CN205380555U - Chemical mechanical polishing device - Google Patents

Abstract

Relate to chemical mechanical polishing device, include: the polishing is dull and stereotyped, is shang mian covered by the polishing pad, the rubbing head is formed with a plurality of pressure cavities of being cut apart by a plurality of next doors, and the bottom plate of diaphragm lies in the downside of pressure cavity, through the pressure of adjust pressure cavity, makes the wafer that lies in the bottom plate downside rotated by under the pressor state, thick liquids supply portion is to at least one the supply thick liquids in polishing pad and the wafer, the first sensor, the thickness distribution of detecting wafer, and a control portio, control the chemically mechanical polishing process, thereby during carrying out the chemically mechanical polishing process till the polished surface that makes the wafer reaches predetermined first polishing thickness, the atmospheric pressure of one side adjust pressure cavity, carry out the chemically mechanical polishing process on one side, with the thickness deviation who reduces the wafer that the first sensor detected, after reaching first polishing thickness, from first polishing thickness to the target thickness till, the non -execution reduces the thickness deviation 's of wafer polishing thickness deviation adjustment, and only carry out polishing process.

Description

Chemical mechanical polishing apparatus

Technical field

This utility model relates to a kind of chemical mechanical polishing apparatus, in more detail, relates to a kind of by chemical-mechanical polishing process, oxide skin(coating) the thickness distribution of the polishing layer of the wafer formed is finished to the chemical mechanical polishing apparatus of target distribution form exactly.

Background technology

Chemically mechanical polishing (CMP) device 1 be in order in the manufacture process of semiconductor element for removing the difference in height between concavo-convex caused cell area and the peripheral circuit area of the wafer surface generated because repeatedly performing mask, etching and cabling processes etc., realize wide area planarization, and in order to improve the wafer surface roughness required along with circuit formation contact/wiring membrane separation and highly integrated element, the surface of wafer is carried out precise polished processing.

As shown in Figure 1, in this chemically mechanical polishing (CMP) device 1, rubbing head 20 in polishing process so that described wafer W is pressurizeed by polishing pad 11 state in opposite directions of the burnishing surface of wafer W and polishing flat board 10, and make described wafer W rotate, meanwhile, make polishing pad 11 also carry out rotation 11d with platform body 12 simultaneously, and perform mechanical polishing process.Further, on polishing pad 11, if slurry supplies from the supply mouth 32 of slurry supply unit 30 to polishing pad 11, then slurry flows into wafer W, and performs the chemical polishing operation of wafer W.

Meanwhile, the adjustment disk of actuator 40 pressurizes downwards, rotates 40d, and the arm 41 of described actuator 40 is while carrying out reciprocal 41d by the angle specified, while the modifying surface to polishing pad 11.

Utilize this chemical mechanical polishing apparatus 1, rotation is together carried out and the polishing layer to wafer W carries out in the process of chemically mechanical polishing, it may occur that wafer W cannot be polished uniformly and the phenomenon of deviation occurs according to the position of wafer in polishing thickness in wafer W and polishing pad 11.In order to prevent this phenomenon, as shown in Figure 1, Figure 2 shown in a, Fig. 2 b, the different radii distance multiple sensors 70,80 of configuration can be centrally located at from from polishing pad, interrupt chemical-mechanical polishing process or carry out chemical-mechanical polishing process, thus after measuring the thickness of polishing layer of wafer, the region that the thickness of polishing layer is high, rubbing head 20 presses downwards with bigger plus-pressure, thus regulating the polishing thickness deviation of the polishing layer of wafer, and can be adjusted in the way of making the thickness of the polishing layer of whole wafer become target thickness distribution.

That is, as it is shown on figure 3, the distribution being deposited with the original depth di of the polishing layer on surface in wafer W can have thickness distribution 91 big for deviation e0 according to position.Thus, if according to sensor 70,80 adjusts the thickness distribution of wafer, adjust polishing thickness deviation, and perform chemical-mechanical polishing process, the thickness deviation of the polishing layer of wafer W will be made to become the thickness distribution 92 only with the deviation e1 well below the initial stage.

But, oxide skin(coating) the polishing layer of the wafer formed can detect the thickness of polishing layer exactly when thickness is fully thick, if but the thickness of polishing layer become to be far smaller than critical thickness dc, the accuracy of the detection of the thickness of polishing layer will be reduced.This, critical thickness dc can according to the kind of the sensor used difference to some extent, if but the thickness of polishing layer becomes very little, the accuracy measuring one-tenth-value thickness 1/10 will be reduced, this is identical.

Therefore, experiments show that, adjust the thickness of polishing layer if based on the thickness measurement of the polishing layer of detection accuracy step-down, compared to the state reaching critical thickness dc, the thickness distribution 93 of the polishing layer of wafer presents bigger deviation e2 on the contrary.Therefore, it is badly in need of the polishing layer of the according to target thickness distribution wafer to being formed by oxide skin(coating) to carry out the scheme of polishing process more accurately.

Item described above is not entirely known structure, the fact that also include rediscovering to derive this utility model.

Utility model content

Solve the technical problem that

This utility model is used for solving problem as above, and the purpose of this utility model is in that, is polished the thickness distribution of the polishing layer of the wafer formed by oxide skin(coating) exactly by required distributional pattern by chemical-mechanical polishing process.

Further, the purpose of this utility model is in that, is polished the thickness distribution of the polishing layer of the wafer formed by the metal such as tungsten or copper exactly by required distributional pattern by chemical-mechanical polishing process.

Namely, the purpose of this utility model is in that, more efficiently it is suitable for the method for thickness deviation that the detection data of the thickness distribution based on wafer compensate the polishing layer of wafer, thus more exactly the thickness distribution of the polishing layer of wafer being polished by required thickness distribution.

Technical scheme

In order to realize technical problem as above, this utility model provides chemical mechanical polishing apparatus, for the polishing layer of the wafer formed by oxide material is carried out chemically mechanical polishing, it is characterised in that, including: polishing flat board, the above polished pad of described polishing flat board surrounds；Rubbing head, is formed with the multiple pressure chamber split by multiple next doors, and the base plate of barrier film is positioned at the downside of described pressure chamber, and the state carrying out pressurizeing with the described wafer being pointed to the downside of described base plate by regulating the pressure of described pressure chamber rotates；Slurry supply unit, at least one the supply slurry in described polishing pad and described wafer；First sensor, for detecting the thickness distribution of described wafer；And control portion, chemical-mechanical polishing process is controlled, thus during performing to make the burnishing surface of described wafer reach the chemical-mechanical polishing process till the first predetermined polishing thickness, while regulating the air pressure of described pressure chamber, while performing described chemical-mechanical polishing process, to reduce the thickness deviation of the described wafer of described first sensor detection, after reaching described first polishing thickness, from described first polishing thickness to target thickness, the polishing thickness not performing to reduce the thickness deviation of described wafer is deviation adjustment, and only performs polishing process.

This is in order to only by while performing chemically mechanical polishing (CMP) operation, and measure the thickness distribution of the polishing layer of wafer, and the operation adjusting the deviation of thickness distribution performs to the first predetermined polishing thickness, rather than whole chemical-mechanical polishing process is performed, for the thickness of the polishing layer thinner than the first polishing thickness, get rid of the thickness distribution of the polishing layer measuring wafer, and the operation that the deviation of thickness distribution is adjusted, and while monitoring whether polishing thickness reaches target thickness, while being polished, thus the thickness distribution of the polishing layer of wafer can be formed by more required shape based on the thickness distribution of inaccurate polishing layer.

