CN102380816A - Chemical mechanical polishing method and system - Google Patents

Abstract

The invention discloses a chemical mechanical polishing method, which comprises the steps of providing a plurality of semiconductor elements to be polished, obtaining the size of each semiconductor element in the plurality of semiconductor elements to be polished, and polishing each semiconductor element according to the size of each semiconductor element. The invention can accurately control the polishing thickness of the elements in the chemical mechanical polishing process without adopting the feedback control flow in the prior art, thereby obviously reducing the yield loss and improving the product quality.

Description

Chemical mechanical polishing method and system

technical field

The invention relates to a chemical mechanical polishing method and system, in particular to advanced process control of the chemical mechanical polishing process.

Background technique

As the size of semiconductor devices continues to shrink, the importance of global planarization of the device's surface in the semiconductor process is also increasing. The most commonly used method for planarizing the entire wafer surface is chemical mechanical polishing (CMP) process, which is to press the wafer surface on the polishing pad covered with polishing liquid and rotate to planarize the surface of the entire wafer.

When using CMP process to polish a semiconductor element, if the polishing time is too long, it will cause over polish (Over Polish). At this time, the resistance value of each metal line on the element will be too high to slow down the speed of the element, and the dielectric layer on it will also be damaged. It will be seriously damaged; and when the polishing time is not long enough, the metal on the dielectric layer is not completely removed, that is, the phenomenon of insufficient polishing (Under Polish), which will also affect the performance of the component. Therefore, controlling the polished thickness of the device in the CMP process can avoid the above-mentioned over-polishing or under-polishing phenomenon, so as to improve the yield of the product.

Please refer to FIG. 1 , which is a prior art method for controlling polishing thickness in a CMP process. This method uses feedback control to adjust the polishing time of the wafer. First, take 2 to 3 wafers for thickness measurement and polishing test (step 10), and use the test results to estimate the optimal polishing time of the first batch (Lot) of wafers (step 11), with the estimated optimal polishing time to polish the first batch of wafers (step 12), after the first batch of wafers completed the CMP polishing process, then sample and measure the polished thickness of the first batch of wafers (step 13), and this The measurement results are fed back to the next batch of wafers to estimate the optimal polishing time for the next batch of wafers (step 14).

As mentioned above, in the existing CMP control method, the polishing parameters of the first batch of wafers are only estimated in a sampling manner, thus resulting in high yield loss (yield loss); in addition, a feedback control system is used to estimate the polishing parameters of subsequent batches of wafers. The polishing parameters are not only costly, but also only provide an estimated polishing time for a batch of wafers, and cannot accurately control the polishing thickness of each wafer, so the polishing failure rate cannot be significantly reduced.

In order to solve the above-mentioned problems in the prior art, the present invention proposes a chemical mechanical polishing method and system to improve the efficiency, accuracy and stability of the semiconductor element process.

Contents of the invention

The present invention proposes a chemical mechanical polishing method and system, which can accurately control the polishing thickness of components in the CMP process without using the feedback control process of the prior art, thereby significantly reducing yield loss and improving product quality.

One aspect of the present invention provides a chemical mechanical polishing method, comprising the following steps: providing a plurality of semiconductor elements; obtaining a size of each semiconductor element in the plurality of semiconductor elements; and determining the size according to the size of each semiconductor element Each semiconductor element is polished.

Another aspect of the present invention provides a method for a chemical mechanical polishing process, the method comprising the steps of: providing a plurality of objects, wherein each object has a physical parameter; obtaining the physical parameters for all of the plurality of objects ; and according to the physical parameter of each object to determine the specific polishing parameters of each object.

Another aspect of the present invention provides a chemical mechanical polishing system, the system is used to polish a plurality of objects, and includes a measuring device, a determining device and a polishing device; the measuring device is used to obtain the a physical parameter of each object; the determining device is connected with the measuring device, and is used to determine a polishing parameter specific to each object according to the physical parameter of each object; the polishing device is connected with the The determining means is connected to polish each object according to the polishing parameters specific to each object.

Description of drawings

Figure 1: Prior art chemical mechanical polishing process;

Fig. 2 (A): an embodiment of chemical mechanical polishing method of the present invention;

Fig. 2 (B): an embodiment of step 22 in Fig. 2 (A);

Fig. 3: another embodiment of chemical mechanical polishing method of the present invention;

Figure 4: A schematic diagram of the chemical mechanical polishing system of the present invention;

Figure 5(A): A schematic diagram of the average thickness of multiple batches of wafers before polishing; and

5(B): A schematic diagram of the average thickness of multiple batches of wafers polished using the chemical mechanical polishing method and system of the present invention.

