CN100584536C - Three-dimensional network for chemical mechanical polishing - Google Patents

Abstract

Under the condition of existence color buffing medium (120), Polishing pad (104) used in at least one of color buffing magnetic, photics and semi-conductor substrate web. Polishing pad (104) includes three-dimensional network structure of interconnect unit (225). interconnect unit (225) is netted, convenient for fluid flow and remove the color buffing debris. Many color buffing element (208, 308, 408) come into being interconnect unit (255) three-dimensional network structure. Color buffing element (208, 308, 408) is provided with first tag end of first neighbouring element which connect to the first juncture (209, 309, 409), and the second tag end of second neighbouring element which connect to the second juncture (209, 309, 409), the cross sectional area is 30% between the first and second juncture (209, 309, 409). multitime colo(u)r buffing operational work is keep in line with glazed surface (200, 300, 400) which is composed of many color buffing element (208, 308, 408).

Description

The three-dimensional net structure that is used for chemically mechanical polishing

Technical field

The present invention relates generally to be used for the polishing pad field of chemically mechanical polishing.Specifically, the present invention relates to have the chemical mechanical polishing pads of the polishing structure that is used for chemically mechanical polishing magnetic, optics and semiconductor substrate.

Background technology

In the manufacture process of integrated circuit and other electronic devices, multilayer conductive, semiconductor and dielectric material are deposited on the semiconductor wafer surface, remove from semiconductor wafer surface again then.Can use many techniques of deposition conductions, semiconductor and thin layer of dielectric material.Conventional deposition technique in the modern wafer processing comprises physical vapor deposition (PVD) (being also referred to as sputter), chemical vapor deposition (CVD), chemical vapour deposition (CVD) (PECVD) that plasma strengthens and electrochemistry plating etc.Conventional clearance technique comprises the isotropism of wet method and dry method and anisotropic etching etc.

Along with material layer by sequential aggradation and removing, it is uneven that the uppermost surface of wafer becomes.Because semiconductor machining subsequently (for example metallization (metallization)) requires this wafer to have flat surfaces, so need carry out complanation (planarize) to this wafer.Complanation is used to remove unwanted surface topography and blemish, for example rough surface, reunion material, crystal lattice damage, cut and contaminated layer or material.

Chemical-mechanical planarization or be that chemically mechanical polishing (CMP) is to be used for the common technology that makes workpiece planarizationizations such as semiconductor wafer or polish.In conventional CMP, chip carrier or rubbing head are fixed on the vehicle group component.Rubbing head is held wafer, and the desk in this wafer and the CMP device or the polishing layer of the polishing pad on the platform are contacted.The vehicle group component provides controlled pressure between wafer and polishing pad.Slurry or other polishing mediums are dispersed on the polishing pad, flow in the space between wafer and the polishing layer.In order to polish, polishing pad and wafer relatively rotate usually.When polishing pad rotated below wafer, wafer is the polishing locus (or being called polishing area) of an inswept annular usually, and wherein this wafer surface is directly in the face of polishing layer.Wafer surface goes up the chemistry of polishing medium and mechanism by polishing layer and surface and polishes and flatten.

In the CMP process, the interaction between polishing layer, polishing medium and the wafer surface be during the decade in the past studied gradually, the problem of analysis and senior mathematical modeling, with the design of optimization polishing pad.Since CMP was at first as semiconductor fabrication process, the development of most of polishing pads virtually completely was by rule of thumb, and it relates to the test of many different porous and non-porous polymer material.The design of most polished surfaces or layer concentrates on provides the layer with various micro-structurals or the pattern of pore region and solid area and macrostructure, perhaps perforate surface or groove arranges, they are claimed and have improved polishing velocity, improved the polishing homogeneity, have perhaps lowered polishing defect (scratch, depression, delamination area and other surface or sub-surface damage).Pass by for many years, only proposed the different micro-structurals and the macrostructure that are used to improve the CMP performance seldom.

For conventional polishing pad, it is important that " finishing " of pad interface or " arrangement " cause the pass to the homogeneous polished surface that keeps being suitable for stablize polishing performance.After after a while, the polished surface loss of polishing pad, one one kinds of phenomenons that are called " glazing (glazing) " of microstructure of having polished polished surface.The plasticity that glazing is derived from because of the polymeric material that shear action caused at contact point place between frictional heat and polishing pad and the workpiece flows.In addition, the chip from CMP technology can block surface pore and the microchannel that slurry stream is crossed polished surface.When this thing happens, the polishing velocity of CMP technology reduced, and cause between the wafer or among inhomogenous polishing appears.Finishing can form new texture on polished surface, be used for keeping required polishing velocity of CMP technology and homogeneity.

Conventional polishing pad finishing is by carrying out with finishing dish (conditioning disk) machine cut polished surface.Described finishing dish has coarse refacing usually, and described refacing generally includes the diamond point of imbedding.When polishing suspends (ex situ) or when (original position), repairs dish and contact with polished surface in the intermittence time-out process of CMP technology when CMP technology is carried out in.Usually, the finishing dish rotates on the position fixing with respect to the polishing pad rotating shaft, and an inswept annular finishing is regional when polishing pad rotates.Described trim process cuts out little groove on polished surface, grinding also digs groove, and reproduce the polishing texture in cushion material.