Thus, it is possible to obtain following effect: pass through chemical-mechanical polishing process, it is possible to the thickness distribution of the polishing layer of the wafer formed by oxide skin(coating) is accurately formed into required thickness distribution form.

At this, described first sensor is formed by the plural optical sensor across different distance from the center of described wafer to radial direction, thus measuring the thickness distribution of the polishing layer of the wafer formed by oxide.

Therefore, described first sensor reflects from the surface of polishing layer reflection light and the phase contrast of the reflection light of the Same Wavelength that reflects of the boundary face from the inside for polishing layer detect the thickness distribution of the polishing layer of wafer.And, whether the polishing layer detecting wafer from the reflection light reflected by the surface of polishing layer and the boundary face from the inside for polishing layer the sinusoidal wave cyclical swing that the reflection interference of light of the Same Wavelength that described first sensor is reflected is formed reaches target thickness.

On the other hand, this utility model can also include amperometric determination portion, described amperometric determination portion is for monitoring the electric current of the motor that polishing flat board rotates driving, described polishing flat board is surrounded by described polishing pad, and described control portion detects from the current variation in described amperometric determination portion whether described control portion reaches target thickness from described first polishing thickness.Namely, resistance reflection based on the friction between polishing layer and polishing pad is presented in motor current value, and compared with the situation fully thick with the thickness of polishing layer, if the thickness of polishing layer is thinning close to target thickness, then it is laminated in the layer of inner side of the boundary face of polishing layer (such as, nitride layer) in change frictional force reflection be presented in motor current value, and hence it is also possible to by monitoring that the motor current that polishing flat board rotates driving detects whether to reach target thickness exactly.

And, till reaching the first polishing thickness, in the position that the thickness of the polishing layer of described wafer is thicker, make the plus-pressure that described wafer is pressurizeed by rubbing head higher, thus realizing this utility model.Or, in the position that the thickness of the polishing layer of wafer is thicker, the height of polishing pad is thinner, in the position that the thickness of the polishing layer of wafer is thinner, the height of polishing pad is higher, and therefore, the thickness of the polishing layer of wafer is more thick, can Adjust and use actuator pressurizes downwards larger plus-pressure, thus realizing this utility model.

After reaching the first polishing thickness, it is possible to whether the thickness of the polishing layer that the mechanical periodicity of the intensity of illumination received by optical sensor detects described wafer reaches described target thickness.I.e., it is possible to the reflection interference of light reflected of the boundary face of inside of the polishing layer by monitoring reflection light and the wafer reflected by the surface of the polishing layer of wafer and the cycle of the intensity of illumination of specific wavelength and the absolute value that are formed detect.

In parallel with this or individually, in described second polishing step, it is also possible to by the polishing flat board surrounded by described polishing pad being rotated whether the thickness of the polishing layer that the current variation of the motor of driving detects described wafer reaches described target thickness.

Till reaching described first polishing thickness, determine according to the sensitivity of the sensor of the thickness distribution of the described polishing layer detecting described wafer.That is, oxide the critical thickness that the detection accuracy of the thickness of the polishing layer of the wafer formed begins to decline is appointed as the first polishing thickness.At this, the first polishing thickness becomes different according to the material of the polishing layer formed by oxide and the kind of sensor.

And, in described first polishing step, the plus-pressure after reaching the first polishing thickness, described wafer pressurizeed can after the thickness distribution of the polishing layer of described wafer reaches required thickness distribution, and the stressed meansigma methods carrying out pressurizeing till reaching described first polishing thickness by the average thickness of the polishing layer of importing wafer realizes.

On the other hand, according to another embodiment of the present utility model, it is provided that chemical mechanical polishing apparatus, for the polishing layer of the wafer formed by metal material is carried out chemically mechanical polishing, it is characterized in that, including: polishing flat board, the above polished pad of described polishing flat board surrounds；Rubbing head, is formed with the multiple pressure chamber split by multiple next doors, and the base plate of barrier film is positioned at the downside of described pressure chamber, and the state carrying out pressurizeing with the described wafer being pointed to the downside of described base plate by regulating the pressure of described pressure chamber rotates；Slurry supply unit, at least one the supply slurry in described polishing pad and described wafer；First sensor, for detecting the thickness distribution of described wafer；And control portion, chemical-mechanical polishing process is controlled, thus in during make the burnishing surface of described wafer reach the chemical-mechanical polishing process till the first predetermined polishing thickness from described slurry supply unit supply slurry execution, while regulating the air pressure of described pressure chamber, while performing described chemical-mechanical polishing process, to reduce the thickness distribution of the described wafer of described first sensor detection, after reaching described first polishing thickness, from described first polishing thickness to target thickness, the polishing thickness not performing to reduce the thickness distribution of described wafer is deviation adjustment, and only perform polishing process.

This is in order to only by while performing chemically mechanical polishing (CMP) operation, and measure the thickness distribution of the polishing layer of wafer, and the operation adjusting the deviation of thickness distribution only carries out to the first predetermined polishing thickness, rather than whole chemical-mechanical polishing process is performed, for the thickness of the polishing layer thinner than the first polishing thickness, get rid of the thickness distribution of the polishing layer measuring wafer, and the operation that the deviation of thickness distribution is adjusted, and while monitoring whether polishing thickness reaches target thickness, while being polished, thus the thickness distribution of the polishing layer of wafer can be formed by more required shape more accurately based on the thickness distribution of inaccurate polishing layer.

Thus, it is possible to obtain following effect: pass through chemical-mechanical polishing process, it is possible to the thickness distribution of the polishing layer of the wafer formed by metal material is accurately formed into required thickness distribution form.

Described first sensor is formed by the more than one eddy current sensor across different distance from the center of described wafer to radial direction, and apply magnetic field to the polishing layer of the wafer formed by metal, thus more than any one in the inductance changed by the eddy current produced at polishing layer, reactance, electrical impedance measure the thickness distribution of the polishing layer of the wafer formed by metal.

On the other hand, this utility model can also include amperometric determination portion, described amperometric determination portion is for monitoring the electric current of the motor that polishing flat board rotates driving, described polishing flat board is surrounded by described polishing pad, and described control portion detects from the current variation in described amperometric determination portion whether described control portion reaches target thickness from described first polishing thickness.Namely, resistance reflection based on the friction between polishing layer and polishing pad is presented in motor current value, and compared with the situation fully thick with the thickness of polishing layer, if the thickness of polishing layer is thinning close to target thickness, then it is laminated in the layer of inner side of the boundary face of polishing layer (such as, nitride layer) in change frictional force reflection be presented in motor current value, and hence it is also possible to by monitoring that the motor current that polishing flat board rotates driving detects whether to reach target thickness exactly.

And, till reaching the first polishing thickness, in the position that the thickness of the polishing layer of described wafer is thicker, the plus-pressure that described wafer is pressurizeed is higher, thus adjusting polishing thickness deviation.In parallel with this or individually, in the position that the thickness of the polishing layer of wafer is thicker, the height of polishing pad is thinner, in the position that the thickness of the polishing layer of wafer is thinner, the height of polishing pad is higher, and therefore, the thickness of the polishing layer of wafer is more thick, can Adjust and use actuator pressurizes downwards larger plus-pressure, thus adjusting polishing thickness deviation.

After reaching the first polishing thickness, it is possible to whether the thickness of the polishing layer that the mechanical periodicity of the intensity of illumination received by optical sensor detects described wafer reaches described target thickness.Namely, in the period that the thickness of the polishing layer of the wafer formed by metal is thicker, the reflection light reflected on the surface of polishing layer can be maintained consistently, if but the thickness of polishing layer is thinning close to target thickness, the light then reflected on the border of the inner side of polishing layer through the surface of polishing layer is together reflected such that it is able to detect centered by the place of two optical interference signals changes.

