Substrate machining method

Abstract

Provided is a substrate machining method capable of suppressing an increase in manufacturing cost of a substrate while suppressing damage to the substrate in a step for dividing the substrate along a scribe line. This substrate machining method cuts out a plurality of chips (100) by dividing a substrate (SL). The substrate machining method comprises: a step (S100) for sticking a first tape (30) containing a tackiness agent having minute tackiness to a first surface (S1) of a substrate (10); a step (S110) for forming a scribe line (SL) on a second surface (S2) opposite to the first surface (S1) of the substrate; a step (S120) for sticking a second tape (40) containing an ultraviolet curable tackiness agent to the second surface (S2); a step (S130) for dividing the substrate (10) along the scribe line (SL); and a step (S160) for removing divided chips (100) from the second tape (S2).

Description

Substrate processing method

[0001] The present invention relates to a substrate processing method.

[0002] A substrate processing method is known in which a substrate (also called a wafer) made of a brittle material such as glass or silicon, on whose surface or interior an electronic circuit pattern is formed, is divided along scribe lines formed on the surface to cut out a plurality of chips (elements).

[0003] Patent Document 1 (JP 2016-68393 A) discloses a substrate processing method including a designated location breaking step and an expand breaking step. In the designated location breaking step, a break bar (break blade) is pressed into the surface of the substrate opposite to the surface on which a scribe line (a line to be divided) is formed, dividing the substrate along the scribe line. In the expand breaking step, an expand tape supported by a dicing frame (dicing ring) and to which a substrate is attached is stretched. The expanding expand tape separates the divided surfaces of the substrate.

[0004] JP 2016-68393 A

[0005] Patent Document 1 discloses that a protective film (protective sheet) is attached to a substrate in a designated location breaking step, and the protective film is then removed in a subsequent expand breaking step. While the use of a protective film can prevent damage to the substrate in the breaking step, it requires a step of removing the protective film, which increases the manufacturing cost of the substrate.

[0006] An object of the present invention is to provide a substrate processing method that can suppress damage to the substrate in the process of dividing the substrate along scribe lines, while also suppressing an increase in the manufacturing cost of the substrate.

[0007] Below, several aspects will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.

[0008] A substrate processing method according to a first aspect of the present invention is a processing method for dividing a substrate into a plurality of chips, comprising the steps of: attaching a first tape having low adhesiveness to a first surface of the substrate; forming a scribe line on a second surface of the substrate opposite the first surface; attaching a second tape containing an ultraviolet-curable adhesive to the second surface; dividing the substrate along the scribe lines; and removing the divided chips from the second tape.

[0009] In this substrate processing method, the second tape is attached to the second surface before the step of dividing the substrate along the scribe lines (breaking step), thereby suppressing damage to the substrate during the breaking step. Furthermore, in this substrate processing method, the second tape is not removed but is used to secure the substrate during the step of removing the divided chips (picking up step). Therefore, this substrate processing method suppresses damage to the substrate during the breaking step while also suppressing increases in substrate manufacturing costs.

[0010] The adhesive contained in the first tape has an adhesive strength of 0.01 N / 20 mm or more and 1.5 N / 20 mm or less.

[0011] A substrate processing method according to a third aspect is the substrate processing method according to the first or second aspect, in which the substrate material is a single crystal material.

[0012] A substrate processing method according to a fourth aspect is the substrate processing method according to the first or second aspect, in which the material of the substrate is glass.

[0013] According to this substrate processing method, damage to the substrate during the breaking step is suppressed, while an increase in the manufacturing cost of the substrate is also suppressed.

[0014] FIG. 1 is a perspective view showing a state in which a substrate 10 is held by a dicing frame 20. FIG. 2 is a schematic cross-sectional view of the substrate 10. FIG. 3 is a diagram showing a flow of steps included in a method for processing a substrate 10 according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a substrate processing method according to an embodiment of the present invention. FIG. 5 is a diagram showing a flow of steps included in a substrate processing method according to a conventional technique. FIG. 6 is a cross-sectional view showing a substrate processing method according to a conventional technique.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the up and down directions correspond to the directions indicated by arrows in the drawings.

