Method for manufacturing small-diameter wafers, and method for setting the planned line for removing small-diameter wafers.

Abstract

This invention provides a novel method for manufacturing a large number of small-diameter wafers from a large-diameter wafer, and a method for setting the planned lines for removing the small-diameter wafers, using a new approach to setting circular cutting lines and crystal orientation marks. [Solution] A method for manufacturing a small-diameter wafer includes: a marking line setting step of setting at least two parallel marking lines 5, 5 corresponding to the crystal orientation of the wafer 11; a marking step of forming a marking M along each marking line 5, 5; an extraction line setting step of setting a first extraction row 31 and a second extraction row 32 by arranging extraction lines 31a, 32a corresponding to the shape of the small-diameter wafer 21 so that they overlap with one of the adjacent marking lines 5, 5; and an extraction step of extracting the small-diameter wafer along each extraction line 31a, 32a to form a small-diameter wafer 21 on which the marking M is formed.

Description

Technical Field

[0001] The present invention relates to a manufacturing method for manufacturing small-diameter wafers with a smaller diameter from a single large-diameter wafer. More specifically, it relates to a technology for efficiently manufacturing a larger number of small-diameter wafers without waste and increasing the number of wafers that can be obtained.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1 for example, there is known a technology for manufacturing wafers with a small diameter (hereinafter referred to as small-diameter wafers) such as about 3 inches (about 75 mm), about 1 inch (about 25 mm), and half inch (0.5 inch (about 12.5 mm)) from wafers with a diameter of 12 inches (about 300 mm) or more (hereinafter referred to as large-diameter wafers).

[0003] In Patent Document 1, it is aimed at improving productivity and quality by protecting the wafer surface. It is described that a protective member coating step of protecting the wafer surface with a protective member is carried out before a cutting step of cutting out a plurality of small-diameter wafers.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, a planned movement line is set so as to overlap with a planned cutting line that is a reference when cutting out a small-diameter wafer, and a laser beam is irradiated onto an arbitrary planned mark formation line that overlaps with the planned movement line to form a laser marking (a mark indicating the crystal orientation) on the small-diameter wafer.

[0006] In Patent Document 1, circular cutting lines corresponding to the shape of a small-diameter wafer are set along multiple parallel moving lines. However, extra space is left between adjacent circular cutting lines along the moving lines, and this space is not cut, resulting in the wasteful discarding of wafer material. Therefore, the challenge became how to reduce such waste and increase the number of small-diameter wafers that can be manufactured from a single large-diameter wafer.

[0007] In view of the above issues, this invention proposes a novel technology for manufacturing a larger number of small-diameter wafers from a large-diameter wafer by employing a novel method for setting circular cutting lines and crystal orientation marks. [Means for solving the problem]

[0008] The problems that this invention aims to solve are as described above, and the means for solving these problems will now be explained.

[0009] According to one aspect of the present invention, a method for manufacturing a small-diameter wafer includes: a marking line setting step of setting at least two parallel marking lines corresponding to the crystal orientation of the wafer; a marking step of forming a marking along each of the marking lines; a removal line setting step of setting a first removal row by arranging removal lines corresponding to the shape of the small-diameter wafer so as to overlap with one of the adjacent marking lines, and setting a second removal row by arranging removal lines corresponding to the shape of the small-diameter wafer so as to overlap with the other marking line; and a removal step of removing the small-diameter wafer along each of the removal lines to form a small-diameter wafer with markings formed on it.

[0010] Furthermore, according to one aspect of the present invention, the marking step involves forming the marking by laser processing.

[0011] Furthermore, according to one aspect of the present invention, the marking forms a crystal orientation mark indicating the crystal orientation of the small-diameter wafer.

[0012] Furthermore, according to one aspect of the present invention, the marking step is performed before or after the line setting step for the planned extraction line.

