CN215240149U - Chemical mechanical polishing device for semiconductor material - Google Patents

Abstract

The utility model discloses a semiconductor material's chemical machinery grinds device of throwing. The device can be suitable for three central liquid supply type grinding and polishing processing methods, which comprise the following steps: a fixed abrasive center liquid supply chemical mechanical polishing method, a small grinding head center liquid supply chemical mechanical polishing method and a disc type fluid dynamic pressure chemical mechanical polishing method. The chemical mechanical polishing device for the semiconductor material comprises a polishing tool, an adjusting ring, an adjusting bolt and a vacuum chuck, wherein the upper surface of the adjusting ring is flush with the upper surface of a wafer by adjusting the adjusting bolt, so that the wafer fracture caused by uneven stress during wafer edge polishing can be effectively avoided. The polishing tool is equipped with a plurality of replaceable polishing pads including a fixed abrasive polishing pad, a porous material polishing pad and a fluid dynamic pressure polishing disk, and the center of the polishing tool is opened with a center through hole to realize chemical polishing liquid supply. The utility model discloses realize semiconductor material precision positioning and grind and throw, be applicable to the full series processing of wafer attenuate, grinding and throwing, ultra-precision polishing.

Description

Chemical mechanical polishing device for semiconductor material

Technical Field

The utility model relates to a semiconductor material grinds device of throwing, especially relates to a semiconductor material attenuate, polish in order to obtain the serialization processingequipment of nanometer super smooth surface.

Background

Semiconductor materials are an indispensable part of high-end chips by virtue of their excellent material properties. The flatness, roughness, metal and particles of the semiconductor device have significant influence on the semiconductor device. With the rapid development of chip technology in the fields of life, industry, medical treatment, national defense science and technology, etc., the efficient and high-precision manufacturing process of semiconductor materials becomes a core technical problem to be broken through urgently.

Currently, semiconductor polishing equipment is mainly based on a conventional chemical mechanical polishing device, i.e., a wafer is absorbed on the lower portion of a carrier head and directly abuts against a rotating polishing pad. In the conventional apparatus, the wafer needs to perform a spinning motion. However, since wafers are generally in the shape of a disk with an extremely thin thickness, such a spinning motion may be a significant cause of wafer breakage and breakage. In addition, the precision requirement of the wafer is very strict, so that the development of a full-series wafer polishing thinning device for preventing the wafer from being broken has great significance in the field of semiconductor processing.

From the principle point of view, the conventional chemical mechanical polishing method usually sprays chemical polishing liquid directly on the polishing disc, so that the chemical polishing liquid flows to a processed area under the action of centrifugal force. Compared with a central liquid supply chemical mechanical polishing method, the chemical polishing liquid directly enters a workpiece contact area of the tool through a central hole of the tool, and the method is particularly beneficial to the efficient utilization of the polishing liquid. In addition, the pressure of a liquid film between the workpiece and a tool can be better controlled by externally controlling the pressure of the polishing liquid or using polishing discs with different shapes, so that the machining precision and efficiency are improved.

SUMMERY OF THE UTILITY MODEL

To the above-mentioned prior art, the utility model provides a semiconductor material's chemical machinery grinds throws device can prevent the wafer fracture at the wafer and grinds the throwing attenuate in-process. In the polishing process, the chemical polishing solution directly enters a contact area between the polishing tool and the workpiece through the central through hole of the polishing tool, so that the efficient utilization of the polishing solution is facilitated. In addition, the pressure of a liquid film between the workpiece and a tool can be better controlled by externally controlling the pressure of the polishing liquid or using polishing discs with different shapes, so that the machining precision and efficiency are improved.

