A device for measuring the landing point of polishing slurry

Abstract

This invention discloses a polishing slurry droplet measuring device, comprising a fixed base, a horizontal plate, and a positioning element. The fixed base is detachably mounted on the outer peripheral wall of the polishing pad of a chemical mechanical polishing (CMP) device. The horizontal plate is connected to the top of the fixed base and extends toward the center of the polishing pad. The positioning element is disposed on the side of the fixed base and located below the horizontal plate. The inner sidewall of the positioning element has an arc structure matching the outer diameter of the polishing pad. The polishing slurry falls onto the upper surface of the horizontal plate, and the upper surface of the horizontal plate is provided with scale lines to measure the droplet position of the polishing slurry. The upper surface of the horizontal plate is formed as a hydrophilic or superhydrophilic surface to prevent the polishing slurry droplets on its surface from forming droplets that move under inertia.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical polishing technology, and more specifically, relates to a polishing slurry landing point measuring device and a polishing system. Background Technology

[0002] Chemical Mechanical Polishing (CMP) is an ultra-precision surface finishing technique that achieves global planarization. During polishing, a polishing slurry is supplied to the upper surface of a polishing pad and distributed between the wafer and the pad, allowing the wafer to undergo chemical and mechanical polishing through a combination of chemical and mechanical processes. The polishing slurry is a crucial factor affecting CMP; its placement directly influences the amount of slurry entering the support head, thus affecting the uniformity of wafer polishing. Therefore, the placement of the slurry in the slurry supply arm must be checked during installation to ensure it meets design and installation requirements.

[0003] In existing technologies, after the polishing slurry drips onto the polishing pad located on top of the polishing disc, the dripping point is typically measured using simple measuring tools such as a steel ruler or tape measure. However, existing measurement methods suffer from low accuracy and the inability to reproduce the exact dripping point, which to some extent affects the installation accuracy and commissioning progress of the chemical mechanical polishing system.

[0004] Furthermore, to detect the landing point of the polishing slurry, a measuring device is required to receive it. When the polishing slurry drips onto the existing measuring device, it forms bead-like droplets on its surface. Under the influence of liquid film tension, these droplets roll towards the outer edge of the measuring device and fall onto the surface of the polishing pad, interfering with the normal operation of chemical mechanical polishing. In addition, the polishing slurry dripping onto the measuring device surface may crystallize into particles. These particles can fall onto the surface of the polishing pad when the landing point is detected, causing scratches on the wafer surface. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems existing in the prior art.

[0006] To this end, a first aspect of the present invention provides a polishing slurry drop point measuring device, including a fixed base, a horizontal plate, and a positioning member. The fixed base is detachably mounted on the outer peripheral wall of a polishing pad in a chemical mechanical polishing (CMP) apparatus. The horizontal plate is connected to the top of the fixed base and extends toward the center of the polishing pad. The positioning member is disposed on the side of the fixed base and located below the horizontal plate. The inner sidewall of the positioning member has an arc structure that matches the outer diameter of the polishing pad. The polishing slurry falls onto the upper surface of the horizontal plate, and the upper surface of the horizontal plate is provided with scale lines to measure the drop position of the polishing slurry.

[0007] The upper surface of the horizontal plate is formed as a hydrophilic or superhydrophilic surface to prevent polishing liquid dripping onto its surface from forming droplets that move under inertia.

[0008] In a preferred embodiment, the projection line of the end face of the horizontal plate facing the polishing pad coincides with the center point of the polishing pad, the scale line is an arc, and the center of the arc coincides with the center of the polishing pad or polishing mat.

[0009] In a preferred embodiment, the polishing liquid droplet measuring device further includes a display test paper disposed on the upper surface of the horizontal plate. After the polishing liquid drips onto the display test paper, the color of the display test paper changes.

[0010] In a preferred embodiment, the fixing base, the horizontal plate, and the positioning element are made of non-metallic materials.

[0011] In a preferred embodiment, the upper surface of the horizontal plate is formed with a surface structure for impeding the movement of the polishing liquid;

[0012] In a preferred embodiment, a partition is disposed along the outer edge of the horizontal plate, the partition extending vertically from the upper surface of the horizontal plate.

[0013] In a preferred embodiment, the partition includes a front partition and a side partition, both integrally formed and disposed on the outer edge of the horizontal plate; the length of the side partition is greater than half the length of the horizontal plate.