[0013] Furthermore, according to one aspect of the present invention, there is a method for setting extraction lines for a small-diameter wafer, which includes a marking line setting step of setting at least two parallel marking lines corresponding to the crystal orientation of the wafer, and an extraction line setting step of setting a first extraction row by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with one of the adjacent marking lines, and setting a second extraction row by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with the other marking line. [Effects of the Invention]

[0014] The present invention provides the following effects: In other words, according to one aspect of the present invention, the area of ​​the non-extraction region surrounded by the extraction line, which corresponds to the shape of the small-diameter wafer to be extracted, can be minimized, and consequently, a large number of small-diameter wafers can be extracted from a single large-diameter wafer. Furthermore, a crystal orientation mark corresponding to the crystal orientation of the large-diameter wafer can be formed on each small-diameter wafer, and the crystal orientation mark can be used in handling the small-diameter wafers. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram of a large-diameter wafer. [Figure 2] A diagram illustrating an example of marking using laser processing. [Figure 3] A diagram illustrating the planned marking lines and planned extraction lines. [Figure 4] A diagram showing an example of the layout of the planned extraction line on a large-diameter wafer with a diameter of approximately 150 mm. [Figure 5] A diagram showing an example of the layout of the planned extraction line on a large-diameter wafer with a diameter of approximately 200 mm. [Figure 6] A diagram showing an example of the layout of the planned extraction line on a large-diameter wafer with a diameter of approximately 300 mm. [Figure 7] A flowchart showing the steps included in an embodiment of the method for manufacturing a small-diameter wafer according to the present invention. [[ID=!1]] [Figure 8] A diagram for explaining the step of setting the planned marking line. [Figure 9] A diagram for explaining the marking step. [Figure 10] A diagram for explaining the extraction step.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a large-diameter wafer 11 to be processed in the method for manufacturing a small-diameter wafer according to the present invention. The wafer 11 is, for example, a disk-shaped wafer made of crystalline silicon (Si).

[0017] A notch 11n indicating the crystal orientation is provided on the outer peripheral edge of the wafer 11. Instead of the notch 11n, a linear orientation flat or the like may be provided. The diameter D1 of this wafer 11 is larger than the diameter of the small-diameter wafer to be taken out later, and a plurality of small-diameter wafers are manufactured from the wafer 11.

[0018] Furthermore, there are no restrictions on the material, shape, structure, size, etc., of the large-diameter wafer 11. For example, a substrate containing other semiconductors, Lamix, resin, metal, or other materials can be used as the wafer 11. In addition, both sides of the large-diameter wafer 11 (front surface 11a and back surface 11b) may be polished to a mirror finish, and both sides of the large-diameter wafer 11 may be covered with a protective material after polishing.

[0019] On one of the surfaces of such a wafer 11 (the surface 11a in the example of Figure 2), as shown in Figure 2, a plurality of parallel marking lines 5, 5 are set to form crystal orientation marks 21c indicating the crystal orientation of the small-diameter wafer to be extracted later, and marking is performed along these marking lines 5, 5 by laser processing or the like.

[0020] The laser marking example shown in Figure 2 involves forming groove-shaped markings M by performing laser ablation processing by irradiating with a laser from a laser irradiation unit 66 along a direction X1 corresponding to the crystal orientation of the notch 11n of the wafer 11. These groove-shaped markings M then form crystal orientation marks 21c on each small-diameter wafer after they have been removed and formed into individual wafers. These crystal orientation marks 21c indicate the crystal orientation of each small-diameter wafer that is formed later. In addition to laser processing, line-shaped (linear) markings may also be formed by cutting with a cutting blade, for example.

[0021] In laser processing, for example, the laser irradiation unit 66 is moved, and a table (not shown) that holds the wafer 11 is also moved, thereby moving the laser irradiation unit 66 and the wafer 11 relative to each other in the X-axis direction. Furthermore, by index feeding in the Y-axis direction, markings M are formed on adjacent marking target lines 5.

[0022] The marking M can be composed of, for example, a series of grooves that are continuous without interruption in the X-axis direction, or grooves that are formed intermittently at predetermined intervals. The depth of the grooves is not particularly limited, and the marking M may be formed as a linear shape with very shallow grooves.

[0023] The orientation in which the marking M is formed, that is, the orientation in which the marking line 5 is set (direction X1), can be, for example, perpendicular to the cutting direction of the V groove that forms the notch 11n of the wafer 11. Alternatively, if the wafer 11 does not have a notch 11n and an orientation flat is formed, the orientation can be parallel to this orientation flat.

[0024] At least two marking lines 5 are set parallel to each other. Between two adjacent marking lines 5, a first extraction row 31 and a second extraction row 32 are set, each consisting of extraction lines 31a and 32a (shown by dotted lines) for small-diameter wafers, arranged along the longitudinal direction of the marking lines 5. One marking line 5 overlaps each extraction line 31a of the first extraction row 31, and the other marking line 5 overlaps each extraction line 32a of the second extraction row 32.