In order to solve the above technical problem, the present invention provides a chemical mechanical polishing device for semiconductor materials, which comprises a wafer fixing device and a polishing tool, wherein the wafer fixing device comprises a vacuum chuck and an adjusting ring; the vacuum chuck comprises a disc supporting seat and a vacuum column array, the vacuum column array is embedded in the disc supporting seat, three axial threaded holes are uniformly distributed in the top of the side wall of the disc supporting seat along the circumferential direction, exhaust holes are formed in the side wall of the disc supporting seat, and each vacuum column in the vacuum column array is connected to the exhaust hole; the adjusting ring is uniformly provided with three radial threaded holes along the circumferential direction, the bottom surface of the adjusting ring is uniformly provided with three blind holes which are respectively communicated with the three radial threaded holes along the circumferential direction, each axial threaded hole of the disc supporting seat is internally provided with an adjusting bolt, and the upper part of each adjusting bolt is an optical axis; the adjusting ring is placed on the top surface of the side wall of the disc supporting seat, optical axis parts of three adjusting bolts are respectively embedded in three blind holes in the bottom surface of the adjusting ring, the three adjusting bolts are used for supporting the adjusting ring, the inner diameter of the adjusting ring is in clearance fit with the outer diameter of a wafer, the wafer adsorbed on the hollow column array of the vacuum chuck is positioned in the adjusting ring, the upper surface of the adjusting ring is flush with the upper surface of the wafer by adjusting the adjusting bolts, and each radial threaded hole is screwed with a locking bolt to prop against the upper optical axis of the adjusting bolt at the corresponding position, so that the height positioning of the adjusting ring is realized; the polishing tool comprises a tool central shaft, a polishing disk base body and a plurality of replaceable polishing pads, one polishing pad is selected during processing, the tool central shaft, the polishing disk base body and the polishing pad are coaxially arranged, and a central through hole penetrating through the tool central shaft, the polishing disk base body and the polishing pad is formed.

Further, semiconductor material's chemical machinery grinds throwing device, wherein:

the vacuum columns of the vacuum column array are arranged in a plurality of concentric rings.

The plurality of replaceable polishing pads includes a fixed abrasive polishing pad, a porous material polishing pad, and a fluid dynamic pressure polishing disk.

The fixed abrasive grinding and polishing pad comprises a grinding and polishing pad base body, wherein array micro-protrusions are arranged on the working surface of the grinding and polishing pad base body, and a plurality of micro abrasive particles are arranged on the surfaces of the array micro-protrusions.

And the working surface of the porous material polishing pad is provided with latticed micro grooves which are communicated with the central through hole.

And the working surface of the fluid dynamic pressure polishing disk is provided with radial micro grooves communicated with the central through hole.

Compared with the prior art, the beneficial effects of the utility model are that:

the utility model discloses a chemical machinery grinds device of throwing can realize the position of adjusting ring and wafer for the adjusting ring can play the effect of supporting tool during wafer edge polishing, by the inhomogeneous and wafer fracture that leads to of atress during can effectively avoiding wafer edge polishing.

The utility model discloses a chemical machinery grinds and throws device disposes removable consolidation abrasive material and polishes pad, porous material polishing pad and fluid dynamic pressure polishing dish, can realize following different polishing methods:

(1) the center of the fixed abrasive supplies liquid for chemical mechanical polishing, and wafer materials are removed mainly by the fixed abrasive on a polishing pad, so that the removal amount is large, and the method is particularly suitable for a semiconductor material thinning process.

(2) The center of the small grinding head is supplied with liquid for chemical mechanical polishing, the chemical solution corrodes and softens the surface of a workpiece, then free abrasive in the polishing liquid is kept by a tool of the small grinding head to remove materials, the removal amount and the polishing quality are moderate, and the small grinding head is particularly suitable for high-precision processing of semiconductor materials.

(3) Disc type fluid dynamic pressure chemical mechanical polishing also softens the surface of a workpiece through chemical solution corrosion in a polishing solution, and abrasives in the polishing solution impact and cut the surface of the workpiece to remove materials. In the polishing process, the disc surface of the fluid dynamic pressure polishing disc is not contacted with the surface of a workpiece and is separated by a micro liquid film, so that the fluid dynamic pressure polishing disc is particularly suitable for ultra-precise polishing of semiconductor materials.

