JP6303861B2 - Single crystal substrate cutting method - Google Patents

Description

  The present invention relates to a method for dividing a single crystal substrate.

  In mass production of semiconductor devices, first, a plurality of portions, each of which becomes a semiconductor chip, are formed on a wafer. A plurality of semiconductor chips are obtained by dividing the single crystal substrate into these portions. For example, according to Japanese Patent Laying-Open No. 2013-4528 (Patent Document 1), a silicon wafer is divided by a rotating disk-shaped dicing blade.

JP 2013-4528 A

  According to the above conventional method, a large amount of chips are generated when the silicon wafer (single crystal substrate) is divided. The swarf may prevent normal division of the single crystal substrate or may remain as a foreign substance on the divided single crystal substrate. Further, scribing and breaking may be performed on a silicon wafer with a tool such as a diamond point in order to reduce chips, but in this case as well, it is difficult to sufficiently suppress the generation of chips. Further, when the diamond point is applied to a silicon wafer having a high hardness, there is a problem that the life of the diamond point is shortened due to wear.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a method for dividing a single crystal substrate that hardly generates chips.

  The method for dividing a single crystal substrate includes the following steps. A single crystal substrate having a first main surface and a second main surface opposite to the first main surface is prepared. Surface cracks are formed on the first main surface of the single crystal substrate. A glass layer covering the surface crack is provided on the first main surface of the single crystal substrate. A crack line extending on the surface of the glass layer is formed. The step of forming the crack line includes a step of pressing the blade edge on the surface of the glass layer and a step of displacing the pressed blade edge on the surface of the glass layer. By applying a stress to the single crystal substrate provided with the glass layer, the single crystal substrate is divided along the crack line.

  According to the present invention, the single crystal substrate is divided by utilizing surface cracks formed on the main surface. The portion of the surface crack that actually contributes to the division is defined by a crack line formed on the glass layer on the single crystal substrate. The crack line on the glass layer can be formed with almost no chips generated by the displacement of the blade edge on the glass layer. Therefore, according to the present invention, it is possible to eliminate almost all chips generated when the single crystal substrate is divided.

It is an end view (A)-(E) which shows roughly the parting method of a single crystal substrate in Embodiment 1 of the present invention. It is a fragmentary end view which expands and shows the part II of FIG. 1 (D). Flow chart (A) schematically showing the structure of the method for dividing a single crystal substrate in the first embodiment of the present invention, and a flow chart (B) schematically showing the structure of a process of forming a crack line as a part thereof ). It is an end view (A)-(D) which shows roughly the division method of the single crystal substrate in Embodiment 2 of the present invention. It is an end elevation which shows the parting method of the single crystal substrate in a comparative example. It is an end elevation (A) and (B) which shows roughly the cutting method of the single crystal substrate in Embodiment 3 of the present invention. It is a flowchart which shows schematically the structure of the process of forming a crack line in the dividing method of the single crystal substrate in Embodiment 4 of this invention. It is an end elevation which shows roughly the structure of the trench line in a crackless state. It is the front view (A) which shows roughly the structure of the blade edge | tip used for the cutting method of the single crystal substrate in Embodiment 4 of this invention, and the figure (B) in the viewpoint IXB. It is the top view (A) and (B) which shows each of the 1st and 2nd process of the cutting method of the single crystal substrate in Embodiment 4 of this invention roughly. It is a top view (A) and (B) which shows each roughly the 1st and 2nd process of the cutting method of the single crystal substrate of the 1st modification of Embodiment 4 of this invention. It is a top view which shows roughly the dividing method of the single crystal substrate of the 2nd modification of Embodiment 4 of this invention. It is a top view which shows roughly the dividing method of the single crystal substrate of the 3rd modification of Embodiment 4 of this invention. It is a top view which shows roughly the 1st process of the cutting method of the single crystal substrate in Embodiment 5 of this invention. It is a top view which shows roughly the 2nd process of the cutting method of the single crystal substrate in Embodiment 5 of this invention. It is a top view which shows roughly the 3rd process of the cutting method of the single crystal substrate in Embodiment 5 of this invention. It is a top view which shows roughly the cutting method of the single crystal substrate of the 1st modification of Embodiment 5 of this invention. It is a top view which shows roughly the cutting method of the single crystal substrate of the 2nd modification of Embodiment 5 of this invention. It is a top view which shows roughly the cutting method of the single crystal substrate in Embodiment 6 of this invention. It is the top view (A) and (B) which each shows roughly each of the 1st and 2nd process of the dividing method of the single crystal substrate in Embodiment 7 of this invention. It is the top view (A) and (B) which each shows roughly each of the 1st and 2nd process of the cutting method of the single crystal substrate in Embodiment 8 of this invention. It is a top view which shows roughly the cutting method of the single crystal substrate of the modification of Embodiment 8 of this invention. It is the front view (A) which shows roughly the structure of the blade edge | tip used for the cutting method of the single crystal substrate in Embodiment 9 of this invention, and the figure (B) in the viewpoint XXIIIB.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
1A to 1E schematically show first to fifth steps of a method for dividing a silicon wafer 3 (single crystal substrate) in the present embodiment.