[0025] As described above, as shown in Figure 3, two rows of extraction rows 31 and 32 are laid out between the two marking lines 5 and 5. In addition, the gap (spacing) between adjacent extraction lines 31a arranged in the first extraction row 31 is to be almost gapless, or a small gap may be provided. This gap can be set appropriately according to the type of process for extracting the small-diameter wafer, i.e., the processing accuracy due to differences in processing types such as laser processing and plasma processing, and the allowable error range of the diameter of the extracted small-diameter wafer. Note that there may be only one extraction line 31a arranged in the first extraction row 31.

[0026] As shown in Figure 3, the planned extraction line 32a of the second extraction row 32 is positioned so as to fit into the gap between adjacent planned extraction lines 31a in the first extraction row 31, thereby realizing a so-called honeycomb layout. This minimizes the area of ​​the non-extraction region 33 (the shaded area) surrounded by the planned extraction lines 31a and 32a, and consequently, ensures a larger number of small-diameter wafers can be extracted from a single large-diameter wafer. Note that the planned extraction lines 31a and 32a are hypothetical lines, but are shown as solid lines in Figure 3. Furthermore, there may be only one planned extraction line 32a arranged in the second extraction row 32.

[0027] Figure 4 shows an example of the layout of extraction lines 31a and 32a on a large-diameter wafer W1 with a diameter of approximately 150 mm. In this example, it is possible to extract 92 small-diameter wafers 21 with a diameter of approximately 12.5 mm.

[0028] Similarly, Figure 5 shows an example of the layout of extraction lines 31a and 32a in a large-diameter wafer W2 with a diameter of approximately 200 mm. In this example, it is possible to extract 170 small-diameter wafers 21 with a diameter of approximately 12.5 mm.

[0029] Similarly, Figure 6 shows an example of the layout of extraction lines 31a and 32a in a large-diameter wafer W3 with a diameter of approximately 300 mm. In this example, it is possible to extract 406 small-diameter wafers 21 with a diameter of approximately 12.5 mm.

[0030] Next, an example of a method for manufacturing small-diameter wafers, based on the above explanation, will be described according to the flowchart shown in Figure 7.

[0031] As shown in Figure 3, the marking line setting step involves setting at least two parallel marking lines 5, 5 corresponding to the crystal orientation of the wafer, A marking step in which marking M is formed along each planned marking line 5,5, The process involves setting up extraction lines 31a to create a first extraction row 31 by arranging extraction lines 31a corresponding to the shape of a small-diameter wafer so that they overlap with one of the adjacent marking lines 5,5, and setting up a second extraction row 32 by arranging extraction lines 32a corresponding to the shape of a small-diameter wafer so that they overlap with the other marking line, and The extraction step involves extracting small-diameter wafers 21 along each extraction line 31a, 32a to form small-diameter wafers 21 on which marking M is formed, This invention relates to a method for manufacturing small-diameter wafers that include [a specific component]. The following describes the details of each step.

[0032] <Steps for setting the planned marking lines> As shown in Figure 8, for example, a large-diameter wafer 11 held on a holding table (not shown) is imaged by a camera 62, and a controller 63 defines a coordinate system for determining the position of the wafer 11 based on the captured image.

[0033] The controller 63 sets a marking line 5 in the coordinate system of the wafer 11, for example, at a predetermined distance from the notch 11n of the wafer 11, and sets another marking line 5 parallel to the first marking line 5 with a predetermined gap between them. The gap between the marking lines 5, 5 can also be called the index width 5y, and this index width 5y is determined by the diameter 21d (Figure 2) of the small-diameter wafer 21 (Figure 2) to be extracted.

[0034] Each marking line 5 is set to be parallel to each other based on the crystal orientation of the wafer 11, and it is preferable to set as many marking lines 5 as possible on the large-diameter wafer 11 in order to maximize the number of small-diameter wafers 21 that can be obtained.

[0035] <Marking Step> As shown in Figure 9, the controller 63 uses the laser irradiation unit 66 to perform laser ablation along the planned marking line 5, thereby forming a continuous groove-shaped marking M.

[0036] <Steps for setting the planned extraction line> As shown in Figure 3, the controller 63 (Figure 8) sets the extraction lines 31a and 32a corresponding to the shape of the small-diameter wafer before or after the marking step. Each extraction line 31a and 32a is set to be in two rows between adjacent marking lines 5, 5, with one marking line 5 overlapping each extraction line 31a of the first extraction row 31 which is made up of extraction lines 31a, and the other marking line 5 overlapping each extraction line 32a of the second extraction row 32 which is made up of extraction lines 32a. Each extraction line 31a and 32a is set so as not to overlap with each other.