Drawings

FIG. 1 is an assembly view of the chemical mechanical polishing apparatus for semiconductor materials of the present invention;

FIG. 2 is an exploded view of the polishing apparatus shown in FIG. 1;

FIG. 3 is a schematic view of a polishing process of the polishing apparatus shown in FIG. 1;

FIG. 4 is a schematic diagram of an edge effect during polishing of the polishing apparatus shown in FIG. 1;

FIG. 5 is a schematic view of the vacuum chuck of the polishing apparatus shown in FIG. 1;

FIG. 6 is a bottom view of the conditioning ring of the polishing apparatus of FIG. 1;

FIG. 7 is a schematic view of a chemical mechanical polishing process using a fixed abrasive central feed liquid;

FIG. 8 is a schematic diagram of the structure of the fixed abrasive polishing pad shown in FIG. 7;

FIG. 9 is a schematic view of a method for implementing center liquid feed chemical mechanical polishing of a small grinding head;

FIG. 10 is a schematic diagram of a small grinding head center liquid feed polishing pad configuration;

fig. 11 is a schematic structural view of a fluid dynamic pressure polishing disk.

In the figure:

1-polishing tool 11-tool central shaft 12-grinding and polishing disk substrate

13-fixed abrasive grinding and polishing pad 131-grinding and polishing pad matrix 132 array micro-protrusion

133-micro abrasive particle 14-porous material polishing pad 141-grid-shaped micro grooves

15-hydrodynamic polishing disk 151-radial microgroove 2-wafer

3-adjusting ring 31-blind hole 4-locking bolt

41-radial threaded hole 5-adjusting bolt 6-vacuum chuck

61-axial threaded hole 62-vacuum column array 63-vent hole

64-disc supporting seat 8-deionized water 9-polishing solution

Detailed Description

The present invention will be further described with reference to the following drawings and specific examples, but the following examples are by no means limiting the present invention.

The utility model discloses a chemical machinery grinds and throws device can realize that consolidation abrasive material center supplies liquid chemical machinery to grind and throws, little bistrique center supplies liquid chemical machinery polishing and disc fluid dynamic pressure chemical machinery polishing. The device aims at realizing the precise positioning and grinding and polishing of semiconductor materials, and is a full-series processing device suitable for wafer thinning, grinding and polishing and ultra-precise polishing.

As shown in fig. 1 and 2, the present invention provides a chemical mechanical polishing device for semiconductor materials, which comprises a wafer fixing device and a polishing tool 1, wherein the wafer fixing device comprises a vacuum chuck 6 and an adjusting ring 3. As shown in fig. 2, the vacuum chuck 6 includes a disk support 64 and a vacuum column array 62, the vacuum column array 62 is embedded in the disk support 64, and the vacuum columns of the vacuum column array 62 are arranged in a plurality of concentric rings. Three axial threaded holes 61 are uniformly distributed in the top of the side wall of the disc supporting seat 64 along the circumferential direction, vent holes 63 are formed in the side wall of the disc supporting seat 64, and each vacuum column in the vacuum column array 62 is connected to the vent holes 63.

