TW201128694A - Method for controling polishing wafer - Google Patents

Abstract

A method for controlling polishing a wafer includes the following step. Firstly, a database storing a number of status data of a polished film of a wafer and a number of polishing parameters corresponding to the status data is established. Each of the polishing parameters includes a head sweep of a polishing head along a redial direction of a polishing platen. The head sweep refers to a movement distance range from a center of the polishing head to a center of the polishing platen during a polishing process. Subsequently, a first wafer having a predetermined status data is provided. Thereafter, the predetermined status data is compared with the status data in the database so as to find out the polishing parameter corresponding to the predetermined status data, thereby determining a first polishing parameter of the first wafer. Afterward, a first polishing process using the first polishing parameter is applied to the first wafer. The method can control the status of a polished film and optimize the polishing parameter.

Description

201128694 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to a wafer polishing process, and more particularly to a method of controlling a wafer polishing process. [Prior Art] With the continuous development of semiconductor technology, the production of semiconductor wafer lines has also benefited from the trend toward higher density. Thus, it is required that a metal film layer (e.g., a copper layer) for forming a wiring on a semiconductor wafer is not only thin but also has a high thickness uniformity. At present, the metal film layer is mainly ground by a chemical mechanical polishing (CMP) process. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a conventional semiconductor wafer polishing process using a chemical mechanical polishing process. A polishing head 10 is used to hold the semiconductor wafer and apply pressure so that the semiconductor wafer 12 is in contact with the polishing pad (not shown) of the polishing table and is ground. The grinding head ίο includes a retaining ring u for controlling the pressure, thereby controlling the thickness distribution of the abrasive metal layer. # The polishing head 10 controls the polishing speed of the semiconductor wafer u by applying different pressures. The pressure applied by the polishing head 10 satisfies the thickness uniformity requirement of the metal layer polishing. The faster the polishing rate of the semiconductor wafer 12 is, the thinner the thickness of the obtained abrasive metal layer is. However, even so, the well-known chemical mechanics and processes can no longer be used in the above-mentioned conventional practices;

Specifically, the process of 12, 121, the second H area is large, and the 201128694 is difficult to control by the grinding pressure. Further, the application of pressure to the first region 121, the second region 122, and the third region 133 by the polishing head 10 can only be simultaneously increased or decreased. Since the pressures of the first region 121, the second region 122, and the third region 133 are simultaneously increased or decreased, the polishing speed of the first region 12, the second region 122, and the third region 133 can only be accelerated at the same time. Or slow down. That is, the polishing head 10 cannot perform pressure adjustment according to different areas. Therefore, the above-described polishing control method does not satisfy the demand when it is required that the metal layer for forming the wiring on the semiconductor wafer directly meets a certain thickness distribution of the fabrication. SUMMARY OF THE INVENTION Yes, this invention provides a method for controlling a wafer polishing process, and the control of the polishing state of the round film layer facilitates the grinding parameters to be achieved in the process.

The method of direct construction of Hi: The present invention proposes a method for controlling the wafer polishing process. The polishing state of the plurality of grinding state data and the at least the polishing head along the === database. Each grinding parameter The distance between the center of the grinding table (4) m, the center of the grinding head to the first wafer during the grinding movement. After the absence, “provide the state data with the predetermined grinding state data, and ^ the number of grinding in the database, to determine the first 曰, va grinding state data of the grinding parameters to the first wafer parameters. Then, according to the first, [si 201128694 in the exemplary embodiment, the above-mentioned - the grinding parameters include the first distance - the grinding process, the grinding secret - the distance within the range of grinding = in the invention - the implementation of the above, The wafer film layer is a film; in the thick production embodiment, the above-mentioned respective state data is a polished 3 thickness knife cloth. In the embodiment of the present invention, each of the above-described grinding-off data is a polishing film layer removal rate distribution. ~ More packaged towel, upper control (4) Grinding process: grinding process - wafer, to obtain the first wafer measurement L comparison measurement grinding state data and predetermined grinding state data, thus obtaining Data, to modify the database, select the grinding parameter corresponding to the spot state data in the modified database to determine the second = grinding number of the second wafer, and perform the second wafer according to the second grinding parameter In the embodiment, in the above comparison, the grinding state data is measured. When the data is calculated, the data is defined in the first wafer, and the correction value is obtained. Zone enemy correction value, etc. _ amount of grinding state data only time domain - strain data value and predetermined grinding state data in the corresponding state data in each _ - (4) (four) recording ^ pre-λ grinding off the van-real complement, the second above The number of grinding materials includes the second distance table = two: in the grinding process, the polishing head grinds the wafer film layers in the second distance range along the grinding 201128694. The range of the radial movement of the grinding table, during the movement, the center of the grinding head to the grinding and polishing. Each grinding parameter includes at least a grinding head circumference, and the moving distance range refers to a distance from the grinding head to the center of the grinding table. cut,. ,=

