TWI735795B - Polishing pad dresser and chemical mechanical planarization method - Google Patents

Abstract

All CMP pad dressers use diamond as the cutting edge, but the height difference between the diamond cutting edge and the most protruding apex is greater than 60 microns, so that the number of working particles of the cutting polishing pad is less than 500. Although there are dressers made of engraved ceramics (such as SiC) coated with diamond film, the diamond film is easy to peel off and cause round scratches. In the present invention, the non-diamond superhard material PcBN is used as the abrasive material to directly engrave customized independent small pieces, which are then assembled into a CMP polishing pad dresser. The corrosion resistance of PcBN is much higher than that of diamond, and it is sintered under ultra-high pressure. The invention can independently customize the size, shape and height of the cutting edge, so the number of cutting edges and the depth of cutting of the polishing pad can be controlled, so the life of CMP consumables can be prolonged, in addition to reducing cost (CoO), it can also speed up CMP efficiency and increase productivity. It is the current weapon in the production of semiconductor products.

Description

Polishing pad dresser and chemical mechanical planarization method

The present invention relates to a polishing pad dresser and a chemical mechanical planarization method, in particular to a PcBN polishing pad dresser, a chemical mechanical planarization method using the PcBN polishing pad dresser, and an integrated circuit manufacturing process.

Chemical mechanical planarization (Chemical mechanical planarization or CMP) is a process that must be used multiple times to manufacture integrated circuits (or integrated circuits, commonly known as ICs, or Integrated circuit circuits). As the circuit line width of Moore's Law increases, Smaller, the stricter the requirements of CMP, and the more times. Take the world’s largest foundry company, Taiwan Semiconductor Manufacturing Company (TSMC) as an example. Its 7nm process requires CMP of IC wafers with a diameter of 300mm (12 inches) for dozens of times, and the polishing rate for each CMP is faster. It is flat and there are no scratches on the IC wafer, so that a small nail-sized chip can be cut from a complete IC wafer. It contains dozens of layers of copper wires with a total length of more than ten kilometers, connecting billions of silicon substrates. Transistors (Transistors) enable the chip to operate with 0 or 1 and become CPU/GPU/NPU and other hardware computers used in mobile phones, computers, robots, and the Internet. CMP is not only used to manufacture IC logic computing units, but also used to manufacture IC memory (such as DRAM, Flash memories, etc.), and even silicon wafers themselves, and even storage (such as hard disks). In short, CMP is a manufacturing large Area (such as sapphire wafer) is a necessary process for highly planarizing the plane.

Specifically, CMP is a polishing method in which a rotating IC wafer is pressed on a rotating polishing pad (usually made of PU), and the polishing pad is coated with a slurry (slurry) containing nano-abrasive particles (such as SiO ₂ and Al ₂ O ₃ ) and chemical reagents (such as acid, alkali, hydrogen peroxide); and the polishing pad usually contains micro-pores to adjust the compression rate and store the slurry. When polishing the wafer, the contact area and distribution of the wafer and the polishing pad must be controlled. Therefore, a diamond disc must be used to trim the polishing pad to produce asperities of moderate size and uniform distribution on the surface of the polishing pad. If the contact area between the wafer and the polishing pad is too large, the polishing rate will be low and the CMP efficiency will be insufficient; otherwise, the local polishing will be too much, resulting in wafer unevenness (Within wafer non-uniformity, referred to as WIWNU), and even dents (Dishing, Erosion) , And even the problem of scratching. In addition, the diamond disc is also responsible for removing the hard chips (Glaze) on the polishing pad. Therefore, the distribution of the apex height of the diamond on the diamond disc controls the depth distribution of the diamond penetration into the polishing pad and affects the various performances of CMP, so it is to control CMP Key consumables for performance.

The diamond disc is usually on a stainless steel disc. The metal material (such as nickel or its alloy) is used to fix and arrange the abrasive particles (Grind grit). The abrasive particles are diamond grit, for example, it can be 150 microns. The fixing methods include electroplating, brazing or sintering. Due to the different sizes of diamond abrasive grains, the apex height varies greatly, and the shape of diamond abrasive grains is irregular, often containing fractured surfaces, so that the sharpness of the cutting polishing pad is difficult to control, making the size and distribution of fluff on the polishing pad uneven, affecting The efficiency and yield of CMP.