On the other hand, in reaching the second polishing step after the first polishing thickness, it is possible to whether the thickness of the polishing layer being detected described wafer by eddy current sensor reaches described target thickness.

In parallel with this or individually, in reaching the second polishing step after the first polishing thickness, it is possible to from whether the thickness that the polishing flat board surrounded by described polishing pad rotates the polishing layer detecting described wafer the current variation of the motor of driving reaches described target thickness.Especially, the border of the inner side of the frictional force between the polishing layer and the polishing pad that are formed by metal and polishing layer is (such as, nitride layer) and polishing pad between mutually the differing greatly of frictional force, therefore, it is relatively big that the current variation value of motor presents, thus the advantage whether thickness with the polishing layer that can also be detected wafer by this exactly arrives target thickness.

In described first polishing step, described first polishing thickness determines according to the sensitivity of the sensor that the thickness distribution of the described polishing layer to described wafer detects.That is, metal the critical thickness reduced the detection accuracy of the thickness of the polishing layer of the wafer formed is appointed as the first polishing thickness.At this, the first polishing thickness becomes different according to the material of the polishing layer formed by metal and the specification of eddy current sensor.

And, in described second polishing step, the plus-pressure that described wafer is pressurizeed can in described first polishing step, after being reached required thickness distribution by the thickness distribution of the polishing layer of described wafer, the stressed meansigma methods carrying out pressurizeing till reaching described first polishing thickness by the average thickness of the polishing layer of importing wafer realizes.

The term " target thickness " being recorded in claims of this specification and utility model is defined as the thickness of the polishing layer at the time point terminating chemical-mechanical polishing process.

It is recorded in the desired thickness distribution of thickness that the term " target thickness distribution " of claims of this specification and utility model is defined as the polishing layer of the position based on wafer at the time point terminating chemical-mechanical polishing process.Generally, target thickness distribution means the distribution that the whole surface of the polishing layer relative to wafer is formed with uniform thickness, but as required, it is also possible to include specific part compared with other parts, the distribution that the thickness of polishing layer is thicker or thinner.

The effect of utility model

nullAs mentioned above，This utility model has the advantages that while performing chemically mechanical polishing (CMP) operation，The first predetermined polishing thickness of the accuracy of the sensitivity of the sensor only performed to the thickness distribution guaranteed for measuring polishing layer on one side，To replace while performing chemical-mechanical polishing process，While measuring by oxide or conductive material (such as，Metal) thickness distribution of the polishing layer of wafer that formed，And whole CMP operation is performed to adjust the operation of the deviation of thickness distribution，And for the thickness of the polishing layer being more thinner than the first polishing thickness，Get rid of the thickness distribution to the polishing layer of wafer to be measured，And adjust the operation of the deviation of thickness distribution，And be polished monitoring whether polishing thickness arrives in the process of target thickness，Thus adjusting in the process of deviation of thickness distribution in the measured value of the thickness distribution based on inaccurate polishing layer，Minimize the problem that the thickness distribution of the polishing layer of wafer form differently distortion with desired distribution，The thickness distribution that finally can make the polishing layer of the wafer of end chemical-mechanical polishing process more accurately forms and is distributed into target thickness.

And, this utility model can obtain following effect: with eliminating, the thickness distribution of the polishing layer of wafer is being measured, and the state adjusting the operation of the deviation of thickness distribution realizes in the second polishing step of chemical-mechanical polishing process, the plus-pressure that wafer is pressurizeed is by measuring the thickness distribution of the polishing layer of wafer and adjusting after the operation of deviation of thickness distribution makes the thickness distribution of polishing layer of wafer reach the thickness distribution identical with target thickness distribution, within the period maintaining this thickness distribution, pressurize with the condition that wafer and/or polishing pad are pressurizeed, so that the thickness distribution arriving the polishing layer of the wafer of the state of the first polishing thickness can also maintain former state when reaching target thickness.

Accompanying drawing explanation

Fig. 1 is the top view of the structure illustrating common chemical mechanical polishing apparatus.

Fig. 2 a is the front view of Fig. 1.

Fig. 2 b, as another kind of form, is the front view of Fig. 1.

Fig. 3 is the chart of the change of the thickness distribution of the polishing layer illustrating the wafer according to conventional cmp method.

Fig. 4 is the precedence diagram of the control method of the chemical mechanical polishing apparatus illustrating first embodiment of the present utility model successively.

Fig. 5 is the brief front view illustrating the chemical mechanical polishing apparatus according to first embodiment of the present utility model.

Fig. 6 is the top view of Fig. 5.

Fig. 7 is the enlarged drawing of " A " part of Fig. 5.

Fig. 8 a is the chart illustrating intensity of illumination that optical sensor receives according to time change.

Fig. 8 b is the figure of the principle of the thickness distribution for the polishing layer illustrating to utilize optical sensor to detect wafer.

Fig. 8 c is the figure of the principle of the target thickness for the polishing layer illustrating to utilize optical sensor to detect wafer.

Fig. 8 d is the figure for illustrating to detect the principle of the target thickness of polishing layer from the current signal driving motor of polishing flat board.

Fig. 9 is the precedence diagram of the control method illustrating the chemical mechanical polishing apparatus according to the second embodiment of the present utility model successively.

Figure 10 is the brief front view illustrating the chemical mechanical polishing apparatus according to the second embodiment of the present utility model.

Figure 11 is the top view of Figure 10.

Figure 12 is the enlarged drawing of " A " part of Figure 10.

Figure 13 a is the figure of the principle of the target thickness for the polishing layer illustrating to utilize optical sensor to detect wafer.

Figure 13 b is the figure for illustrating to detect the principle of the target thickness of polishing layer from the current signal driving motor of polishing flat board.

Figure 14 is the figure of the structure of the rubbing head of the structure of the thickness distribution deviation being shown in the polishing layer adjusting wafer shown in the first polishing step.

Figure 15 is the chart of the change of the thickness distribution of the polishing layer illustrating the wafer according to cmp method of the present utility model.

The explanation of accompanying drawing labelling

100: chemical mechanical polishing apparatus 10: polishing flat board

11: polishing pad 11a: breakthrough part

20: rubbing head 30: slurry supply unit

40: actuator 110', 110 ": optical sensor

120: control portion 130: air pressure supply unit

140: current detecting part 150: optical sensor

C1, C2, C3, C4, C5: pressure chamber W: wafer

Detailed description of the invention

Hereinafter, it is specifically described with reference to the accompanying drawing chemical mechanical polishing apparatus 100 to first embodiment of the present utility model and method (S100).Only, in the process that this utility model is illustrated, omit known function or structure for main idea clearly of the present utility model, and for same or analogous function or structure, then will give same or analogous accompanying drawing labelling.