f #4^^itS^^f,J(advanced process controbApi J2) followed by the use of advanced process control system to control the polishing process of the wafer. First, in order to achieve the above advantages, the present invention also proposes a control wafer polishing process The method is to first supply a plurality of wafers having the same wafer layer. After that, the method of controlling the wafer polishing process of the present invention is to establish a plurality of grinding state data stored by the round film layer. And corresponding to the grinding state data: a plurality of polishing parameter databases, and stored in an advanced process control system to control the polishing process of the wafer. Since each grinding parameter includes at least a range of moving distance of the polishing head along the radial direction of the polishing table, Wafer film layer grinding state, even local area

The grinding state of f & is controlled by adjusting the range of the moving distance of the polishing head in the radial direction of the polishing table. Therefore, the present invention facilitates the grinding parameters to be achieved in the grinding process. ★ To make the invention and other objects, advantages and advantages of the present invention more obvious, the following is a preferred embodiment, and the details are described as follows. [Embodiment] FIG. 2 is a <11_& diagram of a method of controlling a wafer polishing process according to an embodiment of the present invention. As shown in FIG. 2, the package for controlling the wafer polishing process of the present embodiment firstly establishes a plurality of polishing 201128694 state data storing the wafer film layer and a database of a plurality of polishing parameters corresponding to the grinding state data, such as steps. 21 stated. Each of the grinding parameters includes at least a grinding head along the grinding = radial movement distance. This range of moving distance refers to the distance from the center of the polishing head to the center of the polishing table during the grinding movement. In this embodiment, the wafer layer is, for example, a copper layer. Specifically, in step 21+, a plurality of wafers having the same wafer film layer (for example, a copper layer) are first provided, and the wafer layers are sequentially polished, and each wafer corresponds to one polishing. parameter. Referring to Fig. 3, each of the grinding parameters includes a moving range Hs of the grinding head 3G in the radial direction of the grinding table 32. It can be understood that the 'grinding parameters' may also include grinding force, grinding time, and the like. The range of the moving distance as described in Fig. 3 V refers to the range in which the grinding head 30 is moved by the grinding process from the center 0h to the center of the grinding table 0p. This distance range is determined by the radius of the honing head 30 and the radius of the polishing table 32. For the determination of the grinding parameters of the circle, the moving distance range hs can be used to determine the decreasing angle. In addition, the grinding head 30 can move radially in the range of the moving distance range hs '° 1 σ 32. mobile. After this, the film layer is sequentially polished by using the corresponding polishing parameters to complete the number of the polished wafer film layers, thereby obtaining the polishing data of each grinding polishing layer to remove each grinding state data for each crystal. Surrounded = i first 'please cooperate with the reference 4, define the complex moving distance fc around the wafer. The HS is assumed to be 5.3 inches (inches) to 8 3 inches.

