Background technology
Chemically mechanical polishing (Chemical Mechanical Polishing, abbreviation CMP) technology is the combination technique of mechanical skiving and chemical attack, chemical Mechanical Polishing Technique acts on the bright and clean flat surfaces of formation on the polished dielectric surface by the abrasive action of ultramicron and the chemical attack of slurry, has now become the dominant technology of semiconductor machining industry.Chemically mechanical polishing is an integrated circuit (IC) to the product of miniaturization, multiple stratification, slimming, flatening process development, also is wafer to 200mm, 300mm and even larger diameter transition, enhances productivity, reduces the technology of manufacturing cost and substrate globalize planarization indispensability.For instance, typical logical device comprises seven road inner medium layer CMP operations, seven road metal CMP operations with shallow trench isolation from (STI) CMP operation.Therefore say that CMP technology has become the maincenter technology of the semiconductor technology of preparation integrated circuit.
A complete CMP technology mainly is made up of operations such as polishing, back cleaning and measurements.Wherein the cleaning that comprises wafer is cleaned in the back, also comprises the cleaning to each parts of chemical-mechanical polishing mathing.The purpose of back cleaning is that residual particles among the CMP and contamination are reduced to acceptable level.At present, the back cleaning of CMP technology relates generally to the cleaning of the polishing pad of wafer after the CMP technology and CMP equipment, for example, publication number has been 20060040595 the U.S. Patent Application Publication cleaning method and the device of polishing pad behind a kind of CMP process, polishing pad after adopting chemical cleaning solution to Cu and oxide cmp cleans, and for the unexposed cleaning measure of the residue in the groove of rubbing head especially rubbing head.Yet after metal or CMP of Dielectric, the rubbing head of polissoir directly contacts with polishing fluid and wafer, causes polishing fluid bespatter rubbing head, the polishing fluid of the residual a lot of mixing of meeting in the groove of the back side of rubbing head dress screw.
The cleaning polishing head technique only adopts deionized water to clean behind the CMP at present, can't clean the residue of these mixing in the groove of rubbing head, and especially the less abrasive grains that adopts in the CMP technology has increased the difficulty of removing residue.These residues mainly are made up of metallic particles or other foreign material particles of CMP polishing fluid (diameter is 0.1 to 1.0 micron or variation in larger scope), wafer surface.Can crystallization become big when these residues are exposed in the air, pollute the wafer of next group polishing by two kinds of approach: the one, the particle of growing up in the residue directly stains and the scratch chip back surface; The 2nd, these residues enter polishing disk in CMP technology, scratch and contamination wafer surface.These residues are major defect sources of the CMP technology of wafer, mainly form two class defectives: the one, and the contamination of residual polishing fluid, wafer surface metal or other foreign materials; The 2nd, the scratch of wafer surface, groove or pit, this two classes defective produces very big negative interaction to device yield.
Residue on the rubbing head in the groove brings problem to an independent wafer incessantly.In the CMP technological process, the residue on the rubbing head may stain chip back surface and surface, if residue can not get timely cleaning, along with the polishing number of times increases, residue is also accumulated in the groove on rubbing head and propagated, thereby causes the cross pollution of wafer.And in CMP technology, wafer adopts manipulator to take out from process cavity, and residual polishing fluid particle, metallic particles or other particles pass to chip back surface by rubbing head, and these particulates also may be propagated by manipulator, stain other wafers.And if these wafers are also stain, these residues can be assembled on manipulator, cause staiing accumulation.
Therefore need residue in the effective cleaning polishing head groove.
Summary of the invention
The technical problem that the present invention solves is the residue of removing in the rubbing head groove, avoids residue contamination wafer in the rubbing head groove.
For addressing the above problem, the invention provides a kind of cleaning device of new chemical-mechanical polisher.Cleaning device is equipped with brush, and brush comprises brush holder and be installed in the bristle of brush holder one end that bristle can contact with the rubbing head that forwards cleaning positions to of chemical-mechanical polisher.
Cleaning device is provided with pallet, and described pallet is installed on the machine load plate of polissoir by connecting rod, and the other end of the brush holder of brush detachably is installed on the pallet.
