Semiconductor manufacturing apparatus and wafer processing method

A semiconductor manufacturing apparatus and a wafer processing method are disclosed. The semiconductor manufacturing apparatus, comprises a rotatable device for supporting a wafer. A sensor for irradiating a laser beam onto a surface of the wafer and a detector including a plurality of modules for detecting the laser beam reflected from the wafer are also included. The sensor obtains information regarding the wafer, based on a change in the surface status of the wafer, which the modules sense when the laser beam is reflected from the wafer.

CLAIM FOR PRIORITY

This application is based on and claims priority to Korean Patent Application No. 2005-55230 filed on Jun. 24, 2005 in the Korean Intellectual Property Office (KIPO), the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

The present invention relates in general to the field of a semiconductor manufacturing apparatus and a wafer processing method. More particularly, it relates to a semiconductor manufacturing apparatus and a wafer processing method that can detect a process error and perform feedback regarding the wafer.

2. Description of the Related Art

In order to manufacture a semiconductor device, various patterns such as wiring, a transistor and a capacitor are generally formed on a silicon wafer. For the purpose of forming these patterns, a photolithography process of depositing a thin film on a wafer, form a photoresist pattern on the thin film and then etching the thin film according to the photoresist pattern is usually used. The photolithography is the process of coating a photoresist onto the wafer on which the thin film is deposited, illuminating a light onto the photoresist, developing a photoresist pattern reacted to the light, and forming a specific photoresist pattern by selectively removing the photoresist. The photoresist pattern, which is formed through the photolithography process, is used as an etching mask in an etching process.

A series of inspection process is performed for inspecting the photoresist pattern formed through the photolithography process prior to the etching process. These inspection processes include a defect inspection of the photoresist pattern, an edge bead removal (EBR) inspection for removing the photoresist on an edge of the wafer, an EBR size inspection, reticule error inspection, and others. After advancing a photoresist coating process and the following processes, a worker performs monitoring of the EBR size in order to check whether the EBR size is within a set range. In other words, if a poor EBR size is detected after all processes, checking and verifying the irregular EBR size is performed too late, thereby increasing time loss and damage accordingly. Additionally, checking and verifying the EBR size has been limited to accurately perform monitoring, since it depends significantly on a level of skill of an operator. Further, it has caused problems of loss of equipment and quality deterioration of the previously advancing wafer, because proper processing was not performed up until a centering error of the wafer related to the poor EBR size was detected.

SUMMARY

An object of the present invention is to provide a semiconductor manufacturing apparatus and a wafer processing method, which can exactly detect and verify whether an EBR size is irregular and whether there is a centering error on a wafer.

Another object of the present invention is to provide a semiconductor manufacturing apparatus and a wafer processing method, which can correct the centering of a wafer using light and measure an EBR size accurately and reliably.

According to an aspect of the present invention, there is provided a semiconductor manufacturing apparatus, comprising a rotatable device for supporting a wafer. Furthermore, there is a sensor for irradiating a laser beam onto a surface of the wafer. Also, a detector including a plurality of modules for detecting the laser beam reflected from the wafer. The sensor obtains information regarding the wafer, based on a change in the surface status of the wafer which the modules sense when the laser beam is reflected from the wafer. In one embodiment, the sensor includes a projector. In a further embodiment, the rotatable device for supporting a wafer comprises a rotatable chuck.

The information regarding the wafer preferably includes at least one of (a) the centering status of the wafer as supported on the rotatable device, and (b) the edge bead removal size of the wafer. In another embodiment, the laser beam irradiated from the sensor crosses an upper surface of the wafer. In a further embodiment, the sensor irradiates the laser beam on an edge of the rotating wafer.

In another further embodiment, the semiconductor manufacturing apparatus, can comprise a rotatable device for supporting a wafer having a photoresist coated thereon. It can also include a nozzle for spraying chemicals for removing the photoresist coated on an edge of the wafer, a sensor for irradiating a laser beam on the edge of the wafer, and a detector for detecting the laser beam reflected from the wafer, configured to obtain a waveform of a surface status of the wafer. The sensor can measure the width of the wafer edge from which the photoresist is removed by the chemicals and senses at least one of the eccentricity of the wafer and the width of the wafer edge from which the photoresist is removed. In another embodiment, the manufacturing apparatus can comprise a wafer centering device including a light emitter located on an upper part of the wafer edge and a light receiver on a lower part of the wafer edge. The wafer centering device can be configured to detect the wafer centering based on whether the light receiver senses light.

