Background technology
Along with semiconductor devices reduces day by day, because multilayer interconnection or the bigger deposition process of filling depth ratio are brought the excessive fluctuating of wafer surface, cause the photoetching process difficulty focusing, the live width control ability is weakened, thus the uniformity of the live width on the reduction entire wafer.Thus; Industry is introduced the cmp technology that is used for the planarization wafer; This cmp (CMP; Chemical Mechanical Planarization) technology is fast-developing with its overall planarization advantage, is widely used in the complanation of the metal joint in complanation, contact hole and the via hole that deep trouth fills and oxide layer that intermediate steps comprises and the various fields such as complanation of inter-metal dielectric layer.
The CMP operation principle is: wafer is fixed on the grinding head, and wafer surface is contacted with a grinding pad down, make the wafer surface planarization through the relative motion between wafer surface and the grinding pad.In the CMP process; Supply with between above-mentioned wafer surface and the grinding pad abrasive material is arranged; Abrasive material is through relatively rotating between wafer surface and the grinding pad; Be evenly distributed in the slit between wafer surface and the grinding pad, and the material layer generation chemical reaction of desiring to remove with wafer surface and generate the material of easy removal, then the material of the relatively easy removal that wafer surface generation chemical reaction is generated of the mechanism through wafer surface and grinding pad relative motion generation is removed.Be removed owing to the figure of wafer surface eminence contacts with grinding pad more easily, make the figure of wafer surface eminence can be removed quickly, reach the effect of having an even surface of entire wafer than the figure of lower.Therefore, this CMP technology can accurately and be wafer polishing the thickness and the flatness of actual needs equably, and then becomes a kind of grinding technique of extensive use.
Yet industry can be interrupted for semiconductor device structure high-performance, low-cost pursuit with high finished product rate, to its CMP technology that direct influence is arranged also in improvement constantly.The apparatus and method for of many raising CMP efficient and flatness continues to bring out.The CMP equipment that is illustrated in fig. 1 shown below out with a plurality of grinding pad structures.
This CMP equipment comprises base 100 and transmission dish 200.Wherein base 100 is provided with wafer loading/unloading unit 110 and a plurality of grinding stations 120a, 120b and 120c; And be provided with corresponding turntable 121 on each grinding stations; And corresponding grinding pad 122 is positioned on the turntable 121; With rotation under driving at turntable 121, and a plurality of feeding abrasive material device 123 is arranged on the said base 100 respectively and can supplies with abrasive material to grinding pad 122 separately.A plurality of grinder pad finisher 130 1 ends are fixed on the base 100, and the other end is that movable end is used to regulate the abrasive material on the grinding pad 122.Be formed with grinding head whirligig 230 on the transmission dish 200; Grinding head 210 is arranged on the grinding head whirligig 230; And grinding head whirligig 230 control grinding heads 210 rotate, and grind away through the material layer that wafer surface need be removed that relatively rotates between grinding pad 122 and the grinding head 210.
Process of lapping is: wafer at first is admitted to wafer loading/unloading unit 110; And be loaded on the said grinding head 210; The surface that wafer surface promptly contains material layer down; Through grinding head whirligig 230 said grinding head 210 is placed on the said grinding pad 122 then, feeding abrasive material device 123 is supplied with abrasive material to grinding pad 122 simultaneously, relies on relatively rotating between grinding pad 122 and the grinding head 210 (said wafer is fixed on the grinding head 210); Thereby the material of said wafer surface is removed, realizes planarization wafer surface.Usually, the CMP of wafer grinds and comprises repeatedly grinding steps, so above-mentioned CMP equipment is provided with a plurality of grinding pads.
Along with the integrated level of semiconductor devices is increasingly high, the structure of wafer is more and more littler, makes the wafer surface that needs to grind approach micron level.So in the CMP of reality process of lapping; Grinder pad finisher 130 is when regulating grinding pad 122 surperficial abrasive materials; Grinding head 210 with grinding pad rotation relatively bumps easily, thereby causes whole CMP equipment to decommission, and causes the scratch of wafer surface easily.So make above-mentioned grinder pad finisher 130 be damaged easily with grinding head 210; The grinding efficiency of CMP equipment and the service life of board have been reduced simultaneously; Also reduced the performance of semiconductor device structure simultaneously, thereby influenced the efficient of dispatching from the factory of semiconductor device structure because of the scratch phenomenon.Therefore in the process of lapping of wafer, the probability that reduction grinder pad finisher and grinding head bump becomes the current technical issues that need to address.
