JP2010021353A - Method of manufacturing semiconductor apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the occurrence of defects in a semiconductor wafer transfer after a polishing processing. <P>SOLUTION: In a CMP method of a semiconductor wafer using a polishing apparatus, supply of polishing liquid is stopped after completion of CMP polishing of the semiconductor wafer, and pure water containing a surfactant agent is supplied on an interface between a semiconductor wafer 5 and a polishing pad 3, and a hydrophile processing of the interface between the polished semiconductor wafer 5 and the polishing pad 3 is carried out while rotating a semiconductor wafer holding head 4 and a polishing table 1 in the same rotation direction. After completion of the hydrophile processing, the semiconductor wafer 5 held by the semiconductor wafer holding head 4 at a position immediately after the hydrophile processing is separated from the polishing pad 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In recent years, with the progress of microfabrication, higher integration, lower power consumption, higher functionality, and the like of semiconductor integrated circuits (LSIs) have progressed. In microfabrication of a highly integrated semiconductor integrated circuit (LSI), it is very important to flatten the layer or film on the surface of the semiconductor wafer on which the semiconductor integrated circuit (LSI) is formed. A semiconductor wafer polishing apparatus is used as a method for flattening a wiring material (copper (Cu), aluminum (AL), etc.), an interlayer insulating film (TEOS film, Low-K film, etc.) or a resist film provided on the surface of a semiconductor wafer. The CMP (Chemical Mechanical Polishing) method used is often used. After polishing the surface of the semiconductor wafer, which is the surface to be processed, using a polishing liquid, the interface between the polishing pad and the semiconductor wafer becomes hydrophobic, making it difficult to separate the semiconductor wafer. The semiconductor wafer is detached at a position where a part of the semiconductor wafer is separated from the polishing pad. This operation is called, for example, an overhang operation (see, for example, Patent Document 1).

In the semiconductor wafer movement after the polishing process using the polishing apparatus described in Patent Document 1 or the like, a defect such as dust increases on the polished semiconductor wafer surface when the outer peripheral edge of the polishing pad contacts the semiconductor wafer. There is a point.
JP 7-135192 A

  The present invention provides a method of manufacturing a semiconductor device that can reduce the occurrence of defects due to movement of a semiconductor wafer after polishing.

  In one embodiment of the present invention, a method of manufacturing a semiconductor device includes a step of supplying a polishing liquid to a surface to be polished of a semiconductor wafer in contact with a polishing pad to polish the semiconductor wafer, and supplying the polishing liquid after the polishing process is completed. A step of supplying a pure water containing a surfactant to the polished surface of the semiconductor wafer that comes into contact with the polishing pad, and hydrophilizing the interface between the polishing pad and the semiconductor wafer; And removing the wafer from the pad and moving the wafer.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the semiconductor device which can reduce generation | occurrence | production of the defect by the semiconductor wafer movement after a grinding | polishing process can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a method for manufacturing a semiconductor device according to Example 1 of the present invention will be described with reference to the drawings. 1 is a flowchart showing a polishing process of a semiconductor wafer, FIG. 2 is a configuration diagram of a polishing apparatus, FIG. 2A is a plan view thereof, and FIG. 2B is a cross section taken along line AA in FIG. FIG. 3, FIG. 3 is a sectional view showing the hydrophilization of the interface between the semiconductor wafer and the polishing pad and the separation of the semiconductor wafer, FIG. 4 is a flowchart showing the polishing process of the comparative example, and FIG. 5 is a sectional view showing the separation of the semiconductor wafer of the comparative example. is there.

  As shown in FIG. 1, in a CMP (Chemical Mechanical Polishing) method of a semiconductor wafer using a polishing apparatus, polishing pad conditioning (S1), semiconductor wafer polishing (S2), interfacial hydrophilization (S3), semiconductor wafer A series of steps of separation (S4) and post-CMP processing (S5) are performed.

  As shown in FIG. 2A, the polishing apparatus used in the CMP method includes a polishing table 1 provided with a polishing pad 3 on the surface, and a surface to be polished of the semiconductor wafer while holding the back surface of the semiconductor wafer. Semiconductor wafer holding head 4 to be brought into contact with the polishing pad, supply nozzle 6 for supplying a polishing liquid during the polishing process, supply nozzle 7 for supplying pure water or pure water containing a surfactant, etc., and semiconductor wafer holding A semiconductor wafer holding head drive mechanism (not shown) that rotates the head 4 relative to the polishing table 1 and moves the semiconductor wafer holding head 4 in the left-right direction is provided.