Though the designer of pad has made the micro-structural and the configuration of various superficial makings in making cushion material and surfacing, the polishing texture of existing CMP pad is not the best on two importances.The first, under the common applied pressure condition, the real contact area between conventional CMP pad and the conventional workpiece is little in CMP---common the few percent that only accounts for whole relative areas.This is directly caused by excessive conventional surfacing, described surfacing is optionally the solid area of structure to be divided into particle (tatter), cause component contamination or uneven, or owing to different shape and height cause, wherein only the highest part actual contact workpiece.The second, flow to transport the thin layer that the space of polishing chip and heat occupies the pad surface for slurries, make polished waste material keep tight close workpiece, discharge down from workpiece fully up to it.Slurry fluids between pad and workpiece must be through very irregular surface, and walks around any uneven feature of the complete vertical interval between bridge joint pad and the workpiece.This causes workpiece to contact discarded chemical substance and the material of before having removed once more probably.Like this, because contact mechanics and hydrodynamics coupling in the superficial makings, the micro-structural of conventional pad is not the best: the height of uneven feature distributes and also is unfavorable for excellent contact, is unfavorable for that also fluid effectively flows and transports.

Defective among the CMP forms the shortcoming that is derived from conventional pad micro-structural.For example, Reinhardt etc. discloses the use polymer globules texture has been introduced in the polyurethane polishing pad in U.S. Patent No. 5578362.Though definite defective forms mechanism and do not get a thorough understanding of fully, reduce defective formation and require the extreme point stress minimum on the workpiece normally conspicuous.Given applying under load and the polish pressure, actual some contact pressure and real contact area are inversely proportional.The operation and the real contact area at all uneven feature tips are 2% CMP technology applies average out to 150psi (1Mpa) usually to workpiece just (stress) stress under 3psi (20.7kPa) polish pressure.The stress of this magnitude is enough to cause surface and sub-surface damage.On conventional CMP pad, rust and uneven feature in irregular shape also are disadvantageous flow pattern: the local pressure of fluid collision is significant on the uneven feature, and stagnant areas or separately flow and can cause polishing chip and heat accumulation perhaps forms the environment for particle agglomeration.

Except existing potential defective to form the source, conventional polishing pad microstructure is not best, and this is not accurately to duplicate because of the pad surfacing usually.Diamond on the finishing dish is rust in use, makes and will replace trimming device (conditioner) over time; Therefore, in its process, the validity of trimming device changes continuously in service life.Finishing has also influenced the proportion of goods damageds of CMP pad greatly.Usually, pad is about 95% because of the wearing and tearing that cause with diamond trimming device grinding, 5% is to wear and tear because of contacting with workpiece and only have an appointment.Therefore, except reducing defective, the microstructure of improved pad can need not finishing and longer service life.

The key of removing the pad finishing is to design a kind of polished surface that can self refresh, promptly can keep essentially identical geometry and configuration when it weares and teares.Therefore, for the energy self refresh, polished surface must be to make wearing and tearing can significantly not transform solid area.Like this will realistic heart zone can not stand to be enough to the continuous shear action and the heat that cause remarkable plasticity to flow, perhaps construct solid area, make them can be by shear action and spread heat are responded shear action or heat to the mode of other solid area.

Except ratio of defects was low, the polishing structure of CMP pad must have good planarization efficiency.Conventional cushion material requires balance between these two performance metrics, and this is because it is by material more soft more the complying with that become reached that ratio of defects is hanged down, and these identical changes of properties are then unfavorable to planarization efficiency.At last, complanation requires hard planarization material, and low ratio of defects then requires so not hard conformable material.Therefore, be difficult in single material and overcome basic balance between these modules.Conventional mat structure solves this problem in every way, comprises using having the hard formation that mutually combines and the composite of soft formation.Though composite has improvement than single layer structure, still do not develop the material that obtains ideal plane efficient and zero-fault formation simultaneously.

Therefore, though pad micro-structural and trimming device appear at during CMP of the same period uses, still require the CMP pad can obtain higher and real contact area workpiece; More effective slurries flow pattern is to remove the polishing chip; And reduce or eliminate reproducing the demand of texture.In addition, require the CMP mat structure to combine required hard rigid structure of excellent planar efficient and the required so not hard conformal structure of low ratio of defects.

Summary of the invention

One aspect of the present invention provides a kind of at least a polishing pad of magnetic, optics and semiconductor substrate that is used for polishing in the presence of polishing medium, described polishing pad comprises: a) three-dimensional net structure of interconnecting unit, described interconnecting unit is netted, is convenient to fluid and flows, and remove the polishing chip; B) be used to form a plurality of polishing elements of the three-dimensional net structure of interconnecting unit, the height of described interconnecting unit is at least three unit, described polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and between first and second joints, have 30% with interior cross-sectional area; C) polished surface that is formed by a plurality of polishing elements, the surface area of described polished surface (recording being parallel on the plane of polished surface) is consistent with polishing operation repeatedly.

