JP2006319249A - Polisher, semiconductor device manufacturing method using the same and semiconductor device manufactured by the same manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polisher suited for realizing a more fined circuit pattern. <P>SOLUTION: The polisher 1 is composed of a polishing processor 200 having a front and back surface polishing mechanisms 220, 210 for polishing the front and back surfaces of a substrate; a substrate cleaner 300 for cleaning the substrate polished in the polishing processor 200; and transporters 150, 250 for carrying the unpolished substrate in the polishing processor 200, carrying the polished substrate in the substrate cleaner 300, and carrying out the cleaned substrate in the cleaner. Accordingly, the polisher 1 is constituted so that the front and back surfaces of the substrate are polished in the polishing processor 200, and that the substrate is cleaned in the substrate cleaner 300 and carried out by the transporters. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polishing apparatus for a substrate such as a semiconductor wafer.

  A substrate polishing apparatus is widely used as an apparatus for polishing a semiconductor wafer substrate, a quartz substrate, a ceramic substrate, or the like. In semiconductor device manufacturing technology, miniaturization of circuit patterns and multilayering are two pillars as means for realizing higher density of semiconductor devices such as MPUs and system LSIs. In forming a wiring structure efficiently, the key is how each wiring layer can be flattened during the formation process of the multilayer wiring structure. A CMP technique for polishing a substrate surface with high precision by a chemical mechanical polishing method (CMP method) is attracting attention as a technique for realizing this, and a polishing apparatus (referred to as a CMP apparatus) that performs this polishing process is a semiconductor. It is used for the production of devices.

  For example, as disclosed in Patent Document 1, a CMP apparatus includes a carry-in device that carries a semiconductor wafer substrate before polishing into a polishing unit, a polishing unit that polishes the surface of the loaded substrate, and a polishing process. The substrate cleaning unit for cleaning the substrate and the unloading device for unloading the cleaned substrate are used to flatten the substrate surface in the formation process of the multilayer wiring structure. Specifically, a CMP process is incorporated between the CVD process, the electrode formation process, and the photolithography process, and planarization of an interlayer insulating film formed on the surface of a semiconductor wafer substrate (hereinafter referred to as a wafer) or metal Polishing of a film, polishing of a dielectric film, and the like are performed with high accuracy (see Patent Document 1).

JP 2002-93759 A

  On the other hand, in the miniaturization of circuit patterns, the depth of focus becomes shallow as the resolution of the exposure apparatus improves, and the flatness of the wafer surface during exposure has become a serious problem. This is because the dust adhering to the back surface of the wafer in the process before the exposure process and the bulge around the scratches formed on the back surface of the wafer are brought into local contact with the ceramic pin chuck of the exposure device to elastically deform the wafer, Is a problem that causes the image of the circuit pattern to be blurred, and is considered to be a major cause of exposure failure on the wafer surface particularly in wafer exposure after the 65 nm node generation.

  If such a phenomenon is caused by dust attached just before the exposure process, it can be solved by providing a cleaning means for cleaning the back surface of the wafer inside the exposure apparatus and removing the dust. Conceivable. However, such a cleaning means is ineffective against scratches formed on the back surface of the wafer, and it is difficult to remove dust adhered to the back surface of the wafer before the CVD process and firmly fixed through the CVD process. There was a problem of being.

  The present invention has been made in view of the above problems and problems, and an object thereof is to provide a polishing apparatus and a semiconductor device manufacturing method suitable for realizing further miniaturization of circuit patterns. .

  To achieve the above object, the first aspect of the present invention includes a polishing unit for polishing a substrate having a surface polishing mechanism for polishing the surface of the substrate and a back surface polishing mechanism for polishing the back surface of the substrate, and a polishing unit. The substrate cleaning unit for cleaning the substrate polished in step 1 and the substrate before polishing processing are carried into the polishing unit, the substrate after polishing is transported to the substrate cleaning unit, and the substrate cleaned by the substrate cleaning unit is unloaded The polishing apparatus is configured such that the substrate whose front and back surfaces are polished in the polishing processing unit is cleaned in the substrate cleaning unit and is carried out by the transfer device.

  In the second aspect of the present invention, the polishing apparatus is configured such that, in the polishing processing unit, the substrate before polishing is polished by the back surface by the back surface polishing mechanism and then the surface is polished by the surface polishing mechanism.

  According to a third aspect of the present invention, the back surface polishing mechanism has a surface suction chuck that sucks and holds the front surface side of the substrate and a back surface polishing head that polishes the back surface of the substrate. The above polishing apparatus has a back surface chuck for adsorbing and holding and a front surface polishing head for polishing the surface of the substrate, so that the front surface and the back surface of the substrate can be polished without reversing the front and back of the substrate in the polishing unit Configure.