The brush holder that above-mentioned pallet is provided with different screw socket installation positions or brush has different screw socket installation positions, and pallet adopts bolt to pass the brush holder of brush with brush and the screw socket installation position of pallet is connected.After brush used a period of time, bristle wore and tore to some extent, can move forward and backward brush by different screw socket installation positions; When needing to change brush, change by demounting bolt.
The pallet that loads brush all adopts the PVC pvc material with the connecting rod that is connected pallet and machine load plate.
The bristle of brush adopts polyamide nylon-No. 6 or No. 10 materials, and the bristle diameter scope is 0.15-3mm, and the bristle height is 5-7cm, and area is 3 * 3-5 * 5cm
2
The brush holder of brush adopts the PVC pvc material, and area is 5 * 5-7 * 7cm
2, width is 3-5cm.
After the cleaning polishing head technique was finished, brush adopted deionized water to clean, and dries naturally then.
Correspondingly, the invention provides a kind of cleaning method of new chemical-mechanical polisher, adopt when comprising the rubbing head that adopts the washed with de-ionized water chemical-mechanical polisher and can scrub with the contacted brush of the rubbing head that forwards cleaning positions to, described brush comprises brush holder and is installed in the bristle of brush holder one end.
Adopt deionized water and can with the contacted brush of the rubbing head that forwards cleaning positions to of chemical-mechanical polisher simultaneously before the cleaning polishing head step and all adopt the deionized water rinsing rubbing head afterwards
The used cleaning device of above-mentioned cleaning method is provided with pallet, and described pallet is installed on the machine load plate of polissoir by connecting rod, and the other end of the brush holder of brush detachably is installed on the pallet.
The brush holder that above-mentioned pallet is provided with different screw socket installation positions or brush has different screw socket installation positions, and pallet adopts bolt to pass the brush holder of brush with brush and the screw socket installation position of pallet is connected.After brush used a period of time, bristle wore and tore to some extent, can move forward and backward brush by different screw socket installation positions; When needing to change brush, change by demounting bolt.。
The pallet of above-mentioned loading brush all adopts the PVC pvc material with the connecting rod that is connected pallet and machine load plate.
When adopting brush and washed with de-ionized water rubbing head, the rotating speed of rubbing head is 10-30rpm.
The bristle of brush adopts polyamide nylon-No. 6 or No. 10 materials, and the bristle diameter scope is 0.15-3mm, and the bristle height is 5-7 cm, and area is 3 * 3-5 * 5cm
2
The brush holder of brush adopts the PVC pvc material, and area is 5 * 5-7 * 7cm
2, width is 3-5cm.
After the cleaning polishing head technique was finished, brush adopted deionized water to clean, and dries naturally then.
Compared with prior art, advantage of the present invention mainly shows: after CMP technology is finished, employing comprises that deionized water and brush clean the apparatus and method of CMP rubbing head simultaneously, can avoid the particle crystal growth in some residues in the polishing fluid in the groove of bespatter on rubbing head, the wafer that polishes is later on caused cut and is infected with, prevent from simultaneously to cause to stain to accumulate and cross pollution.
The specific embodiment
Below describe specific embodiment in detail by the foundation accompanying drawing, the advantage of cleaning device of the present invention and method will be clearer:
With reference to shown in Figure 1, chemical-mechanical polisher 100 comprises polishing block 110, and corresponding rubbing head 120 and high pressure de-ionized water device 130.When carrying out CMP technology, thrown wafer to be attached on the rubbing head 120, simultaneously, mechanical pressure will be thrown wafer by rubbing head 120 and will be pressed on the polishing block 110 that soaks full polishing fluid, and rubbing head 120 rotates with a fixed angular speed, and it is identical to turn on polishing block 110.The chemical reaction that utilizes polishing fluid to provide, and the wafer mechanical lapping of being born on polishing block 110 are removed dielectric layer or metal level that wafer surface is protruded gradually.High pressure de-ionized water device 130 provides washed with de-ionized water polishing block 110 and rubbing head 120.