On the other hand, CMP is an interface polishing method, and the pressure distribution of the interface is determined by the size and distribution of the fluff of the polishing pad. The height difference of the apex of the diamond abrasive grains of the diamond disc is too large, so that in fact, less than 500 diamond abrasive grains can pierce. Into the polishing pad to form fluff. What's more, the top ten diamond abrasive grains have the problem of piercing too deep (for example, greater than 60 microns), which makes polishing pads that are more expensive than diamond discs more expensive. Therefore, the apex height difference of diamond abrasive grains is too large, which not only shortens the life of the diamond disc and polishing pad, but also causes unevenness of the IC wafer, and even scratches, which reduces the yield of the wafer. In addition, , The downtime for replacing diamond discs and polishing pads is also more frequent, which reduces the single unit shipments.

Although the use of smaller diamond abrasive grains can reduce the peak height difference, it will reduce the protrusion of the diamond abrasive grains, thus causing friction between the metal and the grout that fix the diamond abrasive grains, which will contaminate the IC wafers and reduce the wafers. Yield. The use of regular crystal diamond abrasive grains can reduce the height difference of the apex, but there will be a problem that the diamond abrasive grains are not sharp enough, causing hard debris to remain on the surface of the polishing pad, thus increasing the number of micro-scratches on the IC wafer. Therefore, the diamond disc with fixed diamond abrasive grains has its insurmountable difficulties, including the inability to have both the peak height difference and the sharpness, so that the cost (CoO) and efficiency (Throughput) of CMP cannot be improved.

In view of this, the inventor of this case used a whole piece of polycrystalline diamond (PCD) sintered piece as the grinding structure of the diamond disc, and the diamond disc made by electric discharge machining has uniform apex height and uniform The pyramid shape has become the diamond disc of choice for the Electrolytic CMP (eCMP) developed by Applied Materials Co., which uses current to oxidize copper wires.

However, the above-mentioned PCD contains cobalt as a sintering agent, which evaporates into pores after electrical discharge machining, which is easy to stick to the wear debris, and is not suitable for the CMP process. Therefore, there is still room for improvement.

CMP requires that the surface of the polishing pad has fine and more fluff. The fine fluff can avoid wafer scratches, and the more fluff can speed up the wafer polishing. The fine fluff needs more diamond tips to penetrate, that is, the highest apex of the diamond must be uniform. If the number of working particles is large, the penetration will not be deep. Therefore, the angle of the top of the diamond must be sharp. The diamond inherently has the problems of uneven top and not sharp top.

The main purpose of the present invention is to solve the above-mentioned problems and shortcomings of the conventional polishing pad dresser using diamond material. Another object of the present invention is to prolong the chemical reaction rate of the tip immersed in the CMP slurry, thereby providing better Polishing pad dresser for diamond discs.

The present invention provides a polishing pad dresser used in a CMP process, comprising a plurality of PcBN polishing pads, each of the PcBN polishing pads is formed with a plurality of polishing tips. Highlight height.

In one embodiment, the average penetration depth of the polishing tip is greater than the average size of the pores of the polishing pad.

In one embodiment, the average size of the pores is between 30 μm and 60 μm.

The present invention also provides a polishing pad dresser, comprising a plurality of PcBN polishing pads, and each PcBN polishing pad is formed with a plurality of polishing tips, wherein, among all the polishing tips, the height difference of the polishing tip with the highest distance is 60 The number of the grinding tips in the micrometer range is between 300 and 5000.

In one embodiment, the PcBN abrasive sheet is fixed on a ceramic substrate.

In one embodiment, the PcBN polishing sheet is respectively bonded to a base through a thickness compensating plastic body that adjusts the protrusion height of the polishing tip on the PcBN polishing sheet.

In one embodiment, the thickness compensation plastic body is an organic material.

In one embodiment, the volume percentage of cBN in the PcBN polishing sheet is at least 90%.

In one embodiment, the number of the polishing tips with the highest distance between the polishing tips in the range of 40 microns is between 300 and 1000.

In one embodiment, among the polishing tips on a single PcBN polishing sheet, the number of the polishing tips with the height difference of the polishing tip having the highest distance in the range of 40 microns is between 50 and 500.

In one embodiment, the polishing tip has a sharp peak, and the included angle of the sharp peak is between 40 degrees and 120 degrees.

In one embodiment, the included angle of the peak is between 60 degrees and 100 degrees.

In one embodiment, the shape of the peak is a cone or a ridge.