  According to a fourth aspect of the present invention, the polishing apparatus is configured such that the front surface chuck chucks and holds the front surface side of the substrate from above the substrate, and the back surface polishing head polishes the back surface of the substrate from below the substrate.

  According to a fifth aspect of the present invention, there is provided a semiconductor device manufacturing method including a step of polishing a front surface and a back surface of a semiconductor wafer (substrate) using the polishing apparatus configured as described above.

  The sixth aspect of the present invention is a semiconductor device manufactured by the above semiconductor device manufacturing method.

  According to the polishing apparatus of the present invention, since the back surface polishing mechanism for polishing the back surface of the substrate is provided in the polishing processing unit, dust that is firmly bonded to the back surface of the substrate and the bulge around the scratches formed on the back surface of the substrate Etc. can be flattened, thereby ensuring the flatness of the wafer surface in the exposure step and miniaturizing the circuit pattern. And according to the semiconductor device manufacturing method which has such a grinding | polishing process, a high-density semiconductor device can be produced with a high yield, and the high-density semiconductor device which can be provided at low cost can be obtained.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1 as a plan view, the overall configuration of a polishing apparatus 1 to which the present invention is applied is roughly divided into a cassette index unit 100 that carries in and out a wafer, and a polishing that performs polishing. The processing unit 200, a substrate cleaning unit 300 that cleans the wafer after the polishing process, a transfer device (first transfer robot 150, second transfer robot 250) that transfers the wafer in the polishing apparatus, and the like. Each of them is partitioned by an automatic open / close shutter to form a clean chamber. The operation of the polishing apparatus 1 is controlled by a control device (not shown).

The cassette index unit 100 is provided with a wafer mounting table 120 on which cassettes (also referred to as carriers) C _{1 to} C ₄ each holding a plurality of wafers W are mounted, and an unprocessed wafer before polishing. Is taken out from the send cassettes C ₁ and C ₂ and loaded into the polishing unit 200, and the first transfer robot 150 for storing the processed wafers cleaned by the substrate cleaning unit 300 after polishing in the receive cassettes C ₃ and C ₄ is provided. It is arranged.

  The first transfer robot 150 is an articulated arm type robot, and includes a base 151, a swivel base 152 that can be freely swung horizontally and raised and lowered on the base, and a multi-stage attached to the swivel base 152. The arm 153 includes a joint arm 153, a clamper 155 that is attached to the tip of the multi-joint arm so as to be extendable and contractible. The clamper 155 has three claws that open and close in the circumferential direction, and is configured to be able to hold the wafer by being engaged with and disengaged from the outer peripheral edge of the wafer W. The first transfer robot 150 is configured to be horizontally movable along a linear guide 156 disposed on the floor surface of the cassette index portion.

  The operation of the first transfer robot 150 is controlled by the control device, moves along the linear guide 156 to the front of the send cassette in which the unprocessed wafer is accommodated, and the swivel base 152 is horizontally swung and lifted to move to a predetermined slot height. Then, the clamper 155 is moved and the articulated arm 153 and the clamper 155 are operated to take out the unprocessed wafer stored in the send cassette, or the processed wafer cleaned by the substrate cleaning unit 300 is placed in a predetermined slot of the receive cassette. Store.

  The polishing unit 200 includes a back surface polishing mechanism 210 that polishes the back surface of the wafer, a surface polishing mechanism 220 that polishes the surface of the wafer, and a second transfer robot 250 that transfers the wafer. Both the front and back surfaces of the finished wafer are polished.

  As shown in FIGS. 2A and 2B, the back surface polishing mechanism 210 is a wafer support portion that temporarily supports the wafer W transferred by the second transfer robot 250 as shown in a plan view and a front view of the outline of the mechanism. 211, a surface suction chuck 212 that is positioned above the wafer W temporarily supported by the wafer support 211 and sucks and holds the wafer W from the surface side, and below the wafer supported by the wafer support 211. The back surface polishing head 214 is disposed to polish the back surface of the wafer sucked and held by the front surface suction chuck 212, and the nozzle 216 for supplying slurry to the back surface polishing head 214.

  The wafer support portion 211 illustrates an embodiment configured to support the outer peripheral portion of the back surface of the wafer W with four support legs 211a, 211a... And temporarily support the placed wafer horizontally. The configuration is such that the degree of freedom of arrangement of the polishing head 214 is improved, and the wafer loading / unloading property (portability) by the second transfer robot 250 is enhanced. The wafer support section 211 may be configured to be able to temporarily support the wafer without interfering with the back surface polishing head 214 and the like, for example, configured with three support legs provided at a pitch of 120 degrees, or the back surface polishing head. You may comprise in the ring shape which notched the peripheral part of 214. FIG.