As shown in Figures 5 and 6, oxide skin(coating) etc. is carried out, by light, the device that the layer of transmission is polished as the polishing layer of wafer by the chemical mechanical polishing apparatus 100 of first embodiment of the present utility model, and as the chemical mechanical polishing apparatus that the polishing layer of wafer W is polished, including: polishing flat board 10, the upside of platform body 12 is surrounded by polishing pad 11, described polishing pad 11, while contacting with the burnishing surface of wafer W, rotates, thus the burnishing surface of wafer is polished；Rubbing head 20, the state of burnishing surface to contact wafer on the polishing pad 111 of polishing flat board 110 is pressurizeed downwards wafer W；Actuator 40, rotates with the state to the surface-pressure adjustment disk of polishing pad 11, and polishing pad 11 is modified；Slurry supply unit 30, contacts with described surface polishing 10 in wafer W and supplies the slurry of adjusted temperature in the operation that is polished；Optical sensor 110 ', 110 ", for detecting the thickness distribution of the polishing layer of wafer in chemical-mechanical polishing process；Drive motor M, polishing flat board 10 is rotated driving；Amperometric determination portion 140, drives the motor M current value making polishing flat board 10 required when rotating by the speed specified for the real time measure；Control portion 120, from optical sensor 110 ', 110 " and amperometric determination portion 140 receive measured value to control chemical mechanical polishing apparatus；And air pressure supply unit 130, supply air pressure from pressure chamber from control portion 120 to rubbing head 20 C1, C2, C3, C4, C5.

Described polishing flat board 10 includes: platform body 12, rotates driving by driving motor M；And polishing pad 11, surround above platform body 12, and contact with the burnishing surface of wafer W, while burnishing surface is polished.Thus, polishing pad 11 rotates 11d in chemical-mechanical polishing process.

At this, according to the time, drive motor M to make polishing pad 11 rotate driving by the VELOCITY DISTRIBUTION (such as, constant speed) specified, now, amperometric determination portion 140 survey the orientation drive motors M current value applied.Generally, in chemical-mechanical polishing process, the rotary speed of polishing pad 11 is controlled as maintenance constant speed, but as required, polishing pad 11 rotary speed can include the interval of acceleration or deceleration.

As shown in figure 14, described rubbing head 20 includes: body 25, together rotates by outside rotary drive unit；The barrier film 21 of flexible materials, combines with body 25, thus between body 25, be formed with that next door 21a splits multiple pressure chamber C1, C2, C3, C4, C5；The back-up ring 26 of annular state, for surrounding around the base plate of barrier film 21.Thus, when the downside of base plate making wafer W be positioned at barrier film 21, rubbing head 20 regulates by the different interval plus-pressures imported by by multiple pressure chamber C1, the independent pressure controlled of C2 ..., and plays wafer W of pressurizeing downwards, while making the effect that wafer W rotates.

Polishing pad 11 is pressurizeed by the adjustment disk contacted with polishing pad 11 and rotates by described actuator 40, moves to the direction with radius composition of polishing pad 11 by arm.Now, according to by optical sensor 110 ', 110 " carry out the thickness distribution of the polishing layer of the wafer W of the real time measure; polishing pad 11 is pressurizeed with relatively low plus-pressure by actuator 30 in the thicker part of the thickness of the polishing layer of wafer W; with higher plus-pressure, polishing pad 11 is pressurizeed in the part of the thinner thickness of the polishing layer of wafer W; adjust the frictional force of height tolerance based on polishing pad 11, thus preventing the unbalanced polishing of wafer W.

Described slurry supply unit 30 supplies slurry by supplying mouth 32 to polishing pad 11, induces the chemical polishing of wafer.

As shown in the figure, described optical sensor can measure the thickness of the polishing layer of wafer W constantly by the optical sensor 110 ' of the downside of the breakthrough part 11a being positioned at through polishing pad 11 and platform body 12, and can whenever the downside through wafer W, by optical sensor 110 " measure the thickness of the polishing layer of wafer W, described optical sensor 110 " position be fixed on polishing pad 11 and rotate together with polishing pad 11.

In accompanying drawing though it is shown that optical sensor 110 ', 110 " structure that independently forms with illuminating part 110, light accepting part 115, but in other embodiments of the present utility model, illuminating part 110 and light accepting part 115 can be formed by a main body.Further, though it is shown that the light irradiated from optical sensor is relative to the polishing layer ly of the wafer W structure being irradiated obliquely in accompanying drawing, but the gradient relative to polishing layer ly can be adjusted in many ways.

When by optical sensor 110 ', 110 " measure the thickness of polishing layer of wafer W time; as shown in Figure 8 b; incident illumination Li has phase contrast x1 at the surface Yo of the polishing layer reflection light Lo1 reflected and the intensity reflecting light Lo2 reflect at the inner side edge interface Yx of polishing layer; and from described phase contrast x1, try to achieve the thickness of polishing layer in the polishing layer of the wafer of incident illumination such that it is able to try to achieve the thickness distribution of wafer.

Like this, by optical sensor 110 ', 110 " come the mode of the thickness distribution of the real time measure wafer be continued until for ensure optical sensor 110 ', 110 " the thickness of polishing layer ly of wafer of accuracy of measurement reach the first polishing thickness (such asExtremely) till.

On the other hand, in chemical-mechanical polishing process, the thickness of the polishing layer ly of wafer W can reduce according to polishing, thus, at the surface Y of the polishing layer ly of the wafer W reflection light Lo1 reflected with in the inner side edge interface Yx of the polishing layer reflection light Lo2 reflected generation optical path difference, and interfere because of wavelength.Thus, the reflection light Lo1 reflected and the spacing d reflecting light Lo2 reflected at the inner side edge interface Yx of polishing layer can change constantly.That is, in the thickness to of the polishing layer ly at polishing initial stage, big at the surface Yo of the polishing layer ly reflection light Lo1 ' reflected and the path difference between the boundary face Yx being positioned at the layer Wo of inner side of the polishing layer reflection light Lo2 ' reflected.And, the thickness making polishing layer ly if carried out polishing process is thinning further, then taper at the surface Y of the polishing layer ly reflection light Lo1 reflected and the path difference between the inner side edge interface Yx of the polishing layer reflection light Lo2 reflected, and interfere.Thus, two adjacent reflection light Lo1, Lo2；Lo1 ', Lo2 ' interfere with each other, and form sinusoidal wave intensity of illumination waveform X in the way of as shown in Figure 8 c.

Therefore, two adjacent reflection light Lo1, Lo2；The sinusoidal wave X of the intensity of illumination that Lo1 ', Lo2 ' interfere with each other comprises the thickness information of the polishing layer ly of wafer W.And, reach in the time point of target thickness de at the thickness of the polishing layer ly of wafer W, empirically grasp the position by the sinusoidal wave X reflecting interference of light, thus detection reaches the target thickness de of polishing layer ly.

Now, as shown in Figure 8 a, intensity of illumination by the interference of light according to wavelength is distributed the variation according to polished amount (polishing time), have and cataclysmal wavelength band f1 occurs and the wavelength band f2 of little variation occurs, and select to occur cataclysmal wavelength band f1 can grasp the polishing arriving target thickness de more exactly and terminate time point.

For example, it is possible to by the position Pc of the trough under the state in twice cycle or thus the detection of the position Pc1 under the state of appointment time tx terminate time point for polishing.

On the other hand, can based on whether the thickness of the polishing layer detecting wafer W to the variation value driving the motor M electric current applied for polishing flat board 10 rotates driving reaches target thickness de.This is when the polishing layer ly thickness of wafer W is fully thick, friction by polishing layer ly and polishing pad 11 produces to drive the rotational resistance of motor M, but in removing the process of polishing layer ly thickness of wafer W, the rotational resistance driving motor M can be produced impact by the material of the layer Wo being positioned at the downside of polishing layer ly.

Such as, compared with polishing layer ly, it is positioned in the less situation of hardness of layer on the border of described polishing layer ly, as shown in figure 8d, if the thickness of polishing layer reaches near target thickness de, then the interval that frictional force will be occurred sharply to reduce.Therefore, minimizing along with frictional force, for making driving motor M by the speed specified (such as, constant speed) drive required electric current to reduce, therefore, it can the place shown in the Pc of Fig. 8 d or the place Pc1 detection thus by additional time tx size obtaining further polishing for terminating the target thickness de of time point as polishing.