[Description of main component symbols]

10 Take 2 to 3 wafers to measure the thickness and polish the test steps

11 Steps for estimating the optimal polishing time for the first batch of wafers

12 Steps to polish the first batch of wafers

13 Sampling and measuring the thickness of the first batch of wafers

14 Steps for estimating the optimal polishing time for the next batch of wafers

20 Steps to provide multiple semiconductor components

21 Steps to obtain the size of each semiconductor

22 Polish each semiconductor element according to the size of each semiconductor element

The steps of the piece

221 Steps to define multiple size intervals

222 According to the size range to which the size of each semiconductor component belongs

The steps of the polishing formula

223 The step of polishing each semiconductor element according to the separate polishing recipe

31 Steps to provide multiple objects

32 Steps to obtain the physical parameters of all objects

33 According to the physical parameters of each object to determine the specific throw of each object

The steps of light parameters

4 chemical mechanical polishing system

40 Correspondence table

41 Measuring device

42 decision device

43 polishing device

Detailed ways

The technical means of the present invention will be described in detail as follows. It is believed that the purpose, characteristics and characteristics of the present invention can be obtained from this in-depth and specific understanding. However, the following examples and illustrations are only provided for reference and illustration, and are not used to explain the present invention. be restricted.

Please refer to FIG. 2(A), which is an embodiment of the chemical mechanical polishing method of the present invention. The chemical mechanical polishing method includes the following steps: providing a plurality of semiconductor elements (step 20); utilizing a measuring machine or other component measurement means in the CMP process to obtain a size ( step 21); and, polishing each semiconductor device according to the size of each semiconductor device obtained from step 21 (step 22).

According to the above idea, the plurality of semiconductor elements are, for example, a plurality of wafers, or other objects to be polished suitable for the CMP process.

为单位。For example, the measurement method in step 21 is: measure the size of each semiconductor element one by one to obtain a dimensional data of each semiconductor element, the dimensional data may include a thickness of the semiconductor element, or a thickness of the semiconductor element The thickness of each material layer, for example in Angstroms

as the unit.

Please refer to FIG. 2(B), which is an embodiment of step 22 in FIG. 2(A). Step 22 may include the following steps: defining a plurality of size intervals, each of which corresponds to a specific polishing formula (step 221); according to the size interval to which the size of each semiconductor element belongs and the corresponding The specific polishing recipe is used to provide a separate polishing recipe for each semiconductor device (step 222); and each semiconductor device is polished according to the separate polishing recipe (step 223).

According to the above idea, the setting of the size range and the corresponding table of the specific polishing formula are shown in Table 1, and the content of the corresponding table can be designed or adjusted according to various types of objects to be polished or parameters of the polishing machine.

Table 1

X in Table 1 represents that when the measured thickness of a component does not fall within a preset range, the system will not generate a polishing recipe for the component.

需注意的是，所述尺寸区间所包含的区间数量以及每一区间之间的该区间差皆可依抛光工艺的实际需要来设计。According to the above idea, the respective polishing formula includes a polishing time for each semiconductor element, and may also include other polishing parameters such as temperature, pressure, or polishing material; the size interval may include at least 20 intervals; and the size The difference between intervals is, for example, about 100 Angstroms

It should be noted that the number of intervals included in the size intervals and the interval difference between each interval can be designed according to the actual needs of the polishing process.

Please refer to FIG. 3 , which is another embodiment of the chemical mechanical polishing method of the present invention. The chemical mechanical polishing method comprises the steps of: providing a plurality of objects to be polished (step 31), wherein each object in the plurality of objects has a physical parameter; obtaining the physical parameters of all the plurality of objects (step 32 ); and according to the physical parameters of each object to determine the specific polishing parameters of each object (step 33); wherein step 32 is, for example: measure a size of each object one by one to obtain all the multiple The physical parameters of the object; wherein the physical parameter includes at least a thickness of the object, and the polishing parameter includes at least a polishing time.

According to the above idea, the object is a semiconductor element, such as a wafer.