  The surface adsorption chuck 212 is formed in a thin disc shape using a disc-shaped chuck plate 212a obtained by processing and molding a pad mounting surface with high flatness using a rigid material such as ceramic or stainless steel, and an elastic material such as polyurethane or nonwoven fabric. A suction pad 212b mounted on the lower surface of the chuck plate 212a, a spindle 212c for transmitting rotational driving force to the chuck plate 212a, etc., and the suction pad 212b faces the wafer surface in a downward horizontal posture, and the surface of the wafer W The side can be vacuum-adsorbed.

  The surface adsorption chuck 212 is mounted so as to be movable up and down by a chuck drive mechanism (not shown) and to be rotatable about a spindle 212c. The surface adsorption chuck 212 descends from above the wafer W temporarily supported by the wafer support portion 211 and moves to the wafer surface. Is lifted together with the wafer held by suction and lifted from the wafer support portion 211, and the wafer is horizontally rotated at a processing position where the back surface of the wafer is lifted by about 10 mm.

  Similar to the chuck plate 212a of the front surface chuck, the back surface polishing head 214 includes a polishing plate 214a formed in a disk shape with high rigidity and high flatness, a polishing pad 214b mounted on the upper surface of the polishing plate, and a polishing plate The polishing pad 214b includes a spindle 214c that transmits a rotational driving force to 214a and the like, and a polishing pad 214b is disposed to face the wafer back surface in an upward horizontal posture. The back surface polishing head 214 is formed to have a diameter larger than the wafer radius and smaller than the wafer diameter, and the spindle 214c is disposed offset from the spindle 212c of the surface suction chuck. The entire surface of W can be polished.

  The back surface polishing head 214 is mounted so as to be movable up and down by a polishing head drive mechanism (not shown) and to be rotatable about a spindle 214c. The back surface polishing head 214 is attached below the wafer that is sucked and held by the front surface suction chuck 212 and rotated at the processing position. It is configured to polish the entire back surface of the wafer by rotating and starting up and pressing the relatively rotating polishing pad against the back surface of the wafer with a predetermined pressure. The polishing pad 214b is a known polishing pad, for example, a single-layer polishing pad such as foamed polyurethane or non-woven fabric, or a soft elastic member (foamed chloroprene rubber, elastic non-woven fabric, urethane foam, etc.) combined with these bases. A polishing pad having a layer structure, a polishing pad having a three-layer structure in which a hard elastic member such as a stainless steel thin plate is provided between the polyurethane foam and the soft elastic member, can be used. A slurry introduction groove is formed on the surface of the polishing pad 214b.

  The nozzle 216 is configured by processing and molding a stainless steel pipe, for example, and the tip portion is disposed toward the polishing region where the polishing pad and the wafer back surface are in contact with each other. A slurry supply device that supplies slurry according to the processing purpose is connected to the base end side of the nozzle 216 so that the slurry that matches the processing purpose is selected based on the control program and supplied to the polishing processing unit. It has become. In order to polish the wafer back surface without a circuit pattern in the back surface polishing section, a slurry suitable for polishing the wafer base material is selected and supplied, and after polishing, the slurry adhering to the wafer back surface is washed away. It is controlled so that pure water is supplied.

  As will be described later, a slurry supply structure that feeds slurry to the center of the polishing pad 214b through the center of the polishing plate 214a is provided, and slurry according to the processing purpose at the time of polishing processing is provided at the center of the polishing pad 214b. You may comprise so that it may supply to.

On the other hand, the surface polishing mechanism 220 is divided into four sections around an index table 221 that is rotated and fed every 90 degrees, and a first polishing stage S ₁ and a second polishing stage for polishing the wafer. S ₂ , a third polishing stage S _3, and a transfer stage S ₄ that carries in the unprocessed wafer and carries out the processed wafer.

The index table 221 is a large rotary table as a whole, and the rear surface suction chucks 222, 222,... Hold and hold the rear surface side of the wafer in each section of the table divided into four parts corresponding to the four stages. Is disposed upward in the opening on the upper surface of the table. The three polishing stages of the first polishing stage S ₁ , the second polishing stage S ₂ , and the third polishing stage S ₃ are each provided with a polishing arm 223 that can swing in the horizontal direction with respect to the index table 221. Then, a surface polishing head 224 is attached to the tip of the head from the polishing arm 223.

  FIG. 3 shows an outline of each part in a state where the index table 221 is stopped at a predetermined angular position, the polishing arm 223 is swung above the index table 221, and the polishing head 224 is positioned above the back surface suction chuck 222. Show the relationship. 3A is a plan view, and FIG. 3B is a front view.