Or, it is also possible to after reaching the first polishing thickness, performing chemical-mechanical polishing process by the polishing condition specified in the appointment time of grasp after carrying out experiment repeatedly, whether the thickness of the polishing layer thus grasping wafer W arrives target thickness de.

Described control portion 120 supplies pressure chamber from controlled air pressure to rubbing head 20 C1, C2, C3, C4, C5, if so that in chemical-mechanical polishing process from optical sensor 110 ', 110 " receive the thickness distribution of polishing layer ly of wafer W, then made the thickness distribution of the polishing layer ly of wafer W become target thickness distribution by air pressure supply unit 130.Meanwhile, the adjustment disk of actuator 40 is for the thicker region of the thickness of the polishing layer of wafer, with less plus-pressure, polishing pad 11 is pressurizeed, for wafer polishing layer thinner thickness region for, with higher plus-pressure, polishing pad 11 is pressurizeed, so that the machine glazed finish of polishing pad 11 and wafer W polishing layer ly produces difference.

And, if the thickness distribution of the polishing layer of wafer becomes target thickness distribution before reaching the first polishing thickness dc, then control portion 120 controls air pressure supply unit 130 and actuator 40 in the way of making the thickness distribution of the polishing layer of wafer W maintain target thickness distribution, and records the pressurized conditions during this.Like this, it is performed continuously over the first polishing step for performing chemical-mechanical polishing process, until the meansigma methods of the thickness distribution of the polishing layer of wafer reaches the first predetermined polishing thickness.

Then, if the meansigma methods of the thickness distribution of the polishing layer of wafer reaches the first predetermined polishing thickness (such asExtremely), then by optical sensor and measure, by phase contrast, the probability that the thickness distribution aspect of polishing layer comprises error and start to uprise, therefore, get rid of the thickness distribution measuring wafer and correct the operation of thickness distribution.And, control portion 120 is controlled in the way of performing the second polishing step, described second polishing step is while maintaining the condition (plus-pressure condition) controlling air pressure the supply unit 130 and actuator 40 maintaining the thickness distribution of the polishing layer of wafer W with target thickness distribution in the first polishing step, while performing polishing, until the thickness of the polishing layer of wafer reaches target thickness de.

Hereinafter, the cmp method S100 utilizing the chemical mechanical polishing apparatus 100 constituted in the manner is described in detail.

Step 1: the polishing layer ly of the wafer formed by oxide carries out rotation 20d with the state contacted with polishing pad 11, while making polishing pad 11 rotate 11d, while supply slurry with the state of wafer W of pressurizeing downwards from slurry supply unit 30 by rubbing head 20, and the polishing layer ly for wafer W performs chemical-mechanical polishing process (S110).

Till first polishing step of step S110 is continued for reaching the first polishing thickness, described first polishing thickness be designated as from the original depth do of the polishing layer ly of wafer cannot by optical sensor 110 ', 110 " carry out the critical thickness dc of Accurate Determining polishing thickness distribution.

Step 2: within the period carrying out the first polishing step S110, by multiple optical sensors 110 ' of different radii position of downside of the breakthrough part 11a being configured at polishing pad 11 or be configured at multiple optical sensors 110 of different radii position of polishing pad 11 ", the thickness distribution (S120) of the polishing layer ly of the real time measure wafer in the phase contrast x1 of the surface Y of polishing layer ly of wafer and reflection light Lo1, Lo2 of the border Yx reflection of the inside of polishing layer.

Step 3: control portion 120 from optical sensor 110 ', 110 " receive the thickness profile data of polishing layer ly of wafer, and adjust air pressure supply unit 130 and actuator 40 (S130) in the way of removing the difference between the thickness profile data measured and target thickness distribution.

That is, compared with being distributed with target thickness, in the part than other position relative thick in the thickness of the polishing layer of wafer W, to the air pressure that pressure chamber's supply of the upside of the part being positioned at thickness is higher, so that by thick part, polishing pad 11 can be stressed on high plus-pressure.And, compared with being distributed with target thickness, in the part than other position relative thin in the thickness of the polishing layer of wafer W, the pressure chamber to the upside being positioned at thin part supplies less air pressure, so that by thin part, polishing pad 11 can be stressed on low plus-pressure.Thus, the thickness distribution of the polishing layer ly of wafer guided before reaching the first polishing thickness and is distributed for target thickness.

For this, add or independence ground, control portion 120 is according to by optical sensor 110 ', 110 " thickness distribution of the polishing layer of the wafer W of the real time measure is carried out, come in the part of the thickness thickness of the polishing layer of wafer W, polishing pad 11 is pressurizeed with less plus-pressure by actuator 40, thus guiding the height of polishing pad 11 in the way of higher, and in the part that the thickness of the polishing layer of wafer W is thin, with bigger plus-pressure, polishing pad 11 is pressurizeed, thus inducing the height of polishing pad 11 in the way of relatively low, thus in the region that the height of polishing pad 11 is high, with the frictional force in the region low higher than the height of polishing pad 11, the polishing layer ly of wafer is carried out machine glazed finish, thus compared with being distributed with target thickness, remove the thickness distribution deviation pressing diverse location.

Step 4: step 1 to step 3 is continued until that the thickness of the polishing layer ly of wafer reaches the first polishing thickness dc.And, if the thickness of polishing layer on average reaches the first polishing thickness dc, with regard to interrupt step 2 and step 3 (S140).

Step 5: by step 4, although getting rid of the active control of feedback making the thickness matching of wafer polishing layer ly be distributed in target thickness, but within the period carrying out the first polishing step, before the thickness of the polishing layer of wafer reaches the first polishing thickness, maintain the polishing condition (according to the plus-pressure of the polishing pad position of the actuator imported to polishing pad and rubbing head by the supply air pressure etc. of different pressures chamber) being maintained in target thickness distribution, and continuously carry out the chemical-mechanical polishing process (S150) as the second polishing step.

Now, although the second polishing step S150 can also perform on other polishing pads 11 be not carried out the first polishing step S110, but consider process efficiency, even if performing on identical polishing pad 11, it is also possible to obtain high polishing quality.

Meanwhile, it is also possible to from based on whether sinusoidal wave intensity of illumination signal (Fig. 8 c) of the interference optical sensor and the polishing layer ly for polishing flat board 10 rotates current waveform signal (Fig. 8 d) the middle detection wafer driving motor of driving reach target thickness de.And, if the polishing layer ly being detected as wafer reaches target thickness de, then terminate the second polishing step.

Thus, as shown in figure 15, when reaching the first polishing thickness dc, the thickness distribution 92 of the polishing layer of wafer maintains in the way of similar to target polished distribution (dotted line), and in second polishing step corresponding with the interval of the first polishing thickness dc to target thickness de, get rid of step 2 and step 3, and within the period performing the first polishing step, maintain and before the thickness of polishing layer of wafer reaches the first polishing thickness, maintain into target thickness distribution polishing condition (according to the plus-pressure of the polishing pad position of the actuator imported to polishing pad and rubbing head by the supply air pressure etc. of different pressures chamber), thus, error e 2' between final polishing thickness distribution 903 and target thickness distribution can be obtained well below conventional effect.

nullLike this，The sensitivity of the sensor of the thickness distribution according to the polishing layer measuring wafer，Sensor 110' is guaranteed for benchmark reaching with the first polishing thickness dc、In the first polishing step till the first predetermined polishing thickness dc of sensitivity and high accuracy 110 "，The cmp method S100 of the present utility model constituted in the manner and chemical mechanical polishing apparatus 100 perform to measure polishing thickness and are distributed the operation being corrected，And in the second polishing step more than the first polishing thickness dc，The cmp method S100 of the present utility model constituted in the manner and chemical mechanical polishing apparatus 100 discharge mensuration and the correcting process of polishing thickness distribution，Thus adjusting in the process of deviation of thickness distribution in the measured value of the thickness distribution based on inaccurate polishing layer，Minimize the distortion that the thickness distribution of the polishing layer of wafer form differently with desired distribution，The thickness distribution that may finally obtain the polishing layer of the wafer by terminating chemical-mechanical polishing process is formed as the beneficial effect of target thickness distribution more accurately.

