JP2007512984A - Process and apparatus for continuously forming uniform sheet used as polishing pad for semiconductor - Google Patents

Abstract

  Disclosed are processes and apparatus for continuous production of polyurethane sheets used as polishing pads, particularly polishing pads for chemical mechanical polishing (CMP). This process comprises precise control of the process parameters of supplying a polymer blend, mixing the blend with a curing agent, and dispensing the mixture to the feed end of a steel double belt compressor. Further, the sheet may be cut to a predetermined size and the surface may be adjusted to form a polishing pad. This process is particularly suitable for mass production of stable products, and the stability of the products directly affects the efficiency of polishing.

Description

  The present invention relates to the field of making polishing pads used for polishing and planarization, and in particular, chemical mechanical planarization (CMP) of electronic devices such as integrated circuits, semiconductors, hard disks, magnetic recording heads, and silicon wafers. In particular, it relates to a continuous process for producing a highly efficient polishing pad of uniform thickness.

  Over the years, precision optical devices, quartz crystals, ceramics, metal alloys, silicon wafers, hard disks, integrated circuits, and the like have been polished by chemical mechanical means. In recent years, this technique has been used to planarize a silicon dioxide intermetal dielectric layer in an integrated circuit device and to remove a portion of a conductive layer when the integrated circuit device is constructed on various substrates. As applied.

  For example, an insulating protective layer of silicon dioxide may cover the metal wiring such that the upper surface of the layer is characterized by a series of uneven irregularities corresponding to the height and width of the metal wiring provided in the lower layer. . Non-planar topography can then be planarized or planarized by chemical mechanical planarization (CMP) techniques to add subsequent dielectric layers and interconnects It is said.

  Rapid advances in semiconductor technology have led to the emergence of large scale integrated circuits (VLSI) and ultra large scale integrated circuits (ULSI) obtained by packing larger devices into smaller areas of a semiconductor substrate. The greater the density of devices combined with multilayer interconnect circuits, the greater the demand for topography flatness to maintain the depth of focus of the photolithography process in advanced integrated circuit manufacturing. In addition, due to its low resistivity, copper is increasingly being used for internal connections. Traditionally, etching techniques have been used to planarize the surfaces of conductors (metals) and insulators. However, certain metals (eg, gold (Au), silver (Ag), and copper (Cu)) that have desirable conductive properties when used in interconnect wiring can lead to rapid generation of complex oxide by-products. Therefore, it cannot be easily etched, so chemical mechanical polishing (CMP) has been employed to remove these by-products from the polishing surface.

  In general, various metal wirings are formed through a lithography process or a damascene process. For example, in a lithographic process, a first blanket metal layer is deposited on a first insulating layer, and then electrical wiring is formed by subtractive etching through a first mask. The second layer is formed on the first metal layer, and the hole is formed in the second insulating layer using the second mask. Metal columns or plugs are formed by filling the holes with metal. The second blanket metal layer is formed on the second insulating layer, and the plug electrically connects the first metal layer and the second metal layer. The second metal layer is masked and etched to form a second set of electrical wiring. This process is repeated as necessary to produce the desired device. The damascene technique is described in Patent Document 1.

  At present, VLSI uses aluminum for wiring and tungsten for plugs because of its sensitivity to etching. However, the resistivity of copper is superior to either aluminum or tungsten and its use is desired, but copper does not have desirable properties from an etching point of view.

  Variation in the height of the top surface of the intermetal dielectric layer has several undesirable characteristics. The depth of focus of subsequent photolithography process steps is reduced by the surface of the dielectric layer which is not flat. A reduction in the depth of focus reduces the resolution with which the wiring can be printed. Further, where the step height is high, the coating of the second layer on the dielectric layer can be incomplete and can cause a break.