[0014] The beneficial effects of this invention include:

[0015] The positioning element configured in this invention is concentrically arranged with the polishing pad to ensure the accuracy of polishing pad installation. Furthermore, the upper surface of the horizontal plate is formed as a hydrophilic or superhydrophilic surface to prevent polishing liquid droplets from forming droplets that move under inertia, thus ensuring the accuracy of polishing liquid landing point detection. In addition, the horizontal plate, which is positioned towards the center of the polishing pad, is equipped with scale lines to accurately check the landing point of the polishing liquid, improve the efficiency of polishing liquid supply arm installation and debugging, and ensure that the polishing liquid is supplied according to design requirements. Attached Figure Description

[0016] The advantages of the present invention will become clearer and easier to understand through the following detailed description in conjunction with the accompanying drawings, which are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0017] Figure 1 This is a schematic diagram of the polishing liquid landing point measuring device of the present invention;

[0018] Figure 2 yes Figure 1 Disassembly diagram of the corresponding polishing slurry droplet measuring device;

[0019] Figure 3This is a schematic diagram of the installation of the polishing slurry drop point measuring device of the present invention in the polishing system;

[0020] Figure 4 This is a schematic diagram of an application embodiment of the polishing fluid landing point measuring device of the present invention;

[0021] Figure 5 This is a schematic diagram of the structure of the fixing base of the present invention;

[0022] Figure 6 This is a schematic diagram of the positioning component of the present invention;

[0023] Figure 7 This is a schematic diagram of another embodiment of the horizontal plate described in this invention;

[0024] Figure 8 This is another schematic diagram of the horizontal plate described in this invention. Detailed Implementation

[0025] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0026] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0027] In this invention, "Chemical Mechanical Polishing (CMP)" is also called "Chemical Mechanical Planarization (CMP)," and a wafer is also called a substrate; their meanings and practical functions are equivalent.

[0028] Polishing slurry is a crucial consumable in chemical mechanical polishing (CMP). The location of the slurry supply directly affects its distribution on the rotating polishing disc, its entry point into the carrier head, its flow rate, and ultimately, the control of the wafer removal rate. Therefore, the location of the slurry supply is of paramount importance.

[0029] Figure 1 This is a schematic diagram of the structure of a polishing slurry landing point measuring device 100 according to the present invention, which includes a fixed base 10, a horizontal plate 20, and a positioning member 30; the fixed base 10 is detachably mounted on... Figure 3 The outer peripheral wall of the polishing disc 200 shown has a horizontal plate 20 connected to the top of the fixing base 10 and positioned towards the center of the polishing disc 200; the positioning member 30 is disposed on the side of the fixing base 10 and located below the horizontal plate 20.

[0030] Figure 2 This is a disassembled diagram of the polishing slurry drop point measuring device 100, so as to clearly understand the components of the polishing slurry drop point measuring device and their connection relationships.

[0031] A schematic diagram of the structure of the fixing base 10 of the present invention is shown below. Figure 5 As shown, it is made of non-metallic material. A stepped portion 10a is provided on the top of the fixing base 10, and the step portion 10a is located on one side of the fixing base 10. The positioning member 30 is located on the stepped portion 10a. The inner side surface of the fixing base 10 matches the outer peripheral wall of the polishing disk 200 to ensure a reliable connection between the fixing base 10 and the polishing disk 200. Specifically, the dimensions of the inner side surface of the fixing base 10 are equal to the dimensions of the outer peripheral wall of the polishing disk 200, and the two fit tightly to ensure the consistency of the fixing base 10 installation. That is, the fixing base 10 is positioned and installed with the outer peripheral wall of the polishing disk 200 as a reference, ensuring the consistency of repeated installation of the polishing fluid drop point measuring device 100.

[0032] Figure 5 In this design, the upper surface of the fixed base 10 is provided with a pair of pin holes 10b, spaced apart along the width direction of the fixed base 10. A shaft pin is disposed in the pin hole 10b, and the corresponding horizontal plate 20 is also provided with a positioning pin hole. The pin shaft precisely mates with the pin hole 10b and the positioning pin hole to ensure the parallelism of the horizontal plate 20 after installation and to ensure the accuracy of the polishing liquid droplet alignment. Specifically, there is a pair of pin holes 10b, and the pin shaft is matched and disposed in the pin hole 10b.

