US20070042686A1 - Method and apparatus for cleaning slurry depositions from a water carrier - Google Patents
Method and apparatus for cleaning slurry depositions from a water carrier Download PDFInfo
- Publication number
- US20070042686A1 US20070042686A1 US11/205,382 US20538205A US2007042686A1 US 20070042686 A1 US20070042686 A1 US 20070042686A1 US 20538205 A US20538205 A US 20538205A US 2007042686 A1 US2007042686 A1 US 2007042686A1
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- United States
- Prior art keywords
- carriers
- carrier
- slurry
- spray
- wafer
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/34—Accessories
- B24B37/345—Feeding, loading or unloading work specially adapted to lapping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/02—Cleaning by the force of jets or sprays
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B55/00—Safety devices for grinding or polishing machines; Accessories fitted to grinding or polishing machines for keeping tools or parts of the machine in good working condition
Definitions
- CMP chemical/mechanical polishing
- the CMP process involves holding and rotating, using a wafer carrier, semiconductor wafer against a rotating polishing pad.
- the wafer carrier is typically a plate-like structure having a diameter slightly larger than the semiconductor wafer.
- the carrier is attached to a positioning device through a gimbal on its back side surface that allows the carrier to be spun and to pivot on the gimbal.
- the polishing pad which is conventionally an open-celled, polyurethane pad affixed to a polishing platen, is wetted by a chemical slurry, under controlled chemical, pressure, and temperature conditions.
- the subject invention pertains to a process of cleaning slurry from a back-side of a carrier used for transporting a wafer without having to interrupt the conventional CMP process.
- This process involves spraying the back-side of the carrier with a cleaning fluid at a predetermined time that is coordinated so as not to interfere with the CMP process.
- a specific aspect of the invention pertains to a process comprising spray washing the back side of a carrier concurrently with a conventional spray washing of a front side of the carrier at a time between unloading and loading of wafer from the carrier. In this form, no additional steps are needed to effect cleaning of the carrier so that the cycle time of the CMP process is not effected.
- the indexing area includes spray nozzles and a spray wash process that washes slurry from the front or wafer contact surface of the carrier during a time between unloading of a polished wafer and loading of a next wafer to be polished.
- Applicants have modified the CMP tool by addition of a coupling from the front wafer wash source to a back wafer wash distribution system.
- the system includes flexible tubing and a plurality of spray nozzles mounted to the support mechanism for the wafer carriers. When the system actuates the fluid source for the front carrier wash, a flow of fluid is directed to the added tubing and nozzles to that fluid is sprayed onto the back side of the wafer carriers. Accordingly, both the back side and front side of the carriers are washed concurrently.
- FIG. 2 is an elevation view taken along the lines 2 - 2 of FIG. 1 .
- the turret 16 is provided with a plurality of circumferentially spaced slots 20 that provide a path for the carriers 18 to be moved from a radially outward position around the turret to a radially inner position.
- the inner position is used solely for the purpose of transporting the turret from a loading and an unloading position over the indexing table to a polishing position over the polishing pad 12 .
- the carriers are normally positioned in the outer extreme of each of the slots 20 during the polishing operation at the pad 12 and during the unloading and loading functions over the index table 14 .
- a slurry flows over the polishing pad 12 and is used to achieve polishing of the semiconductor wafers.
- the wafers are unloaded into corresponding ones of a plurality of plastic cups that are located on the indexing table and are indicated in FIG. 1 at 22 .
- the cups 22 define wafer loading and unloading stations.
- the indexing table has an outer wall 24 and an inner wall 26 which defines a trough in which the plastic cups reside. This trough is generally filled with a cleaning fluid, typically water, which is constantly circulated and cleaned and is used to clean the slurry from the wafers.
- the carriers 18 do not protrude into the water on the indexing table and are therefore not cleaned when the wafers are unloaded. As a consequence, it is necessary to clean the carriers 18 between the steps of unloading polished wafers and loading new wafers to be polished. As shown in FIG. 2 , there are multiple spaced spray nozzles 30 located on the indexing table that are angled upward and positioned between the respecting loading and unloading stations for cleaning the underside of the carriers 18 .
- the turret 16 is rotated so that the carriers are positioned between loading and unloading cups 22 and a corresponding one of the spray nozzles sprays a stream of water upward onto the lower face of a respective one of the carriers to wash any slurry away from the carriers so that the slurry will not interfere with the loading of a subsequent wafer into the carrier.