  Referring to FIG. 1A, a silicon wafer 3 having main surfaces S1 (first main surface) and S2 (second main surface opposite to the first main surface) is prepared (FIG. 3 ( A): Step S10). Next, a surface crack FC is formed on the main surface S1 (FIG. 3A: Step S20). The surface crack FC is a large number of fine and dense cracks formed on the main surface S1. The direction of each fine crack included in the surface crack FC may be random. The surface crack FC can be formed by blasting, for example, by sandblasting BL with respect to the main surface S1.

  Referring to FIG. 1B, glass layer 4 covering surface crack FC is provided on main surface S1 of silicon wafer 3 (FIG. 3A: step S30). The silicon wafer 3 and the glass layer 4 are in close contact with each other at least in a region where a trench line is to be formed. The glass layer 4 can be provided, for example, by adhesion of a glass substrate or coating or vapor deposition of a glass material. When the glass layer 4 is provided by bonding the glass substrate, it is necessary to use a bonding material having a high hardness after curing because cracks need to extend to the silicon wafer 3 through the bonding material.

  With reference to FIG.1 (C), the blade edge | tip 51 is pressed on the surface SF of the glass layer 4 (FIG.3 (B): step S42a). Next, the pressed blade edge 51 is displaced on the surface SF of the glass layer 4 (FIG. 3B: step S42b). The displacement of the blade edge 51 is sliding or rolling on the surface SF of the glass layer 4. Thereby, plastic deformation occurs in the glass layer 4, whereby a trench line TL having a groove shape (FIG. 2) is formed on the surface SF of the glass layer 4. Since the trench line TL is generated by plastic deformation of the glass layer 4, almost no chips are generated at this time.

  In the present embodiment, a so-called scribe line SL is formed by the displacement of the blade edge 51. In other words, the trench line TL and the crack line CL are formed (FIGS. 3A and 3B: Step S40). That is, the trench line TL is formed and the crack line CL is formed substantially at the same time. The crack line CL is a crack extending in the thickness direction DT from the recess of the trench line TL, and extends linearly on the surface SF. The crack line CL breaks the continuous connection of the glass layers 4 in the direction DC intersecting the trench line TL immediately below the trench line TL (upward in FIG. 2).

  Next, stress is applied to the silicon wafer 3 provided with the glass layer 4 as a so-called break process. Thereby, the crack line CL (FIG. 2) extends in the glass layer 4 and reaches the main surface S <b> 1 of the silicon wafer 3. A large stress is applied to the position where the crack has reached as described above on the main surface S1. As a result, the surface crack FC existing at this position is the starting point, and the crack extends in the silicon wafer 3.

  Referring to FIG. 1E, the silicon wafer 3 is divided along the crack line CL of the glass layer 4 by the above-described extension of the crack in the silicon wafer 3 (FIG. 3A: Step S50). . That is, the silicon wafer 3 is divided into chips 3a and 3b which are part of the silicon wafer 3. In each of the chips 3a and 3b, 4a and 4b which are part of the glass layer 4 remain.

  According to the present embodiment, the silicon wafer 3 is divided using the surface crack FC formed in the main surface S1. A portion of the surface crack FC that actually contributes to the division is defined by a crack line CL formed on the glass layer 4 on the silicon wafer 3. The crack line CL on the glass layer 4 can be formed with almost no chips generated by the displacement of the cutting edge 51 on the glass layer 4. Therefore, according to the present embodiment, it is possible to eliminate almost all chips generated when the silicon wafer 3 is divided.