[0033] In this invention, the horizontal plate 20 needs to be parallel to the upper surface of the polishing pad 300 to ensure the accuracy of the measurement of the polishing liquid droplet position. In some embodiments, the parallelism between the horizontal plate 20 and the upper surface of the polishing pad 300 is not less than 0.05 mm to ensure the accuracy of the observation of the polishing liquid droplet position. Preferably, the parallelism between the horizontal plate 20 and the upper surface of the polishing pad 300 is 0.03 mm. The parallelism between the horizontal plate 20 and the polishing pad 300 can be ensured by ensuring the perpendicularity between the horizontal plate 20 and the fixing base 10. Specifically, during the structural design, structural design tolerances and assembly errors can be fully considered to strictly ensure the perpendicularity between the horizontal plate 20 and the fixing base 10.

[0034] Preferably, the upper surface of the horizontal plate 20 is formed as a hydrophilic or superhydrophilic surface to prevent polishing liquid dripping onto its surface from forming droplets that move under inertia.

[0035] Furthermore, the upper surface of the horizontal plate 20 is provided with textures or grooves (not shown) extending in the radial direction of the polishing pad, that is, extending in the length direction of the horizontal plate 20, to prevent polishing liquid dripping onto its surface from moving under inertia and affecting the accuracy of the measurement position.

[0036] Furthermore, the upper surface of the horizontal plate 20 is provided with a grid-like texture or groove or similar structure to fix the droplets and prevent them from moving, so as to prevent the polishing liquid dripping onto its surface from moving under inertia and affecting the accuracy of the measurement position.

[0037] The width of the grooves or textures is 0.2 mm to 3 mm, and preferably 1 mm to 2 mm.

[0038] It should be understood that the disadvantage of the measurement method based on optical projection is that when the polishing slurry is directly dripped onto a surface where the polishing slurry is distributed, the measurement error is relatively large due to the fusion effect between the polishing slurries and the refraction of light.

[0039] In one embodiment of the present invention, the inner sidewall of the positioning member 30 is an arc structure 30a. The arc structure 30a of the positioning member 30 can serve as a reference for fixing the polishing pad 300, so as to ensure that the polishing pad 300 and the polishing disk 200 are concentrically positioned. Figure 6 As shown, the dimensions of the arc structure 30a are similar to... Figure 3 The outer diameter of the polishing pad 300 shown is matched.

[0040] As one aspect of this embodiment, the arcuate structure 30a of the positioning member 30 is concentrically arranged with the polishing pad 200. Part or all of the positioning member 30 is located on the upper side of the polishing pad 200, and the height of the positioning member 30 on the upper side of the polishing pad 200 is greater than the thickness of the polishing pad 300. The arcuate structure 30a of the positioning member 30 serves as the mounting reference for the polishing pad 300, effectively ensuring that the polishing pad 300 and the polishing pad 200 are concentrically arranged.

[0041] Figure 1 and Figure 2 In the illustrated embodiment, the positioning element 30 and the fixing base 10 are designed as separate structures. This design reduces the impact of the installation of the fixing base 10 on the positioning position of the positioning element 30, ensuring the accuracy of the positioning element 30's fixation. It is understood that the positioning element 30 and the fixing base 10 can also be designed as a single integral component.

[0042] Figure 1In this embodiment, the length of the positioning element 30 is approximately equal to the width of the horizontal plate 20. As a variation of this embodiment, the length of the positioning element 30 is set to be greater than the width of the horizontal plate 20. For example, the length of the positioning element 30 is 2-5 times the width of the horizontal plate 20, so as to extend the length of the arc structure 30a, increase the contact area between the polishing pad 300 and the positioning element 30, and ensure the accuracy of the installation position of the polishing pad 300.

[0043] In this invention, the positioning component 30 is made of non-metallic materials, such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyester resin (PET), etc., to prevent the components used from generating metal ion contamination.

[0044] As an embodiment of the present invention, the positioning element 30 is required not only to have good machinability, but also to have sufficient strength to avoid the wear of the positioning element 30 itself from affecting the installation accuracy of the polishing liquid drop point measuring device.

[0045] In another embodiment of the present invention, the fixing base 10 and the positioning member 30 can be designed as an integral structure to allow for one-time clamping and forming of materials, ensuring the machining accuracy of the arc structure 30a. The lower part of the inner side surface of the fixing base 10 is connected to the polishing disc 200, and the upper part of the inner side surface of the fixing base 10 serves as a reference for mounting the polishing pad 300.

[0046] A schematic diagram of the installation of the polishing slurry landing point measuring device 100 in a chemical mechanical polishing system according to the present invention is shown below. Figure 3 As shown, the chemical mechanical polishing system includes a polishing fluid supply arm 400, as well as a polishing head and a dressing device (not shown).