In one embodiment, the cone is a polygonal cone, and the number of sides of the polygonal cone is between 3 and 6.

In one embodiment, the shape of the PcBN polishing sheet is a square or a circle.

In one embodiment, the polishing tip includes a blunt top surface, and the width of the top surface is between 2 μm and 20 μm.

In one embodiment, the number of the PcBN polishing sheet is between 4 and 50.

In one embodiment, the polishing tips on each PcBN polishing sheet are arranged to form an array.

The present invention further provides a chemical-mechanical planarization method, which includes the following steps: providing a polishing pad; placing a workpiece on the surface of the polishing pad to grind the workpiece and the polishing pad; and using a dresser as described above to set On the surface of the polishing pad, the debris after grinding of the workpiece is removed.

In one embodiment, the workpiece is a semiconductor device, and the semiconductor device includes one or more layers of copper film, tungsten film, oxide film, barrier layer, or a combination thereof.

Therefore, the PcBN of the present invention is used as the polishing pad of the dresser to replace the traditional diamond disc. The conventional dresser usually only considers the mechanical properties, but ignores that the IC wafer and polishing pad dresser will also involve chemical erosion during CMP. And mechanical polishing, and PcBN not only has high chemical inertness, is suitable for resisting the chemical attack in CMP, but also has excellent mechanical properties compared to most materials, and has better processability than diamond materials. It is suitable for processing the polishing tip into Specific shape and arrangement to meet highly customized requirements.

10: Polishing pad dresser

20: PcBN grinding sheet

20a: The first PcBN polishing sheet

20b: The second PcBN polishing sheet

21a: First grinding tip

21b: Second grinding tip

22a: first top surface

22b: second top surface

23b: Depressed

24: side

25: corner

30: ceramic substrate

40: thickness compensation plastic body

50: Pedestal

51: sunken

60: Hard layer

70: Process

71: steps

72: steps

73: Steps

W: width

"Figure 1" is a schematic diagram of an embodiment of the polishing pad conditioner of the present invention.

"Figure 2" is an enlarged schematic diagram of the first PcBN polishing sheet of "Figure 1".

"Figure 3" is an enlarged schematic diagram of the second PcBN polishing sheet of "Figure 1".

"Figure 4" is a schematic cross-sectional view of "Figure 1" in the A-A direction.

"Figure 5" is a schematic diagram of another embodiment of the polishing pad dresser of the present invention.

"Figure 6" is a schematic diagram of another embodiment of the polishing pad conditioner of the present invention.

[FIG. 7] is a schematic diagram of a step flow diagram of an embodiment of the chemical mechanical planarization method of the present invention.

The detailed description and technical content of the present invention will now be described in conjunction with the drawings as follows: The present invention provides a polishing pad dresser used in the CMP process, which includes a plurality of PcBN polishing pads, each of which is formed with a plurality of polishing pads. The tip, the grinding tip has a protruding height enough to penetrate the polishing pad to remove the abrasive debris. PcBN (Polycrystalline cubic boron nitride) is obtained by ultra high pressure sintered cBN powder. In one embodiment, the average penetration depth of the polishing tip is greater than the average size of the pores of the polishing pad, the average size of the pores may be between 30 microns and 60 microns, and the number of operations of the polishing tip may be higher than 500 pieces.

In another aspect, the present invention provides a polishing pad conditioner made of PcBN. The polishing pad conditioner includes a plurality of PcBN polishing pads, and each of the PcBN polishing pads is formed with a plurality of polishing tips, wherein all of them Among the polishing tips, the number of the polishing tips whose height difference is in the range of 60 micrometers with the highest distance is between 300 and 5000. In one embodiment, the PcBN polishing sheet is fixed on a ceramic substrate, and the PcBN polishing sheet is compensated by a thickness that adjusts the protrusion height of the polishing tip on the PcBN polishing sheet. The plastic body is bonded to a base. In one embodiment, the thickness compensation plastic body is an organic material. In one embodiment, the volume percentage of cBN in the PcBN polishing sheet is at least 90%.

In one embodiment, among all the polishing tips, the number of the polishing tips whose height difference is within the range of 40 micrometers is between 300 and 1,000. In another embodiment, Among the polishing tips on a single PcBN polishing sheet, the number of the polishing tips with the height difference of the polishing tip with the highest distance in the range of 40 microns is between 50 and 500.

