1. Field of the Invention
The present invention generally relates to a method and an apparatus for manufacturing a semiconductor device, and particularly relates to a method and an apparatus for manufacturing a semiconductor device for implementing a wafer grinding process on a wafer fixed on an adhesive tape.
2. Description of the Related Art
A semiconductor manufacturing process includes a wafer process and a subsequent wafer grinding process. In the wafer process, semiconductor elements are formed on one surface (a front surface) of a wafer. In the wafer grinding process, the other surface (a back surface) of the wafer, without any semiconductor element, is ground so as to reduce a thickness of a wafer. However, it is difficult to handle the wafer with reduced thickness since the wafer may easily break.
Accordingly, a method and an apparatus for manufacturing a semiconductor device is required, which makes it easier to handle the wafer with reduced thickness and can prevent the breakage of the wafer.
Also, because the semiconductor manufacturing process is ever complex, more devices are required for manufacturing semiconductors. Therefore, there is a need for improving space efficiency of a semiconductor device manufacturing plant. Thus, further miniaturization of the apparatus for manufacturing semiconductors is also required.
Referring now to FIGS. 1-6, a method and an apparatus of the related art for manufacturing a semiconductor device will be described. FIG. 1 shows a prior device structure for a back grinding process that performs wafer grinding on the back surface of the wafer. FIGS. 2-6 show a method of implementing a prior back grinding process.
As shown in FIG. 1, in the prior back grinding process, the back grinding process is performed on a wafer 14 using a supply cassette 2, a storage cassette 4, a transfer machine 6, a wafer grinder 8, an ultraviolet (UV) irradiation device 10 and a remover 12. Hereinafter, each of the above devices will be described in its operation.
The supply cassette 2 is preloaded with the wafer 14 provided with an ultraviolet sensitive tape 16 (herein after referred to as a UV tape) on the front surface as shown in FIG. 2 (tape laminated). The transfer machine 6 extracts the wafer 14 provided with the UV tape 16 from the supply cassette 2 and transfers it to the wafer grinder 8.
The wafer grinder 8 is generally formed of a wafer grinding section 18 and a drying section 20. First, as shown in FIG. 3, the transfer machine 6 fixes the wafer 14 on a chuck table 28 provided in the wafer grinding section 18. The chuck table 28 is connected to a vacuum device so as to hold the wafer 14 on the chuck table 28 by vacuum. The wafer 14 is fixed on the chuck table 28 with the UV tape 16 placed at the bottom.
Subsequently, a grinding process (back grinding process) is performed until the wafer 14 has a required thickness. A grinding tool 22 comes into contact with the back surface (a surface with no element and provided with the UV tape) of the wafer 14 and then rotates to carry out this grinding process. In order to remove scraps and to cool the wafer 14, cleaning liquid is supplied to the surface subjected to the grinding process.
After being subjected to the grinding process at the wafer grinding section 18, the wafer 14 is transferred to the drying section 20 by the transfer machine 6. Then as shown in FIG. 4, the cleaning liquid is dried using a light source 24 such as a halogen lamp.
As described above, after the back grinding process and the drying process on the wafer 14 in the wafer grinder 8, the transfer machine 6 extracts the wafer 14 from the wafer grinder 8 and then transfers the wafer 14 to the UV irradiation device 10. As shown in FIG. 5, the UV tape 16 is irradiated with ultraviolet (UV) rays from an ultraviolet (UV) lamp 26.
A characteristic feature of an adhesive agent provided on the UV tape 16 is that it becomes stiff when irradiated with the ultraviolet rays. Thus by irradiating the UV tape 16 with the ultraviolet rays, the adhesive agent will become less adhesive. This facilitates the removal of the UV tape from the wafer 14.
As shown above, after irradiating the wafer 14 with the ultraviolet in the UV irradiation device 10, the transfer machine 6 extracts the wafer 14 from the UV irradiation device 10 and then transfers the wafer 14 to the remover 12. As shown in FIG. 6, the UV tape 16 is peeled off from the wafer 14 in the remover 12.
In the related art, the back grinding process is implemented on the wafer 14 using devices 2-12 and processes described above.
However, in the related art, devices such as the transfer machine 6, the wafer grinder 8, the UV irradiation device 10 and the remover 12 were required separately in order to perform the back grinding process. Also, there was a need for the transfer machine 6 in order to mount and extract the water 14 between each of devices 6-12.
Accordingly, it was necessary to provide a large number of devices 8-12 within a semiconductor manufacturing plant and to connect those devices 8-12 via a transfer machine 6. Therefore, there was a problem that a large installation space was needed within the plant.
Also, the transfer machine 6 mounts and extracts the wafer 14 between each device 2-12. Therefore, a considerable time is required between the extraction of the wafer 14 with the UV tape from the supply cassette 2 and the irradiation of the UV tape 16 at the UV irradiation device 10. This can cause a problem since the adhesiveness of the UV-sensitive adhesive agent provided on the UV tape may also change due to radiation from a fluorescent lamp.
Particularly, when a considerably long time is required before ultraviolet irradiation of the UV tape 16 as in the related art, the property of the adhesive agent will be greatly changed by a fluorescent lamp. Accordingly, the adhesive agent will not be sufficiently stiff when the UV tape 16 is irradiated by the ultraviolet in the UV irradiation device 10. This causes a problem that the adhesive agent may remain on the wafer 14 when peeling off the UV tape 16 from the wafer 14 by the remover 12.
Any residual adhesive agent on the wafer 14 will be inconvenient in the following manufacturing process for the semiconductor device. Therefore, in the related art, there was a need for a cleaning process after the removing process for removing any residual adhesive agent. This introduced an additional complexity to the process of manufacturing the semiconductor device.