VACUUM DEVICE BY USING CENTRIFUGAL RESOURCES
A wafer holding vacuum for a wafer polishing system and the wafer suction device for CMP (Chemical Mechanical Polishing) by utilizing existing resources provided by the rotating polishing post is provided. The device introduces a channel configured in the wafer suction device. One end of the channel is exposed at downside of the holding block, and another end of the tube is exposed at lateral side of the holding block. By aforementioned configuration, the channel can suck gas and/or liquid between the wafer and the device, and can discharge them to the outer environment at the lateral side using centrifugal force naturally provided by the polishing post.
The present invention generally relates to a block on the polishing post, in particular, to a wafer suction device of the block.
DESCRIPTION OF THE PRIOR ARTCMP (Chemical Mechanical Polishing) has become an indispensable process in the semiconductor industry due to ever-shrinking feature size of circuits.
Referred to
However, the vacuum source is indispensable in the traditional vacuum suction device. Because the polishing post is rotating during the process, there are two main issues regarding this conventional vacuum suction device: 1. the vacuum pipe has to be configured at the center of the rotary mechanism, which means it has to pass through various complicated elements in the polishing post, so that the manufacturing process becomes difficult and the cost also becomes higher. Additionally, there may exist some gaps since the air pipe are configured between fixed elements and rotary elements, thereby causing air leaking into the vacuum and consequently wasting the vacuum energy. 2. The conventional polishing device requires continuous vacuum energy to maintain the process. Some liquid or gas may leak into the space between the backside of the wafer and the block during polishing. If the vacuum energy is stopped, the liquid or gas leaked into the back of the wafer may loosen the wafer even causing it to be thrown from the block during rotation. This often causes wafer breakage.
Based on aforementioned descriptions, a new configuration is needed to alleviate the wafer breakage issue in the CMP process.
SUMMARY OF THE INVENTIONIn view of the foregoing, the present invention provides a device capable of maintaining vacuum without any vacuum energy, and it can employ the existing rotary resource to generate and maintain the vacuum, thereby significantly saving energy and simplifying the complexity of manufacturing this apparatus.
It was realized that the reason of wafer breakage is due to the shortage of the vacuum strength between the wafer and the contacting surface on the block. Maintaining the continuous vacuum strength requires continuous vacuum energy and complicated polishing post design to support the continuous vacuum under leakage. Therefore, the present invention provides a simple way of holding block design without the need of continuous vacuum energy supplies. The vacuum between the back of the wafer surface and the polishing block is provided by the centrifugal force already generated by the rotating polishing post. When the CMP is polishing the wafer, due to turning and vibrating air and liquid occasionally sip into the contact between the holding block and the back side of the wafer causing the holding block unable to hold the wafer firmly. This is the main cause for wafer to get loose and break out.
One advantage of the present invention is to utilize the natural centrifugal force generated when the polishing post is rotated for polishing purpose, so as to maintain the vacuum, thereby preventing the breakage issue that the wafer is thrown away during the polishing process while reducing the cost of existing continuous vacuum line operations.
Another advantage of the present invention is to provide a wafer suction device with simplified structure and excellent effect, thereby achieving the object of saving cost and resources. The more complex the system design the more error prone the system is. Conventional vacuum line has to go through all the components along the central line of polishing post/post on
In order to meet aforementioned purposes, the present invention provides a wafer suction device, which includes: a block; and at least one channel configured in the block, one end of the at least one channel is exposed at down side of the block, whereby utilizing centrifugal force to suck fluid (including gas and/or liquid) between the block and the wafer, and another end of the at least one channel is exposed at lateral side of the block, whereby discharging the fluid. By aforementioned configuration, the present invention can employs the centrifugal force naturally generated to suck the leaked-in fluid between the wafer and the block and discharge the fluid to environment through the channels when the polishing post is rotated. The vacuum effect can be achieved without any vacuum source. Further, because the polishing post is always rotating during the polishing processes, the centrifugal force may be maintained continuous thus the vacuum is reserved continuously holding the wafer firmly to avoid being thrown out.
The present invention also provides a wafer suction device, which comprises: a block; at least one main channel configured in the block, and one end of the at least one main channel is exposed at lateral side of the block; at least one first sub-channel, wherein one end is exposed at down side of the block and, and another end is connected to another end of the at least one main channel; and at least one second sub-channel, wherein one end is exposed at down side of the block, and another end is connected to body of the at least one main channel; wherein connected zones between the at least one main channel and the at least one second sub-channel are formed as a Ventura tube. In view of the foregoing, the present invention can utilize the Ventura tube at the connected zones between the main channel and the second sub-channel to increase the flowing speed of the fluid, whereby facilitating to generate and maintain the vacuum.