- applicant's have attached another plurality of spray nozzles 32 onto the turret 16 and positioned the nozzles to aim downward toward the backs of the carriers 18 so that a spray of water can be directed onto the back of the carriers at the same time that the front face of the carriers is washed by the spray from the nozzles 30 .
- This process removes any slurry or dried slurry compound from the backside of the wafer carriers so that such compound is not carried back to the polishing pad 12 when a next group of wafers are loaded and transported for polishing.
- the water for washing the back side of the wafer carriers 18 may come from the same source as the water used for washing the front face of the carrier by simply splitting off from the water source and coupling through a flexible tube to a distribution system mounted to the top of the turret 16 .
- a distribution system mounted to the top of the turret 16 .
- CMP machines may be configured to implement a spray function designed for washing the back side of a carrier in conjunction with the polishing process.
- CMP machines may be equipped with one or more spray nozzles and configured such that fluid is ejected out of the nozzle and aimed at the back side of a carrier so as to wash off undesired slurry components.
- the spray nozzle may be mounted to the CMP machine and connected to a fluid source.
- the functioning of the CMP process is typically coordinated by software.
- CMP machine software may be configured to include the function of actuating the spraying of fluid out the spray nozzle at an appropriate time during a normal routine of a CMP machine.
- existing machines may be retrofitted with a spray nozzle and their software reconfigured to implement the spraying of the back of a carrier.
Abstract
Description
- Conventional chemical/mechanical polishing (CMP) is used to create smooth topographies of the various layers of a semiconductor integrated circuit wafer during semiconductor device manufacture. The CMP process involves holding and rotating, using a wafer carrier, semiconductor wafer against a rotating polishing pad. The wafer carrier is typically a plate-like structure having a diameter slightly larger than the semiconductor wafer. The carrier is attached to a positioning device through a gimbal on its back side surface that allows the carrier to be spun and to pivot on the gimbal. The polishing pad, which is conventionally an open-celled, polyurethane pad affixed to a polishing platen, is wetted by a chemical slurry, under controlled chemical, pressure, and temperature conditions. The chemical slurry contains selected chemicals which etch or oxidize selected surfaces of the wafer during CMP in preparation for their mechanical removal. The slurry also contains a polishing agent, such as alumina or silica that is used as the abrasive material for the physical removal of the etched/oxidized material. The combination of chemical and mechanical removal of material during polishing results in superior planarization of the polished surface. In this process it is important to remove a sufficient amount of material to provide a smooth surface, without removing an excessive amount of underlying materials at each level of the manufacturing process to insure uniform and accurate formation of the semiconductor device at all subsequent levels. Accurate material removal is particularly important in today's sub-quarter micron technologies where it is critical to minimize thickness variation because the metal lines are thinner.
- The inventors have discovered that the slurry sometimes splashes on the or back-side surface of the carrier during CMP. Further, when this splashed slurry dries, the silica and/or other components in the slurry become a contamination issue. Dried silica particles falling on the polishing pad is one of the causes of wafer scratches and failing particle counts when process checking a tool. The scratching results in potential wafer yield losses. The failing particle counts during process checking results in diminished tool availability since the tool must be taken out of production and cleaned.
- According to one aspect, the subject invention pertains to a process of cleaning slurry from a back-side of a carrier used for transporting a wafer without having to interrupt the conventional CMP process. This process involves spraying the back-side of the carrier with a cleaning fluid at a predetermined time that is coordinated so as not to interfere with the CMP process. A specific aspect of the invention pertains to a process comprising spray washing the back side of a carrier concurrently with a conventional spray washing of a front side of the carrier at a time between unloading and loading of wafer from the carrier. In this form, no additional steps are needed to effect cleaning of the carrier so that the cycle time of the CMP process is not effected.
- Another aspect of the invention pertains to a CMP machine comprising a spray nozzle associated with the CMP machine such that fluid is ejected out of the nozzle and aimed at the back side of a carrier so as to wash off undesired slurry components. The spray nozzle may be mounted to the CMP machine and connected to a fluid source. Typically, CMP tools comprise a polishing area in which the CMP process is conducted and an indexing area in which wafers are loaded into and unloaded from the wafer carrier. In a specific embodiment, the spray nozzle is mounted within the indexing area such that it directs fluid to the area of need on the carrier, such as the back side of the carrier. The indexing area includes spray nozzles and a spray wash process that washes slurry from the front or wafer contact surface of the carrier during a time between unloading of a polished wafer and loading of a next wafer to be polished. Applicants have modified the CMP tool by addition of a coupling from the front wafer wash source to a back wafer wash distribution system. The system includes flexible tubing and a plurality of spray nozzles mounted to the support mechanism for the wafer carriers. When the system actuates the fluid source for the front carrier wash, a flow of fluid is directed to the added tubing and nozzles to that fluid is sprayed onto the back side of the wafer carriers. Accordingly, both the back side and front side of the carriers are washed concurrently.
