CN111469045A

CN111469045A - Wafer loading cup

Info

Publication number: CN111469045A
Application number: CN202010323556.XA
Authority: CN
Inventors: 赵德文; 孟松林; 赵慧佳
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2020-07-31
Anticipated expiration: 2040-04-22
Also published as: CN111469045B

Abstract

A wafer loading cup, comprising: the bracket is coaxially arranged at the center of the loading cup and is provided with a circular annular edge for receiving the dropped wafer; the supporting clamping ring is coaxially arranged on the periphery of the circumference of the bracket and used for supporting and/or positioning the wafer bearing head, the top surface of the supporting clamping ring is arranged to be higher than the top surface of the bracket, and at least one nozzle which is arranged on the supporting clamping ring and used for jetting fluid to the central axis direction of the loading cup is arranged.

Description

Wafer loading cup

Technical Field

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a wafer loading cup.

Background

Chemical Mechanical Polishing (CMP) is a mainstream wafer polishing method in the field of chip manufacturing. The polishing method generally sucks the wafer to the lower part of a bearing head, one surface of the wafer, which is provided with a deposition layer, abuts against a rotating polishing pad, and the bearing head rotates in the same direction with the polishing pad under the drive of a drive part and gives downward load to the wafer; meanwhile, the polishing solution is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, so that the surface of the wafer is polished under the chemical action generated by the chemical components of the polishing solution and the mechanical action generated by the abrasive particles contained in the polishing solution, and the global planarization is realized.

The carrier head is an important component of the chemical mechanical polishing apparatus, and the operation performance of the carrier head is directly related to the chemical mechanical polishing effect of the wafer. U.S. patent publication No. 20070082589a1 discloses a carrier head for chemical mechanical polishing that includes a first passageway connected to a first pressure input and a second passageway connected to a second pressure input. The carrier head also includes a base assembly having the first and second passageways, a flexible bladder coupled to the base assembly. The flexible bladder generally has a circular body with a lower surface providing a wafer mounting surface. A plurality of pressurizable chambers are formed in the space between the base assembly and the flexible bladder, wherein the first passageway communicates with a first chamber of the plurality of pressurizable chambers and the second passageway communicates with a second chamber of the plurality of pressurizable chambers.

In the prior art, such as those disclosed in US7101253 and US7044832, a chemical mechanical polishing apparatus adsorbs and carries a wafer onto a polishing pad for polishing by a carrier head (carrier/polishing head), and after polishing, the wafer is carried back by the carrier head and unloaded onto a loading cup (loading cup), which is generally referred to as "unloading" and can also be understood as unloading the wafer from the carrier head and loading the wafer onto the loading cup.

But instead. In the process of unloading the wafer, the problem that the wafer is tightly attached to the flexible air bag exists, so that the unloading time is too long, even the unloading fails, and the productivity and the efficiency are reduced. Although a method such as that disclosed in U.S. patent publication No. US20070232209a1, which employs the provision of vents in the surface of the carrier head, assists in unloading the wafer by blowing air in a vertical direction toward the upper surface of the wafer through the bladder/air film, contaminants are easily introduced into the carrier head, creating further problems such as crystal contamination scratches. Further, the failure of wafer unloading is generally divided into two problems, i.e., the flexible airbag is difficult to fall off in the edge area of the wafer and the flexible airbag is difficult to fall off in the area near the central part of the wafer. In addition, the problem of increasing the chip unloading speed while ensuring the chip unloading success rate is also a problem to be solved urgently.

Disclosure of Invention

The present invention provides a wafer loading cup, which aims to solve one of the above technical problems to a certain extent, and discloses a wafer loading cup, which is characterized by comprising: the bracket is coaxially arranged at the center of the loading cup and is provided with a circular annular edge for receiving the dropped wafer; the supporting clamping ring is coaxially arranged on the periphery of the circumference of the bracket and used for supporting and/or positioning the wafer bearing head, and the top surface of the supporting clamping ring is higher than that of the bracket; and at least one nozzle provided to the support collar, the nozzle being configured to eject fluid in a direction of a central axis of the loading cup.

Further, the nozzle is arranged as a non-atomizing nozzle and can spray columnar fluid and/or gas-liquid mixture.

Further, the number of the nozzles is 2 or more.

Further, the nozzles are arranged equidistantly in the circumferential direction of the support collar.

Further, the nozzles are arranged to spray downwardly with respect to a horizontal plane to spray fluid onto the wafer and carrier head interface during unloading.

Further, at least one or all of the nozzles are disposed to be inclined downward by 0 to 30 degrees with respect to a horizontal plane.

Further, all of the nozzles are disposed to be inclined downward by 3 to 15 degrees with respect to a horizontal plane.

