JPH0424860B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a method for manufacturing a semiconductor device, in which a mesa groove is formed on one or both sides of a semiconductor board, and then the semiconductor board is divided at the mesa groove portion by dicing or the like to form device pieces.

[Prior art and its problems]

A method for forming mesa grooves on a semiconductor board is to use a mixed acid such as hydrofluoric acid, nitric acid, and acetic acid as an etching solution, and then protect the surface with a resin film or the like.
A commonly used method is to immerse and oscillate a semiconductor board with only the mesa groove forming portion exposed for etching. However, in this case, not only when the etching conditions, such as the number of semiconductor boards, the pattern of the mesa groove, the composition or temperature of the etching solution, the amount of etching solution, and the method of rocking, are clearly different, but also due to minute differences or variations in them, However, the etching speed changes, and even if etching is performed for the same time, the depth of the mesa groove formed often differs. If the mesa groove depths differ, there will be differences in the mesa groove shape or area of each element piece, making it impossible to obtain desired characteristics. Therefore, to prevent the mesa groove from becoming too deep, the target mesa groove depth is achieved by repeating the cycle of stopping etching midway through, measuring the groove depth created by etching, and re-etching. I had no choice but to find a way to get more. Therefore, in order to always obtain a uniform mesa groove depth, there is a drawback that it takes a very long time to form the mesa groove.

[Purpose of the invention]

Except for the above-mentioned drawbacks, the present invention can always form a uniform mesa groove depth through a short-time etching operation without repeating etching depth measurement or re-etching, and has a desired area and mesa shape. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can obtain a device piece.

[Key points of the invention]

According to the present invention, a linear groove having a predetermined depth from the back surface of the semiconductor board and reaching from the periphery of the semiconductor board to the periphery is formed at the edge of the semiconductor board by machining, and a mesa groove is formed by etching from the surface. When forming, the linear surface portion facing the linear groove is etched at the same time, and the etching is stopped when the linear portion penetrates and the edge of the semiconductor board is separated. Thus, the above objectives are achieved.

[Embodiments of the invention]

Figures 1a, b and 2 show an embodiment of the invention. As shown in FIG. 1a, the lower surface of the semiconductor substrate 1 is covered with a resist 2, and a groove 3 having a depth t is formed by dicing. Next, a resist 2 having a linear exposed pattern 4 similar to the conventional mesa groove formation is applied to the upper surface. In this case, the linear exposed pattern 5 is also formed on the upper surface side facing the dicing groove 3. This linear pattern 5 and the groove 3 below it are provided at the edge of the semiconductor board, as shown in FIG. When the semiconductor board 1 coated with resist is immersed in a mixed acid, mesa grooves 6 are formed by etching as shown in FIG. The grooves 8 formed by the progress of etching from
is separated. The operator recognizes this separation and stops etching. Thereafter, the semiconductor board 1 is separated at the mesa groove 6 by dicing or bending to obtain element pieces. Since the linear pattern 5 and the dicing groove 3 are provided in the margin of the semiconductor board, they do not affect the number of element pieces that can be obtained. During etching, the etching progresses from the dicing groove 3 as described above, so the edge 11 of the semiconductor board is etched.
If the relationship between the depth of the mesa groove 6 formed before separation and the depth t of the dicing groove 3 is investigated in advance and a diagram as shown in FIG. 3 is obtained, the dicing groove depth t can be determined.
By setting , it is possible to always form the mesa groove 6 with a desired depth. FIGS. 4a and 4b show another embodiment in which both mesa-shaped elements are manufactured. As shown in FIG. 4A, the dicing grooves 3 are formed in advance, and the exposed pattern 51 of the resist 2 is also provided in the exposed portions of the dicing grooves 3. As shown in Figure 4b, etching grooves 7 and dicing grooves 3 are formed from the top surface.
The edges 11 of the semiconductor board are separated by the connection of the etched grooves 8 which have proceeded from the beginning, thereby determining the final stage of etching and making it possible to form mesa grooves 6 of uniform depth from both sides.

【Effect of the invention】

According to the present invention, when forming a mesa groove by etching on a semiconductor board, a linear groove reaching from the periphery of the semiconductor board to the periphery is formed in advance from the back side, and the etching groove from the front side advances from the linear groove. By determining the final stage of etching by connecting with the etching groove, there is no need to interrupt etching or repeatedly measure the etching depth.
Mesa groove formation time can be significantly shortened. Even if the etching conditions are different, a mesa groove of a predetermined depth can always be formed, which is extremely effective for manufacturing semiconductor devices with uniform characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the mesa groove forming process in an embodiment of the present invention, FIG. 2 is a plan view corresponding to FIG. 1a, and FIG. 3 is a mesa groove depth to be formed and a dicing groove depth. FIG. 4 is a cross-sectional view showing the process of forming a mesa groove in a different embodiment. 1: Semiconductor board, 2: Resist, 3: Dicing groove, 4, 5: Exposed pattern, 11: Semiconductor board separation part.

Claims (1)

[Claims] 1. In a method of forming a mesa groove from the surface of a semiconductor board by etching and then dividing the semiconductor board at the mesa groove to obtain element pieces, the edge of the semiconductor board has a predetermined depth from the back surface of the semiconductor board, A linear groove reaching from the periphery to the periphery of the semiconductor board is formed by machining, and at the same time when etching is performed to form a mesa groove, the linear surface portion facing the linear groove is also etched, so that the linear portion is removed by etching. A method for manufacturing a semiconductor device, characterized in that etching is stopped when the edge of the semiconductor board is separated.