Summary of the invention
In the summary of the invention part, introduced the notion of a series of reduced forms, this will further explain in specific embodiment part.Summary of the invention part of the present invention does not also mean that key feature and the essential features that will attempt to limit technical scheme required for protection, does not more mean that the protection domain of attempting to confirm technical scheme required for protection.
In order effectively to address the above problem, the present invention proposes a kind of chemical-mechanical grinding device, comprising: grinding head is used for fixing wafer to be ground;
Turntable and the grinding pad that is fixed on said turntable surface, wherein said turntable rotates said grinding pad, makes relative motion between said grinding pad and the said grinding head, so that said wafer is ground;
The feeding abrasive material device is used to supply with abrasive material to said grinding pad;
Grinder pad finisher is used to regulate the distribution that is supplied to the said abrasive material on the said grinding pad; And
Detector is used to detect the distance between said grinder pad finisher and the said grinding head, contacts with said grinding head to prevent said grinder pad finisher.
Further, said detector is positioned on the said grinder pad finisher.
Further, said chemical-mechanical grinding device comprises base, and an end of said grinder pad finisher is fixed on the said base, forms stiff end, and the other end rotates around said stiff end, the formation free end, and said detector is arranged on the said free end.
Further, said detector sends early warning signal when detecting distance between said grinder pad finisher and the said grinding head smaller or equal to predetermined value.
Further, said predetermined value is 0.05 inch.
Further, said detector is electrically connected to controller, and said controller receives said early warning signal, and stops the operation of said chemical-mechanical grinding device according to said early warning signal.
Further, said detector is supersonic detector or electromagnetic wave detector.
According to a further aspect in the invention, the present invention also provides a kind of Ginding process that uses above-mentioned chemical-mechanical grinding device, and said method comprises the following steps:
Wafer to be ground is provided;
Adopt said grinding head to fix said wafer;
Said grinding head is moved on the said grinding pad, and said turntable rotates said grinding pad, makes relative motion between said grinding pad and the said grinding head, so that said wafer is ground;
Adopt said feeding abrasive material device on said grinding pad, to supply with abrasive material;
Adopt said grinder pad finisher to regulate the distribution that is supplied to the said abrasive material on the said grinding pad, and
Adopt said detector to detect the distance between said grinder pad finisher and the said grinding head, contact with said grinding head to prevent said grinder pad finisher.
Further, when said detector detects distance between said grinder pad finisher and the said grinding head smaller or equal to predetermined value, send early warning signal.
Further, receive said early warning signal, and stop the operation of said chemical-mechanical grinding device according to said early warning signal through the controller that is electrically connected with said detector.
Chemical-mechanical grinding device among the present invention can reduce the probability that grinder pad finisher and grinding head bump in the wafer process of lapping, improve the service life of grinding head and grinder pad finisher, the service life of having improved CMP equipment simultaneously.Use chemical-mechanical grinding device of the present invention can not occur in addition because grinder pad finisher and grinding head collide the phenomenon of the wafer surface scratch that causes, thereby can improve the efficient of dispatching from the factory of wafer.
The specific embodiment
In the description hereinafter, a large amount of concrete details have been provided so that more thorough understanding of the invention is provided.Yet, it will be apparent to one skilled in the art that the present invention can need not one or more these details and be able to enforcement.In other example,, describe for technical characterictics more well known in the art for fear of obscuring with the present invention.
The present invention provides a kind of chemical-mechanical grinding device; This equipment increase can detect distance detection device between said grinding head and the said grinder pad finisher; When detecting above-mentioned distance, send early warning signal and contact with said grinding head to prevent said grinder pad finisher less than predetermined value.Chemical-mechanical grinding device in the embodiment of the invention can prevent the collision of grinder pad finisher and grinding head effectively, protects the normal operation of chemical-mechanical grinding device effectively.