The present invention provides a kind of at least a polishing pad of magnetic, optics and semiconductor substrate that is used for polishing on the other hand in the presence of polishing medium, described polishing pad comprises: a) three-dimensional net structure of interconnecting unit, the height of described interconnecting unit is at least 10 unit, described interconnecting unit forms line style polishing element, and described interconnecting unit is netted, be convenient to fluid and flow, and remove the polishing chip; B) a plurality of line styles that are used to form the three-dimensional net structure of interconnecting unit are polished elements, described line style polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and between first and second joints, have 30% with interior cross-sectional area; C) polished surface that is formed by a plurality of polishing elements, the surface area of described polished surface (recording being parallel on the plane of polished surface) is consistent with polishing operation repeatedly.

The present invention provides a kind of on the other hand and polish method at least a in magnetic, optics and the semiconductor substrate with polishing pad in the presence of polishing medium, said method comprising the steps of: between polishing pad and base material, form dynamically contact, polish described base material, described polishing pad comprises: the three-dimensional net structure of interconnecting unit, described interconnecting unit is netted, be convenient to fluid and flow, and remove the polishing chip; Be used to form a plurality of polishing elements of the three-dimensional net structure of interconnecting unit, the height of described interconnecting unit is at least 10 unit, described polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and between first and second joints, have 30% with interior cross-sectional area; By the polished surface that a plurality of polishing elements form, the surface area of described polished surface (recording being parallel on the plane of polished surface) is consistent with polishing operation repeatedly; And the polishing chip in the polishing element of capture three-dimensional net structure.

Description of drawings

Fig. 1 is the part perspective view of the twin shaft polishing machine that is suitable for of the present invention;

Fig. 2 A is the high power amplification sectional view of the present invention of having shown in Figure 1 polishing pad of polishing structure;

Fig. 2 B is the high power amplification view of the present invention of having shown in Figure 1 polishing pad of polishing structure;

Fig. 3 has the high power amplification sectional view that the present invention polishes another polishing pad of structure;

Fig. 4 has the high power amplification sectional view that the present invention polishes another polishing pad of structure.

The specific embodiment

Referring to accompanying drawing, Fig. 1 has described the principal character that is fit to twin shaft chemically mechanical polishing (CMP) machine 100 of polishing pad 104 uses of the present invention usually.Polishing pad 104 generally includes the polishing layer 108 with polished surface 110, described polished surface 110 is in the face of goods such as semiconductor wafer 112 (processing or unprocessed) or other workpiece, as glass, flat-panel monitor or magnetic information recording video disc etc., with the polished surface 116 of polishing workpiece in the presence of polishing medium 120.Polishing medium 120 moves through the optional spiral groove 124 with degree of depth 128.For simplicity, below use term " wafer " by general meaning.In addition, in this specification (comprising claims), term " polishing medium " comprises polishing solution that contains particle and the solution that does not contain particle, as not containing abrasive material (abrasive-free) and active liquid polishing solution.

The present invention generally includes provides the polishing layer 108 with polishing texture 200 (Fig. 2), with respect to solid volume, it has the open volume (open volume) of high hole mark or high percentage, form polishing layer 108 by a series of similar or identical naked eyes elongated member visible or microcosmic, each element limits at one end or multiterminal, it is little that available whole spaces are compared in whole spaces that described element is occupied, the size that the spacing of individual component is compared wafer is little, and described element interconnection becomes three-dimensional structure, to make described network structure firm for shearing and bending.Preferably, these elements have microscopic dimensions to form microtexture.These features are used for providing higher real contact area between described pad and wafer, provide the slurries flow pattern more favourable than conventional polishing pad between pad and wafer, and provide and need not self refresh structure that polishing pad is repaired.In addition, these features also in a certain way on length dimension for polishing pad is provided for the required rigidity of excellent planar efficient, the low required adaptability of ratio of defects also is provided on shorter length dimension simultaneously.

Polishing machine 100 also can comprise the polishing pad 104 that is installed on the platform 130.Platform 130 can be rotated by the platform driver (not shown) along rotating shaft 134.Wafer 112 is supported by chip carrier 138, and described carrier is along rotating shaft 142 rotations of the rotating shaft 134 (and separating with it) that is parallel to platform 130.Chip carrier 138 can play the effect of linkage (gimbaled linkage) (not shown) that universal joint is housed, and makes wafer 112 present the appearance that slightly is not parallel to polishing layer 108, and at this moment rotating shaft 134,142 can be crooked slightly.Wafer 112 comprises the polished surface 116 in the face of polishing layer 108, and in the polishing process midplaneization.Chip carrier 138 is supported by the carrier supported assembly (not shown) that is used to rotate wafer 112, and downforce F is provided, and so that polished surface 116 is pressed to polishing layer 108, thereby produces required pressure during polishing between polished surface and polishing layer.Polishing machine 100 also comprises the polishing medium import 146 that polishing medium 120 is provided to polishing layer 108.