And, this utility model can obtain following effect: in the parameter of the chemical-mechanical polishing process in the second polishing step is controlled, after the thickness distribution of the polishing layer of wafer reaches the thickness distribution identical with target thickness distribution, within the period maintaining described thickness distribution, pressurize with the polishing condition in the first polishing step that wafer and/or polishing pad are pressurizeed, thus the thickness distribution of the polishing layer of the wafer of the state reaching the first polishing thickness can also be maintained in the second polishing step, polishing thickness distribution more accurately may finally be obtained.

Hereinafter, it is specifically described with reference to the accompanying drawing chemical mechanical polishing apparatus 100 to the second embodiment of the present utility model and cmp method S100.Only, in the process that the second embodiment of the present utility model is illustrated, for the structure same or like or corresponding with the structure of described first embodiment, give same or similar accompanying drawing labelling, such that it is able to be clearly understood that the main idea of the second embodiment.

As shown in Figures 10 and 11, the chemical mechanical polishing apparatus 100 of the second embodiment of the present utility model as the polishing layer of wafer to metal level etc cannot the device that is polished of the layer of the conductive material of transmission light swimmingly, including: polishing flat board 10, the polished pad 11 in upside of platform body 12 surrounds, described polishing pad 11 contacts with the burnishing surface of wafer W and rotates, and the burnishing surface of wafer is polished；Rubbing head 20, pressurizes downwards to wafer W with the state contacted on the polishing pad 111 of polishing flat board 110 with the burnishing surface of wafer；Actuator 40, rotates with the state of the surface-pressure adjustment disk at polishing pad 11, and polishing pad 11 is modified；Slurry supply unit 30, wafer W contact with described polishing flat board 10 and in the operation that is polished supply regulate temperature after slurry；Eddy current sensor 110, for detecting the thickness distribution of the polishing layer of the wafer performing chemical-mechanical polishing process；Drive motor M, for polishing flat board 10 is rotated driving；Amperometric determination portion 140, when driving motor M to make polishing flat board 10 rotate by the speed specified, the current value needed for the real time measure；Multiple optical sensors 150, are arranged at different radii distance in polishing pad 11；Control portion 120, receives measured value from eddy current sensor 110, optical sensor 150 and amperometric determination portion 140, controls chemical mechanical polishing apparatus；And air pressure supply unit 130, supply air pressure from pressure chamber from control portion 120 to rubbing head 20 C1, C2, C3, C4, C5.

Described polishing flat board 10 includes: platform body 12, rotates driving by driving motor M；And polishing pad 11, surround above platform body 12, and contact with the burnishing surface of wafer W, while burnishing surface is polished.Thus, polishing pad 11 rotates 11d in chemical-mechanical polishing process.

At this, according to the time, drive motor M to make polishing pad 11 rotate driving by the VELOCITY DISTRIBUTION (such as, constant speed) specified, now, amperometric determination portion 140 survey the orientation drive motors M current value applied.Generally, in chemical-mechanical polishing process, the rotary speed of polishing pad 11 is controlled as maintenance constant speed, but as required, polishing pad 11 rotary speed can include the interval of acceleration or deceleration.

As shown in figure 14, described rubbing head 20 includes: body 25, together rotates by outside rotary drive unit；The barrier film 21 of flexible materials, combines with body 25, thus between body 25, be formed with that next door 21a splits multiple pressure chamber C1, C2, C3, C4, C5；The back-up ring 26 of annular state, for surrounding around the base plate of barrier film 21.Thus, when the downside of base plate making wafer W be positioned at barrier film 21, rubbing head 20 regulates the plus-pressure by different importings by by the pressure of multiple pressure chamber C1, the independent control of C2 ..., and plays wafer W of pressurizeing downwards, while making the effect that wafer W rotates.

Polishing pad 11 is pressurizeed by the adjustment disk contacted with polishing pad 11 and rotates by described actuator 40, moves to the direction with radius composition of polishing pad 11 by arm.Now, according to by eddy current sensor 110 or optical sensor 110 ', 110 " carry out the thickness distribution of the polishing layer of the wafer W of the real time measure; polishing pad 11 is pressurizeed with relatively low plus-pressure by actuator 30 in the thicker part of the thickness of the polishing layer of wafer W; with higher plus-pressure, polishing pad 11 is pressurizeed in the part of the thinner thickness of the polishing layer of wafer W; adjust the frictional force of height tolerance based on polishing pad 11, thus preventing the unbalanced polishing of wafer W.

Described slurry supply unit 30 supplies slurry by supplying mouth 32 to polishing pad 11, induces the chemical polishing of wafer.

As shown in the figure, described eddy current sensor 110 is positioned at the downside of the breakthrough part 11a of through polishing pad 11 and platform body 12, electromagnetic signal is applied, thus generating the eddy current based on magnetic field at polishing layer to the polishing layer ly of the wafer W formed by the metal as conductive material.Thus, the reactance of electromagnetic force that applies from eddy current sensor 110 by eddy current, electrical impedance, inductance etc. can the together changes according to the variation of the thickness of the polishing layer of the wafer W formed by metal, therefore, it can the amplitude of the electromagnetic force from change and phase contrast etc. measure the thickness of the polishing layer formed by metal.

As shown in figure 11, eddy current sensor 110 be arranged at breakthrough part 11a to the radial direction of wafer mutually across multiple position Sx, thus measuring the thickness distribution detecting polishing layer according to the thickness of the polishing layer of wafer W position in real time.

On the other hand, eddy current sensor 110 not only detects the thickness distribution of the polishing layer of wafer, but also whether the polishing layer detecting wafer reaches target thickness.Only, if the lower thickness that eddy current sensor 110 is according to specification polishing layer, then the eddy current because being formed at metal level is irregular and reduce the detection accuracy of the thickness of polishing layer.Therefore, it can the measured value of the meansigma methods based on the measured value except plural eddy current sensor 110 or maximum and minima decide whether to become the target thickness terminating time point as polishing.

As shown in figure 11, described optical sensor 150 is fixed on polishing pad 11 and together rotates with polishing pad 11, and whenever the downside through wafer W, whether the polishing layer of detection wafer W reaches target thickness.Although accompanying drawing is not shown, but when breakthrough part 11a is sufficiently large, optical sensor 150 may be located at the downside of breakthrough part 11a.

Generally, as shown in figure 12, under the situation to that the thickness of polishing layer ly is fully thick, in the polishing layer ly formed by metal, owing to the incident illumination Li of optical sensor 150 all carries out reflection Lo' at the surface Yo of polishing layer, therefore, even if receiving reflection light Lo', the thickness information of medal polish layer ly cannot also be obtained.But, in the polishing layer ly of the wafer process worn and torn, thickness t can be removed, and make a part of the incident illumination Li of optical sensor 150 carry out reflection Lo1 at the surface Y of polishing layer, but other parts can in polishing layer refraction and through afterwards, reflect at the border Yx of other layers (such as, nitride, Wo) of the inner side of polishing layer ly.