SI 7 201128694 In the process of grinding 34 wafer layers in sequence, the moving distance range HS = can be increased according to the step of Q 5 shot, grinding the corresponding wafer. If necessary. When the grinding state data of the region Ri = domain Rn of the corresponding wafer under each moving distance range HS is obtained, thereby obtaining the wafer grinding film removal rate knife establishing database, the region ri can be first standardized to the region Such as shift = rate. For example, the removal rate normalization value of the definition region Ri is equal to the removal rate normalization value of the region R2 is equal to the removal rate absolute value of the region R2, the absolute value of the removal rate of the domain R1, and so on, the second region Rn

The rate value f Γ region Rn removal rate absolute value / region R1 removal φ eight, the region R1 removal rate absolute value is the absolute value of the removal rate of the mean region of the entire region magic R2 6 ^ 2 The average value of the entire area, according to the age, the removal rate of the towel area, such as the average value of the removal rate of the positive area Rn. You save the distance of the moving distance range HS respectively to the corresponding grinding wafer 'in this embodiment' because the moving distance range HS is 〇 = this value is equal to 6. Subsequently, the moving distance range HS ^ is established; the data table of the removal rate after the definition is defined as the first time, ... 1 from the range Hsi grinding parameters, the wafer area Rj (H, 2, ·····二研究=^The layer removal rate normalization value is v(iJ). The data table is established as follows:

8 IS] 201128694 Scope (4) Y=_G.2 ’ where X is the moving distance wj). It is necessary to set up the impurity-normalized value of each region of the wafer. _Get this $

In addition to the rate distribution) and the corresponding grinding parameters (moving distance == by ί to determine the grinding parameters of the wafer layer to be polished. ic (advanced ρ - layer U-bank, and control the wafer through advanced process secrets) The film specifically 'side-side control (10) system control wafer polishing includes: from the ΙΓ ί according to Figure 2 'after the database is established, providing a predetermined grinding pattern ~, the data of the first wafer, as described in step 22. In an embodiment, the predetermined grinding state data of the first wafer is an abrasive film layer removal rate distribution. After that, as described in step 23, using the database stored in the advanced control system to compare the first crystal The scheduled grinding state data and the grinding shape in the database, according to the data. When the advanced priming in the library to find the job - research state data ^ 疋 grinding state data match (same or similar), select in the database Corresponding to the grinding parameter of the grinding state data (or the predetermined grinding state data) as the first grinding state parameter of the first wafer to determine the first grinding parameter of the first wafer. For example, the advanced control (four) is unified in (4) the library towel system 2nd shift The grinding state parameter under the range ^ HS2 is matched with the predetermined grinding state data of the first wafer. 201128694 is matched with 'then the first circle can be determined'. The grinding parameter includes the second moving distance range, and the advanced control system can control The grinding device performs a first polishing process on the first wafer according to the first polishing parameter, as described in step 24. In the first polishing system, the second moving distance range is the first wafer; the first polishing parameter The first distance range, the grinding head 30 can move back and forth along the grinding table 32 in the range of the first distance. The parameters of the Japanese yen mill are optimized to control the phase of the wafer grinding process. The second wafer also has the first-grinding state data, as described in step 25. That is, in this embodiment, the predetermined grinding rate distribution of the second wafer is as shown in step 26. The measurement of the grinding state data of the advanced control, that is, the measurement, thereby obtaining the first wafer measurement grinding state data feedback to the first film removal rate cloth, and obtaining the grinding removal rate in the embodiment, can After the quantity, as in step 27, ten, library, compare (four) (four) series ^ use the money in the first __ unified data to obtain - correction · shape predetermined grinding state data, select and modify the grinding g ' in the library to modify the database, The second polishing of the modified data wafer corresponds to the grinding parameter to determine the second 201128694. In detail, in step 27, the first wafer region Rj can be obtained by comparison (j = 1, 2, respectively. ..... η) correction value of the removal rate of the abrasive film layer u buckle_1 ' 2 ' ...... η). The region Rj (j = 1, 2, ... η) The correction value uj (j = 1, 2, ... n) may be equal to measuring the strain state data in one of the regions Rj (j = 1, 2, ... η) and the predetermined grinding state data The ratio of the strain data values in the corresponding region Rj (j=1, 2..........). The corrected grinding state data can be obtained by measuring the grinding state data and the correction value Uj (i = 1, 2, ..., n). In this embodiment, the corrected grinding state data is equal to the strain data value of the predetermined grinding state data in the first wafer region RjG·-1, 2....n) multiplied by the corresponding correction value uj(j) =1, 2.. η). For example, in this embodiment, the measurement device is used to measure the state of the first wafer, and the normalized value of the measurement removal rate of the first wafer region R1 to the region can be obtained. The strain data of R1 to Rn is a normalized value of the measurement removal rate of the region R1 to the region Rn. According to the standardized value of the measured removal rate of the known rounded area R1 to the area Rn, the respective V(^)' corresponding to the first grinding parameter is updated by the percentage_' to obtain Vnewaj). For example, in the database, the removal rate normalization value v(2 2) of the region R2 of the second moving distance range® HS2 is [2], and the actual measurement dragon is h3 'so new (four) the second machine distance of the library towel Fan = S2 = each νηελγ (2, 』Bu! % 2* (4) in the data table), ^ R .1 2.......n. According to the modified database, the moving film removal rate V(i, j) of each area of the moving distance is linearly fitted off - 22 to 5 o to the modified update 'so corresponding to the corrected grinding state data 2 The human distance range is HS2, so that the second moving distance range HS2 is excellent. It can be understood that the above example only uses the region R2 as an example, and the first wafer has its similar modification in each region of 201128694 to modify the update database. Therefore, the grinding parameter corresponding to the corrected grinding state data (for example, modifying the updated second moving distance range HS2) is selected in the database by the advanced control system as the second grinding state parameter of the second wafer. Thus, the advanced process control system can control the polishing apparatus to perform a second polishing process on the second wafer in accordance with the second polishing parameter, as described in step 28. In the second polishing process, the modified second moving distance range HS2 is the second grinding parameter of the second wafer.