A wafer processing method can also be provided. The method can comprise providing a wafer, coating a predetermined material on the wafer removing the predetermined coating material from an edge of the wafer, irradiating a laser beam onto the wafer edge from which the predetermined material is removed, obtaining information on a predetermined position of the wafer based on a sensing position of the laser beam reflected from the wafer edge, and correcting the position of the wafer, if the information indicates that the wafer is not in the predetermined position. In one embodiment, the step of irradiating the laser beam on the wafer edge from which the predetermined material is removed and obtaining the information on the position of the wafer according to the sensing position of the laser beam reflected from the wafer edge comprises irradiating a laser beam crossing the upper part of the wafer. In another embodiment, the step of irradiating the laser beam on the wafer edge from which the predetermined material is removed and obtaining the information on the position of the wafer according to the sensing position of the laser beam reflected from the wafer edge comprises rotating the wafer and irradiating the laser beam on an edge of the rotating wafer. In a still another embodiment, the step of irradiating the laser beam on the wafer edge, from which the predetermined material is removed, and obtaining the information on the position of the wafer according to the sensing position of the laser beam reflected from the wafer edge further comprises measuring the width of the wafer edge from which the predetermined material is removed.

The present invention may advance the monitoring of the EBR size following conducting an EBR process. It may also automatically control the EBR size or the wafer centering using a feedback system, in case the EBR size is poor, thereby improving the reliability of measuring the EBR size and the quality of the wafer.

The present invention will not be limited to the technical objects described above. Other objects not described herein will be more definitely understood by those skilled in the art from the following detailed description.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Subject matters and features of the exemplary embodiments of the present invention will be covered by the detailed description and drawings.

Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawing.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawing. The embodiments will be explained in detail for enabling those skilled in the art to execute the present invention.

Referring toFIG. 1, a semiconductor manufacturing apparatus200is an example of a coating process unit for coating a photoresist on a wafer and removing the photoresist formed irregularly on an edge of the wafer, namely an edge bead. The apparatus200is provided with a spin chuck110for supporting the wafer (W) using a vacuum absorption method or other suitable methods, and a bowl210arranged around the spin chuck110for preventing the dispersion of the photoresist and the rinse liquid. Additionally, an EBR nozzle220for removing the edge bead formed on the edge of the wafer is provided.

If a photoresist120is coated on the wafer (W), the rinse liquid such as a thinner is discharged from the nozzle220to the edge of the rotating wafer (W) in order to remove the edge bead. As shown inFIG. 2, an EBR size becomes uniform, covering the edge of the wafer, if the wafer centering is accurately adjusted. However, as shown inFIG. 3, the EBR size becomes non-uniform, if the wafer centering is poor. In other words, since the photoresist120is excessively removed from one edge of the wafer and incompletely removed from the other, the EBR size becomes non-uniform.

Accordingly, the semiconductor manufacturing apparatus200includes a sensing unit100having a sensor130configured to detect (a) whether the wafer is eccentric and (b) the EBR size. The sensor130comprises a projector130afor illuminating a laser beam and a detector130bfor sensing the laser reflected from the wafer (W). The projector130aand the detector130bare controlled by a control unit132.

Referring toFIG. 4, the projector130ailluminates a laser onto the wafer (W) which has passed through the EBR process and senses the laser reflected from the detector130b. At this time, the laser illuminated onto a part of which the photoresist120is removed from surface of the wafer (W) enters into the detector130bthrough a light path A. However, the laser illuminated onto a part of which the photoresist120is not removed from the wafer enters into the detector l30bthrough a light path B. In other words, a reflection path of the laser becomes different according to whether the photoresist120is in existence. Additionally, as the spin chuck110is rotating, the sensing operation is performed on the whole edge of the wafer (W).

