JP3916846B2 - Substrate polishing apparatus and substrate polishing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a substrate polishing apparatus and a substrate polishing method for polishing a metal thin film formed on a substrate surface used particularly in a process of forming a metal wiring such as Cu in a semiconductor device manufacturing process.
[0002]
[Prior art]
  As the degree of integration of semiconductor devices increases, it is required to use a material having higher conductivity as a material for forming a wiring circuit. In response to this requirement, a copper or high-conductivity thin film is formed by plating on the surface of the substrate on which the wiring pattern grooves and holes are formed, and the wiring pattern grooves and holes are filled with a polishing apparatus. A method of polishing and removing the alloy by chemical mechanical polishing (CMP) is attracting attention.
[0003]
  As shown in FIG. 1A, the semiconductor substrate W is made of SiO on the conductive layer 101a formed on the semiconductor substrate 101 on which the semiconductor element is formed.₂An insulating film 102 is deposited, a contact hole 103 and a wiring groove 104 are formed by lithography / etching technique, a barrier layer 105 made of TiN or the like, and a power supply seed layer 107 for electrolytic plating are formed thereon. Has been.
[0004]
  Then, as shown in FIG. 1B, the surface of the semiconductor substrate W is plated with copper, so that the contact holes 103 and the grooves 104 of the semiconductor substrate 101 are filled with Cu, and the Cu is formed on the insulating film 102. A plating film layer 106 is deposited. Thereafter, the Cu plating film layer 106 on the insulating film 102 is removed by chemical mechanical polishing, and the surface of the Cu plating film layer 106 filled in the contact hole 103 and the wiring groove 104 and the surface of the insulating film 102 Are almost coplanar. Thereby, a wiring made of the Cu plating film layer 106 as shown in FIG. 1C is formed.
[0005]
  When the barrier layer 105, the power feeding seed layer 107, and the Cu plating film layer 106, which are a plurality of types of films formed on the insulating film 102, are polished by chemical mechanical polishing, two-stage and three-stage polishing conditions are used. Must be changed and polished. In each stage of polishing, polishing is performed by changing the polishing table, so that the number of polishing tables increases, the polishing apparatus becomes larger and the configuration becomes complicated, and the apparatus becomes expensive. In addition, there is a drawback that the throughput of polishing the semiconductor substrate is not improved.
[0006]
[Problems to be solved by the invention]
  The present invention has been made in view of the above points. When polishing a plurality of types of films on a semiconductor substrate, a plurality of stages of polishing are performed on a single polishing table, so that the number of polishing tables can be reduced and the apparatus can be made compact. An object of the present invention is to provide a substrate polishing apparatus and a substrate polishing method that can be configured and can be expected to improve the throughput of semiconductor substrate polishing.
[0007]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, an invention according to claim 1 is provided with a polishing table having a polishing surface and a top ring for holding the substrate, and a semiconductor substrate held by the top ring on the polishing surface of the polishing table is provided. A substrate polishing apparatus for pressing and polishing the semiconductor substrate by relative movement of the semiconductor substrate and the polishing surface,The semiconductor substrate is a semiconductor substrate in which a Cu plating film layer is formed on the barrier layer,There is provided a pressing force variable means for changing the pressing force for pressing the semiconductor substrate, a rotation speed variable means for changing the rotation speed of the top ring and / or the polishing table, and a control means. Polishing through multiple polishing steps on the same polishing table while changing the pressing force and rotation speedThe substrate polishing apparatus further includes an eddy current sensor and an optical sensor in the polishing table, and the eddy current sensor is a predetermined film on which the optical sensor can measure the film thickness of the Cu plating film layer of the semiconductor substrate. Measure until the thickness is reached, and the optical sensor measures when the thickness of the Cu plating film layer is below the specified thicknessIt is characterized by doing.