(Embodiment 2)
In the present embodiment, first, steps similar to those in FIGS. 1A and 1B (Embodiment 1) are performed.

  Referring to FIG. 4A, next, member 11 is provided on main surface S2 of silicon wafer 3. The member 11 includes regions 11a and 11b (first and second regions) separated from each other.

  Referring to FIGS. 4B to 4D, substantially the same steps as in FIGS. 1C to 1E are performed. Thereby, the silicon wafer 3 is divided into the chip 3a provided with the region 11a and the chip 3b provided with the region 11b.

  Referring to FIG. 5, in the comparative example, a dicing blade 59 that rotates at high speed is inserted between regions 11 a and 11 b of member 11, and silicon wafer 3 is removed according to the thickness of dicing blade 59. The wafer 3 is divided. In this case, if the space between the regions 11a and 11b is narrow, it is difficult to insert the dicing blade 59 between the regions 11a and 11b. Further, the cutting using the dicing blade 59 is normally performed as a wet process in which a cutting fluid is used to suppress the thermal effect due to friction and to discharge chips, so that the member 11 or the silicon wafer 3 is affected by moisture. Negative effects may occur.

  On the other hand, according to the present embodiment, it is not necessary to insert any cutting tool between the regions 11a and 11b, and the silicon wafer is not locally removed, so that no chips are generated. Therefore, even if the space between the regions 11a and 11b is narrow, the silicon wafer 3 can be divided between the regions 11a and 11b. Moreover, the process of forming the crack line CL in the glass layer 4 using the blade edge 51 can be performed as a dry process. Therefore, adverse effects due to moisture on the member 11 or the silicon wafer 3 can be avoided. In the present embodiment, since the scribe line SL can be formed by plastic deformation in an amorphous glass layer, generation of chips is suppressed even when the silicon wafer 3 is directly scribed. Can do.

(Embodiment 3)
FIG. 4D of the second embodiment shows a state where the silicon wafer 3 is divided substantially along the thickness direction. In this case, the position where the crack line CL is formed on the surface of the glass layer 4 and the position where the main surface S2 of the silicon wafer 3 is divided substantially coincide with each other as a planar layout. However, in the silicon wafer 3 which is a single crystal substrate, unlike the glass, the extension of cracks may have orientation dependency. For this reason, cracks may extend in the silicon wafer 3 in a direction greatly inclined from the thickness direction. In this case, the difference in planar layout between the position where the crack line CL is formed on the surface of the glass layer 4 and the position where the main surface S2 of the silicon wafer 3 is divided becomes large.

  Referring to FIG. 6A, in the above case, the location where the crack line CL is formed on the surface SF of the glass layer 4 takes into account the orientation dependency of crack extension and the thickness of the silicon wafer 3. And then shift. The position of the crack line CL may be a position deviated from the region W between the regions 11a and 11b in the planar layout. When the break process is performed, the crack extends in the silicon wafer 3 obliquely with respect to the thickness direction, and reaches the region W on the main surface S2. As a result, as shown in FIG. 6B, the division between the regions 11a and 11b is performed.

(Embodiment 4)
In the said Embodiment 1-3, as shown to step S40 (FIG.3 (B)), the case where the crack line CL (FIG. 2) is formed at the time of the displacement of the blade edge | tip 51 (FIG.1 (C)) is demonstrated. did. However, after the trench line TL (FIG. 2) lacking the crack line CL is formed by the displacement of the blade edge 51, the crack line CL can be formed along the trench line TL.

  Referring to FIG. 7, in the present embodiment, step S40L is performed instead of step S40 (FIG. 4A). Specifically, the trench line TL (FIG. 8) is formed in a crackless state (FIG. 7: Step S47), and then the crack is extended (FIG. 7: Step S48). The crack line CL (FIG. 2) Is formed.

  Note that the process of forming the crack line CL in the present embodiment is essentially different from a so-called break process. The break process is to completely separate the substrate by further extending the cracks already formed in the thickness direction. On the other hand, the formation process of the crack line CL brings about a change from a crackless state obtained by forming the trench line TL to a state having cracks. This change is considered to be caused by the release of internal stress that the crackless state has. The state of the plastic deformation at the time of forming the trench line TL and the magnitude and directionality of the internal stress generated by the formation of the trench line TL are the same as in the case where rolling of the rotary blade is used, as in this embodiment. This is considered to be different from the case where the sliding of the blade edge is used, and when the sliding of the blade edge is used, cracks are likely to occur in a wider scribe condition. According to the study of the present inventor, the crack line CL can be easily formed along the trench line TL by optimizing the blade edge and its usage.