The adjusting ring 3 is uniformly provided with three radial threaded holes 41 along the circumferential direction, the bottom surface of the adjusting ring 3 is uniformly provided with three blind holes 31 which are respectively communicated with the three radial threaded holes 41 along the circumferential direction, as shown in fig. 6, each axial threaded hole 61 of the disc support base 64 is internally provided with one adjusting bolt 5, the structure of the adjusting bolt 5 in the utility model is shown in fig. 2, the lower part of the adjusting bolt 5 is a threaded section, the upper part of the adjusting bolt is an optical axis section, a shaft shoulder is arranged between the threaded section and the optical axis section, the threaded section is matched with the radial threaded holes, the optical axis section is in clearance fit with the blind holes 31, the adjusting ring 3 is placed on the top surface of the side wall of the disc support base, and the optical axis parts of the three adjusting bolts 5 are respectively embedded in the three blind holes 31 on the bottom surface of the adjusting ring 3, the shaft shoulders of the three adjusting bolts 5 are propped against the bottom surface of the adjusting ring 3 for supporting the adjusting ring 3, the internal diameter of adjusting ring 3 and the external diameter clearance fit of wafer 2 adsorb in wafer 2 on the empty post array 62 of vacuum chuck 6 is located in adjusting ring 3, makes through adjusting bolt 3 the upper surface of adjusting ring 3 and the upper surface parallel and level of wafer 2, every radial screw hole 41 all screw in has a locking bolt 4, and locking bolt 4 withstands the upper portion optical axis of the adjusting bolt 5 that corresponds the position, thereby realizes the high location of adjusting ring 3. The polishing tool 1 comprises a tool central shaft 11, a polishing disc base body 12 and a plurality of replaceable polishing pads, one of the polishing pads is selected during processing, the tool central shaft 11, the polishing disc base body 12 and the polishing pad are coaxially arranged, and a central through hole penetrating through the tool central shaft 11, the polishing disc base body 12 and the polishing pad is formed.

Example 1:

as shown in fig. 3, during polishing, the wafer 2 is held by the vacuum chuck 6, and the polishing tool 1 rotates while relatively moving with respect to the wafer 2 along a fixed trajectory. As shown in fig. 4, in general, when the polishing tool 1 exceeds the edge of the wafer 2, the wafer and the polishing tool 1 may be unevenly stressed, resulting in breakage of the wafer 2. In order to avoid this, the adjusting ring 4 of the present invention always keeps the upper surface of the adjusting ring 2 flush with the upper surface of the wafer 2 as much as possible when the wafer 2 is fixed. As shown in fig. 5, three 120 ° axisymmetrical threaded holes 61 are formed in the sidewall of the vacuum chuck 6 for mounting the adjusting bolts 5, and vacuum columns 62 arranged in a circular arrangement at the center in a disc support base 64 of the vacuum chuck 6 are connected to the exhaust holes 63. When the wafer 2 is placed on the vacuum chuck 6, the air is sucked out through the exhaust hole 63, so that the wafer 2 is sucked onto the vacuum chuck 6. Thereafter, the screwing length of the adjusting bolt 5 in the vacuum chuck 6 is adjusted, the upper optical axis of the adjusting bolt 5 is embedded in the blind hole 31 on the bottom surface of the adjusting ring 3, the bottom surface of the adjusting ring 3 is adjusted by the shaft shoulder of the adjusting bolt 5, so that the position of the adjusting ring 3 can be adjusted, after the upper surface of the adjusting ring 3 is flush with the upper surface of the wafer 2 by adjusting the adjusting bolt 5, the adjusting bolt 5 is locked by the locking bolt 4, fig. 3 shows that the polishing tool 1 is just positioned at the joint between the wafer 2 and the adjusting ring 3, so that the adjusting ring 3 can play a role of supporting the polishing tool 1 when the edge of the wafer 2 is polished, and the edge effect shown in fig. 4 is avoided. Therefore, the wafer fracture caused by uneven stress during wafer edge polishing can be effectively avoided.

In order to realize a plurality of different polishing methods, the present invention provides a plurality of replaceable polishing pads including a fixed abrasive polishing pad 13, a porous material polishing pad 14 and a fluid dynamic pressure polishing disk 15, as shown in fig. 8, the fixed abrasive polishing pad 13 includes a polishing pad base 131, an array micro-protrusion 132 is provided on the working surface of the polishing pad base 131, the array micro-protrusion 132 in this embodiment is a circular protrusion, and each circular protrusion has a plurality of micro-abrasive particles 133 on the surface. As shown in fig. 10, the working surface of the porous material polishing pad 14 is provided with grid-shaped micro grooves 141 penetrating the central through hole. As shown in fig. 11, the working surface of the fluid dynamic pressure polishing disk 15 is provided with radial micro grooves 151 penetrating the central through hole.