[0008]
  The invention according to claim 2 is the substrate polishing apparatus according to claim 1,Dressing means for dressing the polishing surface of the polishing table or cleaning means for cleaning is provided, and the control means controls the dressing means or cleaning means during the polishing process to perform dressing or cleaning of the polishing surface of the polishing table.It is characterized by that.
[0009]
  The purpose of polishing the semiconductor substrate on which the pattern is formed is to remove and flatten out minute irregularities (for example, irregularities having a width of 0.1 μm to 2 μm and a height of 500 nm to 1000 nm). However, since the polishing pad is elastic, there is a problem in that the unevenness cannot be removed due to the unevenness to some extent. At that time, it tends to become flat when polished with a light load (pressing force) and a high rotational speed. However, since the load is light, the polishing rate becomes slow. Therefore, by polishing through a plurality of polishing steps on the same polishing table while changing the pressing force for pressing the semiconductor substrate and the top ring and / or the polishing table rotation speed as described above, at first heavy load and high rotation speed. Polishing is then performed to remove the step with a light load and to flatten the surface to be polished. Further, it becomes easy to remove the scratches on the surface by reducing the relative speed of the finish polishing.
[0010]
  Claim3The invention described in 1 is a substrate polishing method in which a semiconductor substrate held by a top ring is pressed against a polishing surface of a polishing table, and the semiconductor substrate is polished by relative movement of the semiconductor substrate and the polishing surface,The semiconductor substrate is a semiconductor substrate in which a Cu plating film layer is formed on the barrier layer,Polishing through a plurality of polishing steps on the same polishing table while changing the pressing force for pressing the semiconductor substrate and the top ring and / or polishing table rotation speed.And measuring the film thickness of the Cu plating film layer with an eddy current sensor until the film thickness of the Cu plating film layer of the semiconductor substrate reaches a predetermined film thickness that the optical sensor can measure. When the Cu plating film thickness is equal to or less than the predetermined thickness, the optical sensor measures the film thickness of the Cu plating film layer.It is characterized by that.
[0011]
  Claim4The described invention is claimed.3In the substrate polishing method according to claim 1,
  A method for polishing a substrate, comprising polishing a plurality of polishing steps by adding a polishing solution and / or a chemical solution having a pH on the same side as pH 7.
[0012]
    The invention according to claim 5 is the claim.3In the substrate polishing method according to claim 1,Polishing using the same abrasive grain in multiple polishing processesIt is characterized by doing.
[0013]
    Claim6The invention described in4. The substrate polishing method according to claim 3, wherein a plurality of polishing steps are performed.The polishing surface of the polishing table is washed, and then the next polishing step is performed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a planar arrangement configuration of a substrate processing apparatus provided with a substrate polishing apparatus according to the present invention. The substrate polishing apparatus includes a load / unload unit 1, a first robot 2, a second cleaning machine 3, a second cleaning machine 4, a reversing machine 5, a reversing machine 6, a second robot 7, a first cleaning machine 8, and a first cleaning. A machine 9, a first polishing apparatus 10, and a second polishing apparatus 11 are arranged.
[0015]
  The polishing apparatus 10 includes a polishing table 10-1, a top ring 10-2, a top ring head 10-3, a film thickness measuring device 10-4, a pusher 10-5, and a dresser 10-10. The polishing apparatus 11 includes a polishing table 11-1, a top ring 11-2, a top ring head 11-3, a film thickness measuring device 11-4, a pusher 11-5, and a dresser 11-10.
[0016]
  Further, a dry state film thickness measuring machine 13 for measuring the dry film thickness after polishing is disposed in the vicinity of the first robot 2.
[0017]
  In the substrate processing apparatus having the above configuration, the semiconductor substrate W (see FIG. 1) on which the power supply seed layer 107 and the plating film layer 106 are formed is set in the cassette 1-1 and placed on the load port of the load / unload unit 1. The first robot 2 takes out the semiconductor substrate W from the cassette and passes it to the reversing machine 5 or 6. At this time, the formation surface of the plating film layer 106 of the semiconductor substrate W is upward, and the formation surface of the plating film layer 106 is inverted downward by the reversing machine 5 or the reversing machine 6.