Referring toFIG. 5, a plurality of pixels132bare arrayed in the detector130b. Accordingly, the pixels132bsense respectively the laser entering through the light path A and B. Thus, one of the pixels132bsenses the laser reflected from the part of which the photoresist120is removed from the wafer and another one of the pixels132bsenses the laser reflected from the part of which the photoresist120is formed. The detector130bcan judge whether the photoresist120is removed, based on information on the sensed laser. However, when the laser is continuously illuminated onto the rotating wafer (W), if the laser reflected from the wafer is detected at different location by the detector130b, it means that the EBR size is different, i.e., the wafer centering is poor.

Referring toFIG. 6, the semiconductor manufacturing apparatus200including the sensing unit100is controlled by a main controller500. The main controller500communicates with a machine controller400, and the machine controller400communicates with an input/output board (I/O board)300of the sensor100. The main controller500, as an equipment controller, has main functions of main machine interface and data management, for example, process status, equipment status, recipe management and the like. The machine controller400has main functions of controlling, monitoring and collecting all sorts of data of system hardware including a robot arm and a nozzle.

Referring toFIG. 7, when it is confirmed that the wafer centering is poor (step610), due to the sensing operation of the sensor100, this information is sent to the main controller500through a sensor I/O board300(step620). The main controller500calculates correction data about the wafer centering on the basis of this information (step630), and then transmits the data to the machine controller400which controls the robot and (step640). The robot arm makes it possible to correct the wafer centering on the basis of the corrected data, when the wafer is loaded (step650). The following processes can be conducted after the wafer centering. Though only the wafer centering is explained, it is possible to be applied to other information such as the EBR size as described below including the wafer centering.

Referring again toFIG. 4, the sensor130may measure an EBR size (d). Therefore, in the case where the protector130ailluminates the laser moving from the edge of the wafer (W) toward a central axis of the wafer (W) and the detector130bdetects the laser, when a position of the laser detected by the detector130bis changed, the changed position corresponds to a part of which the photoresist120is coated. Accordingly, the EBR size (d) is from a circumference of the wafer to a part from which the waveform of the laser detected by the detector130bto is changed. If the EBR size is within a predetermined range, the following processes are advanced. If not so, the following processes are not advanced by setting an interlock, and the EBR size (d) is set within the predetermined range by resetting a position of the EBR nozzle220.

Referring toFIG. 8, a sensor140may include a light emitter142and a light receiver144, in order to accurately correct the wafer centering. The light emitter142and the light receiver144may be respectively composed of a charged couple display (CCD) that includes a plurality of pixels. The CCD light receiver144detects light generated from respective pixels of the CCD light emitter142by each pixel, and the light which is not detected from pixels that is located in a part shielded by the wafer (W). Accordingly, the CCD light receiver144determines whether the wafer centering is proper, according to whether the light is detected from respective pixels.

Referring toFIG. 9, a sensing unit900includes a projector700for irradiating a laser and a detector800for sensing the laser and detecting the high and low emissions of an illuminated object. The projector700includes a lamp710as a light source of the laser, an optical cable720for providing a path to the laser generated from the lamp710, an illumination unit730having a lens732and a mirror734, and a projection unit740composed of a projection grating unit742and a window744. The detector800includes a detection unit830, a modulation unit820and a data acquisition module (DAM)810. The detection unit830comprises a window838onto which the laser reflected from the wafer (W) enters, a polarizing lens836, a birefringent plate834and a detection grating unit832. The modulation unit820comprises a mirror828, a lens826, an optical modulator824and a polarizing lens822. The data acquisition module (DAM)810comprises a lens array814and a sensor812.

Referring toFIGS. 10 and 11, the projection grating unit742and the detection grating unit832are respectively composed of a plurality of cells or gratings742aand832a. A ruler is engraved on the gratings742aand832arespectively. For example, the grating742aand832acan be respectively arranged at the width of about 2.80 mm, the height of 2.50 mm and the pitch of 3.40 mm. The gratings742aand832ahaving these configurations make it possible to more accurately measure a search area, though still limited, in comparison with a capture system of taking charge of wide areas.