  First, details of the cutting edge 51 suitable for the present embodiment will be described below.

  With reference to FIGS. 9A and 9B, the cutting tool 50 has a cutting edge 51 and a shank 52. The blade edge 51 is not a rotary blade, but is fixed to the shank 52, that is, a fixed blade.

  The blade edge 51 is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. The plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1, the side surfaces SD2, and SD3 (first to third surfaces) face different directions and are adjacent to each other. The blade edge 51 has a vertex at which the top surface SD1, the side surfaces SD2 and SD3 merge, and the protrusion PP of the blade edge 51 is configured by this vertex. Therefore, the top surface SD1 is connected to the protrusion PP. Further, the side surfaces SD2 and SD3 form ridge lines constituting the side portion PS of the blade edge 51. The side part PS is connected to the protrusion part PP and extends linearly from the protrusion part PP. Moreover, since the side part PS is a ridgeline as mentioned above, it has the convex shape extended linearly.

  The cutting edge 51 is preferably a diamond point. That is, the cutting edge 51 is preferably made of diamond from the viewpoint that the hardness and the surface roughness can be reduced. More preferably, the cutting edge 51 is made of single crystal diamond. More preferably, crystallographically, the top surface SD1 is a {001} plane, and each of the side surfaces SD2 and SD3 is a {111} plane. In this case, although the side surfaces SD2 and SD3 have different orientations, they are crystal surfaces that are equivalent to each other in terms of crystallography.

  Diamond that is not a single crystal may be used. For example, polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may be used. Alternatively, sintered diamond obtained by bonding polycrystalline diamond particles, which are sintered from fine graphite or non-graphitic carbon without containing a binder such as an iron group element, with a binder such as an iron group element is used. May be.

  The shank 52 extends along the axial direction AX. The blade edge 51 is preferably attached to the shank 52 so that the normal direction of the top surface SD1 is approximately along the axial direction AX.

  Next, details of the method for dividing the silicon wafer 3 in the present embodiment will be described below.

  First, as in the first to third embodiments, the glass layer 4 is provided on the silicon wafer 3 provided with the surface cracks FC (see FIG. 1B). Referring to FIG. 10A, the edge surrounding surface SF of glass layer 4 includes side ED1 and side ED2 that face each other. In the example shown in FIG. 10A, the edge has a rectangular shape. Therefore, the sides ED1 and ED2 are sides parallel to each other. In the example shown in FIG. 10A, the sides ED1 and ED2 are rectangular short sides.

  Next, the blade edge 51 (FIG. 9A) is pressed against the surface SF of the glass layer 4 at the position N1 (FIG. 7: Step S47a). Details of the position N1 will be described later. The cutting edge 51 is pressed such that the projection PP of the cutting edge 51 is disposed between the side ED1 and the side PS on the surface SF of the glass layer 4, and the side PS of the cutting edge 51 is the protrusion PP and the side ED2. It is performed so that it may be arrange | positioned between.

  Next, a trench line TL is formed on the surface SF of the glass layer 4. The formation of the trench line TL is performed between the position N1 (first position) and the position N3. A position N2 (second position) is located between the positions N1 and N3. Therefore, trench line TL is formed between positions N1 and N2 and between positions N2 and N3. The positions N1 and N3 may be located away from the edge of the surface SF of the glass layer 4, or one or both of them may be located at the edge of the upper surface SF1. The formed trench line TL is separated from the edge of the glass layer 4 in the former case, and is in contact with the edge of the glass substrate 4 in the latter case.

  Of the positions N1 and N2, the position N1 is closer to the side ED1, and the position N2 of the positions N1 and N2 is closer to the side ED2. In the example shown in FIG. 10A, the position N1 is close to the side ED1 of the sides ED1 and ED2, and the position N2 is close to the side ED2 of the sides ED1 and ED2, but both the positions N1 and N2 are the side ED1 or It may be located near either one of ED2.