[0018]
  The semiconductor substrate W inverted by the reversing machine 5 or the reversing machine 6 is picked up by the second robot 7 and placed on the pusher 10-5 of the polishing apparatus 10 or the pusher 11-5 of the polishing apparatus 11. The semiconductor substrate W is adsorbed by the top ring 10-2 or the top ring 11-2, and polishing is performed by pressing the surface to be polished of the semiconductor substrate W against the polishing surface of the polishing table 10-1 or the polishing table 11-1.
[0019]
  FIG. 3 is a diagram showing a schematic configuration of the polishing apparatus 10. As illustrated, the polishing apparatus 10 includes a polishing table 10-1 rotated by a motor M1 and a top ring 10-2 rotated by a motor M2. The polishing table 10-1 and the top ring 10-2 are controlled by a control unit 20. The rotation speed can be varied. Further, the top ring head 10-3 is swung on the swivel shaft 10-8 so that it can be positioned above the polishing table 10-1, above the film thickness measuring device 10-4, and above the pusher 10-5. It has become.
[0020]
  The polishing surface 10-1a of the polishing table 10-1 is configured by fixing or impregnating polyurethane foam or abrasive grains. Silica is used for the abrasive grains of the abrasive liquid supplied from the polishing liquid supply nozzle 10-6, and a material that oxidizes Cu, such as hydrogen peroxide or ammonia, is used as the oxidizing agent. The polishing table 10-1, slurry, water at the time of dressing, etc. are temperature-controlled to keep the chemical reaction rate constant. In particular, the polishing table 10-1 is made of ceramic such as alumina or SiC having good thermal conductivity, and a temperature-controlled water pipe 10-7 is arranged so that the temperature-controlled water can be supplied inside.
[0021]
  The top ring head 10-3 can be moved up and down by a vertical drive mechanism 10-9, and the semiconductor substrate W held on the top ring 10-2 is changed by pressing the semiconductor substrate W held under the control of the control unit 20. It can be pressed with pressure. Further, an eddy current type or optical type described later is used for the film thickness measuring device 10-4 used for detecting the end point of the film thickness, and the Cu plating film layer 106 and the Cu power supply seed layer 107 are used. The film thickness is measured or the surface of the barrier layer 105 and the insulating film 102 are detected, and the detection output is transmitted to the control unit 20. The surface temperature of the polishing surface 10-1a is detected by a radiation thermometer 10-12, and the detection output is transmitted to the control unit 20. Note that the configuration of the polishing apparatus 11 is the same as that of the polishing apparatus 10, and therefore the description thereof is omitted.
[0022]
  Polishing is performed through a plurality of polishing steps. In the first polishing step, the Cu plating film layer 106 is polished. The main purpose of polishing in the first polishing step is to use a slurry having excellent step characteristics by removing the steps of the Cu plating film layer 106. For example, a Cu plating film layer 106 having a thickness of about 100 μm and an initial step 700 nm of 20 nm or less is used. At this time, as a second polishing step, the control unit 20 puts a polishing condition for reducing the load that presses the semiconductor substrate W against the polishing surface 10-1a of the polishing table 10-1 to less than half that of the first polishing step and improving the step characteristics. . This load is controlled by controlling the vertical drive mechanism 10-9 by the control unit 20.
[0023]
  In the film thickness measuring machine 10-4 that detects the end point of the film thickness in the second polishing step, the Cu plating film layer 106 is provided.50 nm (upper limit value of Cu plating film layer thickness can be measured with an optical film thickness measuring instrument)In the case of leaving the above, an eddy current type film thickness measuring machine, which will be described later, is used, and in the case of less than that or when cutting to the surface of the barrier layer 105, an optical thickness measuring machine is used.