In one embodiment, the polishing tip has a sharp peak, and the included angle of the sharp peak is between 40 degrees and 120 degrees. In another embodiment, the included angle of the sharp peak is between 60 degrees and 100 degrees. In an embodiment, the shape of the peak is a cone or a ridge, the cone is a polygonal cone, and the number of sides of the polygonal cone is between 3 and 6, and in an embodiment Wherein, the polishing tip includes a blunt top surface, and the width of the top surface is between 2 μm and 20 μm.

In one embodiment, the shape of the PcBN polishing sheet is a square or a circle, the number of the PcBN polishing sheet is between 4 to 50, and the polishing tips on each PcBN polishing sheet are arranged to form a Array.

In order to make the content of this case easier to understand, you should refer to the illustrations when reading the following description. It should be noted that many features are not drawn in accordance with the number or scale. In fact, the number or size of various features may increase or decrease to make the The description is clearer.

Please refer to "Figure 1", "Figure 2" and "Figure 3", which are respectively a schematic diagram of an embodiment of the polishing pad dresser of the present invention, an enlarged schematic diagram of the first PcBN polishing sheet of "Figure 1" and "Figure 1" An enlarged schematic view of the second PcBN polishing sheet. The polishing pad dresser 10 of this embodiment includes a plurality of PcBN polishing pads 20, and each PcBN polishing pad 20 is formed with a plurality of polishing tips, wherein the height difference of the tip high points of all the polishing tips is in the range of 60 microns The number within is between 300 and 5000. In this embodiment, the shape of the PcBN polishing sheet 20 is a square, and the The side 24 of the PcBN polishing sheet 20 faces outward. The PcBN polishing sheet 20 includes a first PcBN polishing sheet 20a and a second PcBN polishing sheet 20b. The first PcBN polishing sheet 20a and the second PcBN polishing sheet 20b are staggered Arranged, the first PcBN polishing sheet 20a includes a plurality of first polishing tips 21a, the first polishing tips 21a are in a polygonal cone shape, the number of sides of the polygonal cone is 4, and the first polishing tips 21a include a The first top surface 22a, the first top surface 22a is a flat surface to be blunt, and the second PcBN polishing sheet 20b includes a plurality of second polishing tips 21b, the second polishing tips 21b is a ridge line, the second The polishing tip 21b includes a plurality of second top surfaces 22b and a plurality of recesses 23b intersecting the second top surface 22b. In other embodiments, the second polishing tip 21b may also only include the second top surface 22b, There is no such recess 23b. The width W of the top surface is between 2 μm and 20 μm.

Please refer to "Figure 4", which is a schematic cross-sectional view along the AA direction of "Figure 1." The base 30 is then fixed in the recess 51 of a base 50 with a thickness-compensating plastic body 40. The base 50 can be made of metal, such as stainless steel. The thickness-compensating plastic body 40 can be an organic material, such as thermosetting resin or thermoplastic. The resin has elasticity before hardening. Before hardening, a flat top plate can be used to adjust the thickness of the organic material, such as a hard layer 60 shown in "Figure 4", so as to adjust the polishing tip on the PcBN polishing sheet 20a The protrusion height of 21a relative to a horizontal plane further improves the flatness. In one embodiment, the thickness-compensating plastic body 40 may be epoxy resin. The thickness of the epoxy resin can support the PcBN polishing sheet 20 so that the center can touch the flat top plate, so that all of the polishing pad dresser 10 The height of the center on the PcBN polishing sheet 20 can be controlled.

Please continue to refer to "FIG. 5" and "FIG. 6", which are respectively a schematic diagram of another embodiment and a schematic diagram of another embodiment of the polishing pad dresser of the present invention. In the embodiment of "Figure 4", the first PcBN The edge 24 of the polishing sheet 20a faces outward, and the corner 25 of the second PcBN polishing sheet 20b faces outward; and in the embodiment of "FIG. 5", the PcBN polishing sheet 20 only includes the first PcBN polishing sheet 20 The edge 24 of the first PcBN polishing sheet 20a faces outward. The foregoing is only an example of the configuration of the PcBN polishing sheet 20. In other embodiments, the number, orientation, and tip distribution of the PcBN polishing sheet 20 can be adjusted as required. In particular, in other embodiments of the polishing pad dresser of the present invention, the PcBN polishing sheet 20 can also be arranged on the base 50 in combination with other types of polishing units, such as a polishing unit made of traditional diamond abrasive grains. .