  When the trench line TL is formed, the blade edge 51 is slid (FIG. 7: Step S47b). In the present embodiment, the blade edge 51 is displaced from the position N1 to the position N2, and is further displaced from the position N2 to the position N3. That is, with reference to FIG. 2A, the blade edge 51 is displaced in a direction DA that is a direction from the side ED1 toward the side ED2. The direction DA corresponds to a direction obtained by projecting the axial direction AX extending from the blade edge 51 onto the surface SF. In this case, the blade edge 51 is dragged on the surface SF by the shank 52.

  As the blade edge 51 is slid as described above, plastic deformation occurs in the glass layer 4, whereby a trench line TL having a groove shape is formed on the surface SF of the glass layer 4. The sliding of the blade edge 51 is performed so as to obtain a crackless state in which the glass layer 4 is continuously connected in the direction DC intersecting the trench line TL immediately below the trench line TL (see FIG. 8). . In order to obtain a crackless state, the above-described sliding of the blade edge 51 may be performed with a load that is not excessively large.

  Referring to FIG. 10B, after the trench line TL is formed, the thickness direction DT (FIG. 8) extends from the position N2 to the position N1 along the trench line TL (see the broken line arrow in the figure). The crack of the glass layer 4 is extended (FIG. 7: step S48). As a result, a crack line CL (FIG. 2) is formed. Formation of the crack line CL is started when the assist line AL and the trench line TL intersect each other at the position N2. For this purpose, the assist line AL is formed after the trench line TL is formed. The assist line AL is a normal scribe line with a crack in the thickness direction DT, and releases strain of internal stress in the vicinity of the trench line TL. The method of forming the assist line AL is not particularly limited, but may be formed using the edge of the surface SF as a base point as shown in FIG.

  In the formation of the crack line CL (FIG. 2), the thickness along the trench line TL is such that the continuous connection of the glass layer 4 is broken in the direction DC intersecting the trench line TL immediately below the trench line TL. Cracks in the glass layer 4 in the direction DT are extended.

  In FIG. 10B, the crack line CL is less likely to be formed in the direction from the position N2 to the position N3 than in the direction from the position N2 to the position N1. That is, the ease of extension of the crack line CL has a direction dependency. Therefore, the phenomenon that the crack line CL is formed between the positions N1 and N2 but not between the positions N2 and N3 may occur. Since the present embodiment is intended to divide between the positions N1 and N2, it is necessary to form a crack line CL between the positions N1 and N2, while a crack line between the positions N2 and N3. The difficulty of forming CL is not a problem.

  Next, by performing a so-called break process, the silicon wafer 3 (FIG. 9A) provided with the glass layer 4 is divided along the crack line CL as in the first to third embodiments. .

  Next, the 1st-3rd modification of the said dividing method is demonstrated below.

  Referring to FIG. 11A, the first modified example relates to a case where the intersection of the assist line AL and the trench line TL is insufficient as a trigger for starting the formation of the crack line CL (FIG. 10B). Is. Referring to FIG. 11B, by applying an external force that generates a bending moment or the like to the glass layer 4, a crack in the thickness direction DT extends along the assist line AL. As a result, the glass layer 4 is divided. Is done. Thereby, formation of the crack line CL is started. In the first modification, the separation of the glass substrate 4 releases the internal stress distortion in the vicinity of the trench line TL, thereby starting the formation of the crack line CL. Therefore, the assist line AL itself may be a crack line CL formed by applying stress to the trench line TL.

  Referring to FIG. 12, in the second modification, the blade edge 51 is pressed against the surface SF of the glass layer 4 at a position N3. When the trench line TL is formed, in the present modification, the blade edge 51 is displaced from the position N3 to the position N2, and is further displaced from the position N2 to the position N1. That is, referring to FIG. 9A, the blade edge 51 is displaced in a direction DB that is a direction from the side ED2 toward the side ED1. The direction DB corresponds to a direction opposite to the direction in which the axial direction AX extending from the blade edge 51 is projected onto the surface SF. In this case, the blade edge 51 is pushed forward on the surface SF by the shank 52.

  Referring to FIG. 13, in the third modified example, when each trench line TL is formed, the blade edge 51 is pressed against the surface SF of the glass layer 4 with a larger load at the position N2 than at the position N1. It is done. Specifically, the load on the blade edge 51 is increased when the position of the trench line TL reaches the position N4 with the position N4 as the position between the positions N1 and N2. In other words, the load on the blade edge 51 is increased between the positions N4 and N3, which are the end portions of the trench line TL, as compared with the position N1. Thereby, formation of the crack line CL from the position N2 can be easily induced while reducing a load at a portion other than the terminal portion.