Further, the nozzle is set to have a nozzle diameter of 2mm to 6 mm.

Further, the number of the nozzles is 3 to 8.

Further, the nozzles are arranged at equal intervals, and the nozzles are sequentially inclined downward along a horizontal plane at a small-to-large angle or a large-to-small angle.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: the wafer unloading speed and the wafer unloading success rate of the wafer loaded by the wafer loading cup are increased, the problem of WPH reduction caused by slow wafer unloading is prevented, and other risks caused by improper wafer unloading or wafer unloading failure are avoided. Compared with the method that holes are formed in the flexible air bag (air film) or the holes are opened at other positions of the bearing head to assist in sheet unloading, the technical scheme of the invention does not need to be provided with devices such as air path slide and the like, the manufacturing and maintenance cost is greatly reduced, and the realizability and the optimization possibility are obviously improved.

Drawings

The advantages of the invention will become clearer and more readily appreciated from the detailed description given with reference to the following drawings, which are given by way of illustration only and do not limit the scope of protection of the invention, wherein:

FIG. 1 is a schematic structural view of an embodiment of a wafer loading cup according to the present invention;

FIG. 2 is a schematic diagram of an embodiment of a wafer loading cup according to the present invention;

FIG. 3 illustrates a problem that may be encountered with one embodiment of a wafer loading cup according to the present invention;

FIG. 4 shows a modified variant embodiment of the wafer loading cup according to the invention;

figure 5 shows another modified variant embodiment of the wafer loading cup according to the invention.

Detailed Description

The following describes the technical solutions related to the embodiments of the present invention in detail with reference to the specific embodiments and the accompanying drawings. The examples set forth herein are specific, non-limiting, embodiments of the present invention and are presented to illustrate the concepts and concepts of the present invention; the description is illustrative, exemplary, and schematic and is not to be construed as limiting the embodiments of the invention and the scope of the invention. In addition to all of the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious or will be easily conceived based on the disclosure of the claims and the specification thereof, and these technical solutions include those which employ any obvious replacement or modification of the embodiments described herein. In order to explain the technical means of the present invention, the following description will be given by way of specific examples. In the present application, "Chemical Mechanical Polishing" is also referred to as "Chemical Mechanical planarization", and a substrate (substrate) is also referred to as a wafer (wafer), which means equivalent to the actual function.

Fig. 1 illustrates an operation of a wafer loading cup 200 according to the present invention, in which fig. 1 is a wafer loading cup (load cup)200 according to the present invention except for a carrier head 1, a wafer W and a flexible airbag 11, after the carrier head 1 is aligned with a bracket 2 of the wafer loading cup 200, the air pressure of a chamber in the middle of the flexible airbag 11 is increased and/or the air pressure of an edge chamber is decreased, so that an edge portion of the upper surface of the wafer W is separated from the flexible airbag 11, and further, under the action of gravity, the area of the central region of the upper surface of the wafer W, which is attached to the lower surface of the flexible airbag 11, is gradually decreased until the wafer W is completely separated from the flexible airbag 11 and then falls onto the bracket 2 of the wafer loading cup 200, thereby completing the unloading of the wafer W.

However, during the chemical mechanical polishing process, deionized water (DIW) or polishing liquid often enters between the wafer W and the flexible airbag 11, so that the surface adhesion of the wafer W is increased, and meanwhile, because the weight of the wafer W is small, the wafer W cannot be separated from the flexible airbag 11 by its own gravity.

As shown in fig. 1, a wafer loading cup 200 according to the present invention includes a carrier 2, a support collar 3 at the periphery of the carrier 2, and a nozzle 31. The supporting clamping ring 3 is in a circle shape and used for supporting and blocking the bearing head 1, and the bracket 2 and the supporting clamping ring 3 are arranged concentrically. When unloading wafer W, the carrier head 1 moves to the upper side of the wafer loading cup 200 and aligns to the bracket 2, so as to ensure that the center of the wafer W aligns to the center of the bracket 2 as much as possible, the lower edge of the outer periphery of the bevel angle of the carrier head 1 abuts against the upper edge of the bevel angle of the supporting collar 3 matched in shape to realize positioning, the middle chamber of the flexible air bag 11 is pressurized and/or the edge chamber is depressurized to reduce the adsorption force of the carrier head 1 to the wafer W, so that the wafer W is driven to fall off from the carrier head 1, and finally the wafer W falls off to the circular edge 21 on the bracket 2 for bearing the wafer.