Referring again toFIG. 9, the laser beam generated from the lamp710enters into the projection grating unit742by passing through an illumination unit730via the optical cable720. The laser beam which passes through the projection grating unit742is converted to a slit shape and reflected onto the wafer (W). The laser beam reflected onto the wafer (W) passes through a polarizing lens836. A projection grating image reflected from the polarizing lens836is polarized and projected onto the birefringent plate834. The birefringent plate834divides the incident laser beam into two components. One of these components is an ordinary beam and the other is an extraordinary beam. These beams are crossed each other at an angle of 90 degrees.

The two components are projected onto the detection grating unit832and the laser beam passes through the detection grating unit832where it is detected by the DAM810. The DAM810includes a series of light-sensing diodes.

Referring toFIG. 12, when the wafer (W) is located on a high location, if the beam is illuminated to the photoresist120on the wafer (W), output values of cells on both sides among three cells of the detection grating unit832are higher than that of a cell in the middle. This means that the photoresist120is existed on the wafer (W). In other words, if the wafer centering is poor, it indicates what direction the chuck110for supporting the wafer (W) is moved. Thus, the wafer centering is corrected by information sensed by the sensing unit900ofFIG. 9. Additionally, it may be also useful to control the height of the chuck110. In other words, the height of the chuck110is controlled until there is no a signal output difference among three cells in the detection grating unit832using the sensing unit900.

Referring toFIG. 13, whether the photoresist120is coated on the wafer (W) or not, the detector800detects the height change according to a path change of the laser beam reflected from the wafer (W). The height change (T) on the wafer (W), as shown inFIGS. 14 and 15, is represented as a position change of a slit shape of beam in the detection grating unit832.

Sensing units100and900, as shown inFIGS. 1 and 9, may measure the wafer centering and the EBR size by crossing and sensing the whole surfaces of the wafer (W), as depicted inFIG. 16. On the other hand, as shown inFIG. 17, the sensing units100and900may measure the wafer centering and the EBR size by sensing only edges of the wafer (W) and enabling the wafer (W) to be rotated. As a result of sensing, as shown inFIG. 18, a part (I) having the photoresist on the wafer (W) and a part (II and III) not having the photoresist on the wafer (W) are sensed. If respective widths (d1and d2) of the parts (II and III) are the same (A), the wafer centering is acceptable, and, if not so, the wafer centering is not acceptable.

Referring toFIG. 19, the semiconductor manufacturing equipment1000includes a load port910on which a device configured to load the wafer such as a carrier is placed, a plurality of spinners930,940,950, and960, and a chemical control unit920, where the spinner and control unit perform a desired processing. The spinners930,940,950, and960, respectively, include input/output boards932,942,952, and962, for inputting/outputting information on respective spinners930,940,950, and960. Likewise, the liquid control unit920includes the input/output board922. At least one of the spinners930,940,950, and960, includes a coating process unit200, and the sensing units100and900are installed in the coating process unit200. The semiconductor manufacturing equipment1000is set at a regular interval, scans or transmits the laser beam onto the surface of the wafer (W) after finishing the process of the relevant unit930,940,950, and960, analyzes its waveform (seeFIG. 18), and accordingly calculates the eccentricity of the wafer and an EBR size, respectively. As a result of performing feedback on the result data, if it is determined that the electricity of the wafer and the EBR size are of an acceptable magnitude, the semiconductor manufacturing equipment1000is normally operated, and, if not so, the operation of the semiconductor manufacturing equipment1000is stopped. Additionally, the wafer centering and the EBR size are automatically controlled by the main controller based on the result data.

As described above, the monitoring of the EBR size, according to the present invention, can be advanced, right after the EBR process, and the EBR size and the wafer centering can be automatically controlled using the feedback system. In case the EBR size is poor, it is capable of increasing the reliability of measurement of the EBR size and further the quality of the wafer.

It should be understood by those of ordinary skill in the art that various replacement, modifications and changes in the form and details may be made therein without departing from the sprit and scope of the present invention as defined by the following claims. Therefore, it is to be appreciated that the above described embodiments are for purpose of illustration only and are not to be construed as limitations of the invention.