  According to the present embodiment, the crack line CL can be more reliably formed from the trench line TL. The reason for this is presumed that the configuration of the cutting edge 51 (FIGS. 9A and 9B) and its use are suitable for applying to the glass layer 3 internal stress that easily induces the crack line CL. The Moreover, generation | occurence | production of the chip at the time of parting can be suppressed similarly to Embodiment 1-3.

  In the drawing referred to in the present embodiment, the sides ED1 and ED2 (first and second sides) of the edge of the glass layer 4 are rectangular short sides, but these are the long sides of the rectangle. Also good. The shape of the edge is not limited to a rectangle, and may be a square, for example. Further, the first and second sides are not limited to being linear, and may be curved. In the drawing, the main surface S1 of the silicon wafer 3 is flat, but may be curved. Correspondingly, the surface SF of the glass layer 4 may be flat or curved.

(Embodiment 5)
A method for dividing a single crystal substrate in this embodiment will be described below with reference to FIGS.

  Referring to FIG. 14, in the present embodiment, assist line AL is formed before formation of trench line TL. The method of forming the assist line AL is the same as that in FIG. 10B (Embodiment 4).

  Referring to FIG. 15, next, the blade edge 51 is pressed against the surface SF, and the trench line TL is formed. The method of forming the trench line TL itself is the same as that in FIG. 10A (Embodiment 4). The assist line AL and the trench line TL intersect each other at the position N2.

  Referring to FIG. 16, next, glass layer 4 is divided along assist line AL by a normal break process in which an external force that generates a bending moment or the like is applied to glass layer 4. Thereby, formation of the crack line CL similar to that of the fourth embodiment is started (see the broken line arrow in the figure).

  The configuration other than the above is substantially the same as the configuration of the fourth embodiment described above.

  Referring to FIG. 17, in the first modification, formation of crack line CL is started when assist line AL and scribe line SL intersect each other at position N2.

  Referring to FIG. 18, in the second modified example, when each trench line TL is formed, the blade edge 51 is pressed against the surface SF of the glass layer 4 with a greater force at the position N2 than at the position N1. It is done. Specifically, the load on the blade edge 51 is increased when the position of the trench line TL reaches the position N4 with the position N4 as the position between the positions N1 and N2. In other words, the load on the blade edge 51 is increased between the positions N4 and N3, which are the end portions of the trench line TL, as compared with the position N1. Thereby, formation of the crack line CL from the position N2 can be easily induced while reducing a load at a portion other than the terminal portion.

(Embodiment 6)
Referring to FIG. 19, in forming each trench line TL in the present embodiment, the blade edge 51 is slid beyond the side ED2 from the position N1. When the blade edge 51 passes the side ED2, the stress distortion generated in the substrate immediately below the trench line TL is released, and a crack line extends from the end of the trench line TL located on the side ED2 toward the position N1.

  The load applied to the blade edge 51 when forming the trench line TL may be constant, but when the blade edge 51 is displaced from the position N1 to the position N2, the load applied to the blade edge 51 at the position N2 increases. May be. For example, the load is increased by about 50%. The cutting edge 51 to which the increased load is applied is slid over the side ED2. In other words, the load on the cutting edge 51 is increased at the end of the trench line TL. When the blade edge 51 reaches the side ED2, the crack line extends from the end of the trench line TL located on the side ED2 toward the position N1 via the position N2. When the load is increased in this way, the stress distortion also increases, and the stress distortion is easily released when the cutting edge 51 passes the side ED2, so that the crack line can be formed more reliably. .

  The configuration other than the above is substantially the same as the configuration of the fourth embodiment described above.

(Embodiment 7)
Referring to FIG. 20A, in the method for dividing a single crystal substrate in the present embodiment, trench line TL is formed from position N1 to side ED2 via position N2.

  Referring to FIG. 20B, next, a stress is applied between position N2 and side ED2 so as to release the distortion of internal stress in the vicinity of trench line TL. This induces the formation of crack lines along the trench line TL. Specifically, as the application of stress, the pressed blade edge 51 is slid between the position N2 and the side ED2 (a region between the broken line and the side ED2 in the drawing) on the surface SF. This sliding is performed until the side ED2 is reached. The cutting edge 51 is preferably slid so as to intersect the track of the trench line TL formed first, and more preferably to overlap the track of the trench line TL formed first. The length of this second sliding is, for example, about 0.5 mm. This re-sliding may be performed on each of the plurality of trench lines TL (FIG. 20A) after they are formed, or the formation and re-sliding of one trench line TL may be performed. The process to be performed may be sequentially performed for each trench line TL.