-
FIG. 1 is a top plan view of one form of CMP tool with which the present invention may be used; and -
FIG. 2 is an elevation view taken along the lines 2-2 ofFIG. 1 . - Referring now to
FIGS. 1 and 2 ,FIG. 1 being highly simplified top plan view andFIG. 2 being an elevation view from the line 2-2, there is shown one form of aCMP machine 10 including apolishing pad 12 and an indexing table 14. Above the indexing table is positioned amovable turret 16 to which is attached a plurality ofwafer carriers 18. Theturret 16 is essentially a plate-like structure having a plurality ofwafer carriers 18 mounted thereon. Not shown in either of these views is the mounting mechanism for the wafer carriers which generally comprises a plurality of arms that pass through theturret 16 and are attached to each of the carrier heads through a gimbal (not shown). The attachment through the gimbal allows each of the carriers to be spun at a relatively high speed to achieve the uniform polishing when the turret is moved into the polishing position over thepolishing pad 12. For a more detailed description of theexemplary machine 10, reference may be had to U.S. Pat. No. 6,520,839. - The
turret 16 is provided with a plurality of circumferentially spacedslots 20 that provide a path for thecarriers 18 to be moved from a radially outward position around the turret to a radially inner position. The inner position is used solely for the purpose of transporting the turret from a loading and an unloading position over the indexing table to a polishing position over thepolishing pad 12. The carriers are normally positioned in the outer extreme of each of theslots 20 during the polishing operation at thepad 12 and during the unloading and loading functions over the index table 14. During the CMP polishing process, a slurry flows over thepolishing pad 12 and is used to achieve polishing of the semiconductor wafers. This slurry accumulates on both the wafers and thecarriers 18. When theturret 16 is transported back to the indexing table for unloading of the polished wafers, the wafers are unloaded into corresponding ones of a plurality of plastic cups that are located on the indexing table and are indicated inFIG. 1 at 22. Thecups 22 define wafer loading and unloading stations. Commonly, the indexing table has anouter wall 24 and aninner wall 26 which defines a trough in which the plastic cups reside. This trough is generally filled with a cleaning fluid, typically water, which is constantly circulated and cleaned and is used to clean the slurry from the wafers. However, thecarriers 18 do not protrude into the water on the indexing table and are therefore not cleaned when the wafers are unloaded. As a consequence, it is necessary to clean thecarriers 18 between the steps of unloading polished wafers and loading new wafers to be polished. As shown inFIG. 2 , there are multiple spacedspray nozzles 30 located on the indexing table that are angled upward and positioned between the respecting loading and unloading stations for cleaning the underside of thecarriers 18. More particularly, once thecarriers 18 have unloaded the wafers, theturret 16 is rotated so that the carriers are positioned between loading and unloadingcups 22 and a corresponding one of the spray nozzles sprays a stream of water upward onto the lower face of a respective one of the carriers to wash any slurry away from the carriers so that the slurry will not interfere with the loading of a subsequent wafer into the carrier. - In order to improve this cleaning process, applicant's have attached another plurality of
spray nozzles 32 onto theturret 16 and positioned the nozzles to aim downward toward the backs of thecarriers 18 so that a spray of water can be directed onto the back of the carriers at the same time that the front face of the carriers is washed by the spray from thenozzles 30. This process removes any slurry or dried slurry compound from the backside of the wafer carriers so that such compound is not carried back to thepolishing pad 12 when a next group of wafers are loaded and transported for polishing. It will be appreciated that the water for washing the back side of thewafer carriers 18 may come from the same source as the water used for washing the front face of the carrier by simply splitting off from the water source and coupling through a flexible tube to a distribution system mounted to the top of theturret 16. Such a system is indicated generally at 34. - The present invention provides a method and apparatus associated with the
CMP machine 10 for assuring that the slurry which is routinely deposited on the back side of thecarriers 18 is removed from those carriers at the indexing station so that when the carriers are next positioned over thepolishing pad 12, dried material from the back of the carriers will not be deposited on the polishing pad. It will be appreciated that any such dried material could scratch the semiconductor wafers during the polishing process. - Those skilled in the art will appreciate in view of the teachings herein that different types of CMP machines (or tools) may be configured to implement a spray function designed for washing the back side of a carrier in conjunction with the polishing process. CMP machines may be equipped with one or more spray nozzles and configured such that fluid is ejected out of the nozzle and aimed at the back side of a carrier so as to wash off undesired slurry components. The spray nozzle may be mounted to the CMP machine and connected to a fluid source. The functioning of the CMP process is typically coordinated by software. CMP machine software may be configured to include the function of actuating the spraying of fluid out the spray nozzle at an appropriate time during a normal routine of a CMP machine. Furthermore, existing machines may be retrofitted with a spray nozzle and their software reconfigured to implement the spraying of the back of a carrier.