Fig. 2 is the structure for amplifying schematic diagram of the rubbing head 120 of chemical-mechanical polisher 100, rubbing head 120 mainly is made up of clamping head 122 and chuck, at 12 grooves 202 of rubbing head 120 back side periphery edge distribution, bolt 121 passes groove 202 clamping head 122 is connected with chuck.
Fig. 3 is the structural representation of the embodiment 1 of cleaning device of the present invention, and comprising the cleaning device in rubbing head 120 and the frame of broken lines, cleaning device comprises the brush and the high pressure de-ionized water feedway 130 of interpolation.Brush comprises brush holder 340 and is installed in the bristle 341 of brush holder 340 1 ends that the bristle of brush can contact with the rubbing head that forwards cleaning positions to 120 of chemical-mechanical polisher.
Cleaning device is provided with pallet 345, and pallet 345 is installed on the machine load plate of polissoir by connecting rod, has different screw socket installation positions on the pallet.The other end of the brush holder 340 of brush detachably passes the brush holder 340 of brush by bolt 344 and the screw socket installation position of pallet 345 is installed on the pallet 345.
Fig. 4 A is the amplification profile structural representation of brush, and brush is made up of brush holder 340 and bristle 341, and different screw socket installation positions 411 and 412 is arranged on the brush, and Fig. 4 B provides the installation position schematic diagram of the bristle 341 of brush.
The position of brush can brush holder 340 by screw socket installation positions different on the pallet 345 or brush on different screw socket installation positions 342 and 343 move forward and backward; When needing to change brush, can change by demounting bolt 344.
The relative position of brush, high pressure de-ionized water device 130 and rubbing head 120 is as follows: after the CMP technology in cleaning polishing head 120 technologies, rubbing head 120 forwards cleaning positions to, this moment, the bristle 341 of brush just in time touched with rubbing head 120 side edge, and simultaneously the High-Pressure Water that is come out by the nozzle of high pressure de-ionized water device 130 can clean rubbing head 120.
Rotation rubbing head 120, rubbing head 120 rotating speeds are 10 to 30rpm, the bristle 341 of brush enters in the groove 202 of rubbing head 120 dorsal edge, this is the process of a machinery contact, rotation along with rubbing head 120, rub between the edge of rubbing head 120 and the bristle of brush 341,, take away most of residual particles simultaneously by deionized water rinsing.
After finishing cleaning polishing head 120, adopt deionized water that brush is cleaned, brush dries naturally.
The pallet 345 of the loading brush of above-mentioned cleaning device all adopts the PVC pvc material with the connecting rod that is connected pallet 345 and machine load plate, and thickness is 5 to 10mm.The bristle 341 of brush adopts polyamide nylon-No. 6 or No. 10 materials, and the diameter of bristle 341 is 0.15 to the 3mm scope, and the diameter of the bristle 341 of comparative optimization is 0.15 to the 1mm scope.The height of bristle 341 is 5 to 7cm, and the area of bristle 341 is 3 * 3 to 5 * 5cm
2
Among the embodiment of cleaning device of the present invention, the diameter of the bristle 341 of brush is 0.3mm.
Among another embodiment of cleaning device of the present invention, the diameter of the bristle 341 of brush is 0.8mm.
The brush holder 340 of above-mentioned brush adopts the PVC pvc materials, and area is 5 * 5 to 7 * 7cm
2
Fig. 5 is the flow chart of cleaning method of the present invention, adopt when comprising the rubbing head that adopts the washed with de-ionized water chemical-mechanical polisher and can scrub with the contacted brush of the rubbing head that forwards cleaning positions to, described brush comprises brush holder and is installed in the bristle of brush holder one end.Below just cleaning method second embodiment of the present invention be elaborated.
As shown in Figure 5, execution in step S501 forwards the rubbing head of chemical-mechanical polisher to cleaning positions.
Execution in step S502; adopt deionized water submergence rubbing head; High-Pressure Water makes the part residue acquisition energy at the rubbing head surface and the back side, and these have the residue particle of energy to stop self to reassemble, and scattered residue is pulled away under the impact of current.
Execution in step S503, the rotation rubbing head, the speed of rotation of rubbing head is 10-30rpm.