The present invention further provides a method of chemical mechanical planarization. Please refer to "FIG. 7", which is a schematic diagram of the step flow of an embodiment of the chemical mechanical planarization method of the present invention. The process 70 of this embodiment includes the following steps. Step 71: First provide a polishing pad; Step 72: Set a workpiece on the surface of the polishing pad, so that the workpiece and the polishing pad mutually rotate and grind; and Step 73: Use a polishing pad dresser as described above and set it on the polishing pad On the surface of the pad, remove the debris from the workpiece after grinding. In one embodiment, the workpiece is a semiconductor device, and the semiconductor device includes one or more layers of copper film, tungsten film, oxide film, barrier layer (such as TaN), or a combination thereof.

In the classification of abrasives, common ones include alumina (Al ₂ 0 ₃ ), cubic boron nitride (cBN), silicon carbide (SiC) and diamond (Diamond), also commonly known as A (Al ₂ 0 ₃ ), B (cBN) ), C (SiC), D (Diamond). Among them, AB is temperature-resistant and corrosion-resistant, CD is not temperature-resistant and corrosion-resistant; AC has low hardness (<2500Kg/mm ² ), which is traditional abrasive, BD has high hardness, diamond Knoop Hardness>7000Kg/mm ² , and cBN hardness About 5000Kg/mm ² , BD is collectively called super abrasive, which is made by ultra-high pressure synthesis. For the CMP process, the corrosion resistance and mechanical properties of the abrasive should be considered at the same time. However, the conventional technology only considers the mechanical (Mechanical) and ignores the chemical (Chemical). Therefore, only using diamond as the abrasive cannot optimize CMP. cBN and diamond are both superhard materials, but they have oxidation and corrosion resistance far inferior to those of diamonds. Although diamonds are harder, the CMP slurry is highly corrosive and oxidizing. In terms of the service life of the diamond disc, the service life of the diamond disc used for oxide film flattening is about three times that of the diamond disc used for tungsten film flattening. The reason is that when applied to the flattening of tungsten film or other metal layers When smelting, the abrasive slurry needs to contain strong oxidizing or strong corrosive substances, such as hydrogen peroxide or strong acid, and these strong corrosive or strong reducing substances will accelerate the wear rate of the diamond's sharp edge; , PcBN is chemically inert. For example, diamond is oxidized at about 600°C in the air, while PcBN will only oxidize at 1400°C. In the above-mentioned CMP process, the process temperature applied to the flattening of the tungsten film is relatively high (about 80° C.), and the diamond oxidation is generated at the edge corners and at a higher temperature. In particular, the flattening of the oxide film and the polishing of the polishing pad are performed at the same time (in-situ), while the flattening of the tungsten and the polishing of the polishing pad are performed alternately (ex-situ), so the diamond disc is very important in the tungsten flattening process. Less reaction with the abrasive slurry, even so, the diamond cutting edge is still rapidly oxidized.

According to the above, during CMP, the IC wafer and polishing pad dresser are chemically eroded and mechanically polished at the same time. Although the high hardness of the diamond on the traditional diamond disk is resistant to mechanical polishing, its corrosion resistance is far inferior to that of PcBN, but the latter is slightly lower. The hardness of diamond abrasive grains provides better processing convenience with diamond grinding wheels and wire saws, so that PcBN can engrave diamonds with special patterns, such as specific-shaped pointed cones and the spacing between the pointed cones, which solves the apex height and the diamond The dilemma of sharpness is difficult to balance.

In the traditional technology, there is a polishing pad dresser made of engraved ceramic materials (such as silicon, silicon carbide or tungsten carbide) coated with a diamond film, but the diamond film is coated by vapor chemical deposition (CVD) in a vacuum environment. Not only is there no sintered bond between the diamond particles, but the coated interface is also easy to peel off. Therefore, a thin (for example, 10 microns) diamond film must be used to plate the blunt-topped pyramid. This kind of diamond disc trimming polishing pad has too much plastic pull on the fluff, which increases the contact interface and limits the polishing rate of IC wafers. The thin diamond film also shortens the life of the diamond disc, both of which reduce the productivity of a CMP stand-alone machine.

However, the PcBN polishing pad dresser of the present invention has no fragile coating, so more sharp cones can be used to prolong the life of the polishing pad dresser, and more fluff can be generated on the polishing pad during dressing, which speeds up the CMP polishing of IC crystals. The rate of the circle.