Recognize as those skilled in the art, polishing machine 100 can comprise other parts (not shown), as system controller, polishing medium storage and decentralized system, heating system, purging system and the various controllers that are used to control the glossing each side, be used to control one of the rotary speed of wafer 112 and polishing pad 104 or both speed control and selectors (selector) as (1), (2) be used to change polishing medium 120 and be transported to the speed on the polishing pad and the controller and the selector of position, (3) be used to control the controller and the selector of the directed force F magnitude that is applied between wafer and the polishing pad, and (4) are used to control the controller of wafer rotating shaft 142 with respect to the position of polishing pad rotating shaft 134, brake and selector or the like.It is how installation and operations that those skilled in the art should understand these parts, and their detailed explanation is understood and implemented the present invention those skilled in the art is not essential.

In polishing process, polishing pad 104 and wafer 112 are along they rotating shaft 134 and 142 rotations separately, and polishing medium 120 is distributed on the polishing pad of rotation from polishing medium import 146.Polishing medium 120 (is included in the slit of wafer 112 and polishing pad 104 belows) on polishing layer 108 and spreads out.Polishing pad 104 and wafer 112 common (but not being certain) rotate under the selected velocity of 0.1-150rpm.Directed force F (but not being certain) usually is the magnitude that produces the required pressure of 0.1-15psi (6.9-103kPa) between wafer 112 and polishing pad 104.Recognize as those skilled in the art, polishing pad can be made web form, perhaps make the polishing pad of diameter less than the diameter of wanting polishing substrate.

Referring now to Fig. 2 A-2B,, the embodiment of polishing pad 104 shown in Figure 1 has been described in further detail, especially at surface finish texture 200.With the CMP pad of prior art (wherein, superficial makings or uneven (asperity) removes from material or reforming technology (i.e. finishing)) difference, polishing texture 200 by a series of have the identical of precise geometrical configuration or similarly polish element 204 and 208 constitute.For convenience of explanation, element 208 and substantially horizontal element 204 that polishing texture 200 is shown as by perpendicular constitute, but might not be this situations.Polishing texture 200 is equal to a large amount of this polishing elements 204 and 208 with mean breadth 210 and average cross-sectional area 222, and described element with geometrical mean pitch (pitch) 218 at interval.In this article, term " on average " is meant the arithmetic average on whole amounts of described element or structure.In addition, element 204 and 208 interconnection network architecture have average height 214 and average half height 215.Polishing texture 200 is actually a cover hexahedral element, is that wherein each face (6 faces) is the space cell of square or rectangle, and solid section is empty only at the edge of this space cell at the center of each face and the center of space cell.

The average height 214 of element 208 and the ratio of mean breadth 210 are at least 0.5.Be preferably, the ratio of average height 214 and mean breadth 210 is at least 0.75, and preferably at least 1.Randomly, the ratio of average height 214 and mean breadth 210 is at least 5 or be at least 10.When average height increased, the quantity of the interconnection element 204 that the network structure of the polishing element 208 that hardens in polishing process is required increased.Usually, the chainless end of element 208 that has only outstanding the superiors interconnection element 204 in polishing process under the effect of shearing force free bend.The height of the element 208 between basic unit 240 and the superiors' interconnection element 204 is subjected to limiting significantly, and the power that is applied on arbitrary element 208 is carried effectively by many adjacent elements 204 and 208, is similar to bridge framework or external support.In this case, polishing texture 200 is hard (excellent planarization is required) on length dimension, but on shorter length dimension then because of the element 208 not local deformation of support tip and pliability but local complying with.

Interconnection element 204 and polishing element 208 are combined to form unit 225, and described unit has mean breadth 227 and average length 229.These unit have netted or open-celled structure, have been combined to form three-dimensional net structure.The height of interconnecting unit is 3 unit at least, better is at least 10 unit.Usually, service life and integral rigidity that the height of increase polishing pad has prolonged polishing pad, wherein the latter is favourable to improving complanation.Randomly, the mean breadth 227 of unit is not equal to its average length 229.For example, mean breadth and average length ratio can be at least 2 or at least 4, use required polishing performance with some polishing of further improvement.For example, having the unit that elongates horizontal length provides harder polishing element, to improve complanation; Have the unit that elongates vertical length and have more pliable and tougher polished part, to improve the defective performance.

The high advantage of ratio of the average height of element 208 and mean breadth is that the long-pending long-term maintenance of whole polished surfaces of sectional area 222 is constant.Shown in Fig. 2 A, at polishing layer arbitrary time point in 202 service lifes, though most of contacts area of polishing texture 200 are made up of the cross section 222 of perpendicular elements 208, all or part of some interconnection elements 204 is also in wearing and tearing, and these quilts are specified and are contact element 206.Be preferably, the upright position of interconnection element 204 (vertical position) interlock (stagger), make to be parallel to basic unit's 240 occurring wear only run into fraction at the set point place in a period of time interconnection element 204, and these contact elements 206 have constituted the fraction of total contact area.This permission is polished some base materials with similar polishing performance, and reduces or eliminates the demand of periodically putting or repairing this pad in order.Reduce the service life that finishing has prolonged pad, and reduced its running cost.And, this pad can be transformed into eCMP (electrochemical machinery complanation) polishing pad by perforation, introducing conduction groove or adding electric conductor such as conductive fiber, conductive network structure, metal grate or the metal wire that fills up.The three-dimensional net structure of these pads is convenient to fluid and is flowed, and keeps harsh eCMP to use required homogeneous surface texture.The increase that fluid flows has improved discarded electrolyte and has removed from eCMP technology, and this can improve the homogeneity of eCMP technology.

