CN114346893A - Chemical mechanical polishing method - Google Patents
Chemical mechanical polishing method Download PDFInfo
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- CN114346893A CN114346893A CN202210039252.XA CN202210039252A CN114346893A CN 114346893 A CN114346893 A CN 114346893A CN 202210039252 A CN202210039252 A CN 202210039252A CN 114346893 A CN114346893 A CN 114346893A
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Abstract
The invention provides a chemical mechanical polishing method, which comprises the following steps: the method comprises the steps of grinding a batch of wafers one by utilizing a chemical mechanical grinding device, finishing a grinding pad of the chemical mechanical grinding device when grinding at least two wafers, and generating grinding byproducts which affect the grinding rate in the process of carrying out chemical mechanical grinding on the wafers.
Description
Technical Field
The invention relates to the field of semiconductor manufacturing, in particular to a chemical mechanical polishing method.
Background
In semiconductor manufacturing, as the process technology is upgraded and the sizes of the conductive lines and the gates are reduced, the photolithography (Lithography) technology has higher and higher requirements on the flatness (Non-uniformity) of the surface of the wafer, and the chemical mechanical polishing (cmp) is a technology that can achieve global planarization in the current mechanical processing by combining chemical etching and mechanical removal.
In the process of polysilicon polishing (Poly CMP) of a wafer by using a soft polishing pad, byproducts generated during polishing contribute significantly to the polishing rate, and when the pores in the polishing pad are sufficiently filled with polishing particles in the polishing slurry and polishing byproducts generated during polishing, the polishing rate is stabilized, and the stiffness of the polishing pad can be adjusted, and when the filling of the pores in the polishing pad becomes unstable, the polishing properties are also affected.
In a polysilicon chemical mechanical polishing (Poly CMP) process, a polishing pad dressing process and a polishing process are performed independently, and the dressing time does not change with the change of the polishing time, and a dressing and polishing mode is usually adopted. The polishing pad is trimmed to remove part of the filler on the surface of the polishing pad, and the shape of the fluff layer on the surface of the polishing pad is improved. However, in the chemical mechanical polishing process of some products, the polishing rate of polysilicon is very high, and the filling rate of the micropores during the polishing process is lower than the cleaning rate during the trimming process of the polishing pad, so that the number of polishing particles and polishing byproducts in the micropores is less and less, and the polishing rate is gradually reduced, and the thickness of the polished wafer is increased along with the increase of the number of wafers polished by the same polishing pad during the chemical mechanical polishing process, so that the uniformity of the film thickness among the wafers subjected to chemical mechanical polishing is poor.
Disclosure of Invention
The invention aims to provide a chemical mechanical polishing method, which improves the uniformity of film thickness among wafers after a batch of wafers are subjected to chemical mechanical polishing by using the same polishing pad.
In order to achieve the above object, the present invention provides a chemical mechanical polishing method, comprising:
and grinding a batch of wafers one by utilizing a chemical mechanical grinding device, and trimming a grinding pad of the chemical mechanical grinding device every time at least two wafers are ground.
Optionally, the wafer includes a substrate and a gate structure located on the substrate, and when the wafer is ground, the top of the gate structure of the wafer is ground.
Optionally, before polishing the first wafer, the polishing pad is trimmed at least once.
Optionally, after each wafer is polished, the thickness of the polished wafer is measured, and if the thickness of the polished wafer is smaller than a preset value, the polishing pad is trimmed.
Optionally, the process of dressing the polishing pad and the process of polishing the wafer are independent of each other.
Optionally, the number of the wafers polished between two adjacent times of dressing the polishing pad is the same or different.
Optionally, the polishing pad is dressed once or at least twice each time the polishing pad is dressed.
Optionally, the time for dressing the polishing pad is the same for each time, and each dressing dresses all polishing regions of the polishing pad.
Optionally, the number of times of dressing each time the polishing pad is dressed is positively correlated to the number of the wafers polished after the polishing pad is dressed last time.
Optionally, the grinding time of each wafer is the same.
The invention provides a chemical mechanical polishing method, which comprises the following steps: and grinding a batch of wafers one by utilizing a chemical mechanical grinding device, and trimming a grinding pad of the chemical mechanical grinding device every time at least two wafers are ground. The invention adjusts the number of the grinding byproducts adhered on the grinding pad in the grinding process by adjusting the number of the ground wafers between every two times of dressing in the chemical mechanical grinding process and the dressing times in each dressing process, thereby further homogenizing the grinding rate of the wafers and improving the uniformity of the film thickness among the wafers after the chemical mechanical grinding of a batch of wafers.