Taking the CMP process using a diamond disc on tungsten as an example, the diamond disc penetrates the deepest (about 60 microns) cutting edge of the polishing pad, and the life span is only tens of kilometers, while the same diamond disc CMP oxide film can last nearly two hundred kilometers. It can be seen that the micro-oxidation of the diamond edge is indeed not obvious. This problem can be solved with PcBN trimmer.

Another unobvious fact is that the number of spires that penetrate the polishing pad is inversely proportional to the deepest cutting depth. After a large number of comparisons with the diamond disks used by major semiconductor factories, it is proved that the spires of the diamond disks used in normal CMP The number to be polished is between 300 and 500, which is only about 5% of the number of tens of thousands of diamonds on a general diamond disc. It can be seen that most of the diamonds do not touch the polishing pad. Even if they do, the apex of the diamond is smooth. The obtuse angle does not actually penetrate, but causes the polishing pad to collapse or plastically deform. In addition, the polishing pad usually contains micro-pores to adjust the compression rate and store the grinding slurry. The micro-pores inside the polishing pad are closed, but the micro-pores on the surface of the polishing pad have openings. It is deposited in the open pores on the surface of the polishing pad, so the deglazing of CMP requires that the depth of the diamond apex penetrate the polishing pad to exceed the average pore size of the polishing pad in order to effectively remove debris.

The above problems can be solved with PcBN. Because PcBN can be processed by laser or diamond grinding wheel, it can engrave a specific cutting edge shape and angle, and it can also form a specific tip height difference distribution. Therefore, different dressers can be customized according to the use of CMP. Specifications, which can optimize CMP, extend the life of the dresser and polishing pad, reduce or dilute the slurry, and reduce the cost of CMP (CoO); when the number of effective tips on the dresser increases, the polishing pad will be increased Therefore, the polishing speed of CMP can be increased, so that the productivity of the single machine can be increased.

In addition, there is an unobvious advantage that in the metal (such as copper or tungsten) process, in the presence of strong acids and oxidants, in-situ dressing of wafers can be performed CMP and polishing pads at the same time. This timely The dressing can also speed up the polishing rate of the wafer. Because it does not penetrate the polishing pad excessively, it can extend the life of the dresser and the polishing pad, and even reduce the number of shutdowns to replace consumables. This additional effect further reduces the cost of CMP, and Increase the output of IC wafers.

Another feature of the polishing pad dresser made by engraving PcBN is that the used PcBN can be reground and reused. The worn tip is polished and then formed into a tip, so that the dresser can be reused and the manufacturing cost is reduced. At present, neither diamond abrasive grains nor diamond-coated dressers can be reprocessed and used.

Another myth of the diamond disc is the angle of the apex of the diamond. If the crystal shape of the diamond is complete, the apex is mostly obtuse. Generally, the cracked surface forms an acute angle to penetrate the polishing pad, but the irregularly shaped apex is easy to form a killer diamond, not only excessive When the polishing pad is consumed, it is also easy to break, causing the disaster of scratching the wafer. Many diamond disc manufacturers spend time selecting diamond shapes, increasing costs. What's more, make the sharp point of the diamond upward. It is hard to realize that the sharp point of the diamond wears quickly, not as good as the ridgeline upward, but the angle between the ridgeline of the diamond is mostly obtuse. The angle between the vertical faces is a right angle, but there are very few such ridges. The angle between the octahedron is about 109 degrees, and the angle between the cube and the octahedron is about 140 degrees. Engraving PcBN can customize the ridge angle to extend the life of the dresser and polishing pad.

Example 1

Sintered under ultra-high pressure (>5GPa) into a plurality of PcBN abrasive sheets, the PcBN abrasive sheet contains 90% cBN by volume, and the binder is a ceramic material. After sintering, it is cut into 10mmx10mm squares by laser processing. Then, a diamond grinding wheel was used to grind out 100 four-sided pointed cones (arranged in a matrix of 10×10) on each PcBN polishing sheet with a distance of 1 mm between the tips of the cones. The vertex face angle of each pointed cone is a right angle, The top of the cone is 150 microns high, and the width of the bottom of the cone is 300 microns. The above-mentioned diamond grinding wheel is made by sintering diamond abrasive grains with metal, ceramic or resin bond. In this example, ceramic bond is used for illustration.