  Similar to the above-described front surface suction chuck 212, the back surface suction chuck 222 includes a disc-shaped chuck plate 222a in which a pad mounting surface is processed and formed with high flatness using a rigid material such as ceramic or stainless steel, and polyurethane or nonwoven fabric. The suction pad 222b is formed in a thin disk shape using an elastic material and is mounted on the upper surface of the chuck plate 222a, and the spindle 222c that transmits a rotational driving force to the chuck plate 222a. The suction pad 222b is in an upward horizontal posture. The wafer W can be vacuum-sucked from the back side.

  The back surface chucking chuck 222 is disposed so that suction pads are exposed at the openings of the index table 221 that are arranged in four equal parts, and can be rotated and stopped independently by the chuck driving mechanism with the spindle 222c as an axis. And its operation is controlled by the control device. The diameter of the back surface suction chuck 222 is formed to be slightly smaller than the diameter of the wafer, and the clamper 255 of the second transfer robot can grip the outer peripheral edge of the wafer placed on the back surface suction chuck 222. .

  The polishing arm 223 is disposed on each of the first to third polishing stages so as to be horizontally swingable, and a surface polishing head 224 is attached to the tip thereof. The polishing stage is provided with an arm driving mechanism that swings and drives the polishing arm, and can be controlled to swing independently by a control device.

  The front surface polishing head 224 includes a polishing plate 224a formed in a disk shape with high rigidity and high flatness like the polishing plate 214a of the back surface polishing mechanism described above, and a polishing pad 224b attached to the lower surface of the polishing plate 224a, And a spindle 224c for transmitting a rotational driving force to the polishing plate 224a. The polishing pad 224b is disposed at the tip of the polishing arm 223 in a horizontal posture with the surface facing downward. The diameter of the surface polishing head 224 is formed to be smaller than the diameter of the wafer W, and by swinging the polishing arm 223, the entire surface of the wafer can be uniformly polished with a small apparatus configuration.

  The polishing head 224 is provided with a slurry supply structure that passes through the center of the polishing plate 224a and supplies the slurry to the center of the polishing pad 224b. A slurry is supplied. As the polishing pad 224b, a single-layer to three-layer polishing pad can be used as in the above-described polishing pad 214b. Processing processes such as an interlayer insulating film CMP and metal CMP, circuit pattern fineness, and first order Depending on the processing stage such as polishing (rough polishing) to tertiary polishing (finish polishing), etc., it is appropriately selected and mounted. The surface treatment is configured to supply slurry from the center of the polishing pad, and a flat polishing pad having a groove for introducing slurry on the pad surface, so that fresh slurry is uniformly supplied to the entire polishing region. Yes.

  The surface polishing head 224 is attached to the tip of the polishing arm 223 so as to be rotatable and movable up and down with a spindle 224c as an axis. The surface polishing head 224 is horizontally swung to bring the surface polishing head 224 above the back surface suction chuck 222. While being positioned, the front surface polishing head 224 is lowered while rotating, and the polishing pad 224b is pressed against the surface of the wafer rotated by being sucked and held by the back surface suction chuck 222 with a predetermined pressure, and the polishing arm is supplied while supplying slurry. By oscillating 223, the entire surface of the wafer is polished. An end point detector for optically detecting the polishing state of the wafer being polished is attached to the tip of the polishing arm 223 so that a decrease in film thickness during the polishing process is detected in real time and the polishing process is performed. The end point can be feedback controlled.

Each polishing stage S _{1 to} S ₃ is provided with a pad dresser 227 for dressing the processed surface of the polishing pad 224b. The pad dresser 227 is disposed on the rocking radius of the polishing head 224 when the polishing arm 223 is swung, and the pad dresser 227 performs the polishing pad 224b for each predetermined polishing cycle in each polishing stage. Thus, the clogging of the polishing pad surface is corrected and the flatness is ensured.

  The second transfer robot 250 is an articulated arm type robot similar to the first transfer robot 150, and includes a base 251 and a turntable 252 disposed on the base so as to be capable of horizontal swiveling and raising / lowering operations. An articulated arm 253 attached to 252 and a clamper 255 attached to the tip of the articulated arm so as to be extendable and contracted. The clamper 255 has three claws that open and close in the circumferential direction, and is configured to be able to grip the outer peripheral edge of the wafer W. The second transfer robot 250 is configured to be horizontally movable along a linear guide 256 provided in the polishing processing unit 200.

The operation of the second transfer robot 250 is controlled by a control device, and the unprocessed wafer taken out by the first transfer robot 150 is received and polished in a path for transferring the unprocessed wafer installed in the substrate cleaning unit 300. It is carried into the processing unit 200 and placed on the wafer support portion 211 of the back surface polishing mechanism 210 or the back surface suction chuck 222 of the transport stage S ₄ in the front surface polishing mechanism 220. Further, when the single-side polishing of the wafer is completed, performs the transfer of the wafer between the wafer support portion 211 and the back surface adsorption chuck 222 of the conveying stage S _4. Further, when the polishing process on both the front and back surfaces of the wafer is completed, the processed wafer that has been suctioned on the back surface suction chuck 222 of the transfer stage S ₄ or the processed wafer temporarily supported by the wafer support unit 211 is clamped by the clamper 255. The substrate is gripped and taken out and conveyed to the substrate cleaning unit 300.