  In view of these problems, a plurality of methods have evolved to planarize the upper surfaces of the metal layer and the dielectric layer. One such technique is chemical mechanical planarization or polishing (CMP) using an abrasive abrasive that acts by a rotating pad. A chemical mechanical polishing method is described in Patent Document 2. Conventional polishing pads are made of a relatively soft, flexible material such as nonwoven fibers interconnected by a relatively small amount of polyurethane adhesive binder. It may also be composed of stacked layers whose physical properties vary over the thickness of the pad. Multilayer pads generally comprise a flexible upper polishing layer supported by a layer of hard material.

  The polishing pad may also be made of a uniform material, such as a polyurethane component, and typically the reaction precursor is placed in a closed mold and the precursor is reacted and heat cured to provide a pad. Form material. The pad material may then be punched into a predetermined size and shape and the top surface adjusted to form a polishing pad. Optionally, the reactive precursor may be placed in a cylindrical container to form a log or loaf-like lump and then cut into slices so that it can be used as a polishing pad. Also good. Also, the characteristics of the formed polishing pad may be changed somewhat by annealing, compression, embossing, casting, sintering, or photolithography.

  The process described above is typically a batch process and is produced in a step-wise operation where one pad or sheet material is followed by another pad. This method typically results in variations in both physicochemical and / or morphological characteristics and dimensions of the pad to pad or sheet to sheet. These characteristics and / or dimensional instabilities of the polishing pad cause non-uniformities and defects during polishing, particularly during CMP of electronic devices.

  Several processes for producing polishing pads are disclosed in the prior art. Patents 3, 3, and 5 which are patents owned by Cabot Corporation disclose a beltline-type sintering method. These patent documents describe a thermoplastic sintering method that “applies a minimum pressure above atmospheric pressure or reduces atmospheric pressure to obtain the desired pore size, porosity, density, and thickness of the substrate. It is defined as “a method that does not apply pressure exceeding”. In these patent documents, Patent Document 6, which is a patent owned by Congoleum, is cited. In Patent Document 6, a method of using an endless belt, that is, a belt is preheated and a thermoplastic chip is placed. A method is disclosed in which a chip on the belt is hardened and the chip is heated by a heater installed under the belt and a heater installed on the belt. After this, the chips are compressed through a nip roller to form a sheet, the sheet is heated and passed through a calendar, then the sheet is polished through the nip roller, sprayed with coolant and stripped.

  Patent Document 7, filed on November 27, 2001, which is the name of “a polishing pad composed of a granular material composed of a solid core and a polymer shell”, describes a solid core encapsulated in a polymer shell. In relation to a pad described as having two different materials, the core and the shell. The solid core is said to be an abrasive. For application, reference is made to a closed mold sintering technique as well as sintering through a continuous process.

  Patent document 8 which is a patent owned by Rodel is the name of “a method for producing a polishing pad of a polymer or a polymer composite material”. This is directed to the manufacture of a polishing pad for polishing a semiconductor substrate, and “conveying means of continuous objects, ie a liquid layer polymer component, which forms a support layer to be transferred at a sequential manufacturing station, It relies on a transport means "that is fed onto a transported support layer, molded into a polymer and thermally cured in a curing oven."

  Patent document 9 which is a patent owned by Rodel is the name of “printing of polishing pad”. For applications, “the pad manufacturing process requires the formation of a pad with a uniform surface, especially the continuous process requires the formation of a sheet with a uniform surface”. is described. The application helps present a solution to this challenge, highlighting the use of a “flexible base sheet that is printed continuously by passing between a cylinder and a roller (with a pattern to print on the pad) is doing.