[0024]
  After the polishing of the Cu plating film layer 106 is completed, the barrier layer 105 is polished. Usually, when the barrier layer 105 cannot be removed with the slurry used first, it is necessary to change the composition. Therefore, the slurry in the first polishing step and the second polishing step remaining on the polishing surface when the second polishing step is completed is removed and washed with water polish, water jet, atomizer, or dresser, and the next step 3. Move to the polishing process.
[0025]
  FIG. 4 is a diagram showing a configuration of a cleaning mechanism for cleaning the polishing surface 10-1a of the polishing table 10-1. As shown in the drawing, a plurality (four in the figure) of mixed injection nozzles (atomizers) 10-11a to 10-11d for mixing and injecting pure water and nitrogen gas are arranged on the upper part of the polishing table 10-1. ing. Nitrogen gas pressure-adjusted by the regulator 16 from the nitrogen gas supply source 14 is supplied to the mixing injection nozzles 10-11a to 10-11d through the air operator valve 18, and the pressure is supplied from the pure water supply source 15 by the regulator 17. The adjusted pure water is supplied through the air operator valve 19.
[0026]
  The mixed gas and liquid are changed by the jet nozzle, respectively, by changing parameters such as the pressure and temperature of the gas, the gas, and the nozzle shape. ) Solidified fine particles solidified by liquid, (3) Vaporized liquid evaporated (these (1), (2), and (3) are called atomized or atomized here), liquid-derived components and gas components The mixture is sprayed with a predetermined direction toward the polishing surface of the polishing table 10-1.
[0027]
  When the polishing surface 10-1a and the dresser 10-10 are slid and the polishing surface 10-1a is regenerated (dressed) by relative movement of both, pure water and nitrogen gas are mixed from the mixed injection nozzles 10-11a to 10-11d. The mixed fluid is sprayed onto the polishing surface 10-1a for cleaning. The pressure of nitrogen gas and the pressure of pure water can be set independently. In this embodiment, manual drive regulators are used for both the pure water line and the nitrogen line, but regulators that can change the set pressure based on an external signal may be used. As a result of cleaning the polishing surface 10-1a using the cleaning mechanism, the slurry and polishing residue remaining on the polishing surface in the first polishing step and the second polishing step are removed by cleaning for 5 to 20 seconds. I was able to. In addition, although illustration is abbreviate | omitted, in order to wash | clean the grinding | polishing surface 11-1a of the polishing apparatus 11, the cleaning mechanism same as the structure shown in FIG. 4 is provided.
[0028]
  In the above example, it has been described that both atomizer and mechanical dressing are performed simultaneously. However, the polishing surface cleaning means, such as an atomizer, mechanical dressing, water polish, and water jet, are used alone or in appropriate combination to clean the polishing surface. The mechanical dressing referred to here is generally a diamond dresser having a structure in which a belt-like convex portion in which diamond particles are electrodeposited is provided on the peripheral edge of the lower surface of the disk-like dresser 10-10 shown in FIG. is there. When performing mechanical dressing, both sharpening and cleaning of the polished surface are possible. In addition to diamond dressers, there are dressers with a nylon brushed structure.
[0029]
  Water polish means that the slurry supplied from the polishing liquid supply nozzle 10-6 is replaced with pure water while the semiconductor substrate W is in contact with the polishing surface 10-1a as shown in FIG. It means polishing with. During the water polishing, the pressing force of the top ring 10-2 is made smaller than those in the first polishing process and the second polishing process. By polishing with water, the polishing liquid used in the first polishing step and the second polishing step remaining on the polishing surface is replaced with pure water, and the polishing surface 10-1a is cleaned.
[0030]
  FIG. 5 is a diagram showing a configuration example of a cleaning mechanism for cleaning the polishing surface 10-1a of the polishing table 10-1 using a water jet. As shown in the figure, a dressing unit 10-13 is provided, and a plurality of dressing units 10-13 are arranged at equal intervals along the radial direction on the polishing surface 10-1a of the polishing table 10-1. 6) water jet nozzles 10-13c. Each water jet nozzle 10-13c is fixed to a water jet nozzle arm 10-13a having a flow path 10-13b therein.