  The substrate cleaning unit 300 is composed of four chambers, a first cleaning chamber 310, a second cleaning chamber 320, a third cleaning chamber 330, and a drying chamber 340. Slurry and polishing that the processed wafers carried into the cleaning unit 300 are sequentially sent in the order of the first cleaning chamber 310 → the second cleaning chamber 320 → the third cleaning chamber 330 → the drying chamber 340 and adhere to the polishing processing unit 200. Abrasion powder is removed and washed. There are various examples of cleaning methods in each cleaning chamber. For example, in the first cleaning chamber 310, double-sided cleaning with a rotating brush, in the second cleaning chamber 320, surface pencil cleaning under ultrasonic vibration, third cleaning chamber Then, spinner cleaning with pure water is performed, and the drying process is performed in a nitrogen atmosphere under a nitrogen atmosphere. A passage for conveying the unprocessed wafer is provided below the first cleaning chamber 310.

  As for the operation of the polishing apparatus configured as described above, a wiring groove is formed in the silicon substrate 51 as shown in FIG. 4A, a barrier layer 52 such as TiN or TaN is formed on the groove, and From the state before the polishing process in which the copper conductive layer 53 is formed (hereinafter, the wafer in this state is referred to as an unprocessed wafer for the sake of convenience), the conductive layer 53 and the barrier layer 52 are subjected to the primary polishing by the CMP method. A Cu-CMP process in which the conductor wiring 53a as shown in FIG. 4B is formed on the silicon substrate 51 by flatly polishing by three stages of polishing, secondary polishing, and tertiary polishing. The case where it performs is demonstrated to an example.

In FIG. 5, the unprocessed wafers accommodated in the send cassette C ₁ of the cassette index unit 100 are sequentially polished by the polishing unit 200 to become the processed wafer shown in FIG. 4B, and cleaned by the substrate cleaning unit 300. the flow of wafers to be accommodated and processed to receive a cassette C ₄ of the cassette index part 100 is obtained denoted by the dotted arrow. Note that the operation of the polishing apparatus 1 is controlled by a control device (not shown), and the control device controls the operation of each unit based on a preset control program.

When polishing the program is started by the polishing apparatus 1, the raw wafer first transfer robot 150 is moved to the position of the send cassettes C _1, the swivel base 152 by a horizontal pivot and is raised and lowered operating an object of the clamper 155 The multi-joint arm 153 and the clamper 155 are extended to operate, the raw wafer in the slot is gripped by the clamper 155, and the multi-joint arm 153 is contracted and pulled out. Then, the swivel base 152 is swiveled 180 degrees toward a passage installed below the first cleaning chamber 310, and the unprocessed wafer is delivered to the second transfer robot 250 on the polishing processing unit 200 side in this passage. . That is, the unprocessed wafer taken out from the send cassette passes through the substrate cleaning unit 300 without passing through the cleaning process.

  Upon receiving the unprocessed wafer from the first transfer robot 150, the second transfer robot 250 turns the turntable 252 180 degrees to carry the unprocessed wafer into the polishing unit 200, and the polishing unit 200 polishes both the front and back surfaces. Processing is performed. Here, even if either the back side polishing process or the front side polishing process of the wafer W is performed in advance, dust and scratches attached to the back side of the unprocessed wafer are removed, whereby the next exposure step. The effect of ensuring the flatness of the wafer surface can be obtained.

  However, it is not preferable to chuck the front surface side of the wafer on which the conductor wiring 53a is formed after the first to third polishing on the wafer surface is completed, because the wafer surface may be damaged. High throughput cannot be obtained if a protective tape is applied to the wafer surface. In addition, since the slurry used in the interlayer insulating film CMP and the metal CMP has a high viscosity and is easily dried and fixed, it is preferable to clean as quickly as possible after the polishing process. Therefore, in the polishing apparatus 1, the back surface polishing process is performed prior to the surface polishing process, and after the back surface side of the wafer is polished by the back surface polishing mechanism 210, the front surface side is polished by the surface polishing mechanism 220. It is composed.

  That is, the second transport robot 250 first transports the unprocessed wafer carried into the polishing unit 200 to the back surface polishing mechanism 210, and operates each part of the swivel base 252, the articulated arm 253, and the clamper 255 to operate the unprocessed wafer. Is placed on the wafer support 211.

