said top chuck assembly further comprises:
- a top support chuck bolted to the static gantry;
- a heater support plate in contact with the bottom surface of the top support chuck;
- said heater being in contact with the bottom surface of the heater support plate;
- a top wafer plate in contact with the heater;
- a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer; and
- a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
28. A method for debonding and processing two via an adhesive layer temporary bonded wafers, comprising:
- providing a chamber comprising a top chuck assembly, a bottom chuck assembly, an X-axis carriage drive supporting the bottom chuck assembly and an X-axis drive control configured to drive horizontally the X-axis carriage drive and the bottom chuck assembly from a loading zone to a process zone and from the process zone back to the loading zone and wherein said bottom chuck assembly comprises a vacuum chuck;
- loading a wafer pair comprising a carrier wafer bonded to a device wafer via an adhesive layer upon said bottom chuck assembly at the loading zone oriented so that the unbonded surface of the device wafer is in contact with the bottom chuck assembly;
- driving said X-axis carriage drive and said bottom chuck assembly to the process zone and placing said the top chuck assembly on top of said bottom chuck assembly;
- placing the unbonded surface of the carrier wafer in contact with the top chuck assembly and holding said carrier wafer by said top chuck assembly;
- heating said carrier wafer with a heater comprised in said top chuck assembly to a temperature above said adhesive layer's melting point;
- initiating horizontal motion of said X-axis carriage drive along the X-axis by said X-axis drive control while heat is applied to said carrier wafer and while said carrier wafer is held by said top chuck assembly and said device wafer is held by said vacuum chuck and thereby causing the device wafer to debond and slide away from the carrier wafer;
- moving said top chuck assembly with the debonded carrier wafer away from the process zone;
- moving a cleaning module into the chamber over said debonded device wafer and removing any residual adhesive off said device wafer;
- moving said cleaning module out of the chamber after any residual adhesive is removed off said device wafer;
- moving a taping module into the chamber over said debonded and cleaned device wafer and applying a tape to a surface of the debonded device wafer; and
- removing the taped debonded device wafer from the bottom chuck assembly and placing it into a device wafer cassette.
29. The method of claim 28 wherein said residual adhesive is removed by using a solvent and applying spin cleaning techniques.
30. The method of claim 28, wherein said top chuck assembly further comprises:
- a top support chuck bolted to the static gantry;
- a heater support plate in contact with the bottom surface of the top support chuck;
- said heater being in contact with the bottom surface of the heater support plate;
- a top wafer plate in contact with the heater;
- a Z-axis drive for moving the top wafer plate in the Z-direction and placing the top wafer plate in contact with the unbonded surface of the carrier wafer; and
- a plate leveling system for leveling the top wafer plate and for providing wedge error compensation of the top wafer plate.
Type: Application
Filed: Dec 22, 2010
Publication Date: Feb 16, 2012
Patent Grant number: 8343300
Applicant: SUSS MICROTEC INC (WATERBURY, VT)
Inventor: JAMES HERMANOWSKI (WATERBURY, VT)
Application Number: 12/975,521
International Classification: B32B 38/10 (20060101);