[0031]
  Pure water pressurized by the pump 23 is supplied to the water jet nozzle 10-13c through the tube 22, and the water jet is jetted from the water jet nozzle 10-13c toward the polishing surface 10-1a. The water pressure of the water jet nozzle arm 10-13a is adjusted by a control unit (not shown) of the pump 23 so as to be maintained at a predetermined pressure. The water jet nozzles 10-13c use the same nozzle so that the jet pressure and speed of the water jet from each nozzle are substantially constant. The water jet pressure is controlled by controlling the pump 23 to 5 to 30 kg / cm.²The predetermined pressure in the range can be maintained.
[0032]
  FIG. 9 is a diagram showing an example of the flow up to the first to third polishing steps, the types of abrasive grains and slurry used in the polishing step, the top ring pressing force, and the top ring rotation speed. As shown in the figure, in the first polishing step, silica and Cu polishing slurry are used as abrasive grains and slurry, and the top ring pressing force is 400 g / cm.²The top ring rotation speed is set to 70 rpm. In the subsequent second polishing step, silica and Cu polishing slurry are used as abrasive grains and slurry, and the top ring pressing force is 200 g / cm.²The top ring rotation speed is set to 70 rpm. It is confirmed by endpoint measurement whether the Cu plating film layer 106 and the power feeding seed layer 107 have been removed.
[0033]
  When the polishing removal of the Cu plating film layer 106 and the power supply seed layer 107 is confirmed by the end point measurement, the slurry in the first polishing step and the second polishing step remaining on the polishing surface 10-1a is the water polish or water. Removal and cleaning are performed by a jet, an atomizer, or a dresser, and the process proceeds to the third polishing step. In the third polishing step, silica and Ta polishing slurry are used as abrasive grains and slurry, and the top ring pressing force is 200 g / cm.²The top ring rotation speed is 50 rpm.
[0034]
  The abrasive grains used in the polishing slurry for the barrier layer 105 in the third polishing step are the same as those used for polishing the Cu plating film layer 106 and the power supply seed layer 107 in the first polishing step and the second polishing step. Things are desirable. In addition, the pH of the polishing liquid in each polishing step or the chemical solution (oxidant or the like) added to the slurry is close to either the acidic side or the alkaline side in each step. By using such a polishing liquid, the residue remaining on the polishing surface 10-1a in the first polishing step and the second polishing step on the cloth constituting the polishing surface 10-1a and the polishing used in the third polishing step The condition is that the compound does not react with the liquid.
[0035]
  In the experiment, silica particles were used for both, and good results were obtained for both alkaline and acidic cases. For the film thickness end point detection in the third polishing process, since the film thickness is thin, an optical film thickness measuring machine is used to detect the remaining barrier layer 105 and transmit the detection signal to the control unit 20. In the polishing using a fixed abrasive (abrasive grains dispersed and fixed in a binder), the polishing is performed by supplying a chemical solution or pure water without using a slurry as a polishing solution.
[0036]
  In this case, the polishing liquid used in the first and second polishing steps and the polishing liquid used in the third polishing step are preferably both alkali or both acidic. A polishing liquid exhibiting a pH on the same side as pH 7 is desirable. However, when a neutral polishing liquid is used, it is possible to use neutral or neutral / alkali or neutral / acidic combinations in each step. In short, it is sufficient that both acidic and alkaline polishing liquids are not used on the same polishing table.