The support collar 3 is provided with one, two or more nozzles 31, the outlets of the nozzles 31 being arranged on the inner wall of the support collar 3 and/or on the top (upper surface) of the support collar 31 and pointing in the direction of the centre axis of the carrier 2. As a non-limiting embodiment, the body of the nozzle 31 may be embedded in the support collar 3, the tail end of the outside being in communication with a delivery duct (not shown) to supply the nozzle 31 with gas and/or liquid for spraying. The delivery conduit is connected to a fluid supply for delivering gas and/or liquid to the nozzle 31. In one embodiment of the present invention, the fluid supply device may provide one and/or a mixture of pressurized nitrogen gas, pressurized isopropyl alcohol gas, isopropyl alcohol-containing liquid, cleaning agent, deionized purified water (DIW), and the like. Although not shown in the drawings, it is easily understood that the loading cup 200 according to the present invention may be further provided with a liquid storage means, a gas-liquid mixing means, a gas compression means, a gas storage means, a liquid pressurizing means, and/or a liquid mixing means, etc. for changing the state and/or speed, etc. of the fluid ejected from the nozzle 31.

Fig. 2 is a schematic diagram of the wafer rapid unloading according to the embodiment of the invention, the support collar 3 and the nozzle 31 are arranged such that when the carrier head 1 abuts on the support collar 3, the nozzle 31 is arranged as close as possible to the top surface of the support collar 3, in particular, the distance of the centre of the outlet of the nozzle 31 from the top surface of the support collar 3 should be as small as possible, for example not exceeding 30mm, and preferably 8mm or less, so that the fluid can be ejected through the nozzles 31 between the lower surface of the flexible bladder 11 and the upper surface of the wafer W rather than below the wafer at the first time when the carrier head 1 starts unloading the wafer (unloading the wafer), thereby helping to fast unload the wafer, avoiding wasting the sprayed fluid when the fluid is sprayed below the wafer W after the carrier head 1 starts unloading the wafer and wasting time because the fluid cannot play a role of assisting in unloading the wafer, and reducing the whole output (WPH) of the polishing equipment.

Further, it is generally expected that the fluid is sprayed onto the periphery of the junction between the flexible bladder 11 and the wafer W at an appropriate flow rate and speed to break the junction between the flexible bladder 11 and the wafer W by the scouring force of the fluid directly to achieve rapid wafer unloading. However, the pressure of the factory water in a general Fab is difficult to ensure such effects or requires a separate pressurizing device to achieve such ejection intensity or distance. In order to increase the ejection distance and the ejection strength of the nozzle 31 so that the columnar fluid can be ejected to the central bonding region of the wafer W in a manner as little as possible scattering, it is preferable to provide the nozzle 31 in a non-atomized direct injection configuration or a beam-jet pressurized configuration so as to ensure that the pressure and the distance of the fluid ejection can achieve the effect of assisting the wafer unloading.

Considering that the factory terminal water supply flow rate of the wafer factory is generally 2L/min to 5L/min, the nozzle 31 should be designed such that the spray distance of the fluid is greater than the radius of the wafer W, for example, greater than the radius of a common 300mm wafer, i.e., greater than 150mm, and preferably such that the spray distance reaches 200mm or more, and since the sprayed fluid will reside on the surface of the wafer W, it is desirable to spray as much fluid as possible and to reside on the surface of the wafer W so as to increase the possibility that the wafer W falls down by gravity for the purpose of rapid wafer unloading, the outer diameter (diameter) of the nozzle should not be greater than 7mm, and should not be less than 1mm, and preferably 2mm to 5mm, so as to spray a columnar fluid having a diameter greater than 2mm and a spray distance greater than 150 mm.

As shown in fig. 3, in addition to avoiding jetting fluid under the wafer W, it is more desirable to accurately jet fluid at the bonded interface (i.e., interface) of the flexible bladder 11 and the wafer W; however, as the flexible bladder 11 expands, the joint interface moves downward, so that the fluid is blocked by the expanded flexible bladder 11 and cannot reach the joint interface easily; in other words, if the nozzle 31 continues to spray horizontally at an angle parallel to the wafer W, the marginal effect of the sprayed fluid on the unloading aid is rapidly decreased after the flexible bladder 11 continues to expand.

To this end, as shown in fig. 4, a nozzle angle adjusting device 300, such as a telescopic rod driven by a cylinder, an electromagnet or a lead screw, may be configured for the support collar 3 to adjust the spray angle α of the nozzle 31, i.e. the included angle between the columnar fluid sprayed by the nozzle 31 and the plane of the wafer W, so that the fluid can still be sprayed to the junction of the wafer W and the flexible bladder 11 after the flexible bladder 11 is inflated and swollen, specifically, the nozzle angle adjusting device 300 is a position control device with a reset function, such as an electric control push rod, and may linearly or non-linearly control the spray angle of the nozzle 31, so that the nozzle 31 sprays the fluid at a horizontal angle first and sprays the fluid in a downward inclined manner after the flexible bladder 11 is inflated and swollen for 0.3S to 1 second, and then sprays the fluid at a fixed angle of 0.5 ° to 30 ° to the junction of the flexible bladder 11 and the wafer W, as an alternative embodiment, the spray angle α of the nozzle 31 may be set to gradually contact with the flexible bladder 11 at a preset height difference between the wafer W and the wafer W when the flexible bladder 11 is tilted downward inclined angle is changed from 632 ° to 52 ° and the wafer W is set to a preset height difference between the wafer W.