  The polishing apparatus includes a wiring material (copper (Cu), aluminum (AL), etc.) on the surface of a semiconductor wafer (for example, a 12-inch semiconductor wafer) on which a semiconductor integrated circuit (LSI) is formed, an interlayer insulating film (TEOS film, Low− K film, etc.), insulating film, bare semiconductor wafer, resist film, etc. are used for planarization treatment.

  As shown in FIG. 2B, a spindle 2 that supports the polishing table 1 and rotates the polishing table 1 is provided below the polishing table 1. The semiconductor wafer holding head 4 holds the semiconductor wafer 5 to be polished on the polishing pad 3, and is provided with a retainer ring 11, a membrane 12, an upper plate 13, and a spindle 14. Although not shown here, a dresser for treating the surface of the polishing pad 3 to adjust the surface state is provided on the polishing pad 3.

  The retainer ring 11 is provided at an end portion of the semiconductor wafer holding head 4, is in contact with the side surface of the semiconductor wafer 5, and holds the semiconductor wafer 5 so that the semiconductor wafer 5 does not jump out of the semiconductor wafer holding head 4 during polishing. The membrane 12 is provided between the semiconductor wafer 5 and the upper plate 13, abuts against the back surface (second main surface) opposite to the surface (first main surface) to be polished of the semiconductor wafer 5, and the semiconductor wafer 5 Hold. The upper plate 13 holds the retainer ring 11 and the membrane 12. The spindle 14 is provided on the upper plate 13, rotates the semiconductor wafer holding head 4, and is rotationally controlled by a semiconductor wafer holding head driving mechanism (not shown).

  In the CMP method of a semiconductor wafer using a polishing apparatus, for example, immediately after the polishing pad 5 is replaced, the polishing pad 3 is dressed before the semiconductor wafer 5 is polished. Specifically, the surface of the polishing pad 3 is modified so as to enable CMP polishing of the semiconductor wafer by rotating the dresser while supplying pure water or the like (step S1).

  Next, the surface of the semiconductor wafer 5 to be polished is brought into contact with the polishing pad 3, the back surface of the semiconductor wafer 5 is held by the membrane 12, and the side surface of the semiconductor wafer 5 is held by the retainer ring 11 and polished from the supply nozzles 6 and 7. Liquid, pure water or the like is supplied to the interface between the semiconductor wafer 5 and the polishing pad 3, and the semiconductor wafer is subjected to CMP polishing while the semiconductor wafer holding head 4 and the polishing table 1 are rotated in the same rotational direction.

  Due to the CMP polishing process, the interface between the semiconductor wafer 5 and the polishing pad 3 becomes more hydrophobic than before the CMP polishing. This is because the interior of the material to be polished by CMP polishing is exposed and the original properties of the material appear. For example, if the material to be polished is hydrophobic with respect to water, such as copper (Cu) or SiOC, it becomes more prominent. In addition, the more polished material remains at the interface between the semiconductor wafer 5 and the polishing pad 3, the more hydrophobic the material becomes. As the hydrophobicity increases, the adhesion between the semiconductor wafer 5 and the polishing pad 3 increases, and the separation of the semiconductor wafer 5 becomes difficult (step S2).

  Subsequently, as shown in FIG. 3, after the CMP of the semiconductor wafer is completed, the supply of the polishing liquid is stopped, and pure water containing a surfactant is supplied to the interface between the semiconductor wafer 5 and the polishing pad 3 to hold the semiconductor wafer. A hydrophilic treatment is performed on the interface between the polished semiconductor wafer 5 and the polishing pad 3 while rotating the head 4 and the polishing table 1 in the same rotation direction.

  In the hydrophilization treatment, a surfactant is supplied to the surface of the semiconductor wafer 5 that has been hydrophobized, and the surface of the semiconductor wafer 5 is hydrophilized. Further, the surface of the polishing pad 3 is also made hydrophilic. Since the water containing the surfactant is sufficiently supplied to the interface between the semiconductor wafer 5 and the polishing pad 3 rather than the water alone, dust adhering to the surface of the polished semiconductor wafer 5 is sufficiently removed, and a water mark or the like is removed. Occurrence can also be suppressed. For this reason, the hydrophilicity of the interface between the semiconductor wafer 5 and the polishing pad 3 is improved, the adhesion between the polishing pad 3 and the semiconductor wafer 5 is lowered, and the semiconductor wafer 5 can be easily detached from the polishing pad 3. .