Each of these references discloses a process that is subject to control of important process parameters to ensure optimal uniformity of the product, which is rather complex. Therefore, what is needed is a process of supplying a polishing pad, which may be used for chemical mechanical polishing, is basically manufactured continuously, and has a uniform surface by process control, With uniform thickness and highly efficient polishing characteristics.
US Pat. No. 4,789,648 U.S. Pat. No. 4,944,836 US Pat. No. 6,126,532 US Patent No. 6117000 US Pat. No. 6,062,968 US Pat. No. 3,835,212 US patent application Ser. No. 09/995025 US Pat. No. 6,428,586 US patent application Ser. No. 09/766155

  The present invention relates to a continuous process for producing a polishing pad, and more particularly to a continuous process for producing a polishing pad useful for chemical mechanical planarization (CMP). The process of the present invention consists of a two-stage approach, which is a series of networked process controls and feedback loops to ensure sheet surface uniformity, which allows for characteristics and dimensions. Efficient and continuous production of highly uniform polishing pads on both sides is possible.

  In the first step, one or more high viscosity polymer precursors are mixed with one or more fillers at a controlled temperature under vacuum to produce a liquid mixture with controlled viscosity and consistency. This liquid polymer has a chemically active functional group. Such chemically active polymers (referred to as precursors) encompass a range of monomers, oligomers, prepolymers, and high molecular weight polymers of organic or inorganic origin. Furthermore, various modifiers such as a thickener, a diluent, a colorant, an anti-ultraviolet agent and a heat stabilizer, a surface tension modifier (surface active agent) may be added to the mixture. In the second step, the curing agent or thermosetting agent is uniformly dispersed in the polymer mixture so that it chemically reacts with the liquid polymer. The amount of curing agent or thermosetting agent is precisely controlled to a specific ratio relative to the polymer mixture to achieve the desired product properties. In addition, the temperature and viscosity of the reactant mixture as well as the ambient pressure and atmosphere are precisely controlled to predetermined specifications. Typically, a high vacuum higher than 28 inches of water may be applied during the entire mixing process, and if the mixture has to be stored for an extended period of time, nitrogen gas will be “blankted”. May be used as

  The reactive mixture may be formed between a pair of endless steel belts stacked vertically and dispensed into a pre-set gap, the pair of steel belts being one or both A heater may be provided on the back of the belt to provide feedback control of parameters such as conveyor speed, belt pressure, temperature, and belt gap to form a uniform sheet. The sheet is then cut to length and post-cured in an oven and stamped to form the polishing pad of the present invention.

  The object of the present invention is therefore constituted by an in-line, automated and / or manual networked series of process controls and test and inspection metrology instruments, especially for chemical mechanical planarization. It is to provide a continuous process for forming a polishing pad.

  It is also an object of the present invention to provide an apparatus for use in a continuous process that comprises a series of networked process controls and forms a uniform polishing pad, particularly a polishing pad for chemical mechanical planarization. It is.

  It is a further object of the present invention to provide a polishing pad for high chemical uniformity within each pad and between pads, particularly for chemical mechanical planarization, to ensure product uniformity. A polishing pad produced by a series of process control is supplied.

  It is also an object of the present invention to provide an automated two-step process for providing a highly uniform polishing pad.

  It is also an object of the present invention to prevent accidental contamination where all raw materials and in-process materials are kept in a well-controlled sealed environment and can be detrimental to the final polishing application by foreign materials. It is to provide an avoided polishing pad.

  In addition, other objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, wherein the preferred form of the invention is shown and described by way of illustration of the best mode contemplated for carrying out the invention. Will be readily apparent. It will be apparent that the invention is capable of other and different forms, and its several details are capable of modifications in various obvious respects, within the scope of the invention. Accordingly, the description is exemplary in nature and not limiting.

  The features, functions, and advantages of the present invention can be better understood from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wherein FIG. 1 illustrates the general features of a continuous process according to the present invention. It is a block diagram.

  FIG. 2 is a schematic view of an apparatus for continuous production of a polishing pad according to the present invention.

