Improve the device of defects of wafer edgeTechnical field
The present invention relates to thin film deposition field, and in particular to a kind of device for improving defects of wafer edge.
Background technology
With the development of integrated circuit technology, wafer specifications gradually develop to large scale, and 12 cun have been increasingly becoming integrated electricityThe main flow of road manufacture, it is following even to develop into 18 cun and more than 18 cun.The expansion of wafer size causes crystal round fringes accordinglyThe expansion of area, the control to defects of wafer edge seem more important.
So-called defects of wafer edge, refers to that thin film (being particularly the poor thin film of some adhesions) is accumulated in crystal round fringes(generally requiring through thin film deposition several times) to a certain extent after, internally occur to peel off in the presence of stress or external force,If dropping to the device region on wafer, just becoming affects the defect of product yield, serious defect to result even in product rejection.As shown in figure 1, after the thin film deposition processes of a period of time, due to edge response contact angle it is bigger, therefore can deposition of thickThe thicker thin film of degree, and the film thickness in other regions compare it is then relatively thin at marginal position.Traditional defects of wafer edge controlMethod processed is possible peeling source to be removed by way of cleaning wafer edge, due to needing to increase special angle of inclinationCleaning (bevel clean) technique, therefore the complexity of technological process can be increased, while increased manufacturing cost.
Fig. 2 is schematic diagram of the wafer in reaction chamber in prior art, and Fig. 3 is the signal of heating pedestal in prior artFigure.A pedestal 100 with heating function is provided with chamber 150, wafer 101 on pedestal 100, is placed with.In pedestal 100On be provided with a groove (wafer pocket), place wafer 101.In deposition process, radio frequency produces plasma gass(plasma) be passed through to chamber 150, and wafer 101 heated using pedestal 100, thin film is formed on surface.But in this process, the film thickness at 101 edge of wafer typically can be thicker, the structure shown in Fig. 1 is formed, with reactionConstantly carry out, the thin film of edge can be increasingly thicker, and then may produce and peel off and be possible to fall to the device region in wafer,And then affect product yield, even without producing peeling, the film thickness of crystal round fringes and middle part film thickness due to exist compared withBig diversity, therefore certain impact can be caused on its device performance, and to be all that those skilled in the art are be reluctant above see's.
The content of the invention
The invention provides a kind of device for improving defects of wafer edge, when thin film deposition is carried out, by wafer sideEdge purges noble gases, improves the thickness evenness of crystal column surface deposition film, and in order to realize the technique effect, the present invention is publicA kind of device for improving defects of wafer edge is opened, which includes：One is used to place the pedestal of wafer, and the susceptor edges surround and setThere is gas hole；
Wafer is placed on carry out thin film deposition processes on the pedestal when, by the gas hole to the wafer sideEdge purge gas, to improve the uniformity of crystal round fringes surface film thickness.
Above-mentioned device, wherein, a cavity is provided with the pedestal, by the gas hole by the gas pair in cavityCrystal round fringes are purged.
Above-mentioned device, wherein, the external gas transfer pipeline of the cavity, the gas transfer pipeline are used to conveying lazyProperty gas is to the cavity.
Above-mentioned device, wherein, the noble gases are nitrogen.
Above-mentioned device, wherein, the susceptor edges are less than the pedestal central region.
Above-mentioned device, wherein, electrode, heater and thermocouple are embedded with the pedestal, and the heater is uniformIn the pedestal.
Above-mentioned device, wherein, the gas hole is purged to the crystal round fringes surface with non-parallel angle.
Above-mentioned device, wherein, the gas hole is purged to the crystal round fringes surface with vertical angle.
Can be effectively improved in thin film deposition processes are carried out using device of the present invention, crystal round fringes and other areasThe uniformity of the film thickness that domain covers, reduces the generation of defect, while unnecessary cleaning process can be reduced, has saved peoplePower material resources, are conducive to improving production efficiency.
Description of the drawings
By reading the detailed description made to non-limiting example with reference to the following drawings, the present invention and its feature, outwardShape and advantage will become more apparent upon.In whole accompanying drawings, identical labelling indicates identical part.Not deliberately proportionallyDraw accompanying drawing, it is preferred that emphasis is the purport of the present invention is shown.
Fig. 1 is the schematic diagram in crystal column surface deposition film back edge film thickness more than central region thickness；
Fig. 2 is schematic diagram of the wafer in reaction chamber in prior art；
Fig. 3 is the schematic diagram of heating pedestal in prior art；
A kind of side view of the device of improvement defects of wafer edge that Fig. 4 is provided for the present invention；
A kind of top view of improvement defects of wafer edge that Fig. 5 is provided for the present invention；
Fig. 6 is the schematic diagram using the present invention after crystal column surface deposition film.
Specific embodiment
In the following description, a large amount of concrete details are given to provide more thorough understanding of the invention.SoAnd, it is obvious to the skilled person that the present invention can be able to without the need for one or more of these detailsImplement.In other examples, in order to avoid obscuring with the present invention, for some technical characteristics well known in the art do not enterRow description.
In order to thoroughly understand the present invention, detailed step and detailed structure will be proposed in following description, so as toExplaination technical scheme.Presently preferred embodiments of the present invention is described in detail as follows, but in addition to these detailed descriptions, thisInvention can also have other embodiment.