Be preferably, do not have solid material in the polishing texture 200, be not included in the polishing element 204 and 208.Randomly, abrasive grains or fiber can be fixed in the polishing element 204 and 208.Correspondingly, in arbitrary independent element 204 or 208, do not have voidage, the polishing texture 200 in all voidages better be present in the polishing element 204 and 208 between and outside.But polishing element 204 and 208 is chosen wantonly has hollow or loose structure.One end of polishing element 208 keeps pitch 218 firmly to invest in the basic unit 240, and makes polishing element 208 keep vertical substantially direction.The orientation of element 208 also keeps by the interconnection element 204 of joint (junction) 209, describedly connects on the adjacent polishing element 204 and 208 in conjunction with 209.Joint 209 can comprise adhesive, and perhaps chemical bond fixes element 204 and 208.Be preferably the interconnection of joint 209 expression same materials, the preferably seamless interlinkage of same material.

Preferably, on all the polishing elements 208 between the joint 209, pass through all homogeneous or near homogeneous, perhaps homogeneous on the child group of polishing element 208 of polishing width 210 of element 208 and pitch 218.For example, polishing width 210 of element 208 and pitch 218 remain on separately in the polishing layer 202 between contact 206 and half height 215 more fortunately mean breadth or pitch 50% in.Be better, polishing width 210 of element 208 and pitch 218 remain on separately in the polishing layer 202 between contact 206 and half height 215 more fortunately mean breadth or pitch 20% in.Best is, the width 210 of polishing element 208 and pitch 218 remain on separately in the polishing layer 202 between contact 206 and half height 215 more fortunately mean breadth or pitch 10% in.In particular, the cross-sectional area of polishing element 204 and 208 between adjacent bond place 209 remained on 30% with interior favourable to uniform polishing performance.Be preferably, described pad remains on the cross-sectional area between the adjacent bond place 209 in 20%, preferably in 10%.And polishing element 204 and 208 better is a line style, and this is more favourable to the homogeneous polishing.A direct result of these features be exactly the polishing element 208 cross-sectional area 222 in vertical direction can marked change.Therefore, when polishing element 208 wear and tear in polishing process and height 214 when reducing, the area 222 of facing wafer can change hardly.The homogeneity of surface area 222 provides the polishing texture 200 of a homogeneous, and provides the repetition polishing operation required homogeneous polishing.For example, homogeneous structural allows polishing to form the wafer of a plurality of patterns, need not the setting of adjustment instrument.In this manual, polished surface or texture 200 expression polishing elements 204 and 208 surface area (recording being parallel on the plane of polished surface).Be preferably, whole cross-sectional areas 222 of polishing element 208 highly remain in 25% between 215 in half of the vertical volume of originally polished surface or contact element 206 and unit 225.Best is, whole cross-sectional areas 222 of polishing element 208 highly remain in 10% between 215 at half of the vertical column (column) of originally polished surface and unit 225.As mentioned above, the upright position of interconnection element 204 is more preferably staggered, the variation minimum of whole cross-sectional areas when component abrasion.

Randomly, polishing element 208 can be arranged in the alternate grouping (spacedgrouping) of some polishing elements 208---for example, the polishing element comprises the annular grouping that is not contained the zone encirclement of polishing element.In each grouping, the preferably spacing of interconnection element 204 energy holding elements 208 groupings and effectively rigidity.In addition, can adjust polishing element 204 or 208 density in zones of different, the homogeneity of rate and polishing or wafer is removed in meticulous adjustment.And the passage that the polishing element arrangements can be become open wide is as circular channel, X-Y passage, radial passage, crooked radial passage or helical duct.Introduce optional passage and help removing big chip, and can improve the homogeneity of polishing or wafer.

The height 214 of polishing element 208 is a homogeneous on all elements.Preferred heights 214 remain on the polishing texture 200 in average height 20%, be more preferably 10% of average height, be more preferably 1% of average height.Randomly, polishing element as described in cutting device can periodically cut as cutter, high speed rotating knife or laser, the height of formation homogeneous.And, the diameter of cutter and speed can be randomly cutting and polishing element at a certain angle, adjust polished surface.For example, the polishing element of cutting at a certain angle with circular cross section will obtain and the most advanced and sophisticated texture of the interactional polishing of base material.The homogeneity of height guarantees to polish all polishing elements 208 and the interconnection contact elements 206 on all abrasive planes of texture 200 can contact workpiece.In fact, because having, industrial CMP instrument will not wait polish pressure to be applied to mechanical device on the diverse location of wafer, and since the fluid pressure that under wafer, produces be enough to make wafer to leave level just in time and be parallel to the position of the average level (mean level) of this pad, therefore, some polish not contact wafer of elements 208.But, in the arbitrary region that polishing pad 104 comes in contact, require polishing element 208 as much as possible to have enough height, so that contact to be provided.And because the terminal dynamic contacting mechanism because of polishing usually of the not constraint of polishing element 208 is crooked, the long-pending wearing and tearing usually of initial polished surface are to adapt to this crooked angle.For example, will wear and tear in initial round tip surface, form the tip end surface of band angle, and the direction that experiences in polishing process variation will form multiple wear patterns.

