BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a peeling apparatus for peeling a protective member from a wafer and discarding the protective member into a trash box.

Description of the Related Art

In a case where a wafer having a flat surface is to be fabricated in a semiconductor wafer manufacturing process, an as-sliced wafer in a disk shape is obtained by, for example, thinly cutting a circular cylinder ingot of silicon or the like with use of a wire saw or the like. An undulation or a warp is present on both sides of the wafer. Thus, the undulation or the warp is removed by making a rotating grinding stone abut against the cut surface of the wafer.

In order to perform grinding processing, a protective member is formed by a liquid resin on one surface of the disk-shaped wafer. This is to accommodate the undulation or the warp of the wafer by the protective member, and hold the wafer flatly under suction by a chuck table of a grinding apparatus. Specifically, a predetermined amount of liquid resin or the like is supplied onto a circular sheet having a larger diameter than that of the wafer. Then, the other surface of the wafer is held under suction by a holding unit, and the wafer is pressed from above against the liquid resin on the sheet that is disposed so as to face the one surface of the wafer. Thus, the liquid resin is spread, and the whole of the one surface of the wafer is covered with a resin layer. A protective member is then formed by curing the resin layer by ultraviolet irradiation, for example. The protective member includes a protruding portion in which the sheet protrudes from the peripheral edge of the wafer.

Thereafter, the wafer is flatly held under suction by the chuck table of the grinding apparatus such that the other surface on which the protective member is not formed is oriented upward. Grinding is then performed by the grinding stone. Thereafter, the protective member is peeled from the wafer by a tape peeling apparatus (see Japanese Patent Laid-Open No. 2018-198290, for example), and the one surface of the wafer which was protected by the protective member is ground. The wafer both surfaces of which are flat can thus be fabricated.

The tape peeling apparatus disclosed in Japanese Patent Laid-Open No. 2018-198290 peels the resin layer from the wafer and discards the peeled protective member into a trash box. Specifically, the peeled protective member is slid downward on two inclined pipes, and is bent and dropped from a space between the two inclined pipes into the trash box located below the pipes. It is thus made possible to put many protective members into the trash box by properly stacking the protective members within the trash box. Because the protective members are thus thrown into the trash box in such a manner as to be stacked in piles, the frequency of work of extracting the protective members from the trash box is decreased, and a burden on a worker is reduced.

SUMMARY OF THE INVENTION

In the tape peeling apparatus described in Japanese Patent Laid-Open No. 2018-198290, the hardness of the cured resin or the thickness of the resin is changed by using different liquid resins depending on the magnitude of unevenness, an undulation, or a warp of the as-sliced wafer. If the hardness or the thickness differs among resins (for example, the hardness and the thickness are increased), a force necessary to bend the protective member on the two pipes under the own weight of the protective member changes, and a degree of bending differs among the protective members when only the two pipes are used. Thus, protective members cannot be passed between the pipes and properly be stacked within the trash box, in some cases.

In such a case, because the protective members are not properly stacked within the trash box, a sensor which is configured to detect that the trash box is filled with protective members detects the protective members improperly stacked within the trash box even though the trash box is not filled with protective members. Consequently, the frequency of extracting the protective members from the trash box by the worker is increased, so that the burden on the worker is increased.

It is accordingly an object of the present invention to provide a peeling apparatus that peels a protective member from a wafer and that discards the protective member into a trash box, and particularly a peeling apparatus that can discard the protective member by properly stacking the protective member into the trash box even when a force necessary to bend the protective member may change due to a change in hardness of a resin or a change in thickness of the resin.

In accordance with an aspect of the present invention, there is provided a peeling apparatus that peels, from a wafer, a sheet-shaped protective member formed on one surface of the wafer and that discards the protective member by stacking the protective member in a trash box having an opening in an upper surface of the trash box. The peeling apparatus includes a holding unit configured to hold another surface of the wafer under suction on a holding surface, a peeling unit configured to peel, from the wafer, the protective member formed on the wafer held by the holding unit, and a discarding unit configured to discard the protective member by stacking the protective member in the trash box. The peeling unit includes a gripping unit configured to grip a peripheral edge of the protective member and a moving unit configured to move the gripping unit and the holding unit relative to each other so as to make the gripping unit and the holding unit pass each other in parallel with the holding surface and in a direction from a periphery to a center of the wafer. The discarding unit includes an inclined dropping unit configured to drop the protective member gripped by the gripping unit obliquely downward to the opening of the trash box, and a first inclined plate and a second inclined plate that are arranged so as to face each other in a direction orthogonal to a traveling direction of the protective member when the protective member dropping obliquely downward above the opening is viewed from above. The first inclined plate and the second inclined plate are arranged such that a gap through which the protective member can pass is formed between a lower side of the first inclined plate and a lower side of the second inclined plate, and the first inclined plate and the second inclined plate are inclined such that a distance between an upper side of the first inclined plate and an upper side of the second inclined plate is larger than a distance between the lower side of the first inclined plate and the lower side of the second inclined plate. The protective member is bent in a protruding shape toward the trash box when dropping obliquely downward and entering the gap between the first inclined plate and the second inclined plate, and the protective member is stacked in a horizontal orientation within the trash box after passing through the opening of the trash box and further dropping.