Namely, even if chemically the initial stage of mechanical polishing process proceeds by polishing process, also the thickness information of polishing layer ly cannot be obtained in the light accepting part of optical sensor 150, if but the lower thickness of the polishing layer ly of wafer, become able to reach the degree of target thickness de, then as depicted in fig. 13 a, two the reflection light reflected in different surfaces relative to a wavelength interfere, and obtain the signal X of sharply change.Thus, can based on the point of inflection Pc of the holding wire steeply risen or start the experimental data repeatedly that the thickness proceeding the polishing layer of the polishing of appointment time tx is corresponding with the target thickness of the polishing layer ly of wafer from described point of inflection Pc, the polishing of the target thickness detecting the polishing layer ly reaching wafer exactly terminates time point.

On the other hand, can based on whether the thickness of the polishing layer detecting wafer W to the variation value driving the motor M electric current applied for polishing flat board 10 rotates driving reaches target thickness de.When the polishing layer ly thickness of wafer W is fully thick, this can produce to drive the rotational resistance of motor M by the friction of the polishing layer ly of metal material and polishing pad 11, if but the polishing layer ly lower thickness of wafer W, then it is positioned at the layer of downside of polishing layer ly (such as, nitride, Wo) material the rotational resistance driving motor M can be produced impact.

Especially, the polishing layer ly of the wafer formed by metal and polishing pad present high frictional behavior, therefore, when the thickness of polishing layer ly is fully thick, only can also produce to make polishing flat board rotate the resistance driven by the contact of metal and polishing pad, if but the lower thickness of polishing layer ly, friction is produced impact by the rigidity or the elastic meeting that are then positioned at the nitride layer of the inner side of the polishing layer ly of metal material, and by less frictional force to generation effect between wafer W and polishing pad 11, thus presenting for making polishing flat board 10 by the speed specified (such as, constant speed) rotate the signal Sm of the motor current value needed for the driving tendency sharply declined.

Therefore, along with the polishing layer ly of wafer and the frictional force of polishing pad 11 reduce, can for making driving motor M by the speed specified (such as, constant speed) to be driven the time point that required electric current reduces be benchmark, it is possible to using the place shown in the Pc of Figure 13 b or thus obtain the place Pc1 of polishing by additional time tx size further and detect into the target thickness de terminating time point as polishing.

Or, it is possible to after reaching the first polishing thickness, by repeatedly testing in the appointment time grasped with specified polishing condition to perform chemical-mechanical polishing process, whether the thickness of the polishing layer that thus can detect wafer W reaches target thickness de.

If in chemical-mechanical polishing process, receive the thickness distribution of the polishing layer ly of wafer W from eddy current sensor 110, described control portion 120 just can supply, to pressure chamber C1, C2, C3, C4, C5 of rubbing head 20, the air pressure being controlled in the way of to be made the thickness distribution of the polishing layer ly of wafer W reach target thickness distribution by air pressure supply unit 130.Meanwhile, the region that the adjustment disk of actuator 40 is thick relative to the thickness of the polishing layer of wafer, with less plus-pressure, polishing pad 11 is pressurizeed, the region thin relative to the thickness of the polishing layer of wafer, with higher plus-pressure, polishing pad 11 is pressurizeed, so that the machine glazed finish of the polishing layer ly of polishing pad 11 and wafer W produces difference.

And, if becoming target thickness distribution before the thickness distribution of the polishing layer of wafer reaches the first polishing thickness dc, control portion 120 just controls air pressure supply unit 130 and actuator 40 so that the thickness distribution of the polishing layer of wafer W maintains target thickness distribution, and records the pressurized conditions during this.Like this, it is performed continuously over the first polishing step for performing chemical-mechanical polishing process, until the meansigma methods of the thickness distribution of the polishing layer of wafer reaches the first predetermined polishing thickness.

Then, if the meansigma methods of the thickness distribution of the polishing layer of wafer reaches the first predetermined polishing thickness (such asExtremely), then measure, by eddy current sensor, the probability that the thickness distribution aspect of polishing layer comprises error and start to uprise, therefore, get rid of the thickness distribution measuring wafer and correct the operation of thickness distribution.And, control portion 120 is controlled in the way of performing the second polishing step, described second polishing step is while maintaining the condition (plus-pressure condition) controlling air pressure the supply unit 130 and actuator 40 maintaining the thickness distribution of the polishing layer of wafer W with target thickness distribution in the first polishing step, while performing polishing, until the thickness of the polishing layer of wafer reaches target thickness de.

Hereinafter, the cmp method S100 utilizing the chemical mechanical polishing apparatus 100 constituted in the manner is described in detail.

Step 1: the polishing layer ly of the wafer formed by metal material carries out rotation 20d with the state contacted with polishing pad 11, while making polishing pad 11 rotate 11d, while supply slurry with the state of wafer W of pressurizeing downwards from slurry supply unit 30 by rubbing head 20, and the polishing layer ly for wafer W performs chemical-mechanical polishing process (S110).

Till first polishing step of step S110 is continued for reaching the first polishing thickness, described first polishing thickness is designated as the critical thickness dc that cannot carry out the distribution of Accurate Determining polishing thickness from the original depth do of the polishing layer ly of wafer by eddy current sensor 110.

Step 2: within the period carrying out the first polishing step S110, multiple eddy current sensors 110 of different radii position by the downside of the breakthrough part 11a being configured at polishing pad 11, and by being formed at the variation of more than the electrical impedance caused by eddy current on surface of polishing layer ly of the wafer formed by metal and any one in inductance, carry out the thickness distribution (S120) of the polishing layer ly of the real time measure wafer.

Step 3: control portion 120 receives the thickness profile data of the polishing layer ly of wafer from eddy current sensor 110, and adjusts air pressure supply unit 130 and actuator 40 (S130) in the way of removing the difference between the thickness profile data measured and target thickness distribution.

That is, compared with being distributed with target thickness, in the part than other position relative thick in the thickness of the polishing layer of wafer W, to the air pressure that pressure chamber's supply of the upside of the part being positioned at thickness is higher, so that by thick part, polishing pad 11 can be stressed on high plus-pressure.And, compared with being distributed with target thickness, in the part than other position relative thin in the thickness of the polishing layer of wafer W, the pressure chamber to the upside being positioned at thin part supplies less air pressure, so that by thin part, polishing pad 11 can be stressed on low plus-pressure.Thus, the thickness distribution of the polishing layer ly of wafer guided before reaching the first polishing thickness and is distributed for target thickness.

For this, add or independence ground, the control portion 120 thickness distribution according to the polishing layer of the wafer W carrying out the real time measure by eddy current sensor 110, come in the part of the thickness thickness of the polishing layer of wafer W, polishing pad 11 is pressurizeed with less plus-pressure by actuator 40, thus guiding the height of polishing pad 11 in the way of higher, and in the part that the thickness of the polishing layer of wafer W is thin, with bigger plus-pressure, polishing pad 11 is pressurizeed, thus inducing the height of polishing pad 11 in the way of relatively low, thus in the region that the height of polishing pad 11 is high, with the frictional force in the region low higher than the height of polishing pad 11, the polishing layer ly of wafer is carried out machine glazed finish, thus compared with being distributed with target thickness, remove the thickness distribution deviation pressing diverse location.

Step 4: step 1 to step 3 is continued until that the thickness of the polishing layer ly of wafer reaches the first polishing thickness dc.And, if the thickness of polishing layer on average reaches the first polishing thickness dc, with regard to interrupt step 2 and step 3 (S140).