Select the size and the spacing of polishing element 204 and 208, between pad and wafer, providing high contact area 222, and enough open flow areas (open flow area) 226 of removing the polishing chip for slurries.Usually, polishing element 204 and 208 accounts for below 80% of polishing pad volume (recording) in basic unit 240.Be preferably, polishing pad 204 and 208 accounts for below 75% of polishing pad volume (recording) in basic unit 240.For example, element 204 and 208 accounts for the 5-75% (recording) of polishing pad volume usually in basic unit 240.The polishing pad that is used for high contact area accounts for the 40-80% of polishing pad volume (recording) usually in basic unit 240.There is intrinsic balance between these targets: in the useful space of polishing texture 200, increase more polishing element 204 and 208 and increased total contact area 222, but reduced flow area 226, formed the obstacle that more obstruction slurry fluids 230 and polishing chip are removed.It is enough very thin that substantive characteristics of the present invention is to polish element 204 and 208, and enough wide at interval, makes the good balance of maintenance between contact area and the flow area.Polishing element 208 with rectangle or square cross section helps increasing contact area.According to this balance, the pitch 218 of polishing element 208 is at least 2 with the ratio of the width 210 of polishing element 208 is optional.Under these restrictions, the contact area 222 of polishing texture 200 can reach 75% (that is, (1-width/pitch) square) or more than, flow area 226 be effective area 50% (that is 1-width/pitch) or more than.Usually, polishing element 208 plays the effect of collecting or capturing the polishing chip on the pad surface with upper/lower positions.This feature helps reducing ratio of defects by capture harmful chip on the position of the product surface that can not contact or swipe in polishing process.And, the height 214 of polishing element 208 and the ratio of width 210 can also be chosen wantonly and be at least 4, make flow area 226 maximums, allow polishing chip horizontal feed between polishing element 204 and 208, between the chip of this conveying and wafer, still form vertical range simultaneously.

Polishing texture 200 is also further optimized by the shape of cross section of selecting polishing element 204 and 208, that is, make for main appearance slurry fluids 230 in the horizontal direction to be streamlined (streamline).Main body is made the streamlined fluid resistance minimum that makes, and this is the principle of knowing on the engineering, and becomes the science that is suitable for usually when design aviation, navigation, the vehicles, propeller and other object that moves in gas or liquid.The fluid flow equation of adjusting people's yardstick (human scale) object of these back is suitable for the macrostructure yardstick or the micro-structural yardstick of CMP pad equally.In fact, streamlining is by selecting progressively crooked cross section and not sharp-pointed turnover to form, makes the external fluid fluid can be around the cross section process, and can not leave described surface, can not form the circulation whirlpool of consumption fluid energy.For this consideration, compare square or rectangular cross section, polishing element 204 and 208 circular cross sections 222.And, the local flow that the shape of polishing element 208 is made streamlined confirmation request slurry fluids 230 to.Because pad and wafer are in rotation, slurry fluids 230 reaches polishing element 204 and 208 with various angles, is not the most satisfied concerning the airflow design correct the approach of reaching of an angle just to the approach that reaches of other angle.The fluid of all directions is reached approach, and all equally to be fairshaped unique shape be exactly circular cross section, therefore circular under normal conditions.If can determine main flow direction, in platform speed and the very high CMP technology of the ratio of bearer rate, the cross section that is more preferably polishing element 204 and 208 is streamlined for this direction.

Shown in Fig. 2 A, polishing pad 104 comprises polishing layer 202, and can comprise time pad (subpad) 250.Should notice that time pad 250 might not need, polishing layer 202 can directly be fixed on the platform of polishing machine by basic unit 240, platform 130 for example shown in Figure 1.Polishing layer 202 can be fixed on time pad 250 as adhesives (for example, using pressure sensitive adhesive layer 245 or hot-melt adhesive), heat bonding, chemical bonding, ultrasonic bonding etc. in any suitable manner by basic unit 240.Basic unit 240 or inferior pad 250 can be as the polishing substrates that links polishing element 208.Be preferably, the base part of polishing element 208 extends to basic unit 240.

Can make ins all sorts of ways makes polishing texture 200.For the network structure of large-size, these comprise little processing, laser or the fluid injection is etched with and other removes the method for material from solid raw material; And the laser polymerisation that focuses on, selective light chemosetting (preferential optical curing), biological growth and other make up the method for material in initial empty volume.For the network structure of reduced size, can use crystallization, crystal seed polymerisation, lithography or other selective material deposition technology, and electrophoresis, the nuclear technology of coordinating or other set up template for after the method for material self assembly.

The polishing element 204 of micro-structural 200 and 208 and basic unit 240 can make by the material of any appropriate, as Merlon, polysulfones, nylon, polyethers, polyester, polystyrene type (polystyrenes), acrylate copolymer, polymethyl methacrylate class (polymethyl methacryl ates), polyvinyl chloride (polyvinylchlorides), polyvinyl-fluoride (polyvinlyflurides), polyethylene kind (polyethylenes), PP type (polypropylenes), polybutadiene (polybutadienes), polyethyleneimine: amine (polyethylene imines), polyurethane, polyether sulfone, polyamide, polyimide, polyketone, epoxy resin, silicone, their copolymer (as, polyether-polyester copolymer) and their mixture.Polishing element 204 and 208 and basic unit 240 also can make by non-cohesive material, as the solid phase form of pottery, glass, metal, stone material, timber or simple material as icing.Polishing element 204 and 208 and basic unit 240 also can make by the compound of polymer and one or more non-cohesive materials.