For a second range of distances of φ, the abrading head 30 is movable radially back and forth along the polishing table 32 over a second range of distances. D iiisss: It can be understood that the grinding state data of the wafer film layer can also be performed by using other data other than the film removal rate, for example, to use an abrasive film layer. The removal of the thick m_val dirty deletion) is divided into 3 thicknesses 5f, ^T residual film thickness distribution). Please refer to Fig. 5A. The grinding state data of each of the __, (4) is the wafer thickness of each wafer (that is, the remaining film thickness distribution). The obtained grinding resources are not detailed here. The control wafer grinding r@*· η ti 12 201128694 of the present invention has a range of moving distance of the head along the radial direction of the polishing table, and therefore, the wafer layer grinding state, and even the partial grinding state of each region can be adjusted by adjusting the grinding head edge The polishing table is controlled by the radial movement distance range. Therefore, the present invention facilitates optimization of the polishing parameters in the polishing process to make the polishing of the wafer film layer meet the requirements. Although the present invention has been disclosed above in the preferred embodiment, However, it is not intended to limit the invention, and any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [Simplified Schematic] FIG. 1 is a schematic view showing a conventional method of polishing a semiconductor wafer by a chemical mechanical polishing process. FIG. 2 is a diagram showing control of an embodiment of the present invention. FIG. 3 is a schematic view of a polishing apparatus for a wafer polishing process according to an embodiment of the present invention. FIG. 4 is a schematic view showing a definition of a wafer polishing area according to an embodiment of the present invention. 5A to 5F are schematic diagrams showing the thickness distribution of the polishing film layer of each wafer according to another embodiment of the present invention. [Description of main component symbols] 10 ' 30 · Grinding head 11 : Fixed retaining ring 12 : Semiconductor Wafer 13 201128694 2 Bu 22 '23, 24, 25, 26 ' 27, 28: Step 32: Grinding table 121: First area 122: Second area 123: Third area

Rj (j=l, 2..η): Wafer grinding area

Oh : Grinding head center Op: Grinding table center HS: The moving distance of the grinding head along the radial direction of the grinding table is Hsi (i=l, 2..m): the i-th moving distance range V(i , j) (i=l, 2..m; j=l, 2..n): removal of the abrasive film layer of the i-th moving distance range wafer grinding area j Rate normalization value

Vnew(i,j) (i=l, 2..m; j=l, 2 . . . η): modify the updated i-th moving distance range wafer grinding area j Abrasive film removal rate normalization value

14

Claims (1)