  When the unprocessed wafer is placed on the wafer support portion 211 and the second transfer robot 250 is retracted, the surface suction chuck 212 descends, vacuum-sucks the surface of the unprocessed wafer, and rises together with the unprocessed wafer held by suction. The wafer starts rotating at a processing position where the back surface of the wafer is lifted about 10 mm from the wafer support portion 211. Further, as the backside polishing head 214 starts to rotate, slurry is supplied from the nozzle 216 toward the backside of the wafer. Then, the polishing head 214 rises toward the unprocessed wafer that rotates at the processing position, and the polishing pad 214b is pressed against the wafer back surface with a predetermined pressure, whereby the wafer back surface is polished.

  At the time of polishing, the back surface of the wafer is polished flat by the interaction between the unrotated processed wafer, the polishing pad 214b, and the slurry supplied from the nozzle 216, and the dust adhered to the back surface of the wafer and the periphery of the scratch formed in the previous step As a result, the flatness (global planarity and local planarity) of the back surface of the wafer is ensured. When CMP polishing for a predetermined time is completed, pure water is supplied from the nozzle 216 to perform rinsing polishing, and then the polishing head 214 is lowered while supplying pure water to the back surface of the wafer. Thereby, the slurry remaining on the back surface of the wafer is washed away, and the cleanliness of the back surface of the wafer is ensured. When the back surface polishing is completed, the front surface suction chuck 212 is lowered to release the vacuum suction, and the unprocessed wafer is placed on the wafer support portion 211 and moved up to the retracted position.

Thus the wafer back surface of the polishing of the back surface grinding mechanism 210 is completed, grasping the outer periphery of the wafer W to the second transfer robot 250 is supported on the wafer support portion 211 is conveyed to the surface polishing mechanism 220, a transfer stage S ₄ It is placed on the rear surface suction chuck 222 of the index table 221 whose positioning has been stopped. When the wafer W is placed on the back surface suction chuck 222, the back surface suction chuck 222 holds the back surface of the wafer by vacuum suction, and the second transfer robot 250 retreats.

Thereafter, polishing is started in the first polishing stage S ₁ to the third polishing stage S ₃ of the surface polishing mechanism 220. Since the wafer surface polishing performed in such a three-stage polishing stage is already known (for example, Japanese Patent Application Laid-Open No. 2002-93759 by the present applicant), detailed description thereof is omitted in this specification. The following is a brief description.

When the second transfer robot 250 retracts, the index table 221 is wafer W attracted and held by being rotated 90 degrees clockwise to the rear surface suction chuck 222 is positioned in the first polishing stage S _1, at the same time the polishing arm 223 GaYura The polishing head 224 is moved on the wafer by being moved. Then, the polishing head 224 and the back surface suction chuck 222 are rotated in the opposite directions and the polishing head 224 is lowered to press the polishing pad 224b against the wafer surface to perform the first polishing process. During the polishing process, while supplying slurry from the axis of the polishing head 224, the polishing arm 223 is swung so that the polishing pad reciprocates between the rotation center of the wafer and the outer peripheral end, and the wafer surface is moved. Uniform flat polishing. The first polishing process is time control, and when a predetermined time has elapsed, the polishing head 224 is raised to end the first polishing process. Also in the primary polishing, the back surface grinding mechanism and 210, is made back surface polishing of the following raw wafer, carried on the rear surface suction chuck transfer stages S ₄ polished wafers by the second transfer robot 250 To wait.

When the first polishing process is completed, the control device further rotates the index table 221 by 90 degrees in the clockwise direction, and waits the wafer after the first polishing process at the second polishing stage S ₂ and at the transfer stage S ₄ . positioning the been wafer in the first polishing stage S _1. Then, the polishing head 224 is lowered on the first and second polishing stages, respectively, and the first polishing process and the second polishing process are simultaneously performed in parallel. The secondary polishing process is an end point detection process, and when it is determined that the processed film thickness detected by the end point detector has decreased to a predetermined film thickness set in advance, the polishing head 224 is raised to perform the secondary process. Finish the polishing process.

When the second polishing process is completed, the control device checks whether or not the first polishing process is completed, and when the first polishing process is completed, the control table is further rotated 90 degrees clockwise. Rotate the wafer that has finished the second polishing process to the third polishing stage S ₃ , the wafer that has finished the first polishing process to the second polishing stage S ₂ , and the wafer that has been waiting on the transfer stage to the second polishing stage S ₂ 1 positioned in the polishing stage S _1, lowers the polishing head 224, respectively, first, second, to take such a third-order polished simultaneously. The third polishing process is an end point detection process similar to the second polishing process, and when it is determined that the processed film thickness detected by the end point detector has decreased to a predetermined film thickness set in advance, the polishing head 224 is raised to finish the polishing process.