  The present invention is directed to an essentially continuous mass production process for forming polishing pads used in chemical mechanical polishing. One key to the process is the many networked process controls that are used to monitor and feed back information in real time as the product is being produced. This provides a highly sheet-like material in terms of composition, properties, thickness and surface uniformity, resulting in a high degree of polishing stability and efficiency for the polishing pad. The

  As illustrated in FIG. 1, the manufacturing process of the present invention consists of two basic steps. Step A is the mixing of a suitable high viscosity liquid polymer precursor and Step B is the continuous discharge and sheet formation of the liquid polymer precursor mixed with the curing agent. The sheet material is then cut to the desired length, post-cured to establish optimal properties, and cut into a shape that forms a polishing pad.

  In Step A (see FIG. 1), the mixing step, a highly viscous mixture of liquid polymers, preferably polyurethane, is first heated to equilibration in vacuum for several hours. Examples of such polymer sources are Adiprene Polyurethane Pre-polymer provided by Crompton Corporation and Airtan Polyurethane Pre-polymer from Air Products. Any required additives such as antifoaming agents, anti-UV stabilizers, anti-thermal stabilizers, and surface tension modifiers are also mixed uniformly into the polymer mixture. Any required filler material, organic or inorganic, of various particle shapes and sizes, soluble or insoluble, is then added, preferably under vacuum or under a nitrogen gas blanket, uniformly in the mixture Distributed. The temperature, the overall viscosity of the mixture, the degree of vacuum (in the mixing vessel headspace) or the ambient nitrogen concentration also continue to be precisely controlled throughout the mixing, storage and subsequent steps.

  In addition, the amounts and relative proportions of all components in the overall mixture are precisely measured and controlled.

  In addition, as described above, a filler component may optionally be included, and about 1 to 5% by weight of the hollow expanset @microspheres from Expansel Corporation having a diameter of 20 to 90 microns. Preferably, it is contained at a concentration of 3% by weight. The dry filler component preferably has a specific gravity of about 0.03 grams to about 0.12 grams per cubic centimeter. One purpose of the dry filler component is to provide the polishing pad with a porous surface after it has been conditioned for use. Conditioning the surface by scraping off the outermost surface of the pad removes a thin layer of reacted polymer and destroys the surface microspheres to provide a controlled level of porosity. Alternatively, other materials may be used as filler components to provide specific polishing or porous properties of the polishing pad. For example, water soluble fibers and soluble products such as salts, particulate or powdered polymers that can be washed away after surface buffing to create a porous surface are used. However, it is not limited to these.

  The uniform liquid precursor mixed in Step A preferably has a specific gravity of about 0.50 grams to about 1.2 grams per cubic centimeter and is used in a continuous process stage (Step B). Therefore, it is stored at 25-40 ° C.

  Turning now to the continuous process of ejection and sheet formation, step B is shown in the simplified diagram of FIG. The precursor of the liquid polymer preferably comprises a polyurethane prepolymer, an additive, and a filler component dispersed in the additive, preferably in a vacuum or in an inert gas (eg nitrogen gas) atmosphere, preferably Pumped or gravity fed to a continuously replenished supply tank 10 held at about 20-40 ° C. Curing agents or thermosetting agents, such as (MOCA or Ethacure), are stored in a tank 20 that is blanketed with air or nitrogen gas. For the reaction, the thermosetting agent and liquid polymer precursor are accurately measured at 12.22 with a Coriolis flow meter and are preferably pumped into a continuous static or dynamic mixer. The stoichiometric ratio of thermosetting agent to polyurethane precursor is preferably between 0.85 and 1.05. Depending on the set of ratios and process conditions, the viscosity of the mixture is preferably between 20,000 and 400,000 Pascal seconds.

  Dynamic mixers or static mixers may be used in conditions where minimal air is introduced.

  When discharged from the mixer, the reaction component 32 is uniformly fed into the feed end 42 of the steel double belt press 40. The supply end of the double belt press as well as the double belt press itself is also preferably held under a chamber 60 controlled to a uniform temperature and pressure in front of the squeezed and heated compartment, To ensure a more thorough polymerization inside.