Drawings
FIG. 1 is a schematic view of a chemical mechanical polishing apparatus according to an embodiment of the present invention;
FIG. 2 is a graph showing a grinding rate line when continuous grinding is performed;
FIG. 3 is a line graph showing the thickness variation of each wafer after polishing and when dressing the polishing pad;
FIG. 4 is a schematic view of a chemical mechanical polishing method according to an embodiment of the present invention;
FIG. 5 is a line graph showing the thickness variation of each three wafers after being polished while the polishing pad is being dressed;
FIG. 6 is a line graph showing the thickness variation of the wafers as the pad is trimmed from every three wafers polished to every five wafers polished;
wherein the drawings are described as follows:
100-a wafer; 102-a polishing pad; 104-a polishing head; 106-finishing brush; 108-mechanical arm.
Detailed Description
The following describes in more detail embodiments of the present invention with reference to the schematic drawings. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
In the following, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances. Similarly, if the method described herein comprises a series of steps, and the steps presented herein are not necessarily the only order in which the steps may be performed, some of the described steps may be omitted or some other steps not described herein may be added to the method.
The present invention provides a chemical mechanical polishing method, in which a chemical mechanical polishing apparatus is used to polish a batch of wafers one by one, and fig. 1 is a schematic structural diagram of the chemical mechanical polishing apparatus provided in this embodiment, as shown in fig. 1, the chemical mechanical polishing apparatus includes: a grinding unit and a grinding slurry supply unit.
Specifically, the polishing unit includes a polishing pad 102 and a polishing head 104 for fixing a polished wafer 100, the wafer 100 is located between the polishing pad 102 and the polishing head 104, a diameter of the wafer 100 is smaller than or equal to a radius of the polishing pad 102, and the wafer 100 is located on one side of the polishing pad 102.
When the wafer 100 needs to be polished, the polishing head 104 drives the wafer 100 to move downward, so that the surface of the wafer 100 to be polished contacts the polishing pad 102, and the polishing slurry supply unit sprays polishing slurry containing polishing particles onto the surface of the polishing pad 102; in the process of polishing the wafer 100, the polishing head 104 continuously applies a downward pressure to the wafer 100 to ensure that the surface of the wafer 100 is in close contact with the polishing pad 102, the polishing head 104 drives the wafer 100 to rotate, and the polishing pad 102 simultaneously rotates to polish the wafer 100.
The wafer 100 includes a substrate and a gate structure located on the substrate, and when the wafer is ground, the top of the gate structure of the wafer is ground.
Further, the polishing pad 102 includes: the wafer polishing device comprises a base plate, and an adhesive layer and a fluff layer which are sequentially arranged on the base plate, wherein during a polishing process, generated polishing particles are adhered in the fluff layer, and the polishing particles are used for polishing the wafer 100. During the polishing of the wafer 100, polishing by-products are continuously generated, the adhesive layer adheres the polishing by-products into the fluff layer, and the polishing by-products are continuously accumulated in the fluff layer as the polishing is continuously performed. The polishing byproducts and the polishing particles can adjust the stiffness of the polishing pad 102. Fig. 2 is a graph showing a polishing rate line when performing continuous polishing, and as shown in fig. 2, it can be seen from data of two tests that when a plurality of wafers are continuously polished by using the same polishing pad, the polishing rate of the wafers by the polishing pad is increased as the number of the wafers continuously polished increases.
Since the time for polishing each wafer 100 is not changed, if the polishing by-products and the polishing particles accumulated in the fluff layer are not cleaned, the faster the polishing speed is, the smaller the thickness of the wafer 100 after polishing in the same time, which may affect the performance of the semiconductor device.
With continued reference to fig. 1, the cmp apparatus further includes a conditioning unit including a robot 108 and a conditioning brush 106 disposed at an end of the robot 108. The finishing brush 106 is used to remove a portion of the abrasive particles and the polishing by-products from the surface of the polishing pad 102 while finishing the shape of the fluff layer.
The trimming brush 106 is a nylon brush, and the softer trimming brush 106 can better protect the fluff layer, thereby increasing the service life of the polishing pad 102.
The dressing unit is separate from and independent of the polishing unit polishing the wafer 100 to dress the polishing pad 102. Each time the polishing pad 102 is dressed, the dressing brush 106 brushes across the entire polishing area of the polishing pad 102, and the dressing time is independent of the polishing process.
In the conventional chemical mechanical polishing method, the polishing pad 102 is trimmed after each wafer 100 is polished, but in the process of polishing the polysilicon layer, since the time for polishing the polysilicon is short, the accumulated amount of the polishing byproducts in the polishing process of the fluff layer is small, and if the method of trimming after each wafer is continuously polished is adopted, even if the number of trimming times in the trimming process is reduced to one time, the amount of the polishing byproducts removed in the trimming process is still larger than the accumulated amount of the polishing byproducts in the fluff layer in the polishing process, the amount of the polishing byproducts in the fluff layer is continuously reduced along with the increase of the number of the wafers polished in the chemical mechanical polishing process, and further, the polishing rate of the wafer 100 is gradually reduced. Fig. 3 is a line graph showing thickness variation of the wafer when the polishing pad is dressed after polishing one wafer, and as shown in fig. 3, when the polishing time for each wafer is constant, the thickness of the polished wafer increases as the number of the wafers polished by the polishing pad increases when the polishing pad is dressed after polishing one wafer.