Execution in step S504 adopts brush to scrub rubbing head dorsal edge groove, carries out mechanical friction between brush and the rubbing head, and scattering by mechanical friction accumulates in residue in the rubbing head dorsal edge groove.When adopting brush to scatter the residue of assembling in the groove of rubbing head dorsal edge,, take away part residue particle by high pressure de-ionized water rinse.
Repeated execution of steps S502 immerses rubbing head in the deionized water again, makes remaining residual particles further scatter.
Repeated execution of steps S503, the rotation rubbing head.
Repeated execution of steps S504 utilizes the mechanical friction between brush and the rubbing head, and brush is scrubbed the residue of assembling in the rubbing head groove, and these residue particles further scatter.
Execution in step S505 by high pressure de-ionized water rinse, takes away remaining residue particle.
After the rubbing head cleaning is finished, need clean brush, the rubbing head of chemical-mechanical polisher is forwarded to usual position.Execution in step S506 opens the high pressure de-ionized water device, and brush is washed.
The used cleaning device of above-mentioned cleaning method is provided with pallet, and described pallet is installed on the machine load plate of polissoir by connecting rod, and the other end of the brush holder of brush detachably is installed on the pallet.
The brush holder that above-mentioned pallet is provided with different screw socket installation positions or brush has different screw socket installation positions, and pallet adopts bolt to pass the brush holder of brush with brush and the screw socket installation position of pallet is connected.After brush used a period of time, bristle wore and tore to some extent, can move forward and backward brush by different screw socket installation positions; When needing to change brush, change by demounting bolt.
The pallet of the brush holder of above-mentioned brush, loading brush all adopts the PVC pvc material with the connecting rod that is connected pallet and machine load plate.
When adopting brush and washed with de-ionized water rubbing head, the rotating speed of rubbing head is 10 to 30rpm.
In the implementing process of the present invention, when adopting brush and washed with de-ionized water rubbing head, the rotating speed of rubbing head is 20rpm.
The bristle of brush adopts polyamide nylon-No. 6 or No. 10 materials, and the bristle diameter scope is 0.15 to 3mm.
In conjunction with Fig. 5, and above-mentioned unit describe, present embodiment provides the concrete implementing process of a cleaning polishing head, and is as follows:
In the cleaning, the rubbing head of chemical-mechanical polisher is forwarded to cleaning positions behind the chemical-mechanical polisher.
Adopt deionized water submergence rubbing head, High-Pressure Water makes the part residue acquisition energy at the rubbing head surface and the back side, and these have the residue particle of energy to stop self to reassemble, and scattered residue is pulled away under the impact of current.
The rotation rubbing head, the speed of rotation of rubbing head is 25rpm.
Adopt brush to scrub rubbing head dorsal edge groove, scattering by the mechanical friction of carrying out between brush and the rubbing head accumulates in residue in the rubbing head dorsal edge groove, meanwhile, by high pressure de-ionized water rinse, takes away part residue particle.
Repeat above step, rubbing head is immersed in the deionized water again, make remaining residual particles further scatter; The rotation rubbing head utilizes the mechanical friction between brush and the rubbing head, and brush is scrubbed the residue of assembling in the rubbing head groove, and these residue particles further scatter; By high pressure de-ionized water rinse, take away remaining residue particle; At last, rubbing head is forwarded to usual position, open the high pressure de-ionized water device, brush is washed.
In the cleaning process, only adopt high pressure de-ionized water cleaning polishing head after CMP technology, the wafer to polishing next time carries out surperficial scratch scanning detection then.Found that: after only adopting high pressure de-ionized water cleaning polishing head, the wafer surface after the polishing has high defect concentration, is mainly scratch.Represent to detect the cut 601 and Fig. 6 B that only produce as Fig. 6 A and represent the big cut 602 of the another kind that produces with polished wafer surface behind the deionized water rinsing rubbing head; After adopting the auxiliary washed with de-ionized water device of brush, cut does not appear in the wafer surface of polishing.
Though the present invention discloses as above with preferred embodiment, the present invention is defined in this.Any those skilled in the art without departing from the spirit and scope of the present invention, all can do various changes and modification, so protection scope of the present invention should be as the criterion with claim institute restricted portion.