[0037]
  The abrasive grains used in the first polishing process, the second polishing process, and the third polishing process may have different particle diameters as long as they have the same composition. Moreover, although the example which uses a slurry (the liquid which suspended the abrasive grain) was shown here as polishing liquid, it is not limited to a slurry. For example, in the third polishing step, polishing may be performed only with a chemical solution that does not contain abrasive grains. In that case, only the pH of the polishing solution becomes a problem in the first polishing step, the second polishing step, and the third polishing step. That is, it is only necessary that the polishing liquid is unified to be acidic or alkaline in a series of steps.
[0038]
  Although not shown, film thickness measuring devices 10-4 and 11-4 disposed in the vicinity of the polishing table 10-1 of the polishing apparatus 10 and the polishing table 11-1 of the polishing apparatus 11 are provided with film thicknesses with an image processing apparatus. The film thickness measured by the film thickness measuring machine is left as a processing record of the semiconductor substrate W, and it is determined whether or not the polished semiconductor substrate W can be transferred to the next step. Further, if the predetermined polishing amount is not reached even though the polishing is completed, re-polishing is performed. If some abnormality occurs and the polishing exceeds a predetermined amount, the apparatus is stopped so that the next polishing is not performed so as not to increase the number of defective products.
[0039]
  As described above, since the first polishing step to the third polishing step can be performed by one polishing table 10-1 or 11-1, the number of polishing tables can be reduced, and the apparatus can be miniaturized. It is possible to improve the substrate polishing throughput.
[0040]
  After completion of polishing, the semiconductor substrate W is returned to the pusher 10-5 or 11-5 by the top ring 10-2 or 11-2, the semiconductor substrate W is picked up by the second robot 7 and is put into the first cleaning machine 8 or 9. Perform primary cleaning. At this time, chemicals may be sprayed onto the front and back surfaces of the semiconductor substrate W in the pusher 10-5 or 11-5 to remove particles or make it difficult to adhere.
[0041]
  In the first cleaning by the first cleaner 8 or 9, the front surface and the back surface of the semiconductor substrate W are scrubbed. FIG. 6 is a diagram showing a configuration of the first cleaning machine 8. As shown in the figure, the first cleaning machine 8 is configured such that the semiconductor substrate W is sandwiched between a plurality of substrate rotating rollers 8-1 and rotates in a horizontal plane. The rotating PVA sponge rolls 8-2 and 8-2 are arranged so as to contact the upper and lower surfaces of the semiconductor substrate W. Further, an anode ion water nozzle 8-4 and a DHF nozzle 8-5 having an ultrasonic vibrator 8-3 are disposed above and below the semiconductor substrate W. The surface of the semiconductor substrate W is supplied with pure water, a surfactant, a chelate material, and a pH adjuster mainly for particle removal, and is scrubbed with a PVA sponge roll 8-2. On the back surface of the semiconductor substrate W, a strong chemical solution such as DHF is jetted to etch the diffused Cu, or if there is no problem of diffusion, scrub cleaning with a PVA sponge roll or the like using the same chemical solution as the front surface . The first cleaning machine 9 has the same configuration as the first cleaning machine 8.
[0042]
  After the cleaning by the first cleaning machine 8 or 9, the semiconductor robot W is picked up by the second robot 7 and transferred to the reversing machine 5 or 6, and the semiconductor substrate W is inverted. The first robot 2 picks up the semiconductor substrate from the reversing machine 5 or 6 and puts it in the second cleaning machine 3 or 4 to perform the secondary cleaning. Although the illustration of the second washing machine 3 or 4 is omitted, the second washing machine 3 or 4 has the same configuration as the first washing machines 8 and 9. Further, pure water, a surfactant, a chelating material, or a pH adjusting material may be added to clean the surface with a pencil sponge. Thereafter, spin drying is performed, and then the semiconductor substrate W is picked up by the first robot 2.
[0043]
  When the first robot 2 measures the film thickness with the film thickness measuring machines 10-4 and 11-4 in the vicinity of the polishing tables 10-1 and 11-1, the semiconductor substrate W is directly loaded and unloaded 1 Is returned to the cassette 1-1 placed on the unload port. When performing multilayer film measurement, since it is necessary to perform measurement in a dry state, the film thickness is measured by the dry state film thickness measuring machine 13. Therefore, it is determined whether it can be left as a processing record of the semiconductor substrate or can be transferred to the next process.