Preferably, the first inclined plate and the second inclined plate each have a first air jetting port configured to jet air, the first air jetting port being formed in each of upper surfaces of the first inclined plate and the second inclined plate.

Preferably, the discarding unit further includes two pipes that are arranged individually on a lower end side of the first inclined plate and a lower end side of the second inclined plate and that each have a second air jetting port configured to jet air, and the air jetted from the second air jetting port generates airflow moving upward from below, on an upper surface of the first inclined plate and an upper surface of the second inclined plate.

Preferably, the discarding unit is formed such that an interval between a lower end of the first inclined plate and a lower end of the second inclined plate is smaller on a side far from the inclined dropping unit than the interval on a side close to the inclined dropping unit.

In the peeling apparatus according to one aspect of the present invention, the discarding unit that discards the protective member by stacking the protective member in the trash box includes the inclined dropping unit that drops the protective member gripped by the gripping unit obliquely downward to the opening of the trash box, and the first inclined plate and the second inclined plate that are arranged so as to face each other in the direction orthogonal to the traveling direction of the protective member when the protective member dropping obliquely downward above the opening is viewed from above. The gap through which the protective member can pass is formed between the lower side of the first inclined plate and the lower side of the second inclined plate. The first inclined plate and the second inclined plate are inclined such that the distance between the upper side of the first inclined plate and the upper side of the second inclined plate is larger than the distance between the lower side of the first inclined plate and the lower side of the second inclined plate. Thus, even when a force necessary to bend the protective member may change due to a change in hardness of the protective member or a change in thickness of the protective member, the protective member in contact with the first inclined plate and the second inclined plate is bent in a protruding shape toward the trash box because the protective member dropping obliquely downward enters a space between the first inclined plate and the second inclined plate. Further, a bent part can be widened by the first inclined plate and the second inclined plate according to a position at which the protective member is dropping obliquely downward. Hence, as compared with the conventional peeling apparatus in which only two pipes form the protective member into a protruding shape toward the opening of the trash box, the first inclined plate and the second inclined plate assist the protective member in forming into a protruding shape toward the opening of the trash box from a state in which the protective member is at a position higher than the opening of the trash box. Then, the protective member in a protruding shape passes through the opening of the trash box, assumes a horizontal orientation due to the own elasticity of the protective member while further dropping within the trash box, and is then stacked within the trash box. It is thus possible to discard a sufficient number of protective members by properly stacking the protective members in the trash box.

In a case where the first inclined plate and the second inclined plate have the first air jetting ports, air is jetted from the first air jetting ports, and thus, the air can reduce a friction between the upper surfaces of the first inclined plate and the second inclined plate and the protective member when the protective member is bent in a protruding shape toward the trash box by entry of the protective member dropping obliquely downward between the first inclined plate and the second inclined plate. The protective member can thus be bent in a protruding shape toward the trash box, over the trash box with less resistance.

In a case where the two pipes that are arranged on the respective lower end sides of the first inclined plate and the second inclined plate and that have the second air jetting ports configured to jet air are provided, the air jetted from the second air jetting port generates airflow moving upward from below, on the upper surface of the first inclined plate and the upper surface of the second inclined plate when the center of the protective member is bent in a protruding shape toward the trash box by entry of the protective member dropping obliquely downward between the first inclined plate and the second inclined plate. Thus, the air can reduce the friction between the upper surfaces of the first inclined plate and the second inclined plate and the protective member. The protective member can thus be bent in a protruding shape toward the trash box, over the trash box with less resistance.

In a case where the interval between the lower end of the first inclined plate and the lower end of the second inclined plate is smaller on the side far from the inclined dropping unit than that on the side close to the inclined dropping unit, the speed of the protective member dropping obliquely downward is decreased by the reduced interval between the first inclined plate and the second inclined plate. Thus, the protective member is prevented from passing over the trash box, and the protective member can be bent in a protruding shape and dropped into the trash box.

The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing a preferred embodiment of the invention.