201128694 VII. Patent application scope: 3=® Grinding process method, including: Establishing the 贞科库, the data inventory-status data and the corresponding number of grinding grinding parameters of the Japanese yen film layer include at least: grinding: According to the plurality of grinding parameters, each of the heads (headsweep), one of the radial movements of the grinding head is in the radial direction of the grinding process, and the grinding head is provided in the grinding movement to provide a range of distances from the center of the first movement; Comparing the predetermined grinding state data ^ data, f ' and selecting the corresponding number in the database; ===; the number, so that the grinding parameter of the first - the first wafer is based on the first grinding The parameter is for the first; ^ and the number of the second one = the first distance within the range along the grinding table ===, the grinding head is in the steel layer. The method described in claim 1 wherein the wafer film layer is 4. The data of the scope of the patent application is - the thickness distribution of the face layer. Each of the grinding state data is an abrasive film removal rate (removalmte) distribution. 6. The method of claim 1, further comprising: providing a second wafer having the predetermined grinding state data; measuring the first wafer by the first grinding process Obtaining the measured grinding state data of one of the first wafers; comparing the measured grinding state data with the predetermined grinding state data, thereby obtaining a corrected grinding state data of S1 15 201128694 to modify the selection and the correction in the data The grinding state data corresponds to the grinding parameter of the second wafer - the second grinding parameter; and the number is determined to be the second grinding material; the round item - the item 7. The square grinding method as described in claim 6 When the state data and the predetermined grinding state data are ^ = from, the corrected value of one of the regions, the ratio of the upper == lining value to the pre-(10) Μ* fox domain strain data value, and the modified research state Each of the green state strain data values is multiplied by the corresponding correction value. Or the method of claim 6, wherein the second grinding parameter comprises a first distance range, and in the second grounding shoe, the radial distance of the grinding table is within a second distance of the visitor Move back and forth. 9. 9. The method of claim 6, wherein the data is an abrasive film thickness distribution. / / (4) The method described in the sixth item, wherein the abrasive data of each of the towels is - the removal rate of the abrasive film layer (face _ me). 11. A method for controlling a wafer polishing process comprising: providing a wafer having the same one of a wafer layer; a grinding condition = a 1' round film layer for grinding, each of the polishing parameters including at least -. / 口二: mouth control to - the distance of the head (head sweep), the 刭: giant Γ f means that the grinding head in the grinding process during the grinding head two; S: grinding = number 2 away and measured The wafers are ground to obtain the corresponding data of the state data; the library is used to establish the grinding parameters and the grinding parameters of the SI 16 201128694 storage ° Xuan > library in an advanced process control (Avc) And the method of controlling the polishing process of a wafer by using the advanced process control system. The method of claim 11, wherein the grinding state data is a thickness distribution of the abrasive layer. 13. The method according to claim 11, wherein each of the abrasive data is a removal rate distribution of the abrasive film layer, such as the method of claim 11 of the patent scope, the advanced process of Xiang Control System: System Control - Wafer - Research The process includes: providing a first wafer having a predetermined grinding state data; and the seat Φ t-way control system determines the grinding parameter corresponding to the predetermined grinding state data according to the predetermined grinding state data, thereby determining a first grinding parameter of the first day of the Japanese yen; and a plurality of pairs of rounds = _ system; 1 grinding device utilizes the first grinding parameter = two wafers, which also has the expected grinding state data; Controlled by the control system—the measuring device measures the grinding state data of the first grinding quantity and the second core I to obtain the first grinding data of the first wafer and feeds back to the advanced process control system; The measuring the grinding state data and the predetermined data i, correcting the 'reconstruction state data from the ton, and modifying the grinding parameter 1 of the modified database to select and correct the grinding state data pair, the private control system controls the The grinding device utilizes the second pair of polishing parameters 17 Si 201128694, and the second crystal: performs a second polishing process. The polishing crystal described in claim 9 The control side of the process is different from the predetermined correction state of the grinding state data and the predetermined grinding state data, and the day circle defines a plurality of regions', thereby obtaining the correction value of each side region of one of the regions is equal to the measurement grinding state Data in each of the domain variable data values and the fiscal grinding state data corresponding to each of the regions The grinding state correction is based on the predetermined value. The value of the strain data is multiplied by the corresponding correction.