Please refer to FIG. 4 , which is an embodiment of the chemical mechanical polishing system of the present invention. The chemical mechanical polishing system 4 includes: a measuring device 41 for obtaining a physical parameter of each object in a plurality of objects to be polished; a determining device 42 connected with the measuring device 41 for determining according to The physical parameters of each object determine the specific polishing parameters of each object; and a polishing device 43 is connected with the determining device 42 for polishing according to the specific polishing parameters of each object The each object. In FIG. 4 , the direction of the arrow represents the conveying direction of the object in the chemical mechanical polishing system 4 .

According to the above idea, the determining device 42 is, for example, a polishing recipe generator, which can be built in or input a corresponding table 40 such as Table 1 by the operator. When the determining device 42 receives the each object from the measuring device 41 After the physical parameter of each object is obtained, a specific polishing recipe can be generated for each object according to the physical parameter of each object and the corresponding table 40, and the specific polishing recipe includes the unique polishing parameters of each object.

According to the above idea, the object is a semiconductor element, such as a wafer; the physical parameter of each element includes at least a thickness of each object, and the polishing parameter includes at least a polishing time.

Please refer to Fig. 5(A) and Fig. 5(B), wherein Fig. 5(A) shows the average thickness of each batch of wafers of 25 batches of wafers before polishing, and Fig. 5(B) is the average thickness of each batch of wafers using this After polishing the 25 batches of wafers by the inventive chemical mechanical polishing method and system, the average thickness of each batch of wafers can be seen that the thickness of the polished semiconductor elements can be quite uniform using the polishing method and system of the present invention.

In summary, compared with the closed-loop control system of the prior art to polish each batch of objects according to the feedback signal, the present invention uses an open-loop automation system to control each batch of objects in the CMP process. The object to be polished produces a polishing formula, which has the advantages of reducing the complexity of the system mechanism and precisely controlling the polishing thickness of the component. Therefore, the present invention is obviously superior to various existing technologies at present, and is a creation with great industrial value.

Although the present invention has been disclosed above with a number of preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (20)

1. cmp method comprises:

A plurality of semiconductor elements are provided;

Obtain a size of each semiconductor element in these a plurality of semiconductor elements; And

Polish this each semiconductor element according to this size of this each semiconductor element.

2. method according to claim 1, wherein these a plurality of semiconductor elements are a plurality of wafers.

3. method according to claim 1, the wherein said step that obtains this size of this each semiconductor element comprises this size of measuring this each semiconductor element one by one.

4. method according to claim 1, wherein this size comprises a thickness of this each semiconductor element.

5. method according to claim 1, the step of wherein polishing this each semiconductor element comprises:

Be of a size of this each semiconductor element other polishing prescription that provides a fen according to this of this each semiconductor element; And

Polish this each semiconductor element according to other polishing prescription of this branch.

6. method according to claim 5, wherein other polishing prescription of this branch comprises a polishing time.

7. method according to claim 5, the wherein said step of other polishing prescription of this branch that provides comprises the following step:

Define between a plurality of size field a corresponding separately specific polishing prescription between each size field; And

According to pairing this specific polishing prescription between the size field under this size of this each semiconductor element and between this each size field, coming provides this branch polishing prescription else for this each semiconductor element.

8. method according to claim 7 comprises at least 20 intervals between wherein said size field.

9. method according to claim 7, the interval difference of one between wherein said size field is 100 dusts.

10. method that is used for a CMP process, this method comprises:

A plurality of objects are provided, and wherein each object in these a plurality of objects has a physical parameter;

Obtain those physical parameters of all these a plurality of objects; And

According to this physical parameter of this each object with determine this each object proprietary burnishing parameters.

11. method according to claim 10, wherein this object is a semiconductor element.

12. method according to claim 10, wherein this object is a wafer.

13. method according to claim 10 more comprises the following step:

A size of measuring this each object one by one is to obtain those physical parameters of all these a plurality of objects.

14. method according to claim 10, wherein this physical parameter comprises a thickness of this object.

15. method according to claim 10, wherein this burnishing parameters comprises a polishing time.

16. a chemical-mechanical polishing system comprises:

One measurement mechanism is in order to obtain the physical parameter that each object had in a plurality of objects;

One determination device is connected with this measurement mechanism, in order to this physical parameter according to this each object decide this each object proprietary burnishing parameters; And

One burnishing device is connected with this determination device, in order to according to this each object proprietary burnishing parameters polish this each object.

17. system according to claim 16, wherein this object is a semiconductor element.

18. system according to claim 16, wherein this object is a wafer.

19. system according to claim 16, wherein this physical parameter comprises a thickness of this object.

20. system according to claim 16, wherein this burnishing parameters comprises a polishing time.

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