- While the invention has been described in what is presently considered to be preferred embodiment, other modifications and variations will become apparent to those skilled in the art. It is intended therefore that the invention not be limited to the specific disclosed embodiment but be interpreted within the full spirit and scope of the appended claims.
Claims (8)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/205,382 US7172496B1 (en) | 2005-08-17 | 2005-08-17 | Method and apparatus for cleaning slurry depositions from a water carrier |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US11/205,382 US7172496B1 (en) | 2005-08-17 | 2005-08-17 | Method and apparatus for cleaning slurry depositions from a water carrier |
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Publication Number | Publication Date |
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US7172496B1 US7172496B1 (en) | 2007-02-06 |
US20070042686A1 true US20070042686A1 (en) | 2007-02-22 |
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US11/205,382 Expired - Fee Related US7172496B1 (en) | 2005-08-17 | 2005-08-17 | Method and apparatus for cleaning slurry depositions from a water carrier |
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Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2015062956A (en) * | 2012-09-19 | 2015-04-09 | 株式会社荏原製作所 | Polishing device |
CN103878668A (en) * | 2012-12-20 | 2014-06-25 | 上海华虹宏力半导体制造有限公司 | Washing device used for chemical mechanical polishing equipment |
CN108673326A (en) * | 2018-06-11 | 2018-10-19 | 彭春剑 | A kind of bamboo and wood processing surface polishing device |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5733171A (en) * | 1996-07-18 | 1998-03-31 | Speedfam Corporation | Apparatus for the in-process detection of workpieces in a CMP environment |
US5779520A (en) * | 1993-11-09 | 1998-07-14 | Sony Corporation | Method and apparatus of polishing wafer |
US6251001B1 (en) * | 1999-05-10 | 2001-06-26 | Applied Materials, Inc. | Substrate polishing with reduced contamination |
US6402598B1 (en) * | 1999-06-16 | 2002-06-11 | Samsung Electronics Co., Ltd. | Chemical mechanical polishing apparatus and method of washing contaminants off of the polishing head thereof |
US6505636B1 (en) * | 2000-06-26 | 2003-01-14 | Lam Research Corporation | Apparatus for wafer carrier in-process clean and rinse |
US6520839B1 (en) * | 1997-09-10 | 2003-02-18 | Speedfam-Ipec Corporation | Load and unload station for semiconductor wafers |
US6629883B2 (en) * | 2000-05-16 | 2003-10-07 | Ebara Corporation | Polishing apparatus |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0798302B2 (en) * | 1986-03-25 | 1995-10-25 | スピ−ドフアム株式会社 | Flat polishing machine |
-
2005
- 2005-08-17 US US11/205,382 patent/US7172496B1/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5779520A (en) * | 1993-11-09 | 1998-07-14 | Sony Corporation | Method and apparatus of polishing wafer |
US5733171A (en) * | 1996-07-18 | 1998-03-31 | Speedfam Corporation | Apparatus for the in-process detection of workpieces in a CMP environment |
US6520839B1 (en) * | 1997-09-10 | 2003-02-18 | Speedfam-Ipec Corporation | Load and unload station for semiconductor wafers |
US6251001B1 (en) * | 1999-05-10 | 2001-06-26 | Applied Materials, Inc. | Substrate polishing with reduced contamination |
US6402598B1 (en) * | 1999-06-16 | 2002-06-11 | Samsung Electronics Co., Ltd. | Chemical mechanical polishing apparatus and method of washing contaminants off of the polishing head thereof |
US6629883B2 (en) * | 2000-05-16 | 2003-10-07 | Ebara Corporation | Polishing apparatus |
US6505636B1 (en) * | 2000-06-26 | 2003-01-14 | Lam Research Corporation | Apparatus for wafer carrier in-process clean and rinse |
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