  The double belt press 40 is generally composed of two endless steel belts driven by rollers rotating in opposite directions, with the outer surfaces of both belts facing each other and pressing the material passing between them. The temperature increase is achieved by one or more temperature-controlled press plates, press chambers, or infrared heaters provided at the back of the squeeze area. The steel belt forming the top and bottom surfaces of the continuously formed urethane sheet is preferably heated and maintained at 80-110 ° C. so that the urethane polymerizes into a solid compound under constant pressure conditions. Can be. The compression region 44 is formed between the mutually opposing outer surfaces of the compression belt.

  The endless belt is preferably made of steel and preferably can be maintained in a precisely controlled pressure level of about 4 MPa (550-600 psi), but in the present invention the pressure is 1-10 MPa (1 .45 psi to 1450 psi). The pressure may be generated by the weight of the upper unit plate of the endless belt and / or by a mechanical or hydraulic method. As the formed sheet moves between opposing steel belts, the sheet is preferably compressed over a distance of about 4.5 meters at 44 and is compressed to a final thickness and fed from a heated belt. It is solidified by heat. In a preferred embodiment of the invention, the thermosetting process is initiated by heat from the exothermic reaction of the urethane and amine reaction and by heat from the endless belt.

  The process of forming a continuous uniform sheet may be fully PLC controlled with an interactive exchange of information between mechanical parts, each mechanical part having process control, data trends, and process There may be built-in means for expansion. All liquid ingredients, not just solids, are monitored for accurate temperature and viscosity and administered for compounding and mixing. The system may preferably use the rapid communication protocol “PROFIBUS” to monitor and control all system elements. The system is built for easy operator control and the interface is built for monitoring and adjusting process parameters via a touch screen. Real-time testing and inspection / measurement equipment incorporated into the process for monitoring material properties such as thickness, density, hardness, compressibility, and surface roughness, and for contamination inspection by imaging systems, Can be fully integrated. The system also incorporates on-line continuous data storage, statistical analysis, trend analysis and CRT display along with alarms to workers in case of process deviations.

  The belt press 40 can produce a continuous urethane sheet 32A having a density of 1.0 g / cc or less, preferably by process control during use. The measured density change per square yard is 2.0% or less. The thickness of the sheet is controlled from 50 mm to 50 +/− 0.05 mm by a micrometer adjuster. The reference thickness of the sheet 32A formed as described above may preferably be between 1 mm and 3 mm or more.

  The resulting urethane sheet 32A is removed from the belt press 40 at the release end and is preferably cut to a predetermined length using a roller blade cutter labeled 62. Other types of cutting machines may also be used. Sheets 32B cut to length are then stacked in 70, preferably for post-heat curing at a temperature specified for a given type of urethane and thermosetting agent, preferably for 16-24 hours. Moved to oven 80. Here, the temperature typically varies from 150 ° F to 450 ° F.

  The heat-cured urethane sheet is then cooled to ambient temperature at a controlled cooling rate, tested and re-inspected to remove any surface polymer “skin” and expose the body structure of the sheet Can be buffed or sharpened. Also, the buffing or sharpening is designed and controlled to give the urethane sheet surface a predetermined microstructure that reduces the run-in time in the final use polishing application.

  The preferred material composition for continuous production of the polishing pad of the present invention is a mixture of filler and liquid, but precursor compositions of other materials may also be processed through the apparatus of the present invention and are limited. However, it may contain dry polymers, powders, other solid compounds, and fillers, which may be soluble or insoluble. The kneading of these materials may require corresponding changes in process temperature and other parameters.

  Table 1 lists several polishing pad property values that were anticipated and targeted for production by the continuous process of the present invention.

* Note that the values obtained for deflection from a flat surface are measured over the 1 meter x 1 meter range of the pad. Therefore, if the undulation between the end and the body is <0.5 ", this value does not exceed the upward deflection or undulation in the pad when placed flat. Corresponds to a 1 meter x 1 meter range of pads, preferably <0.1 ".