To prevent the reverse fluid flow in the block channel when the polishing post is not rotating, the present invention employs a check valve at the end of the channel thereby preserving the vacuum to hold the wafer in place.
Additionally, in order to prevent the fluid from spraying around, the present invention may also introduce a fluid-guiding device at the exit of the channel, so that the fluid can be directed downwards to join the recovered polishing fluid to be discharged.
Some sample embodiments of the invention will now be described in greater detail. Nevertheless, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited expect as specified in the accompanying claims.
The present invention relates to a wafer suction device of the polishing post. Generally speaking, the present invention introduces at least one channel in the block of the wafer suction device, wherein one end is exposed at down side of the block, and another side is exposed at lateral side of the block. By aforementioned configuration, the gas and/or liquid between the wafer and the block are sucked to the environment by the induced centrifugal force generated in the channel when the polishing post is being rotated. When the gas and/or liquid are sucked out the vacuum status is created. Therefore, the vacuum sucking force can be generated to enable wafer adherence to the polishing post thus preventing the wafer breakage.
Referred to
The preferred embodiment of the wafer suction device of the present invention is shown in
Figure
Referred to
As will be understood by persons skilled in the art, the foregoing preferred embodiment of the present invention is illustrative of the present invention rather than limiting the present invention. Having described the invention in connection with a preferred embodiment, modification will now suggest itself to those skilled in the art. Thus, the invention is not to be limited to this embodiment, but rather the invention is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures. While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
Claims
1. A wafer suction device, comprising:
- a block; and
- at least one channel configured in said block, and one end of said at least one channel is exposed at a contact surface between said block and a wafer, whereby utilizing centrifugal force to suck fluid between said block and said wafer, and another end of said at least one channel is exposed at lateral side of said block, whereby discharging said fluid.
2. The wafer suction device according to claim 1, further comprising at least one check valve configured at said another end of said at least one channel.
3. The wafer suction device according to claim 1, wherein a fluid-guiding device is configured at an exit of said channel, whereby making said fluid outflows along a specific direction.
4. The wafer suction device according to claim 1, wherein said at least one channel having a main channel and at least one sub-channel connected to said main channel, and one end of said main channel is exposed at said lateral side of said block, one end of said at least one sub-channel is exposed to said contact area between said block and said wafer, and another end of said at least one sub-channel is connected to said main channel for discharging said fluid.
5. The wafer suction device according to claim 4, wherein connected zones between said main channel and said at least one sub-channel are formed as a Ventura tube.
6. The wafer suction device according to claim 4, wherein said at least one sub-channel is non-vertically connected to said main channel.
7. The wafer suction device according to claim 4, further comprising at least one check valve configured at one end of said main channel.
8. The wafer suction device according to claim 4, wherein a fluid-guiding device is configured at an exit of said main channel, whereby making said fluid discharged along a specific direction.
9. The wafer suction device according to claim 1, further comprising a fixing ring configured at down side of said block for fixing said wafer.
10. A wafer polishing system, comprising:
- a polishing post body; and
- a wafer suction device configured at bottom of said polishing post body for attaching a wafer;
- wherein said wafer suction device containing: a block; and at least one channel configured in said block, and one end of said at least one channel is exposed at a contact surface between said block and said wafer, whereby utilizing centrifugal force to suck fluid between said block and said wafer, and another end of said at least one channel is exposed at lateral side of said block, whereby discharging said fluid.
11. The wafer polishing system according to claim 10, further comprising a check valve configured at another end of said at least one channel.
12. A wafer polishing system, comprising:
- a polishing post body; and
- a wafer suction device configured at bottom of said polishing post body for attaching a wafer;
- wherein said wafer suction device containing: a block; at least one main channel configured in said block, and one end of said at least one main channel is exposed at lateral side of said block; at least one first sub-channel, wherein one end is exposed at contact surface between said block and said wafer, and another end is connected to another end of said at least one main channel; and at least one second sub-channel, wherein one end is exposed at said contact surface between said block and said wafer, and another end is connected to body of said at least one main channel; wherein connected zones between said at least one main channel and said at least one second sub-channel are formed as a Ventura tube.
13. The wafer polishing system according to claim 12, further comprising at least one check valve configured at said end of said at least one main channel.
Type: Application
Filed: Jan 17, 2012
Publication Date: Sep 27, 2012
Inventor: Dongliang Daniel Sheu (Hsin Chu)
Application Number: 13/352,032
International Classification: B24B 41/06 (20120101);