Usually, polishing element 204 and 208 and the material of basic unit 240 applicability of selecting to be subjected to polish the goods that make by concrete material in required mode limited.Similarly, inferior pad 250 can be made by the material of any appropriate, is used to polish element 204 and 208 and the material of basic unit 240 as above-mentioned.Polishing pad 104 can be chosen wantonly and comprise that the polishing pad that is used for polishing machine is fixed to the securing member on the platform (for example, platform 130 shown in Figure 1).Described securing member can be the hook portion and the circle part of for example adhesive phase such as pressure sensitive adhesive layer 245, hot-melt adhesive, machanical fastener such as hook circle securing member.Also can use one or more fibre optics end points (endpoint) device 270 or similar transmitting device in scope of the present invention, they occupy one or more spaces of polishing texture 200.

Referring to Fig. 3, second embodiment of the present invention's polishing pad 104 shown in Figure 1 is described at another surface finish texture 300--side cross-sectional view shown in Figure 3 has the similar asymmetric pattern of interference networks unit in the polishing layer 302.Similar with the described polishing pad of Fig. 2 A, adhesive phase 345 is fixed to basic unit 340 on the optional inferior pad 350, and the optional end-point devices 370 that comprises.Polishing texture 300 is different from the polishing texture 200 shown in Fig. 2 A aspect three.At first, the element 308 of polishing texture 300 is not strict with basic unit 340 and horizontal plane, but and they be arbitrarily angled between the 45-90 degree, and some elements 308 are crooked, rather than straight.And interconnection element 304 not all is a level, but some and basic unit 340 and horizontal plane are the 0-45 degree.Like this, polishing texture 300 is made up of the unit, but difference on the quantity of the shape of described unit and face.These features are not stood test (nonwithstanding), can not change basically in the polishing texture 300 of the height 314 of element 308 between half height of polishing layer or polishing element 306 and polishing texture 300.The second, element 304 is compared polishing element 208 respective attributes and is had more variation (variation) with 308 width 310, pitch 318 and cross-sectional area 322.The 3rd, flow through element 304 and 308 and the slurry fluids in element 304 and 308 330 along than flow through the polishing element 208 fluid 230 more irregular path flow.Yet polishing texture 300 comprises fundamental property of the present invention, and wherein, element 306 forms polished surface.Concrete is, element 304 and 308 is formed on the network structure that interconnects on the three dimensions in joint 309 interconnection, and its interconnection degree is enough to provide whole fastness to the polishing texture, and the end that element 308 does not fetter provides local pliability, to comply with workpiece.In addition, element 304 and 308 is still enough very thin, and enough wide at interval, to keep in touch balance favourable between area and the flow area, the ratio of the geometrical mean pitch 318 of element 308 and the mean breadth 310 of element 308 is at least 2, and the height 314 of element 308 and the ratio of mean breadth 310 are at least 4.Like this, the polishing texture 300 contact area 322 can reach 25% or more than; When more irregular than the flow area 326 of polishing texture 300, flow area 326 is enough big, is convenient to polish chip horizontal feed in element 304 and 308, and still provides vertical range between chip of carrying and wafer.

Polishing texture 300 shown in Figure 3 has illustrated and the present invention includes unlimited interconnection network architecture that wherein, independent element is from being purely horizontal to all vertical angles fully.In addition, the present invention includes the array of the fully random very thin element of interconnection, wherein, not have the size of obviously repetition or the space of shape, perhaps wherein many element heights bendings, branch or tangle mutually.The common image of polishing pad micro-structural in the scope of the invention is the human neural cells of bridge truss, macromolecular ball-and-stick model and interconnection.In all cases, described structure must have identical key feature, promptly has enough interconnection in the three-dimensional structure, to strengthen the overall network structure; Wearing and tearing on horizontal plane produce and have the terminal very thin element of local constraint from the network structure of upper surface, are provided on the short length compliance to workpiece; And the unlimited space of element and length-width ratio meet the above geometry restriction that provides.