  Here, the surfactant used has a value of 3-12 HLB (Hydrophile Lipophile Balance) at room temperature and has a hydrophilic / lipophilic balance. When dissolved in water, a cation or an anion is used. It is preferable to use a nonionic surfactant having a hydrophilic group that does not generate water. When HLB is less than 3, lipophilicity increases, and when HLB is greater than 12, hydrophilicity increases. The nonionic surfactant makes the surface of the semiconductor wafer 5 subjected to CMP polishing hydrophilic, but does not modify the surface of the semiconductor wafer 5 with cations or anions.

  Among nonionic surfactants, polyether-type nonionic surfactants having high chemical resistance and defoaming properties, such as polyoxyethylene alkyl ether (AE) and polyoxyethylene alkylphenyl ether (APA) or the like is preferably used. In the foaming surfactant, the generation of bubbles inhibits the hydrophilicity of the interface between the semiconductor wafer 5 and the polishing pad 3.

  The concentration of the surfactant in pure water is preferably 0.1% by weight or more and less than 50% by weight. When the concentration is less than 0.1% by weight, the effect of the surfactant does not appear, and when the concentration is more than 50% by weight, the solubility of the surfactant in pure water decreases. The Atlas method is used for calculating the HLB, but the Griffin method, the Davis method, the Kawakami method, etc. may be used instead (step S3).

  After the hydrophilic treatment, the semiconductor wafer 5 held by the semiconductor wafer holding head 4 is detached from the polishing pad 3 at a position immediately after the hydrophilic treatment without moving the semiconductor wafer holding head 4 to the end of the polishing table 1. (Step S4).

  Next, the polished semiconductor wafer 5 whose surface is made hydrophilic is moved to a semiconductor wafer cleaning section of a polishing apparatus (not shown), and post-CMP processing is performed in the semiconductor wafer cleaning section.

  In this case, it is preferable to perform post-CMP treatment while the surface of the semiconductor wafer 5 is hydrophilic. When the surface of the semiconductor wafer 5 changes from hydrophilic to hydrophobic during the movement of the semiconductor wafer 5, the surrounding dust or the like is likely to be physically adsorbed on the surface of the semiconductor wafer 5, so that, for example, pure water containing a surfactant Is preferably sprayed onto the surface of the semiconductor wafer 5 to maintain the hydrophilicity of the surface of the semiconductor wafer 5.

  In the post-CMP treatment, damage removal on the CMP residue and the surface portion is performed. For example, in CMP polishing of copper (Cu) by the damascene method, removal of complexes formed on the surface of copper (Cu), removal of copper (Cu) ions, removal of polishing pad material residue, removal of copper (Cu) oxide film, etc. Is performed (step S5).

  As shown in FIG. 4, in the CMP method of the semiconductor wafer using the polishing apparatus of the comparative example, polishing pad conditioning (S1), semiconductor wafer polishing (S2), semiconductor wafer movement (S11), semiconductor wafer separation (S4), A series of steps of CMP post-processing (S5) is performed. In the comparative example here, the polished semiconductor wafer is moved to the outer peripheral edge of the polishing pad. In addition, description is abbreviate | omitted about the process same as a present Example, and only a different part is demonstrated.

  As shown in FIG. 5, after the CMP of the semiconductor wafer is completed, the supply of the polishing liquid is stopped, pure water is supplied to the interface between the semiconductor wafer 5 and the polishing pad, and the semiconductor wafer holding head 4 and the polishing table 1 are rotated in the same rotational direction. The polishing liquid on the surface portion of the semiconductor wafer 5 polished while rotating is replaced with pure water. Note that pure water replacement alone does not sufficiently remove dust and the like adhering to the polished semiconductor wafer 5 surface, and it is difficult to suppress generation of water marks and the like.

  Since the surface of the polished semiconductor wafer 5 is more hydrophobic than before polishing, it is difficult to separate the semiconductor wafer 5 from the polishing pad 3 at this position. After the replacement with pure water, the semiconductor wafer 5 held by the semiconductor wafer holding head 4 is moved in parallel to the outer peripheral end of the polishing pad 3. Specifically, a part of the surface of the semiconductor wafer is exposed and moved until the adhesion between the polishing pad 3 and the semiconductor wafer 5 is lowered and the semiconductor wafer 5 can be detached from the polishing pad. At this time, since the outer peripheral edge of the polishing pad 3 is in contact with the semiconductor wafer 5, defects such as dust on the semiconductor wafer 5 increase (step S11).

  Next, after moving the polished and pure water-substituted semiconductor wafer 5 to the outer peripheral end of the polishing pad 3, the semiconductor wafer 5 held by the semiconductor wafer holding head 4 is detached from the polishing pad 3 (step S12). . Since the subsequent steps are the same as in the present embodiment, description thereof is omitted.