Shown in figure 2A, Fig. 2 A is the vertical view of the chemical-mechanical grinding device 310 in the embodiments of the invention.This CMP equipment 310 comprises base 300 and transmission dish 307.Wherein base 300 is provided with wafer loading/unloading unit 309 and at least one grinding stations.Each grinding stations is provided with rotatable turntable, is fixed with grinding pad 302 on this turntable, and grinding pad 302 rotates around a direction under turntable drives.Describe for ease, only show a grinding stations among Fig. 2 A, correspondingly, among Fig. 2 A other parts that should grinding stations are also all shown one, need to prove among the present invention grinding stations and can be more than one corresponding to each parts of this grinding stations.
Transmission dish 307 is provided with at least one rotatable grinding head whirligig 306; This grinding head whirligig 306 is fixedly connected grinding head 304 at the end near grinding pad 302; And grinding head 304 rotates along with the rotation of grinding head whirligig 306; Said wafer to be ground is fixed on the said grinding head 304, and wherein the surface that need grind of wafer is towards the direction of said grinding pad 302.Make relative motion (comprising in the same way or counter-rotating) between grinding pad 302 and the said grinding head 304 on the turntable, so that said wafer is ground.In the present embodiment, illustrate, do not limit the quantity of this grinding head whirligig 306 among the present invention, can set according to the process requirements of reality with a grinding head whirligig 306.In addition, the surface that is installed on the wafer in the grinding head comprises medium and metal level in material layer or the multiple-layer metallization interconnection structure.Particularly, wafer loading/unloading unit 309 is installed on first wafer 303 of required grinding on the said grinding head 304, and the wafer surface that will grind is towards grinding pad 302 (promptly deviating from grinding head 304).When 310 operations of CMP equipment; The grinding head 304 that grinding head whirligig 304 will be fixed with first wafer 303 is pressed to said grinding pad 302 downwards; Control said grinding head whirligig 304 and turntable rotation simultaneously; As can make grinding pad 302 and grinding head 304 rotate (when rotating in the same way, the speed of rotation of the speed of rotation of grinding pad 302 and grinding head 304 is different) each other in the same way or make its mutual counter-rotating, and then can the uneven material layers on first wafer, 303 surfaces be removed; The surface of in the present embodiment, preferably using grinding pad 302 and grinding head 304 mutual counter-rotatings to grind first wafer 303.
In addition; Also be provided with feeding abrasive material device 305 on the base 300; This feeding abrasive material device 305 is used for supplying with abrasive material to grinding pad 302; This abrasive material with the material layer reaction on first wafer, 303 surfaces, and then is removed the material layer on first wafer, 303 surfaces fast under the effect of grinding pad 302 and grinding head 304.
In addition; Shown in Fig. 2 A; Also be provided with grinder pad finisher 301 on the base, these grinder pad finisher 301 1 ends are fixed on (formation stiff end) on the base, and the other end can rotate (formation free end) around stiff end; The free end of this grinder pad finisher 301 is used to regulate the distribution that feeding abrasive material device 305 is supplied to the abrasive material on the grinding pad 302; Or can prevent to exist between grinding pad 302 and the grinding head 304 unnecessary abrasive material to scratch the surface of first wafer, so that grinding pad and grinding head can effectively grind first wafer surface in order to remove unnecessary abrasive material on the grinding pad 302.Further, this grinder pad finisher 301 also can be used for the abrasive material above the grinding pad 302 is evenly distributed.