  Because of the size and nature of this continuous process, variations in the composition and properties of the final product are minimized. Raw materials can be blended in large quantities and can be continuously fed to the mixer by a recycle feed system.

  Therefore, these materials can be formulated under precise control of temperature, vacuum, ratio, and viscosity. Due to the essence of the sheet forming process, the process controls the feed temperature, belt temperature, pressure, feed speed, conveyor speed, sheet thickness and density monitoring data and feedback data so that uniform sheets can be produced. Precise control for production is possible.

  A large number of polishing pads with little variation can be cut from the sheet.

  The above forms are merely examples of the invention and are not intended to limit the scope thereof. Since the described embodiments can be modified by those skilled in the art, the technical scope of the present invention includes all such modifications that are within the spirit or technical scope of the present invention. .

It is a block diagram which shows the general characteristic of the continuous process which concerns on this invention. 1 is a schematic view of an apparatus for continuous production of a polishing pad according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Supply tank 20 ... N2 atmosphere tank 30 ... Mixer 32A ... Urethane sheet 32B ... Cut sheet 40 ... Double steel belt press 42 ... Supply end 44 ... Compression region 60 ... Chamber 80 ... Oven

Claims (22)

A method of continuously forming the polymer sheet used as a polishing pad,
(A) A step of preparing a pair of endless compression belts, wherein one belt is stacked on the other belt in a controlled atmosphere, and the stacked belts have a common supply end and a common take-out end. When,
(B) supplying a reactive compound having a precursor and a curing agent to the belt;
(C) heating the pair of stacked endless compression belts to the curing temperature of the precursor and the curing agent;
(D) compressing the reactive mixture between the belts, applying pressure, and feeding the stacked endless compression belts at a selected speed to form a polymer sheet with a selected thickness; Rotating in a direction approaching each other from the end toward the take-out end;
(E) passing the polymer sheet through the take-out end of the opposed endless belt;
A method for continuously forming the polymer sheet used as a polishing pad.   The method of claim 1, wherein the controlled atmosphere comprises an inert gas.   The reactive formulation comprising a precursor and a curing agent is a liquid having a viscosity in the range of about 20,000 Pascal seconds to 400,000 Pascal seconds at room temperature. the method of.   In the step (d), one or more of the thickness of the polymer sheet, the temperature of the belt, the pressure applied to the sheet between the belts, and the speed of the belt are further controlled via a closed loop process control system. The closed loop process control system compares thickness, temperature, pressure, and / or speed values with a selected range of target values and includes the thickness, temperature, pressure And / or maintaining the speed within a range of the target value.   And (ii) cutting the polymer sheet to a desired length, and (ii) at least one of the steps of post-curing the polymer sheet to establish the final properties of the sheet. The method of claim 1, characterized in that   The method according to claim 1, wherein the opposed endless belts are constructed of a steel double belt press.   The method of claim 1, wherein the polymer sheet comprises polyurethane.   The method of claim 1, wherein step (c) comprises providing a molten precursor.   8. The method of claim 7, wherein the polyurethane comprises a toluene diisocyanate prepolymer blended with an isoferon diisocyanate prepolymer.   The step of supplying the reactive compound comprising the precursor and the curing agent to the belt is performed by mixing the precursor and the curing agent in a mixer before supplying the reactive mixture to the belt. The method according to claim 1, comprising steps.   The method of claim 10, wherein the mixer is either a static mixer or a dynamic mixer.   The method of claim 1, wherein the reactant blend is compressed at a pressure between 1 MPa and 10 MPa.   The method according to claim 1, wherein the precursor in the step (b) further contains a filler.   The method of claim 13, wherein the filler comprises hollow microspheres.   The method of claim 13, wherein the filler comprises a water soluble polymer.   And (ii) cutting the polymer sheet into a polishing pad having an upper surface, and (ii) adjusting at least one of the polishing pad by grinding the upper surface. The method according to claim 3.   A polishing pad for chemical mechanical polishing according to the method of claim 16. (A) A pair of endless compression belts in which one belt is stacked on the other belt in a furnace in an inert gas atmosphere, and the stacked belts have a common supply end and a common take-out end. The process of preparing