  As a modification, in order to apply a stress between the position N2 and the side ED2, instead of the above-described re-sliding of the cutting edge 51, laser light is irradiated between the position N2 and the side ED2 on the surface SF. May be. Due to the thermal stress generated thereby, the distortion of the internal stress in the vicinity of the trench line TL is released, thereby inducing the start of formation of the crack line.

  The configuration other than the above is substantially the same as the configuration of the fourth embodiment described above.

(Embodiment 8)
Referring to FIG. 21A, in the method for dividing a single crystal substrate according to the present embodiment, the cutting edge 51 is moved from position N1 to position N2, and further to position N3, thereby separating from the edge of surface SF. A trench line TL is formed. The method of forming the trench line TL itself is almost the same as that in FIG. 10A (Embodiment 4).

  Referring to FIG. 21 (B), the same stress application as in FIG. 20 (B) (Embodiment 7 or its modification) is performed. This induces the formation of crack lines along the trench line TL.

  The configuration other than the above is substantially the same as the configuration of the fourth embodiment described above.

  Referring to FIG. 22, as a modification of the process of FIG. 21A, in forming trench line TL, blade edge 51 may be displaced from position N3 to position N2 and from position N2 to position N1.

(Embodiment 9)
Referring to FIGS. 23 (A) and (B), in each of the above embodiments, blade edge 51v may be used instead of blade edge 51 (FIGS. 9 (A) and (B)). The blade edge 51v has a conical shape having a vertex and a conical surface SC. The protruding part PPv of the blade edge 51v is constituted by a vertex. The side portion PSv of the blade edge is configured along a virtual line (broken line in FIG. 23B) extending from the apex to the conical surface SC. Thereby, the side part PSv has a convex shape extending linearly.

3 Silicon wafer (single crystal substrate)
4 Glass layer 11 Member 51, 51v Cutting edge AL Assist line CL Crack line FC Surface crack S1 Main surface (first main surface)
S2 main surface (second main surface)
SF surface SL scribe line TL trench line

Claims (6)

Providing a single crystal substrate having a first main surface and a second main surface opposite to the first main surface;
Forming a surface crack on the first main surface of the single crystal substrate;
Providing a glass layer covering the surface cracks on the first main surface of the single crystal substrate;
Forming a crack line extending on the surface of the glass layer, and forming the crack line,
Pressing the blade edge onto the surface of the glass layer;
Displacing the pressed blade edge on the surface of the glass layer,
A method for dividing a single crystal substrate, further comprising: dividing the single crystal substrate along the crack line by applying stress to the single crystal substrate provided with the glass layer.   The method for cutting a single crystal substrate according to claim 1, wherein the step of forming the surface crack is performed using a blast method.   The method for dividing a single crystal substrate according to claim 1, wherein the single crystal substrate includes a silicon substrate.   Before the step of dividing the single crystal substrate, the method further comprises a step of providing a member on the second main surface of the single crystal substrate, and the member includes a first region and a second region separated from each other. The single crystal substrate is divided into a portion provided with the first region and a portion provided with the second region by the step of dividing the single crystal substrate. The method for dividing a single crystal substrate according to any one of the preceding claims. A trench line (TL) having a groove shape is formed on the surface of the glass layer by causing plastic deformation in the glass layer by the step of displacing the blade edge,
The method for dividing a single crystal substrate according to claim 1, wherein the crack line is formed when the trench line is formed. The step of displacing the blade edge includes a step of sliding the blade edge on the surface of the glass layer, and plastic deformation occurs in the glass layer by the step of sliding the blade edge, whereby the surface of the glass layer On the top, a trench line having a groove shape is formed, and the step of sliding the blade edge is a crack in a state where the glass layer is continuously connected in a direction intersecting the trench line immediately below the trench line. It is done so that the state of less is obtained,
The step of forming the crack line includes cracking the glass layer along the trench line so that continuous connection of the glass layer is broken in a direction intersecting the trench line immediately below the trench line. The method for dividing a single crystal substrate according to any one of claims 1 to 4, comprising a step of stretching.

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