In the present embodiment, this grinder pad finisher 301 is provided with detector 308, is used to detect the distance between grinder pad finisher 301 and the grinding head 304, contacts with grinding head 304 to prevent grinder pad finisher 301.Preferably, detector 308 is arranged on the free end of grinder pad finisher 301, and detector 308 starts and starts along with grinder pad finisher 301.When detector 308 detects distance between grinder pad finisher 301 and the grinding head 304 smaller or equal to predetermined value, send early warning signal.In addition, this detector 308 also can be electrically connected on the controller 311 of said CMP equipment 310 operations of control.When detector 308 detects distance between grinder pad finisher 301 and the grinding head 304 smaller or equal to predetermined value; Send early warning signal; Detector 308 transmits this early warning signal to controller 311 simultaneously; Controller 311 receives said early warning signal, and carries out this early warning signal chemical-mechanical grinding device 310 out of service, promptly stops the relative motion between grinding pad 302 and the grinding head 304.In the equipment of reality; Detector 308 is electrically connected in the controller 311 of control CMP equipment 310 operations, and makes grinder pad finisher 301, grinding head 304, grinding pad 302 be positioned at relatively airtight space, and detector 308 can preferably use supersonic detector thus; Like ultrasonic range finder; Ultrasonic radar detectors etc., the controller 311 of wherein controlling said CMP equipment operation can be a control terminal, like computer or single-chip microcomputer etc.In addition, the predetermined value in the present embodiment can be 0.05 inch, when detecting above-mentioned distance less than 0.05 inch of predetermined value, sends early warning signal.Certainly, in other embodiment, predetermined value can be according to the requirement of the chemical-mechanical grinding device of reality and is set, and the present invention does not limit this.Further, detector 308 can be an electromagnetic wave detector, for example the infra-red electromagnetic survey meter.Detector 308 can be as having the sensor of display unit, and this sensor includes emitter, receiving system and display.When detector 308 detected distance between above-mentioned grinder pad finisher 301 and the grinding head 304 smaller or equal to predetermined value, this emitter sent a signal to receiving system, this receiving system receive signal and through the display demonstration can alarm signal/image.
Preferably, the detector shown in Fig. 2 A 308 is installed on the free end of grinder pad finisher 301.In the chemical-mechanical grinding device of reality; Detector 308 can also be installed on other position, base of grinder pad finisher 301, on the grinding head side or other position of whole CMP equipment 310, and it can realize that the distance that detects between grinding head 304 and the grinder pad finisher 301 gets final product.In addition, size and shape to detector 308 in the present embodiment do not limit, as long as can be installed on the free end of grinder pad finisher 301, for example the shape of detector 308 can be a rectangle, and its length and width can be 3cm*6cm or 4cm*4cm.Generally speaking, the length of the clinodiagonal of detector is preferably less than 15cm, and the weight of detector 308 is preferably below 2 kilograms.
The use of the chemical-mechanical grinding device shown in Fig. 2 A can for: at first first wafer 303 is loaded on the grinding head 304 through this wafer loading/unloading unit 309; And surface to be ground in this first wafer 303 is deviated from grinding head 304 to be fixed; Through grinding head whirligig 306 said grinding head 304 is pressed on said grinding pad 302 then; Promptly first wafer 303 contacts with grinding pad 302; Simultaneously feeding abrasive material device 305 is supplied with abrasive materials to grinding pad 302, relies on relatively rotating between grinding pad 302 and the grinding head 304 (said first wafer 303 be fixed in and grinding head 304 on) that the surface of first wafer 303 is ground.In addition; In the process that grind on the surface of the additional grinding pad 302 that abrasive material arranged, 304 pairs first wafers 303 of grinding head; Need to adopt the abrasive material on 301 pairs of grinding pads of grinder pad finisher, 302 surfaces to clean, make this abrasive material be uniformly distributed in the grinding pad surface, or remove unwanted abrasive material.When grinder pad finisher 301 started, detector 308 started with the distance between detection grinding head 304 and the grinder pad finisher 301 thereupon, and then can prevent effectively that grinding head 304 and grinder pad finisher 301 from bumping.
Shown in figure 2B, Fig. 2 B is the vertical view of the chemical-mechanical grinding device in the another embodiment of the present invention.CMP equipment 320 comprises three grinding stations of rounded symmetrical distribution; These three grinding stations are adjacent with a determining deviation each other; First grinding stations shown in Fig. 2 B, second grinding stations and the 3rd grinding stations; Correspondingly, each grinding stations is provided with corresponding turntable, grinding pad, feeding abrasive material device, grinder pad finisher, detector, grinding head whirligig and grinds first-class.(can comprise first detector on the free end of the grinder pad finisher that each grinding stations that is separately positioned on above-mentioned detector matches like the detector of corresponding first grinding stations, second grinding stations and the 3rd grinding stations respectively; Second detector and the 3rd detector); In the chemical-mechanical grinding device shown in Fig. 2 B; This first detector detect independently on first grinding stations grinder pad finisher and to the distance between should the grinding head of grinder pad finisher; Second detector detects the grinder pad finisher on second grinding stations independently and to the distance between should the grinding head of grinder pad finisher, and the 3rd detector detects grinder pad finisher on the 3rd grinding stations independently and to the distance between should the grinding head of grinder pad finisher.First detector among Fig. 2 B, second detector and the 3rd detector include corresponding independently display respectively, like first display, second display and the 3rd display.First display, second display and the 3rd display are respectively applied for its first corresponding detector of real-time demonstration, signal/image that second detector and the 3rd detector detect.When the detected said signal/image of a certain detector during smaller or equal to predetermined value (predetermined value at this place is to predetermined value that should signal/image), its corresponding display shows alarm.Certainly; These three detectors can a shared display; Corresponding each detector has one independently viewing area (scheme not shown), perhaps these three detectors is electrically connected in the controller that control CMP equipment 320 moves independently of each other, when the detected distance of any one detector during less than predetermined value; Can send a signal to controller, this controller stops the operation of said CMP equipment 320 according to said signal.