In Fig. 4, shown another embodiment of the present invention, and by the polishing layer 402 of the interconnection tetrahedron lattice with regular spaces.It is identical with width that all elements 404 and 408 are shown as length, and link at joint 409, though might not want like this.In illustrated embodiment, described unit is the tetrahedron of rule, wherein, each face (4) is an equilateral triangle, its side is the pitch 418 of network structure, and the width 410 of solid member is only along four edges of space cell, and the center of each gore and space cell is whole to be empty.Because the symmetry of tetrahedron lattice, side cross section shown in Figure 4 becomes identical net-like pattern with planar graph.This polishing texture provides the fastness of high likelihood, and this is because there is the polyhedron of gore can not be out of shape.When the wearing and tearing of described structure, free terminal forms on element 408, provides local deformable and to the compliance of workpiece.In embodiment shown in Figure 4, tetrahedral network structure is structured in the basic unit 440 that is wedge shape a little, makes the plane of network structure all be parallel to inaccuracy the plane that contacts with wafer.At specified point place sometime, only the subelement of element 406 grinds along its longest size, and most contact-making surface is provided by the smaller cross-sectional area 422 of the element that grinds along its shorter size.This makes its contact-making surface highly remain unchanged substantially between 415 at the polishing layer or the polishing element 406 and half of polishing texture 400.In wedge shape basic unit 440, supply the average area 426 of slurry fluids 430 to change a little.In order to make this variation minimum, in fact basic unit 440 carries out classification, makes a series of wedge-like portion that repeat support described network structure.Structure shown in Figure 4 is about 1 repetitive.Be similar to the pad shown in Fig. 2 A, adhesive phase 445 is fixed to basic unit 440 on the optional inferior pad 450, and randomly comprises end-point devices 470.

The invention provides the advantage of removing correlation between contacting mechanism and the fluid mechanism.Concrete is that it provides in this pad, and fluid is mobile effectively, is convenient to remove easily the polishing chip.In addition, it allows to adjust fastness, height and the pitch of polishing element, with the contacting mechanism of control and substrate.And the shape of described polishing element can reduce or eliminate to prolonging the finishing that polishing pad carries out service life.At last, the cross section of described homogeneous allows a plurality of substrates of polishing, as the figuratum wafer with similar polishing characteristic.

Claims (10)

1. one kind is used for polishing the entirely few a kind of polishing pad of magnetic, optics and semiconductor substrate in the presence of polishing medium, and described polishing pad comprises:

A) three-dimensional net structure of interconnecting unit, described interconnecting unit is netted, is convenient to fluid and flows, and remove the polishing chip;

B) a plurality of line styles that form the three-dimensional net structure of interconnecting unit are polished elements, the height of described interconnecting unit is at least three unit, described a plurality of line style polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and described a plurality of line style polishing element has 30% with interior cross-sectional area between first and second joints; With

C) polished surface that forms by described a plurality of line styles polishing elements, the surface area that is parallel to the described polished surface that records on the plane of polished surface and repeatedly polishing operation be consistent.

2. polishing pad as claimed in claim 1 is characterized in that described three-dimensional net structure invests in the basic unit, and when recording in basic unit, described a plurality of line style polishing elements account for the 5-75% of polishing pad volume.

3. polishing pad as claimed in claim 1 is characterized in that, partly highly locating between the cross section gross area of the initial cross section gross area and interconnecting unit, the variation of total cross-sectional area of described polished surface is less than 25%.

4. polishing pad as claimed in claim 1 is characterized in that, partly highly locating between the cross section gross area of the initial cross section gross area and interconnecting unit, the variation of total cross-sectional area of described polished surface is less than 10%.

5. polishing pad as claimed in claim 1 is characterized in that, the cross section of described a plurality of line style polishing elements is rectangles.

6. polishing pad as claimed in claim 1 is characterized in that, flows with respect to the fluid in the cross section of described a plurality of line style polishing elements, and the cross section of described a plurality of line style polishing elements is streamlined.

7. one kind is used for polishing at least a polishing pad of magnetic, optics and semiconductor substrate in the presence of polishing medium, and described polishing pad comprises:

A) three-dimensional net structure of interconnecting unit, the height of described interconnecting unit are at least 10 unit, and described interconnecting unit forms line style polishing element, and described interconnecting unit is netted, are convenient to fluid and flow, and remove the polishing chip;

B) a plurality of line styles that form the three-dimensional net structure of interconnecting unit are polished elements, described line style polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and between first and second joints, have 30% with interior cross-sectional area; With

C) polished surface that forms by a plurality of line styles polishing elements, the surface area that is parallel to the described polished surface that records on the plane of polished surface and repeatedly polishing operation be consistent.

8. polishing pad as claimed in claim 7 is characterized in that, in polishing process, the linear element of three-dimensional net structure is in the polishing layer place bending of three-dimensional net structure.

9. one kind is polished method at least a in magnetic, optics and the semiconductor substrate with polishing pad in the presence of polishing medium, said method comprising the steps of:

Form dynamically contact between polishing pad and base material, polish described base material, described polishing pad comprises: the three-dimensional net structure of interconnecting unit, and described interconnecting unit is netted, is convenient to fluid and flows, and remove the polishing chip; Form a plurality of line style polishing elements of the three-dimensional net structure of interconnecting unit, the height of described interconnecting unit is at least 10 unit, described line style polishing element has first end that is connected to the first adjacent polishing element at first joint, with second end that is connected to the second adjacent polishing element at second joint, and between first and second joints, have 30% with interior cross-sectional area; The polished surface that forms by a plurality of line styles polishing elements, the surface area that is parallel to the described polished surface that records on the plane of polished surface and repeatedly polishing operation be consistent; And

Polishing chip in the polishing element of capture three-dimensional net structure.

10. method as claimed in claim 9 is characterized in that, a series of figuratum semiconductor wafers are polished in described dynamic contact.

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