Take stainless steel (SS316) with a diameter of 108mm as the base, press the eight square arrays on the thermosetting resin or thermoplastic resin with a silicone cover cloth, and fix the arrays on the periphery of the base. The square array can be outwards or sharp corners. Or interactive configuration. During hot pressing, the thickness of thermosetting glue or thermoplastic can compensate the thickness of PcBN to make the top height of PcBN consistent.

Example 2

Same as the above example, but PcBN is ground into 10 right-angled edges with a diamond wheel. Use a diamond wire saw perpendicular to the ridgeline to cut out arcs so that the ridgelines are about 50 microns long each.

Example 3

Same as Example 1 or Example 2, but the number of centers within 40 microns of the highest apex is more than half of the total number of centers.

Example 4

In order to reduce the height difference of the center and remove surface cracks, the assembled diamond disc can be over-pressed to trim the polishing pad to make the sharp point slightly blunt.

The present invention has been described in detail above, but what is described above is only a preferred embodiment of the present invention, and should not limit the scope of implementation of the present invention. That is, all equal changes and modifications made according to the scope of application of the present invention should still fall within the scope of the patent of the present invention.

10: Polishing pad dresser

20: PcBN grinding sheet

20a: The first PcBN polishing sheet

20b: The second PcBN polishing sheet

24: side

25: corner

50: Pedestal

Claims (18)

A polishing pad dresser, comprising a plurality of PcBN polishing pads, each PcBN polishing pad is formed with a plurality of polishing tips, wherein, among all the polishing tips, the height difference of the polishing tip with the highest distance is in the range of 60 microns The number of grinding tips is between 300 and 5000. According to the polishing pad dresser described in item 1 of the scope of patent application, the PcBN polishing sheet is fixed on a ceramic substrate. According to the polishing pad dresser described in item 2 of the scope of patent application, the PcBN polishing sheet is respectively bonded to a base through a thickness-compensating plastic body that adjusts the protrusion height of the polishing tip on the PcBN polishing sheet. The polishing pad dresser described in item 3 of the scope of patent application, wherein the thickness-compensating plastic body is an organic material. According to the polishing pad dresser described in item 1 of the scope of patent application, the volume percentage of cBN of the PcBN polishing sheet is at least 90%. The polishing pad dresser according to the first item of the scope of patent application, wherein the number of the polishing tips whose height difference is within 40 micrometers is between 300 and 1,000. The polishing pad dresser according to item 1 of the scope of patent application, wherein, among the polishing tips on a single PcBN polishing sheet, the number of the polishing tips whose height difference of the polishing tip with the highest distance is within the range of 40 microns is between 50 Between one and 500. According to the polishing pad dresser described in claim 1, wherein the polishing tip has a sharp peak, and the included angle of the sharp peak is between 40 degrees and 120 degrees. According to the polishing pad dresser described in item 8 of the scope of patent application, the included angle of the peak is between 60 degrees and 100 degrees. According to the polishing pad dresser described in item 9 of the scope of patent application, the shape of the peak is a cone or a ridge. According to the polishing pad dresser described in item 10 of the scope of patent application, the cone is a polygonal cone, and the number of sides of the polygonal cone is between 3 and 6. According to the polishing pad dresser described in item 1 of the scope of the patent application, an outline of the PcBN polishing sheet is a square or a circle. The polishing pad conditioner according to the first item of the scope of patent application, wherein the polishing tip includes a blunt top surface, and the width of the top surface is between 2 μm and 20 μm. According to the polishing pad dresser described in item 1 of the scope of patent application, the number of the PcBN polishing pads is between 4 and 50. The polishing pad dresser described in item 14 of the scope of patent application, wherein the polishing tips on each of the PcBN polishing sheets are arranged to form an array. A method for chemical-mechanical planarization includes the following steps: providing a polishing pad; placing a workpiece on the surface of the polishing pad to grind the workpiece and the polishing pad; The dresser described in any one is arranged on the surface of the polishing pad to remove debris from the workpiece after grinding. According to the method for chemical mechanical planarization described in claim 16, wherein the workpiece is a semiconductor element, and the semiconductor element includes one or more layers of copper film, tungsten film, oxide film, barrier layer, or a combination thereof. A polishing pad dresser, comprising a plurality of PcBN polishing pads and a plurality of polishing units made of diamond abrasive grains, each of the PcBN polishing pads is formed with a plurality of polishing tips, of which, all Among the polishing tips, the number of the polishing tips whose height difference is in the range of 60 micrometers with the highest distance is between 300 and 5000.

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