JP3054452B2 - Semiconductor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing method. More specifically, a wafer having a warp in which the periphery is curved in the thickness direction with respect to the center due to the lattice constant changing in the thickness direction is chemically etched using an etching solution. To a method of etching the substrate.

[0002]

2. Description of the Related Art Conventionally, when a wafer having such a warp is chemically etched, the following is performed. First, as shown in FIG. 2A, a chemically stable hot melt type wax (which melts at a high temperature and solidifies at a normal temperature) is applied to a glass plate 3. On this, the warped wafer 1 is placed as shown in FIG. And
The wax 2 is once heated using a hot plate 4, and the wafer 1 is attached to a glass plate 3. Next, as shown in FIG. 2C, the wafer 1 is immersed in an etching solution 5 to chemically etch the surface 1a on the side not in contact with the wax 2. Finally, as shown in FIG.
The wafer 1 is removed from the etching solution 5, the wax 2 is heated again using the hot plate 4, and the wafer 1 is removed from the glass plate 3.

[0003]

When the wafer 1 having the above-mentioned warp is etched and the thickness of the wafer 1 changes, the warp of the wafer 1 originally tends to change so as to minimize the internal stress. . However, in the above-mentioned conventional etching method, since one surface 1b of the wafer 1 is completely fixed by the wax 2, during the progress of the etching shown in FIGS. 2 (c) and 2 (d) and during the removal of the wafer,
A large distortion is generated inside the wafer 1 and cracks (cracks) 6
And the crystallinity is degraded.

Accordingly, an object of the present invention is to provide a wafer having a warp in which a peripheral portion is curved in a thickness direction with respect to a center portion due to a change in a lattice constant in a thickness direction. An object of the present invention is to provide an etching method capable of preventing generation of cracks and deterioration of crystallinity when chemically etching using an etchant.

[0005]

In order to achieve the above object, the etching method according to the present invention is characterized in that the peripheral portion is thicker than the central portion because the lattice constant changes in the thickness direction. A method of chemically etching a wafer having a warp in a direction curved in a direction by using an etching solution, wherein the entire surface opposite to the etching surface of the wafer is chemically stable and flexible and has ultraviolet light. Reduced by light irradiation
A step of attaching a UV sheet having an adhesive property, and immersing the wafer in a state in which the UV sheet is attached in an etchant, and chemically etching the other surface of the wafer, so that the lattice constant is reduced. A step of changing the degree of warpage of the wafer caused by the change in the thickness direction so that the internal stress is minimized, and removing the wafer from the etching solution and irradiating the UV sheet with ultraviolet light. The method includes a step of reducing the adhesiveness of the UV sheet and a step of peeling the UV sheet having reduced adhesiveness from the wafer.

[0006]

When a wafer having the above-mentioned warpage is immersed in an etching solution with a UV sheet attached thereto, the surface of the wafer on which the UV sheet is attached is protected by being masked by the UV sheet, The other side of the wafer is chemically etched by the etchant. Unlike the conventional case, the wafer is only attached to a flexible UV sheet, so that when the wafer is etched and the thickness of the wafer changes, the degree of warping of the wafer is such that the internal stress is minimized. Changes easily. Therefore, during the progress of etching and after removal from the etching solution, generation of cracks and deterioration of crystallinity are prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The etching method of the present invention will be described below in detail with reference to embodiments.

First, as shown in FIG. 1A, a wafer 1 having a warp to be etched is prepared. This warpage is a mode in which the peripheral portion is curved in the thickness direction with respect to the center portion due to the lattice constant changing in the thickness direction. A chemically stable and flexible UV sheet 7 is attached to the entire one surface 1b of the wafer 1.
Next, the wafer 1 on which the UV sheet 7 is adhered is immersed in an etching solution 5 to chemically etch the other surface 1a of the wafer 1. Here, one surface 1b of the wafer 1 is protected by being masked by the UV sheet 7, while the other surface 1a of the wafer 1 is protected by the etching solution 5
Is chemically etched. Next, as shown in FIG. 1C, the wafer 1 is taken out of the etching solution 5 and the UV sheet 7 is irradiated with ultraviolet light 8. Thereby, the adhesiveness of the UV sheet 7 is reduced. Finally, as shown in FIG. 1D, the UV sheet 7 having reduced adhesiveness is peeled off from the wafer 1 to complete the process.

In this case, unlike the conventional case, since the wafer 1 is merely attached to the flexible UV sheet 7, when the wafer 1 is etched and the thickness of the wafer changes, Changes easily so that the internal stress is minimized. Therefore, it is possible to prevent the occurrence of cracks and deterioration of crystallinity in the wafer 1 during the progress of etching and after removal from the etching solution.

[0010]

As is clear from the above, the etching method of the present invention performs etching while attaching the wafer to a flexible UV sheet. , Cracks and deterioration of crystallinity can be prevented.

[Brief description of the drawings]

FIG. 1 is a process chart showing an etching method according to an embodiment of the present invention.

FIG. 2 is a process chart showing a conventional etching method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 1a The other surface 1b One surface 5 Etching liquid 7 UV sheet 8 Ultraviolet light

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Claims (1)

(57) [Claims] 1. A wafer having a warp in which a peripheral portion is curved in a thickness direction with respect to a center portion due to a change in a lattice constant in a thickness direction is chemically etched using an etching solution. A semiconductor manufacturing method for chemically etching, wherein the entire surface opposite to the etched surface of the wafer is chemically stable and flexible, and is reduced by ultraviolet light irradiation.
A step of attaching a UV sheet having an adhesive property, and immersing the wafer with the attached UV sheet in an etchant to chemically etch the other surface of the wafer so that the lattice constant is large. Changing the degree of warping of the wafer caused by the change in the vertical direction so that the internal stress is minimized; and taking out the wafer from the etching solution,
A semiconductor manufacturing method, comprising: irradiating a V sheet with ultraviolet light to reduce the adhesiveness of the UV sheet; and removing the UV sheet having reduced adhesiveness from the wafer.