In the process of unloading the wafer W, the nozzle 31 may spray a pressurized fluid at an interface between a central region of an upper surface of the wafer W and a central region of a lower surface of the flexible bladder 11, so that an adhesion state at the interface is rapidly released, and at the same time, the air pressure between the wafer W and the flexible bladder 11 is increased, which helps the wafer W to be rapidly separated from the flexible bladder 11, and accelerates the unloading speed of the wafer.

The number and the position of the nozzles 31 can be set according to actual requirements, 4 nozzles 31 which are equidistantly and equiangularly symmetrically arranged are shown in fig. 5, and actually, the number of the nozzles can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or more, and can be odd number or even number. In order to ensure a uniform progress of separation of the wafer W in the circumferential direction, the plurality of nozzles 31 are preferably uniformly provided at the same intervals in, on and/or inside the support collar 3 to eject the fluid toward the center of the carrier 2.

As a further variation to take into account the spray angles, the spray angles of the nozzles 31 at different positions may be different, taking the four nozzles 31 in FIG. 5 as an example, the uppermost nozzle 31A is arranged to spray fluid horizontally, i.e., the fluid sprayed from the uppermost nozzle has an angle α of 0 degrees with the wafer surface, the adjacent left nozzle 31B is arranged to spray fluid with a downward inclination of 5 degrees, the lowermost nozzle 31D in the top view sprays fluid with a downward inclination of 10 degrees, and the rightmost nozzle 31C in the top view sprays fluid with a downward inclination of 15 degrees, and indeed, no matter how many nozzles are arranged, as long as at least two of the nozzles are arranged with different angles, at least one of which is inclined downward with respect to the horizontal plane, so that different nozzles can spray fluid to a region near the interface at different times of chip unloading, improved better chip unloading effect and faster chip unloading speed can be achieved.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the above embodiments, the description of the embodiments is focused on, and these embodiments can be arbitrarily combined, and a new embodiment formed by combining them is also within the scope of the present application. For parts of one or some embodiments that are not described or specified in detail, reference may be made to the description of other embodiments. Moreover, the present invention will not be described in detail with respect to finished components such as angle and/or position adjustment devices, nozzles, etc., which are known in the art or are commercially available. The above embodiments and implementation manners are only used for illustrating the technical solutions of the present invention, and are not limited or restricted thereto; although the present invention has been described with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be replaced with similar or equivalent ones; such modifications and substitutions should not be considered as included within the scope of the present invention, unless they depart from the spirit or essential characteristics or points of the present invention. In other words, while embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wafer loading cup, comprising:

the bracket is coaxially arranged at the center of the loading cup and is provided with a circular annular edge for receiving the dropped wafer;

the supporting clamping ring is coaxially arranged on the periphery of the circumference of the bracket and used for supporting and/or positioning the wafer bearing head, and the top surface of the supporting clamping ring is higher than that of the bracket;

and at least one nozzle provided to the support collar, the nozzle being configured to eject fluid in a direction of a central axis of the loading cup.

2. The wafer loading cup of claim 1, wherein the nozzle is configured as a non-atomizing nozzle that can spray a column of fluid and/or gas-liquid mixture.

3. The wafer carrier cup of claim 1, wherein the number of nozzles is 2 or more.

4. The wafer carrier cup of claim 3, wherein the nozzles are equally spaced along a circumference of the support collar.

5. The wafer loading cup of claim 1 wherein the nozzles are arranged to spray downwardly with respect to a horizontal plane to spray fluid to a junction of the wafer and the carrier head during unloading.

6. The wafer loading cup of claim 5, wherein at least one or all of the nozzles are disposed at a downward inclination of 0 ° to 30 ° with respect to a horizontal plane.

7. The wafer loading cup of claim 6 wherein all of said nozzles are disposed at a downward inclination of 3 ° to 15 ° with respect to a horizontal plane.

8. The wafer loading cup of claim 1, wherein the nozzle is configured to have a nozzle diameter of 2mm to 6 mm.

9. The wafer loading cup of claim 6, wherein the number of nozzles is 3 to 8.

10. The wafer loading cup of claim 9, wherein the nozzles are arranged at equidistant intervals and are sequentially inclined downwardly along a horizontal plane at a small to large or large to small angle.