[0047] Figure 3 In the image, the area near the center of the polishing pad shows a grooved structure for guiding the polishing slurry. It can be understood that other areas of the polishing pad also have concentric grooved structures to facilitate the flow of the polishing slurry across its surface. The structure of the upper surface of the polishing pad is related to its model; major models include IC1000, IC1400, IC2000, and SUBAIV, all featuring grooved structures on their upper surfaces to ensure the fluidity of the polishing slurry.

[0048] In another embodiment of the present invention, a horizontal plate 20 is disposed between the polishing pad 300 and the polishing liquid supply arm 400. The polishing liquid drips from the end of the polishing liquid supply arm 400 onto the upper surface of the horizontal plate 20. The upper surface of the horizontal plate 20 is provided with... Figure 1 The scale line 20a shown is for accurately measuring the drop position of the polishing liquid.

[0049] The technical solution provided by this invention uses the outer peripheral wall of the polishing disc 200 as the installation reference to install and fix the polishing slurry drop point measuring device 100 on the polishing disc 200. A horizontal plate 20 located on the upper side of the polishing disc 200 is provided with scale lines 20a, which are used to detect and verify the drop position of the polishing slurry. This structural form has the advantages of convenient operation and quick verification, which helps to improve the verification efficiency of polishing slurry supply performance.

[0050] Figure 4 This is a schematic diagram of an application embodiment of the polishing slurry drop point measuring device of the present invention. In this embodiment, the projection line of the end face of the horizontal plate 20 toward the polishing disk 200 coincides with the center point of the polishing disk 200. The scale line 20a is an arc line, and the center of the arc line coincides with the center of the polishing disk 200 or the polishing pad 300, so as to quickly and accurately check the drop position of the polishing slurry.

[0051] Furthermore, the horizontal plate 20 is also made of non-metallic materials, such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc.

[0052] Figure 4 In the illustrated embodiment, the polishing slurry drop point measuring device further includes a display test paper 40 to preserve the drop position and prevent the liquid from flowing from the horizontal plate 20 and affecting the determination of the drop point. The display test paper 40 is disposed on the upper surface of the horizontal plate 20. After the polishing slurry drips onto the display test paper 40, the color of the display test paper 40 changes, so as to accurately and quickly identify the drop position of the polishing slurry. Figure 4 In the image, the area near the center of the polishing pad shows a groove structure for guiding the polishing fluid. It is conceivable that other areas of the polishing pad also have similar groove structures.

[0053] As one aspect of this embodiment, the display test paper 40 is matched with the polishing liquid and is adhered to the upper surface of the horizontal plate 20. One end of the display test paper 40 is flush with the end face of the horizontal plate 20 facing the center of the polishing disk 200.

[0054] Chemical mechanical polishing systems require minimal or no use of chemicals during installation and commissioning. Therefore, when approving the performance of the polishing slurry supply, the liquid introduced into the polishing slurry supply arm 400 can be deionized water. Consequently, the indicator paper 40 can be selected as a water-sensitive color-changing test paper.

[0055] To ensure the proper functioning of the polishing slurry drop point measuring device 100, the horizontal plate 20 is positioned parallel to the polishing pad 300, with a distance of 5mm-10mm between the lower surface of the horizontal plate 20 and the upper surface of the polishing pad 300. It is understood that the horizontal plate 20 can also be positioned almost flush against the upper surface of the polishing pad 300. To prevent the horizontal plate 20 from contacting the upper surface of the polishing pad 300 and affecting the parallelism of its fixation, a certain gap is required between the horizontal plate 20 and the polishing pad 300, which can be 2mm-4mm. Preferably, the gap between the horizontal plate 20 and the polishing pad 300 is 2.5mm-3mm.

[0056] Figure 7 This is a schematic diagram of another embodiment of the horizontal plate 20 of the present invention. A partition 21 is disposed along the outer edge of the horizontal plate 20, and the partition 21 extends vertically from the upper surface of the horizontal plate. The partition 21 can prevent the crystals formed by the polishing liquid dripping onto the upper surface of the horizontal plate 20 from falling onto the upper part of the polishing pad, thereby effectively preventing scratches on the surface of the polished wafer.