(B) supplying a reactive compound comprising a polyurethane precursor and a curing agent to the belt;
(C) heating the pair of stacked endless compression belts to a curing temperature of the polyurethane precursor and the curing agent;
(D) Select the pair of endless compression belts stacked to compress and apply pressure to form the polyurethane sheet of a predetermined thickness, density and hardness between the belts Rotating at a speed that is close to each other from the supply end toward the take-out end;
(E) delivering the polyurethane sheet through the take-out end of the opposed endless belt;
With
In step (b), the reactive formulation has a viscosity in the range of about 20,000 Pascal seconds to 400,000 Pascal seconds, the reactive formulation has a selected thermosetting temperature;
In step (d), (i) the predetermined thickness is in the range of about 10 mil to 130 mil, and (ii) the predetermined density is in the range of 0.3 g / cc to 1.2 g / cc. (Iii) The predetermined hardness is about 30 to 80 in Shore D hardness.
A method of continuously forming a polyurethane sheet used as a polishing pad.   Further, the polyurethane sheet has (iv) a compressibility up to about 10.0%, (v) has a void volume in the range of about 15% to 60% of the total volume, and (vi) < 19. A method according to claim 18, having a deflection from a flat surface of 0.5 ". An apparatus for forming a polymer sheet used as a polishing pad,
A pair of endless compression belts arranged such that one belt opposes the other belt, the opposed belts having a supply end and a common take-out end;
A supply system for supplying one or more precursors to the supply ends of the opposed endless compression belts;
A control atmosphere that rotates the endless compression belts toward each other from the supply end toward the take-out end; and
With
One or more of the thickness of the polymer sheet, the temperature of the belt, the pressure applied to the sheet between the belts, the speed of the belt is continuously monitored via a closed loop process control system,
The closed-loop process control compares thickness, temperature, pressure, and / or speed values to a selected target value range, and compares the thickness, temperature, pressure, and / or speed to the target value range. To keep in,
An apparatus for forming a polymer sheet used as a polishing pad. In particular, a system for making a polishing pad for chemical mechanical planarization,
(A) means for storing and adjusting the raw material before mixing;
(B) means for blending in a vacuum while controlling the temperature in order to supply a precursor composed of the raw materials;
(C) means for recycling the precursor to replenish the precursor;
(D) One belt is disposed so as to face the other belt, and the opposed belt includes a supply end and a common take-out end, and the belt compresses between the belts. A pair of endless compression belts configured to rotate in a direction approaching each other from the supply end toward the removal end at a selected speed to supply pressure between the belts;
(E) a mixer for supplying the precursor under controlled conditions to the supply ends of the pair of metal endless belts to form a molded polymer sheet;
(F) an inert gas atmosphere surrounding the supply ends of the pair of opposed metal compression belts;
(G) continuously monitoring one or more of the thickness of the polymer sheet, the temperature of the belt, the pressure applied to the sheet between the belts, the speed of the belt, and the thickness, temperature, pressure, and / or Or closed loop process control that compares the speed value with a selected target value range and maintains the thickness, temperature, pressure, and / or speed within the target value range;
(H) means for cutting the polymer sheet to a specific length;
(I) means for controlling the dimensions of the polymer sheet to make the sheet a polishing pad;
A system for making a polishing pad, especially for chemical mechanical planarization, comprising:   The system of claim 21, wherein the polishing pad has a top surface and further comprises a buffing or sharpening adjustment method to provide a desired surface microstructure.

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