The invention provides a kind of device for improving defects of wafer edge, with reference to shown in Fig. 4 and Fig. 5, Fig. 4 is the deviceSide view, Fig. 5 are the top view of the device, and which includes pedestal 100, and the pedestal 100 is used to place wafer 101, pedestal frontside edgeAround being provided with gas hole 109, wafer is placed on carry out thin film deposition processes on pedestal when, by gas hole 109 to waferEdge purge gas, to improve the uniformity of crystal round fringes surface film thickness.
In the present invention, an embodiment that is preferred but not merely limiting to is in pedestal 100 to be provided with a cavity200, the gas in cavity 200 is purged to the edge of wafer 101 by gas hole 109.Meanwhile, the cavity 200 is externalOne gas transfer pipeline 110, can convey the noble gases of process compatible carried out with reaction chamber by the gas transfer pipeline 110To cavity 200, can be purged by the edge of wafer 101 of the gas hole 109 to placing on pedestal 100 afterwards.Here is selectedAt utmost can avoid adversely affecting reaction because being passed through unnecessary gas with noble gases, while may also function as adjustingThe effect of chamber pressure and within the chamber gas homogeneity.In actual mechanical process, the gas stream of the conveying of gas transfer pipeline 110The setting of amount is according to practical situation scalable, it is therefore an objective to ensure crystal round fringes not deposition film (or few deposition as far as possible), while brilliantThe thin film deposition of circle central region is unaffected.Preferably, the noble gases can select nitrogen (N2), nitrogen early has application to halfThe every field of conductor production, Technical comparing are compatible, while cost is relatively low.It should be appreciated to those skilled in the art thatThis is only a kind of preferably embodiment from nitrogen, other noble gases may also be employed in a practical situation and is passed through to thisIt is bright to have no impact, will not be described here.
In the present invention, an embodiment that is preferred but not merely limiting to is to purge at the edge to wafer 101When, gas hole 109 is purged to 101 edge surface of wafer with non-parallel angle, it is further preferred that purge gas and wafer101 edge surfaces are perpendicular.It is perpendicular with 101 edge surface of wafer by the gas for ensureing purging, and then strengthen purge gasPurging effort to 101 surface of wafer.
Fig. 4 is continued referring to, the edge of the pedestal 100 forms a boss, area less than the middle top region of pedestal 100100 top surface of pedestal not in conventional art is provided with depression (i.e. wafer pocket), and pedestal of the present invention can be morePlus the sufficient contact area for increasing by 101 edge of wafer and purge gas, and then it is thick further to improve the thin film of crystal round fringesThe uniformity of degree.
Electrode (not shown), heater 105 and thermocouple 107 are embedded with pedestal 100.Electrode passes through earth lead108 ground connection (GND)；Heater 105 is uniformly located in pedestal 100, and external heating cable 106, for carrying out adding to wafer 101Heat；And during heating, real-time temperature is detected using thermocouple 107, it is to avoid due to temperature it is too high or it is too low enterAnd affect normal process production.
The direction of arrow shown in Fig. 4 is the direction that noble gases flow in cavity 200, when thin film deposition processes are carried out,Noble gases are purged to the edge of wafer 101 by passage simultaneously, so even constantly carrying out with reaction, crystal round fringesFilm thickness and middle part surface film thickness will not also produce larger diversity, and then advantageously reduce due to crystal round fringesThin film it is thicker so as to being peeling and fall to the defect formed by integrated circuit area, improving product yield.
For example with PECVD (Plasma Enhanced Chemical Vapor Deposition, plasma enhancingLearn gas deposition) deposition 50nm thickness silicon nitride as a example by, dominant response gas be NH3And SiH4.In traditional depositional modeUnder, the central region of wafer will deposit the silicon nitride film of 50nm or so, and crystal round fringes are bigger due to reaction contact angle, JingIt is 60nm to cross and measure its thickness, while constantly carrying out with reaction, through other follow-up thin film deposition process, crystal round fringesThin film will be increasingly thicker, and be increasingly becoming defect source, the thin film at marginal position produces and peels off and wither and fall to circuit region(such as static memory circuit region), defines defect.And pass through technical method proposed by the present invention, only need to be in passage correspondenceBody transfer pipeline in flow into a certain amount of nitrogen, to purge to crystal round fringes, and then improve crystal column surface positionThe uniformity of deposited film thickness, after the completion of technique, forms the structure shown in Fig. 6, and the film thickness at its marginal position will notIt is blocked up, and then reduce the situation of defect generation.
In sum, due to present invention employs as above technical scheme, when thin film deposition is carried out, by gas hole toward crystalline substanceRounded edge purges noble gases, and then is effectively improved in thin film deposition processes, the film thickness covered by crystal round fringes with it is brilliantThe excessive problem of circle middle part film thickness difference, and then reduce as crystal round fringes film thickness is blocked up so as to easily peel offAnd fall to integrated circuit area the defect for being formed, effectively increase product yield, it is to avoid unnecessary cleaning process, saveHuman and material resources, improves the production efficiency of product.
Above presently preferred embodiments of the present invention is described.It is to be appreciated that the invention is not limited in above-mentionedParticular implementation, wherein the equipment and structure that do not describe in detail to the greatest extent are construed as giving reality with the common mode in this areaApply；Any those of ordinary skill in the art, under without departing from technical solution of the present invention ambit, all using the disclosure aboveMethods and techniques content make many possible variations and modification to technical solution of the present invention, or be revised as equivalent variations etc.Effect embodiment, this has no effect on the flesh and blood of the present invention.Therefore, every content without departing from technical solution of the present invention, foundationThe technical spirit of the present invention still falls within the present invention to any simple modification made for any of the above embodiments, equivalent variations and modificationIn the range of technical scheme protection.