Example 2: according to the difference of instrument selection, the utility model discloses a grind and throw device can realize being used for different polishing methods.

(1) The chemical mechanical polishing method mainly depends on the fixed abrasive on a polishing pad to remove wafer materials, so that the removal amount is large, and the method is particularly suitable for a semiconductor material thinning process. The processing process is shown in fig. 7, and deionized water 8 or a polishing solution mixed by deionized water and a chemical agent with a certain pressure is introduced into the central through hole of the central shaft 11 of the tool during the processing process. On one hand, the surface of the workpiece is corroded by a chemical reagent, so that the material removal efficiency is improved, on the other hand, the polishing tool 1 generates buoyancy under the action of the deionized water 8, the fine adjustment of the position between the polishing tool 1 and the wafer 2 is realized, the depth of the abrasive on the surface of the polishing tool 1 penetrating into the workpiece is changed, and the balance between the workpiece removal efficiency and the sub-surface damage inhibition is realized. The fixed abrasive polishing pad 13 is shown in fig. 8, and in the utility model, for example, a polishing pad having a plurality of circular protrusions is used, and a plurality of micro abrasive particles 133 are uniformly distributed on each circular protrusion.

(2) The chemical mechanical polishing method comprises the steps of corroding and softening the surface of a workpiece through a chemical solution in polishing liquid, and then keeping free abrasive materials in the polishing liquid through a small grinding head tool to remove materials. The processing process is shown in fig. 9, and is different from the chemical mechanical polishing of the fixed abrasive center liquid supply in the difference between the polishing pad and the polishing liquid. The polishing method is realized by adopting a polyurethane polishing pad and the like, and the polishing solution 8 is prepared by deionized water, a chemical reagent, micro-abrasive particles and the like. The chemical agent in the polishing liquid 8 functions to achieve corrosion and softening of the surface of the workpiece, and the fine abrasive grains function to achieve mechanical removal of the surface of the workpiece. During processing, the abrasive slurry flows through the central through-hole of the polishing tool into the contact area between the polishing tool 1 and the wafer workpiece, and the polishing tool provides a force to remove the semiconductor material softened or eroded by the chemical agent with the abrasive slurry. In order to improve the performance of holding abrasive grains by a tool, a porous material polishing pad 14 such as polyurethane is generally used, and as shown in fig. 10, a mesh-like micro groove 141 penetrating a central through hole is provided on a working surface of the porous material polishing pad 14.

(3) Disc type fluid dynamic pressure chemical mechanical polishing, the polishing method also softens the surface of a workpiece through chemical solution corrosion in the polishing solution, and the abrasive in the polishing solution impacts and cuts the surface of the workpiece to remove materials. The method differs from the small grinding head center feed liquid chemical mechanical polishing in that the polishing pad is different. As shown in fig. 11, the polishing pad used in the method is a fluid dynamic pressure polishing disk 15, and radial micro-grooves 151 penetrating through the central through hole are formed on the working surface of the fluid dynamic pressure polishing disk 15 to control the pressure and speed of the polishing liquid. In the polishing process, the fluid dynamic pressure polishing disk 15 rotates at a certain speed, and the polishing solution 9 is injected along the central through hole of the tool to form fluid dynamic pressure, so that the disk surface is not in contact with the surface of a workpiece and is isolated by a micro liquid film. The chemical agents and abrasives in the polishing liquid 9 erode the surface of the impact material in the liquid field created by the hydrodynamic pressure of the polishing disk 15. The method is easy to obtain a nano-level smooth surface after polishing, so that the method is particularly suitable for ultra-precise polishing of semiconductor materials.