In addition; This CMP equipment 320 can grind first wafer through first grinding stations, second grinding stations and the 3rd grinding stations successively in turn; As, utilize first grinding stations, the material layer of first wafer is carried out the grinding of first grinding steps; Then utilize second grinding stations to carry out second grinding steps, and after second grinding steps, the first above-mentioned wafer is continued the 3rd grinding steps by the 3rd grinding stations again.The speed of this first grinding steps, second grinding steps and the 3rd grinding steps, the distribution of abrasive material can set up on their own, and correspondingly the detector in each grinding steps all is separate work, and it can not produce interference phenomenon each other.Certainly, above-mentioned CMP equipment 320 can also be that first grinding stations, second grinding stations and the 3rd grinding stations are ground three different wafers respectively simultaneously.The grinding rate of said this first grinding stations, second grinding stations and the 3rd grinding stations, the distribution of abrasive material also can be identical or different; And the detector of corresponding first grinding stations, second grinding stations and the 3rd grinding stations also can be set to different detection equipment; But what need to guarantee is that the work of each detector is separate, and does not produce interference phenomenon.In addition, in the CMP of reality equipment, the spacing of each grinding stations can be less than 0.1 millimeter.
Preferably, grinding pad in the CMP equipment and the abrasive material between the grinding head can contain the alumina composition and perhaps contain grinding agent compositions such as silica, and adoptable pressure is approximately 1 to 6 pounds per square foot (psi) between grinding pad and grinding head.
Grind in the process of first wafer at the CMP of reality equipment, can detect constantly, when the thickness of this first wafer reaches setting value, stop to grind through the thickness that end point determination, current of electric detection or optical end point detect said first wafer.Grinding head whirligig in the present embodiment can adopt motor control.
With reference to shown in Figure 3, shown in Figure 3 is the flow chart that uses the Ginding process of the chemical-mechanical grinding device in the foregoing description, and its step comprises:
Step 401: wafer to be ground is provided;
Step 402: adopt said grinding head to fix said wafer;
Step 403: said grinding head is moved on the said grinding pad, and said turntable rotates said grinding pad, makes relative motion between said grinding pad and the said grinding head, so that said wafer is ground;
Step 404: adopt said feeding abrasive material device on said grinding pad, to supply with abrasive material, adopt said grinder pad finisher to regulate the distribution that is supplied to the said abrasive material on the said grinding pad; And
Step 405: adopt said detector to detect the distance between said grinder pad finisher and the said grinding head, contact with said grinding head to prevent said grinder pad finisher.
When said detector detects distance between said grinder pad finisher and the said grinding head smaller or equal to predetermined value, send early warning signal.Further, receive said early warning signal, and stop the operation of said chemical-mechanical grinding device according to said early warning signal through the controller that is electrically connected with said detector.
In addition, need to prove that above step needn't be carried out in strict accordance with said order, wherein the order of some step can be put upside down or carry out simultaneously.For example, step 403 and step 404 can be put upside down and carry out, and step 404 and step 405 can be carried out or the like simultaneously.
The present invention is illustrated through the foregoing description, but should be understood that, the foregoing description just is used for for example and illustrative purposes, but not is intended to the present invention is limited in the described scope of embodiments.It will be appreciated by persons skilled in the art that in addition the present invention is not limited to the foregoing description, can also make more kinds of variants and modifications according to instruction of the present invention, these variants and modifications all drop in the present invention's scope required for protection.Protection scope of the present invention is defined by appended claims book and equivalent scope thereof.