  Next, the defects generated on the polished semiconductor wafer surface will be described with reference to FIG. FIG. 6 is a diagram showing the number of defects in the semiconductor wafer. Here, a defect inspection apparatus is used to observe the number of defects and the distribution of the defects by irradiating the object with laser light, but a halogen light source, strobe light source, electron beam, etc. may be used instead of the laser light. Good.

  As shown in FIG. 6, in this embodiment, after the surface of the semiconductor wafer 5 is polished, the surface of the semiconductor wafer 5 polished with pure water containing a surfactant is hydrophilized to hold the semiconductor wafer 5. Since the holding head 4 is not moved to the outer peripheral end of the polishing pad 3, the occurrence of defects can be greatly suppressed.

  On the other hand, in the comparative example, since the semiconductor wafer 5 is moved to the outer peripheral end portion of the polishing pad 3, defects concentrate on the portion where the semiconductor wafer 5 contacts the outer peripheral end portion of the polishing pad 3. For this reason, the number of defects is large and the defect distribution is not uniform.

  As described above, in the semiconductor device manufacturing method of this embodiment, in the CMP method of the semiconductor wafer using the polishing apparatus, the supply of the polishing liquid is stopped after the CMP polishing of the semiconductor wafer, and Water is supplied to the interface between the semiconductor wafer 5 and the polishing pad 3, and the interface between the polished semiconductor wafer 5 and the polishing pad 3 is hydrophilized while rotating the semiconductor wafer holding head 4 and the polishing table 1 in the same rotation direction. . After the hydrophilic treatment is completed, the semiconductor wafer 5 held by the semiconductor wafer holding head 4 is detached from the polishing pad 3 at a position immediately after the hydrophilic treatment, and then the semiconductor wafer 5 is moved.

  For this reason, it is not necessary to move the semiconductor wafer 5 as the outer peripheral edge of the polishing pad 3 comes into contact with the semiconductor wafer 5, and the separation operation of the semiconductor wafer 5 can be minimized. It is possible to prevent defects such as dust from adhering to the surface.

  The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the invention.

  For example, in the polishing apparatus of the embodiment, the CMP polishing is performed using the polishing liquid, but the ECMP polishing apparatus that uses the electrolytic solution and applies the voltage between the polishing table and the semiconductor wafer to perform the electrolytic polishing. Can be applied.

1 is a flowchart showing a polishing process of a semiconductor wafer according to Embodiment 1 of the present invention. The schematic block diagram which shows the grinding | polishing apparatus which concerns on Example 1 of this invention, FIG. 2 (a) is the top view, FIG.2 (b) is sectional drawing which follows the AA line of Fig.2 (a). BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the hydrophilization of a semiconductor wafer and polishing pad interface, and semiconductor wafer separation which concern on Example 1 of this invention. The flowchart which shows the grinding | polishing process of the comparative example which concerns on Example 1 of this invention. Sectional drawing which shows semiconductor wafer separation of the comparative example which concerns on Example 1 of this invention. The figure which shows the defect number of the semiconductor wafer which concerns on Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polishing table 2 and 14 Spindle 3 Polishing pad 4 Semiconductor wafer holding head 5 Semiconductor wafer 6 and 7 Supply nozzle 11 Retainer ring 12 Membrane 13 Upper plate

Claims (4)

Polishing the semiconductor wafer by supplying a polishing liquid to the surface to be polished of the semiconductor wafer in contact with the polishing pad;
After completion of the polishing process, the supply of the polishing liquid is stopped, pure water containing a surfactant is supplied to the polished surface of the semiconductor wafer that contacts the polishing pad, and the interface between the polishing pad and the semiconductor wafer is supplied. Hydrophilizing, and
After the hydrophilic treatment, detaching the wafer from the pad and moving the wafer;
A method for manufacturing a semiconductor device, comprising:   2. The method of manufacturing a semiconductor device according to claim 1, wherein the separation of the semiconductor wafer is performed on a surface of the polishing pad where an end portion of the semiconductor wafer does not contact an end portion of the polishing pad.   The method for manufacturing a semiconductor device according to claim 1, wherein the surfactant is a polyether type nonionic surfactant and has an HLB in the range of 3 to 12 at room temperature.   4. The method of manufacturing a semiconductor device according to claim 1, wherein a concentration of the surfactant with respect to the pure water is in a range of 0.1 wt% to 50 wt%. 5.

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