When the third polishing process is completed, the control device checks whether the first polishing process and the second polishing process are completed, and when all the polishing processes are completed, the control unit displays the index table 221 as a clock. further by 90 degrees rotation about, the tertiary polishing carrier stage S ₄ of the wafer has ended, even wafer positioned at other stages positioning is moved by the first stage in the same manner as described above.

When the positioning of the index table 221 is stopped and the wafer whose surface polishing is finished through the first to third polishing stages is positioned on the transfer stage S ₄ , the second transfer robot 250 is moved to the turntable 252, the articulated arm 253, By operating the clamper 255 and the like, the outer peripheral edge of the processed wafer whose vacuum suction is released on the back surface suction chuck is gripped and lifted and swiveled, moved horizontally along the linear guide 256 and moved to the substrate cleaning unit 300. Transport. In addition, after the processed wafer is transferred, the unprocessed wafer is received from the first transfer robot 150 and transferred to the polishing processing unit 200.

In the substrate cleaning unit 300, double-sided cleaning with a rotating brush in the first cleaning chamber 310, surface pencil cleaning under ultrasonic vibration in the second cleaning chamber 320, spinner cleaning with pure water in the third cleaning chamber 330, and drying chamber 340 The drying process is performed in a nitrogen atmosphere. Then, the thus washed finished wafer is removed from the substrate cleaning unit 300 by the first transfer robot 150 of the cassette index portion is accommodated in the specified slot from the receive cassette C _4.

The above operations are sequentially repeated, and after the polishing of the first wafer is completed, the wafer whose front and back surfaces are polished flat is stored in the cassette C ₄ at every rotation interval of the index table 221. . The rotation interval of the index table 221 is defined by the polishing time divided into three stages. For example, a finished wafer is continuously produced at every time interval of the first polishing process.

  As described above, in the polishing apparatus 1, since the back surface polishing mechanism 210 for polishing the back surface of the wafer is provided in the polishing processing unit 200, for example, dust attached to the back surface of the wafer in the preceding CVD process is firmly fixed. Even in the case where the back surface of the wafer is damaged and the surrounding area is raised, these can be flattened in the polishing step. For this reason, the flatness of the wafer surface attracted and held by the pin chuck in the subsequent exposure process can be ensured, and further miniaturization of the circuit pattern can be realized.

  In the polishing apparatus 1, the unprocessed wafer before polishing is polished by the back surface polishing mechanism 210 and then polished by the surface polishing mechanism 220 in the polishing unit 200. For this reason, it is possible to obtain a wafer that is polished on both sides without touching the wafer surface on which the conductor wiring is formed by flat polishing precisely by the first polishing to the third polishing, and the wafer is removed early after the surface polishing. Since it can be cleaned, it is possible to prevent the slurry for interlayer insulating film CMP and metal CMP from being dried and fixed and to improve the cleaning efficiency.

  Further, in the polishing processing unit 200, the arrangement of the front surface adsorption chuck and the rear surface polishing head of the rear surface polishing mechanism 210 and the rear surface adsorption chuck and the front surface polishing head of the front surface polishing mechanism 220 are arranged upside down. The front and back surfaces of the wafer can be polished without reversing the front and back surfaces, whereby the configuration of the entire polishing apparatus including the transfer robot can be configured easily and inexpensively, and the configuration can also contribute to an improvement in throughput.

  Further, the front surface suction chuck 212 sucks and holds the front surface side from above the wafer, and the back surface polishing head 214 polishes the back surface of the wafer from below the wafer, that is, polishes in a downward processing posture. Therefore, the slurry used at the time of back surface polishing is easy to flow down, and the slurry can be easily removed by rinsing after the processing and pure water cleaning.

In the embodiment, the case where the conductor wiring is formed on the substrate of the silicon wafer by the Cu-CMP process is exemplified, but the present invention is not limited to such a use, and the interlayer insulating film processing process, the STI process, etc. In addition to the wafer processing as described above, the present invention can be similarly applied to processing processes such as a quartz substrate, a glass substrate, and a ceramic substrate. Further, in the front surface polishing mechanism 220 and the back surface polishing mechanism 210, the polishing pads 224b and 214b having a diameter smaller than the diameter of the wafer are used for polishing, but a polishing pad having a diameter larger than the diameter of the wafer is used for polishing. Also good. Moreover, the finished product wafer after the washing has been and is accommodated to receive cassette C _4, wafers may be accommodated in the slots that are vacant send cassette C ₁ which is housed when not working.

  Next, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described. FIG. 6 is a flowchart showing a semiconductor device manufacturing process. When the semiconductor manufacturing process is started, first, in step S200, an appropriate processing step is selected from the following steps S201 to S204, and the process proceeds to any step.