[0044]
  FIG. 7 is a diagram showing an external configuration example of the second robot 7. As shown in the figure, the second robot 7 has two hands 7-1 and 7-1 on the upper and lower sides, and the hands 7-1 and 7-1 are attached to the tips of the arms 7-2 and 7-2, respectively. It can be swiveled. The hands 7-1 and 7-1 can be used to pick up the semiconductor substrate W (drop the semiconductor substrate W) and transfer it to a predetermined location.
[0045]
  FIG. 8 is a diagram showing a configuration example of a film thickness measuring device provided in the first polishing apparatus 10 for measuring the film thickness of the semiconductor substrate W being polished. As shown in the figure, an eddy current film thickness measuring device 10-14 and an optical film thickness measuring device 10-15 are provided in the polishing table 10-1, and are held by the top ring 10-2.TheThe film thickness of the polished surface of the semiconductor substrate being polished is measured.
[0046]
  The eddy current type film thickness measuring device 10-14 generates a eddy current in the conductive film (the Cu plating film layer 106 and the power feeding seed layer 107) of the semiconductor substrate W by passing a high frequency current through the sensor coil. The current changes with the film thickness, and the film thickness is measured by monitoring the combined impedance with the sensor circuit.
[0047]
  The optical film thickness measuring device 10-15 includes a light projecting element and a light receiving element. The light projecting element irradiates the surface to be polished of the semiconductor substrate W, and receives the reflected light from the surface to be polished. Is configured to do. A thin film having a predetermined thickness of the conductive film (Cu film) of the semiconductor substrate W(Film thickness 50nm or less)Then, a part of the light irradiated to the surface to be polished from the light projecting element passes through the conductive film, and an oxide film (SiO 2 under the conductive film)₂There are two types of reflected light, reflected light reflected from the surface of the conductive film and reflected light reflected from the surface of the conductive film. The film thickness is measured by receiving and processing these two types of reflected light with a light receiving element.
[0048]
【The invention's effect】
  As described above, according to the invention described in each claim, the following excellent effects can be obtained.
[0049]
  The eddy current sensor measures the film thickness of the Cu plating film layer of the semiconductor substrate until it reaches a predetermined film thickness that can be measured by the optical sensor, and the optical sensor measures the film thickness of the Cu plating film layer. By measuring when it becomes below, an eddy current sensor and an optical sensor can be used according to the film thickness of a semiconductor substrate, and a mutual characteristic can be supplemented. In other words, since the sensitivity of the eddy current sensor decreases when the film thickness of the Cu plating film layer becomes thin, an optical sensor that can measure the film thickness is used instead of the eddy current sensor when the sensitivity decreases. The film thickness is measured. As a result, polishing is performed through a plurality of polishing steps on the same polishing table,The number of polishing tables is small,Since the equipment can be downsized and the polishing end point can be detected accurately,Substrate polishing throughputTheAn excellent effect of improving is obtained.
[Brief description of the drawings]
FIG. 1A to FIG. 1C are explanatory views for forming circuit wiring on a semiconductor substrate.
FIG. 2 is a diagram showing a planar configuration example of a substrate processing apparatus including a substrate polishing apparatus according to the present invention.
FIG. 3 is a diagram showing a configuration example of a polishing apparatus of a substrate polishing apparatus according to the present invention.
FIG. 4 is a diagram showing a configuration example of a polishing surface cleaning mechanism of a polishing table of a substrate polishing apparatus according to the present invention.
FIG. 5 is a diagram showing a configuration example of a polishing surface cleaning mechanism of a polishing table of a substrate polishing apparatus according to the present invention.