Fig. 4 is a schematic view of a chemical mechanical polishing method provided in this embodiment, and as shown in fig. 4, the present invention provides a chemical mechanical polishing method, including:
step S1: and grinding a batch of wafers one by utilizing a chemical mechanical grinding device, and trimming a grinding pad of the chemical mechanical grinding device every time at least two wafers are ground.
By increasing the number of the wafers ground between two adjacent times of trimming, the accumulated number of the grinding byproducts generated by grinding the wafers between two adjacent times of trimming in the fluff layer is larger than or equal to the number of the grinding byproducts removed in each trimming process, the number of the grinding byproducts in the fluff layer is prevented from being reduced too much, and the ground thickness between the wafers is uniform.
Fig. 5 is a line graph showing the variation of the thickness of the wafer when the polishing pad is trimmed every three wafers are polished, as shown in fig. 5, it can be known from the results of two tests that the thickness of the polished wafer fluctuates around a predetermined thickness with a small fluctuation range, and the absolute value of the difference between the thickness of the polished wafer and the predetermined thickness is smaller than that of the polished wafer when the polishing pad is trimmed every three wafers are polished
Each of the crystals after polishingThe thickness between the circles has good uniformity.
Further, the polishing time of each wafer is the same, and the number of the wafers polished between two adjacent times of polishing the polishing pad may be the same or different, for example, three wafers are polished to polish the polishing pad, and then two wafers are polished to polish the polishing pad.
The time for dressing the polishing pad is the same each time, and the whole polishing area of the polishing pad is dressed each time. The polishing pad may be dressed once or at least twice each time the polishing pad is dressed. The trimming times of each time of trimming the polishing pad are positively correlated with the number of the wafers polished after the polishing pad is trimmed last time, so that the polishing rate of the wafers can be adjusted by adjusting the trimming times of each time of trimming and the number of the wafers polished between each time of trimming.
Fig. 6 is a line graph showing the thickness variation of the wafers when the polishing pad is trimmed after every three wafers are polished and then changed to five wafers are polished, and as shown in fig. 6, the polishing pad is trimmed after every three wafers are polished and then changed to five wafers, and the number of the polished wafers is adjusted in real time according to the thickness of the polished wafers, so as to better improve the uniformity of the thickness among the polished wafers.
In addition, before the first wafer is polished, the polishing pad is trimmed at least once. The polishing pad is trimmed before polishing, the shape of the fluff layer is adjusted, and meanwhile dust and impurities on the surface of the polishing pad are removed, so that the impurities on the surface of the polishing pad are prevented from scratching the surface of the wafer, and unnecessary loss is avoided.
In other alternative embodiments, the thickness of each polished wafer may be measured after polishing of each wafer is completed, and when the thickness of each polished wafer is smaller than a preset value, the polishing pad is trimmed. And measuring the thickness of the ground wafer in real time, and judging whether the grinding pad is trimmed or not according to the size relation between the thickness of the ground wafer and a preset value, so that the influence of the individual difference of the wafer is eliminated, and the too thin thickness of the ground wafer is avoided.
In summary, the present invention provides a chemical mechanical polishing method, including: and grinding a batch of wafers one by utilizing a chemical mechanical grinding device, and trimming a grinding pad of the chemical mechanical grinding device every time at least two wafers are ground. The invention adjusts the number of the grinding byproducts adhered on the grinding pad in the grinding process and the number of the grinding byproducts removed on the grinding pad in the trimming process by adjusting the number of the grinding byproducts ground between every two trims in the chemical mechanical grinding process and the trimming times in each trimming process, thereby further uniformly grinding the wafers and improving the uniformity of the film thickness among the wafers after the chemical mechanical grinding of a batch of wafers.
The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A chemical mechanical polishing method, comprising:
and grinding a batch of wafers one by utilizing a chemical mechanical grinding device, and trimming a grinding pad of the chemical mechanical grinding device every time at least two wafers are ground.
2. The chemical mechanical polishing method of claim 1, wherein the wafer comprises a substrate and a gate structure on the substrate, and the top of the gate structure of the wafer is polished during polishing of the wafer.
3. A chemical mechanical polishing method as recited in claim 1, wherein at least one conditioning of the polishing pad is performed prior to polishing a first of the wafers.