Step 5: by step 4, although getting rid of the active control of feedback making the thickness matching of wafer polishing layer ly be distributed in target thickness, but within the period carrying out the first polishing step, before the thickness of the polishing layer of wafer reaches the first polishing thickness, maintain the polishing condition (according to the plus-pressure of the polishing pad position of the actuator imported to polishing pad and rubbing head by the supply air pressure etc. of different pressures chamber) being maintained in target thickness distribution, and continuously carry out the chemical-mechanical polishing process (S150) as the second polishing step.

Now, although the second polishing step S150 can also perform on other polishing pads 11 be not carried out the first polishing step S110, but consider process efficiency, even if performing on identical polishing pad 11, it is also possible to obtain high polishing quality.

Meanwhile, it is also possible to from intensity of illumination signal (Figure 13 a) of optical sensor with for making whether the polishing layer ly that polishing flat board 10 rotates more than any one current waveform signal (Figure 13 b) driving motor of driving detection wafer reaches target thickness de.And, if be detected that the polishing layer ly of wafer reaches target thickness de, just terminate the second polishing step.

Thus, as shown in figure 15, when reaching the first polishing thickness dc, the thickness distribution 92 of the polishing layer of wafer maintains in the way of similar to target polished distribution (dotted line), and in second polishing step corresponding with the interval of the first polishing thickness dc to target thickness de, get rid of step 2 and step 3, and within the period performing the first polishing step, maintain and before the thickness of polishing layer of wafer reaches the first polishing thickness, maintain into target thickness distribution polishing condition (according to the plus-pressure of the polishing pad position of the actuator imported to polishing pad and rubbing head by the supply air pressure etc. of different pressures chamber), thus, error e 2' between final polishing thickness distribution 903 and target thickness distribution can be obtained well below conventional effect.

nullLike this，The sensitivity of the sensor of the thickness distribution according to the polishing layer measuring the wafer formed by metal，With the first polishing thickness dc for the benchmark the first polishing step till reaching to guarantee the first predetermined polishing thickness dc of the sensitivity and high accuracy of first sensor 110，The cmp method S100 of the present utility model constituted in the manner and chemical mechanical polishing apparatus 100 perform to measure polishing thickness and are distributed the operation being corrected，And in the second polishing step more than the first polishing thickness dc，The cmp method S100 of the present utility model constituted in the manner and chemical mechanical polishing apparatus 100 discharge mensuration and the correcting process of polishing thickness distribution，Thus adjusting in the process of deviation of thickness distribution in the measured value of the thickness distribution based on inaccurate polishing layer，Minimize the distortion that the thickness distribution of the polishing layer of wafer form differently with desired distribution，The thickness distribution that may finally obtain the polishing layer of the wafer by terminating chemical-mechanical polishing process is formed as the beneficial effect of target thickness distribution more accurately.

And, this utility model can obtain following effect: in the parameter of the chemical-mechanical polishing process in the second polishing step is controlled, after the thickness distribution of the polishing layer of wafer reaches the thickness distribution identical with target thickness distribution, within the period maintaining described thickness distribution, pressurize with the polishing condition in the first polishing step that wafer and/or polishing pad are pressurizeed, thus the thickness distribution of the polishing layer of the wafer of the state reaching the first polishing thickness can also be maintained in the second polishing step, polishing thickness distribution more accurately may finally be obtained.

Above; although describing preferred embodiment of the present utility model in the way of exemplary; but protection domain of the present utility model is not limited to specific embodiment as above, and can be by this utility model person of an ordinary skill in the technical field and carry out suitable change in the category described in utility model protection scope of the present utility model.

Claims (9)

1. a chemical mechanical polishing apparatus, for the polishing layer of the wafer formed by oxide material is carried out chemically mechanical polishing, it is characterised in that including:

Polishing flat board, above polished pad cover；

Rubbing head, is formed with the multiple pressure chamber split by multiple next doors, and the base plate of barrier film is positioned at the downside of described pressure chamber, by regulating the pressure of described pressure chamber, makes the described wafer being positioned at the downside of described base plate rotate when pressurized；

Slurry supply unit, at least one the supply slurry in described polishing pad and described wafer；

First sensor, for detecting the thickness distribution of described wafer；And

Control portion, chemical-mechanical polishing process is controlled, thus during performing to make the burnishing surface of described wafer reach the chemical-mechanical polishing process till the first predetermined polishing thickness, while regulating the air pressure of described pressure chamber, while performing described chemical-mechanical polishing process, to reduce the thickness deviation of the described wafer of described first sensor detection, after reaching described first polishing thickness, from described first polishing thickness to target thickness, the polishing thickness not performing to reduce the thickness deviation of described wafer is deviation adjustment, and only performs polishing process.

2. chemical mechanical polishing apparatus according to claim 1, it is characterised in that

Described first sensor is, from the center of described wafer to radial direction across the plural optical sensor of different distance.

3. chemical mechanical polishing apparatus according to claim 1, it is characterised in that

Described first sensor is the optical sensor for detecting the state reaching described target thickness.

4. chemical mechanical polishing apparatus according to claim 1, it is characterised in that

Also including amperometric determination portion, described amperometric determination portion is for monitoring the electric current of the motor that polishing flat board rotates driving, and described polishing flat board is covered by described polishing pad,

By the current variation in described amperometric determination portion, described control portion detects whether described control portion reaches target thickness from described first polishing thickness.

5. a chemical mechanical polishing apparatus, for the polishing layer of the wafer formed by metal material is carried out chemically mechanical polishing, it is characterised in that including:

Polishing flat board, above polished pad cover；

Rubbing head, is formed with the multiple pressure chamber split by multiple next doors, and the base plate of barrier film is positioned at the downside of described pressure chamber, by regulating the pressure of described pressure chamber, makes the described wafer being positioned at the downside of described base plate rotate when pressurized；

Slurry supply unit, at least one the supply slurry in described polishing pad and described wafer；

First sensor, for detecting the thickness distribution of described wafer；And

Control portion, chemical-mechanical polishing process is controlled, thus in during make the burnishing surface of described wafer reach the chemical-mechanical polishing process till the first predetermined polishing thickness from described slurry supply unit supply slurry execution, while regulating the air pressure of described pressure chamber, while performing described chemical-mechanical polishing process, to reduce the thickness distribution of the described wafer of described first sensor detection, after reaching described first polishing thickness, from described first polishing thickness to target thickness, the polishing thickness not performing to reduce the thickness distribution of described wafer is deviation adjustment, and only perform polishing process.

6. chemical mechanical polishing apparatus according to claim 5, it is characterised in that

Described first sensor is, from the center of described wafer to radial direction across the more than one eddy current sensor of different distance.

7. chemical mechanical polishing apparatus according to claim 5, it is characterised in that

Described first sensor is the eddy current sensor for detecting the state reaching described target thickness.

8. chemical mechanical polishing apparatus according to claim 5, it is characterised in that

Also include the second sensor, described second sensor is sensed by reaching the optical sensor of the state of described target thickness and is formed, and the intensity of illumination change that described second sensor receives when reaching target thickness according to the thickness of described polishing layer detects the state reaching described target thickness.

9. chemical mechanical polishing apparatus according to claim 5, it is characterised in that

Also including motor current determination part, described motor current determination part is for monitoring the electric current of the motor that polishing flat board rotates driving, and described polishing flat board is covered by described polishing pad,

By the current variation in described amperometric determination portion, described control portion detects whether described control portion reaches target thickness from described first polishing thickness.