FIG. 6 is a diagram showing a configuration example of a first cleaning machine of the substrate polishing apparatus according to the present invention.
FIG. 7 is a diagram showing an external configuration example of a second robot of the substrate polishing apparatus according to the present invention.
FIG. 8 is a diagram showing a configuration example of a film thickness measuring apparatus for measuring a substrate film thickness during polishing of the substrate polishing apparatus according to the present invention.
FIG. 9 is a diagram showing an example of a polishing process flow of the polishing apparatus of the present invention, types of abrasive grains and slurry, top ring pressing force, and top ring rotation speed.
[Explanation of symbols]
    1 Load / Unload Department
    2 First robot
    3 Second washing machine
    4 Second washing machine
    5 reversing machine
    6 Reversing machine
    7 Second robot
    8 First washing machine
    9 First washing machine
    10 First polishing apparatus
    11 Second polishing apparatus
    13 Drying state film thickness measuring machine
    14 Nitrogen gas supply source
    15 Pure water source
    16 Regulator
    17 Regulator
    18 Air operator valve
    19 Air operator valve
    20 Control unit
    22 tubes
    23 Pump

Claims (6)

A polishing table having a polishing surface; and a top ring for holding the substrate. The semiconductor substrate held by the top ring is pressed against the polishing surface of the polishing table, and the semiconductor substrate and the polishing surface are moved relative to each other. A substrate polishing apparatus for polishing a semiconductor substrate,
The semiconductor substrate is a semiconductor substrate in which a Cu plating film layer is formed on a barrier layer,
A pressing force variable means for changing the pressing force for pressing the semiconductor substrate, a rotation speed variable means for changing the rotation speed of the top ring and / or the polishing table, and a control means are provided,
The control means performs polishing through a plurality of polishing steps on the same polishing table while changing the pressing force and the rotation speed through the pressing force variable means and the rotation speed variable means ,
The substrate polishing apparatus further includes an eddy current sensor and an optical sensor in the polishing table, and the eddy current sensor has a predetermined thickness that allows the optical sensor to measure the film thickness of the Cu plating film layer of the semiconductor substrate. The substrate polishing apparatus is characterized in that measurement is performed until the film thickness is reached, and the optical sensor measures when the film thickness of the Cu plating film layer becomes equal to or less than the predetermined film thickness . The substrate polishing apparatus according to claim 1 ,
A dressing means for dressing the polishing surface of the polishing table or a cleaning means for cleaning;
The substrate polishing apparatus, wherein the control means controls the dressing means or the cleaning means during the polishing process to dress or clean the polishing surface of the polishing table. A substrate polishing method of pressing a semiconductor substrate held by a top ring on a polishing surface of a polishing table and polishing the semiconductor substrate by relative movement of the semiconductor substrate and the polishing surface,
The semiconductor substrate is a semiconductor substrate in which a Cu plating film layer is formed on a barrier layer,
Polishing is performed through a plurality of polishing steps on the same polishing table while changing the pressing force for pressing the semiconductor substrate and the top ring and / or the polishing table rotation speed . The film thickness of the Cu plating film layer is measured by an eddy current sensor until the film thickness of the Cu plating film layer reaches a predetermined film thickness that can be measured by the optical sensor, and the Cu plating film thickness is less than or equal to the predetermined thickness. A substrate polishing method , wherein the thickness of the Cu plating film layer is measured by the optical sensor when it becomes . The substrate polishing method according to claim 3 , wherein
A method for polishing a substrate, comprising polishing a plurality of polishing steps by adding a polishing solution and / or a chemical solution having a pH on the same side as pH 7. The substrate polishing method according to claim 3 , wherein
A substrate polishing method, wherein polishing is performed using the same abrasive grains in the polishing in the plurality of polishing steps. The substrate polishing method according to claim 3, wherein
A substrate polishing method, wherein a polishing surface of a polishing table is washed between the plurality of polishing steps , and then a subsequent polishing step is performed.

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