4. A chemical mechanical polishing method as claimed in claim 1 or 3, wherein after each wafer is polished, the thickness of the polished wafer is measured, and if the thickness of the polished wafer is less than a predetermined value, the polishing pad is trimmed.
5. A chemical mechanical polishing method as recited in claim 1, wherein the dressing of the polishing pad is performed independently of the polishing of the wafer.
6. A chemical mechanical polishing method as claimed in claim 1, wherein the number of wafers polished between two adjacent times of dressing the polishing pad is the same or different.
7. A chemical mechanical polishing method according to claim 6, wherein the polishing pad is dressed once or at least twice each time.
8. The method of claim 7, wherein the polishing pad is dressed at the same time each time, and each dressing trims the entire polishing area of the polishing pad.
9. A chemical mechanical polishing method as claimed in claim 7, wherein the number of times of dressing each time the polishing pad is dressed is positively correlated with the number of wafers polished after the polishing pad was dressed last time.
10. A chemical mechanical polishing method as claimed in claim 1, wherein the polishing time for each wafer is the same.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210039252.XA CN114346893B (en) | 2022-01-13 | 2022-01-13 | Chemical mechanical polishing method |
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| CN202210039252.XA CN114346893B (en) | 2022-01-13 | 2022-01-13 | Chemical mechanical polishing method |
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| CN114346893B CN114346893B (en) | 2023-06-30 |
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10315131A (en) * | 1997-05-23 | 1998-12-02 | Hitachi Ltd | Polishing method of semiconductor wafer and device therefor |
| JP2001088008A (en) * | 1999-09-16 | 2001-04-03 | Toshiba Corp | Polishing method and device |
| JP2002052459A (en) * | 2000-08-09 | 2002-02-19 | Hitachi Ltd | Polishing method and polishing device |
| JP2003151934A (en) * | 2001-11-15 | 2003-05-23 | Seiko Epson Corp | Cmp system and method of adjusting polishing pad for cmp |
| CN102452039A (en) * | 2010-10-19 | 2012-05-16 | 上海宏力半导体制造有限公司 | Chemical-mechanical grinding method |
| CN102672598A (en) * | 2012-05-22 | 2012-09-19 | 上海宏力半导体制造有限公司 | Grinding pad using method and wafer grinding method |
| CN105328562A (en) * | 2014-07-16 | 2016-02-17 | 中芯国际集成电路制造(上海)有限公司 | Chemical and mechanical grinding method |
| CN105364699A (en) * | 2014-07-25 | 2016-03-02 | 中芯国际集成电路制造(上海)有限公司 | A chemical mechanical polishing method and a chemical mechanical polishing apparatus |
| CN107914213A (en) * | 2016-10-10 | 2018-04-17 | 中芯国际集成电路制造(上海)有限公司 | A kind of chemical and mechanical grinding method |
| CN110549239A (en) * | 2018-05-31 | 2019-12-10 | 长鑫存储技术有限公司 | Chemical mechanical polishing device and polishing pad surface dressing method |
-
2022
- 2022-01-13 CN CN202210039252.XA patent/CN114346893B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10315131A (en) * | 1997-05-23 | 1998-12-02 | Hitachi Ltd | Polishing method of semiconductor wafer and device therefor |
| JP2001088008A (en) * | 1999-09-16 | 2001-04-03 | Toshiba Corp | Polishing method and device |
| JP2002052459A (en) * | 2000-08-09 | 2002-02-19 | Hitachi Ltd | Polishing method and polishing device |
| JP2003151934A (en) * | 2001-11-15 | 2003-05-23 | Seiko Epson Corp | Cmp system and method of adjusting polishing pad for cmp |
| CN102452039A (en) * | 2010-10-19 | 2012-05-16 | 上海宏力半导体制造有限公司 | Chemical-mechanical grinding method |
| CN102672598A (en) * | 2012-05-22 | 2012-09-19 | 上海宏力半导体制造有限公司 | Grinding pad using method and wafer grinding method |
| CN105328562A (en) * | 2014-07-16 | 2016-02-17 | 中芯国际集成电路制造(上海)有限公司 | Chemical and mechanical grinding method |
| CN105364699A (en) * | 2014-07-25 | 2016-03-02 | 中芯国际集成电路制造(上海)有限公司 | A chemical mechanical polishing method and a chemical mechanical polishing apparatus |
| CN107914213A (en) * | 2016-10-10 | 2018-04-17 | 中芯国际集成电路制造(上海)有限公司 | A kind of chemical and mechanical grinding method |
| CN110549239A (en) * | 2018-05-31 | 2019-12-10 | 长鑫存储技术有限公司 | Chemical mechanical polishing device and polishing pad surface dressing method |
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| CN114346893B (en) | 2023-06-30 |
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