[0057] Specifically, before chemical mechanical polishing, the polishing slurry drop point measurement device described in this invention needs to be used for calibration. Figure 4 The setting position of the polishing slurry supply arm 400 is shown. During polishing slurry drop point measurement, polishing slurry drips onto the upper surface of the level plate 20. If the polishing slurry on the level plate 20 is not cleaned in time, it will form crystals on the level plate 20. These crystals will fall onto the upper surface of the polishing pad during polishing slurry drop point measurement, scratching the polished wafer and reducing the wafer polishing yield.

[0058] As one aspect of this embodiment, the partition 21 includes a front partition and a side partition, both integrally formed and disposed on the outer edge of the horizontal plate 20. The front partition is disposed facing the center of the polishing pad, and the side partitions are disposed on the side of the horizontal plate 20. It is understood that the length of the side partitions may be equal to or less than the length of the horizontal plate 20. Figure 7 In the embodiment shown, the length of the side partition is half that of the horizontal plate 20 because the upper surface of the horizontal plate 20 is configured with a surface structure that hinders the movement of the polishing fluid, and the surface structure can, to a certain extent, hinder the large movement of the polishing fluid.

[0059] In some embodiments, the partition 21 may also be disposed entirely along the outer edge of the horizontal plate 20 to prevent the polishing liquid on it from crystallizing and falling onto the surface of the polishing pad, causing scratches on the polished wafer.

[0060] In addition, the present invention also discloses a chemical mechanical polishing system, which includes the polishing slurry drop point measuring device 100 described above, so as to quickly check the drop position of the polishing slurry on the polishing pad and check whether the supply performance of the polishing slurry meets the design requirements.

[0061] The following is a brief description of the steps for using the polishing slurry droplet measuring device of the present invention:

[0062] First, the fixing seat 10 is installed on the outer peripheral wall of the polishing disc 200, and then the positioning member 30 is fixed to the stepped portion 10a of the fixing seat 10;

[0063] Next, the polishing pad 300 is installed using the arc structure 30a of the positioning member 30 as a reference. After the polishing pad 300 is bonded and fixed, the horizontal plate 20 is installed on the top of the fixing base 10 to check the drip position of the polishing liquid using the scale line 20a on the upper surface of the horizontal plate 20.

[0064] When verifying the location of the polishing slurry droplet, the polishing disc needs to be rotated at a low speed so that the supply port at the end of the polishing slurry supply arm 400 is located above the horizontal plate 20 of the polishing slurry droplet measuring device 100. In some embodiments, the operator may attach a display test strip 40 to the upper surface of the horizontal plate 20 to preserve the droplet point of the polishing slurry and accurately verify the location of the polishing slurry droplet.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these 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 device for measuring the landing point of polishing slurry, characterized in that, The device includes a fixed base, a horizontal plate, and a positioning element. The fixed base is detachably mounted on the outer peripheral wall of the polishing pad of a chemical mechanical polishing (CMP) device. The horizontal plate is connected to the top of the fixed base and extends toward the center of the polishing pad. The positioning element is disposed on the side of the fixed base and located below the horizontal plate. The inner sidewall of the positioning element has an arc structure that matches the outer diameter of the polishing pad. Polishing liquid falls onto the upper surface of the horizontal plate, and the upper surface of the horizontal plate is provided with scale lines to measure the dripping position of the polishing liquid. The upper surface of the horizontal plate is formed as a hydrophilic or superhydrophilic surface to prevent polishing liquid dripping onto its surface from forming droplets that move under inertia; the distance between the lower surface of the horizontal plate and the upper surface of the polishing pad is 5-10 mm. It also includes a display test strip, which is disposed on the upper surface of the horizontal plate. After the polishing liquid is dripped onto the display test strip, the color of the display test strip changes. A partition is provided along the outer edge of the horizontal plate, which extends vertically from the upper surface of the horizontal plate; the partition includes a front partition and a side partition, which are integrally formed and disposed along the outer edge of the horizontal plate; the length of the side partition is greater than half the length of the horizontal plate.

2. The polishing slurry landing point measuring device as described in claim 1, characterized in that, The projection line of the horizontal plate toward the end face of the polishing pad coincides with the center point of the polishing pad, and the scale line is an arc line, the center of which coincides with the center of the polishing pad or polishing mat.

3. The polishing slurry landing point measuring device as described in claim 1, characterized in that, The mounting base, horizontal plate, and positioning element are made of non-metallic materials.

4. The polishing slurry landing point measuring device as described in claim 1, characterized in that, The upper surface of the horizontal plate has a surface structure designed to impede the movement of the polishing fluid.

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