  Here, step S201 is an oxidation process for oxidizing the surface of the wafer. Step S202 is a CVD process for forming an insulating film or a dielectric film on the wafer surface by CVD or the like. Step S203 is an electrode forming process for forming electrodes on the wafer by vapor deposition or the like. Step S204 is an ion implantation process for implanting ions into the wafer.

  After the CVD process (S202) or the electrode formation process (S203), the process proceeds to step S205. Step S205 is a CMP process. In the CMP process, the polishing apparatus according to the present invention performs planarization of the interlayer insulating film, polishing of the metal film on the surface of the semiconductor device, formation of damascene by polishing of the dielectric film, and the like.

  After the CMP process (S205) or the oxidation process (S201), the process proceeds to step S206. Step S206 is a photolithography process. In this step, a resist is applied to the wafer, a circuit pattern is printed on the wafer by exposure using an exposure apparatus, and the exposed wafer is developed. Further, the next step S207 is an etching process in which a portion other than the developed resist image is etched away, and then the resist is peeled off to remove the unnecessary resist after etching.

  Next, it is determined in step S208 whether all necessary processes are completed. If not completed, the process returns to step S200, and the previous steps are repeated to form a circuit pattern on the wafer. If it is determined in step S208 that all processes have been completed, the process ends.

  In the semiconductor device manufacturing method according to the present invention, since the polishing apparatus according to the present invention is used in the CMP process, the flatness of the back surface of the semiconductor device is improved. For this reason, when baking a circuit pattern by exposure using an exposure apparatus, it is possible to improve the flatness of the device surface in a state where it is sucked and held by the pin chuck, and further miniaturization of the circuit pattern and further increase in the density of the semiconductor device. Can be realized. Note that the polishing apparatus according to the present invention may be used in the CMP process of a semiconductor device manufacturing process other than the semiconductor device (semiconductor wafer). Moreover, since the semiconductor device manufactured by the semiconductor device manufacturing method according to the present invention can produce a high-density semiconductor device with a high yield, a low-cost semiconductor device can be supplied.

It is a top view which shows the example of whole structure of the grinding | polishing apparatus to which this invention is applied. It is (a) top view and (b) front view which show the outline | summary of a back surface grinding | polishing mechanism. It is (a) top view and (b) front view which show the outline | summary of a surface grinding | polishing mechanism. It is shown as an example of the grinding | polishing process by the said grinding | polishing apparatus. (A) Sectional drawing of wafer before grinding | polishing process, (b) Sectional drawing of wafer after grinding | polishing process. It is explanatory drawing which shows the flow of the wafer in the said polishing apparatus. 3 is a flowchart of a semiconductor device manufacturing method according to the present invention.

Explanation of symbols

W wafer (substrate)
1 Polishing device 150 First transfer robot (transfer device)
200 Polishing Processing Section 210 Back Surface Polishing Mechanism 212 Front Surface Adsorption Chuck 214 Back Surface Polishing Head 220 Front Surface Polishing Mechanism 222 Back Surface Adsorption Chuck 224 Surface Polishing Head 250 Second Conveying Robot (Conveying Device)
300 Substrate cleaning section

Claims (6)

A polishing portion that has a surface polishing mechanism that polishes the surface of the substrate and a back surface polishing mechanism that polishes the back surface of the substrate, and polishes the substrate;
A substrate cleaning section for cleaning the substrate polished in the polishing section;
The substrate before polishing processing is carried into the polishing processing unit, the substrate after polishing processing is transported to the substrate cleaning unit, and a transport device that unloads the substrate cleaned by the substrate cleaning unit,
The polishing apparatus, wherein the substrate whose front and back surfaces have been polished in the polishing processing unit is cleaned in the substrate cleaning unit and carried out by the transfer device.   2. The polishing apparatus according to claim 1, wherein the polishing unit is configured such that the substrate before polishing is polished by the back polishing mechanism and then polished by the surface polishing mechanism. . The back surface polishing mechanism has a surface adsorption chuck that adsorbs and holds the front surface side of the substrate and a back surface polishing head that polishes the back surface of the substrate,
The surface polishing mechanism has a back surface chuck for chucking and holding the back surface side of the substrate and a surface polishing head for polishing the surface of the substrate,
The polishing apparatus according to claim 1, wherein the polishing processing unit is configured to polish the front surface and the back surface of the substrate without inverting the front and back surfaces of the substrate.   The front surface chuck is configured to suck and hold the surface side of the substrate from above the substrate, and the back surface polishing head is configured to polish the back surface of the substrate from below the substrate. 3. The polishing apparatus according to 3. The substrate is a semiconductor wafer;
A method for manufacturing a semiconductor device, comprising a step of polishing the front surface and the back surface of the semiconductor wafer using the polishing apparatus according to any one of claims 1 to 4. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 5.

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