To sum up, the utility model provides a semiconductor material's chemical machinery grinds device of throwing. The polishing method is suitable for three polishing methods, namely fixed abrasive center liquid supply chemical mechanical polishing, small grinding head center liquid supply chemical mechanical polishing and disc type fluid dynamic pressure chemical mechanical polishing. The three methods have the advantages that the material removal rate is sequentially decreased, but the polishing precision is sequentially increased, and the method is particularly suitable for processing stages of wafer thinning and grinding and polishing. Therefore, the device is a full-series processing device for manufacturing the nanoscale ultra-smooth wafer.

Although the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit of the present invention.

Claims (6)

1. A chemical mechanical polishing device for semiconductor materials, comprising a wafer holding device and a polishing tool (1), characterized in that the wafer holding device comprises a vacuum chuck (6) and an adjusting ring (3);

the vacuum chuck (6) comprises a disc supporting seat (64) and a vacuum column array (62), the vacuum column array (62) is embedded in the disc supporting seat (64), three axial threaded holes (61) are uniformly distributed in the top of the side wall of the disc supporting seat (64) along the circumferential direction, exhaust holes (63) are formed in the side wall of the disc supporting seat (64), and each vacuum column in the vacuum column array (62) is connected to the exhaust hole (63);

three radial threaded holes (41) are uniformly distributed in the adjusting ring (3) along the circumferential direction, three blind holes (31) which are respectively communicated with the three radial threaded holes (41) are uniformly distributed in the bottom surface of the adjusting ring (3) along the circumferential direction, an adjusting bolt (5) is assembled in each axial threaded hole (61) of the disc supporting seat (64), and the upper part of each adjusting bolt (5) is an optical axis;

the adjusting ring (3) is placed on the top surface of the side wall of the disc supporting seat, optical axis parts of three adjusting bolts (5) are respectively embedded in three blind holes (31) in the bottom surface of the adjusting ring (3), the three adjusting bolts (5) are used for supporting the adjusting ring (3), the inner diameter of the adjusting ring (3) is in clearance fit with the outer diameter of a wafer (2), the wafer (2) adsorbed on a hollow column array (62) of the vacuum chuck (6) is positioned in the adjusting ring (3), the upper surface of the adjusting ring (3) is flush with the upper surface of the wafer (2) by adjusting the adjusting bolts (5), and each radial threaded hole (41) is screwed with a locking bolt (4) to prop against the upper optical axis of the adjusting bolt (5) at a corresponding position, so that the height positioning of the adjusting ring (3) is realized;

the polishing tool (1) comprises a tool central shaft (11), a polishing disc base body (12) and a plurality of replaceable polishing pads, one polishing pad is selected during processing, the tool central shaft (11), the polishing disc base body (12) and the polishing pad are coaxially arranged, and a central through hole penetrating through the tool central shaft (11), the polishing disc base body (12) and the polishing pad is formed.

2. Chemical mechanical polishing device for semiconductor materials according to claim 1, characterized in that the arrangement of the vacuum columns of the array of vacuum columns (62) is arranged according to a plurality of concentric rings.

3. The chemical mechanical polishing device of semiconductor material as recited in claim 1, wherein the plurality of replaceable polishing pads comprise a fixed abrasive polishing pad (13), a porous material polishing pad (14), and a hydrodynamic polishing disk (15).

4. The semiconductor material chemical mechanical polishing device as claimed in claim 3, wherein the fixed abrasive polishing pad (13) comprises a polishing pad base body (131), an array of micro-protrusions (132) are arranged on the working surface of the polishing pad base body (131), and the surface of each array of micro-protrusions (132) is provided with a plurality of micro-abrasive particles (133).

5. A chemical mechanical polishing device for semiconductor materials according to claim 3, characterized in that the working surface of the porous material polishing pad (14) is provided with grid-like micro-grooves (141) penetrating the central through hole.

6. A chemical mechanical polishing device for semiconductor materials according to claim 3, wherein the working surface of the fluid dynamic pressure polishing disk (15) is provided with radial micro-grooves (151) penetrating the central through hole.

Images