[0037] Furthermore, the planned extraction lines 31a and 32a may have different diameters, and the index width 5y, which is the distance between the planned marking lines 5, 5, is appropriately set according to the diameter of each planned extraction line 31a, 32a.

[0038] As shown in Figure 3, for example, in the first extraction row 31, if the diameter 21d of each extraction line 31a is approximately 1 inch (approximately 25 mm), the marking line 5 will overlap the extraction line 31a at a predetermined distance K = 5 μm (micrometers) from the outer edge of the extraction line 31a. The same applies to the second extraction row 32.

[0039] Depending on the dimensions of the large-diameter wafer 11, the index width 5y (Figure 8), and the planned extraction lines 31a and 32a, only the first extraction row 31 or only the second extraction row 32 may be set near the outer edge of the large-diameter wafer 11. Figure 8 shows an example where only the first extraction row 31 is formed near the outer edge on the side furthest from the notch 11n.

[0040] <Removal Step> As shown in Figure 10, the controller 63 removes (cuts) the small-diameter wafers 21 along each planned removal line 31a, 32a, thereby forming small-diameter wafers 21 on which crystal orientation marks 21c (marking M) are formed.

[0041] Here, the small-diameter wafer 21 can be removed (cut out) by, for example, irradiating the wafer 11 with a laser beam of a wavelength that absorbs the wafer 11 along each planned removal line 31a, 32a using a laser irradiation unit 66. Alternatively, it can be done by positioning the focal point of a laser beam of a wavelength that transmits to the wafer 11 inside the wafer 11 and irradiating the laser beam along each planned removal line 31a, 32a to form a modified layer inside the wafer 11. Alternatively, it can be done by cutting and cutting the wafer 11 with a core drill having an annular cutting blade (grinding wheel). Alternatively, it can be done by masking the areas corresponding to each planned removal line 31a, 32a with a protective film and removing the areas other than the protective film by plasma etching.

[0042] As described above, according to the present invention, as shown in Figure 3, the area of ​​the non-extraction region 33 (shaded area) surrounded by the extraction lines 31a and 32a, which correspond to the shape of the small-diameter wafer 21 to be extracted, can be minimized, and consequently, a large number of small-diameter wafers can be extracted from a single large-diameter wafer 11. Furthermore, as shown in Figure 2, a crystal orientation mark 21c corresponding to the crystal orientation of the large-diameter wafer 11 can be formed on each small-diameter wafer, and the crystal orientation mark 21c can be used in handling the small-diameter wafer 11. [Explanation of Symbols]

[0043] 5. Planned marking lines 5y index width 11 wafers 11n Notch 21 Small Diameter Wafer 21c crystal orientation mark 31 1st take-out row 31a Scheduled extraction line 32 2nd take-out row 32a Planned extraction line 33 Non-extraction area 62 Cameras 63 Controllers 66 Laser irradiation unit D1 diameter K predetermined distance M marking

Claims

1. A marking line setting step involves setting at least two parallel marking lines corresponding to the crystal orientation of the wafer, A marking step in which markings are formed along each of the planned marking lines, The process involves setting up extraction lines, which are adjacent to each other, by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with one of the planned marking lines to set up a first extraction row, and by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with the other planned marking line to set up a second extraction row, and A removal step in which small-diameter wafers are removed along each of the planned removal lines to form small-diameter wafers with markings, A method for manufacturing small-diameter wafers, including [specifically, a wafer manufacturing method].

2. In the marking step, the marking is formed by laser processing. The method for manufacturing a small-diameter wafer according to feature 1.

3. The marking forms a crystal orientation mark indicating the crystal orientation of the small-diameter wafer. A method for manufacturing a small-diameter wafer according to claim 1 or 2.

4. The marking step is performed before or after the line setting step for the planned extraction line. A method for manufacturing a small-diameter wafer according to claim 1 or 2.

5. The marking step is performed before or after the line setting step for the planned extraction line. The method for manufacturing a small-diameter wafer according to feature 3.

6. A marking line setting step involves setting at least two parallel marking lines corresponding to the crystal orientation of the wafer, The process involves setting up extraction lines, which are adjacent to each other, by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with one of the planned marking lines to set up a first extraction row, and by arranging extraction lines corresponding to the shape of the small-diameter wafer so as to overlap with the other planned marking line to set up a second extraction row, and A method for setting up the planned extraction line for small-diameter wafers, including [specific details omitted].

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