[0016] 1. First Embodiment (1) Overview A substrate processing method according to an embodiment of the present invention (hereinafter also referred to as the present invention method) divides a substrate 10 to cut out a plurality of chips 100 having electronic circuit patterns formed on or inside the substrate 10.

[0017] First, the substrate 10 and the dicing frame 20 will be described. Fig. 1 is a perspective view showing the substrate 10 held by the dicing frame 20. Fig. 2 is a schematic cross-sectional view of the substrate 10. Fig. 1 is a view showing the substrate 10 and the dicing frame 20 immediately after a first tape application step, which will be described later.

[0018] The substrate 10 includes a brittle material layer 11 and a metal layer 12. The brittle material layer 11 has an electronic circuit pattern 11a formed on or inside the surface. The brittle material layer 11 is made of silicon carbide (SiC). The metal layer 12 is made of nickel, silver, gold, copper, platinum, or the like. Hereinafter, for convenience, the surface of the substrate 10 facing the brittle material layer 11 will be referred to as a first surface S1, and the surface facing the metal layer 12 will be referred to as a second surface S2. The second surface S2 is the surface opposite the first surface S1.

[0019] The substrate 10 is circular as shown in FIG. 1 . The substrate 10 may have a notch (orientation flat) on part of its periphery to indicate the crystal orientation. The size of the substrate 10 is a maximum diameter of 12 inches. In the case of the substrate 10 in which the brittle material layer 11 is made of silicon carbide, the size of the substrate 10 is a diameter of 4 inches to 8 inches.

[0020] The thickness of the substrate 10 is 50 μm or more and 700 μm or less. In the case of the substrate 10 in which the brittle material layer is made of silicon carbide, the thickness is 50 μm or more and 500 μm or less.

[0021] The dicing frame 20 is a plate-like member that holds the substrate 10 in the method of the present invention. The dicing frame 20 has an annular shape with a circular opening 21 formed in the center that is large enough to accommodate the substrate 10. The thickness of the dicing frame 20 is greater than that of the substrate 10. Before the method of the present invention is started, a first tape 30 is attached to one surface of the dicing frame 20 so as to cover the opening 21.

[0022] The first tape 30 is a dicing tape having an adhesive layer (not shown) containing a slightly adhesive agent formed on a substrate (not shown). The first tape 30 is attached to the dicing frame 20 so that the adhesive layer faces the opening 21.

[0023] The base material of the first tape 30 is a film made of, for example, polyvinyl chloride (PVC), polyethylene terephthalate (PET), or the like. The adhesive layer of the first tape 30 is formed of an acrylic adhesive or the like. The adhesive strength of the first tape is preferably 0.01 N / 20 mm or more and less than 1.5 N / 20 mm. The thickness of the first tape 30 is 50 μm or more and 180 μm or less.

[0024] (2) Processing Method Next, each step of the method of the present invention will be specifically described. Fig. 3 is a diagram showing a flow of steps included in the method of processing substrate 10 according to an embodiment of the present invention. Fig. 4 is a cross-sectional view showing the method of processing substrate 10 according to an embodiment of the present invention. The method of the present invention includes a first tape applying step S100, a scribing step S110, a second tape applying step S120, a breaking step S130, a first tape peeling step S140, a second surface side ultraviolet ray irradiation step S150, and a pick-up step S160.

[0025] The method of the present invention is carried out by processing apparatus 50. Processing apparatus 50 carries out a first tape application step S100, a scribing step S110, a second tape application step S120, a breaking step S130, a first tape peeling step S140, a second surface side ultraviolet irradiation step S150, and a pick-up step S160 in this order.

[0026] The processing device 50 includes a table 51 , a scribing wheel 52 , and a breaking bar 53 .

[0027] (2-1) First Tape Attaching Step S100 (FIG. 4A) In the first tape attaching step S100, the processing device 50 attaches the first tape 30 to the first surface S1 of the substrate 10.

[0028] In this step, the processing device 50 positions the substrate 10 relative to the dicing frame 20 placed on the table 51 so that the adhesive layer of the first tape 30 faces upward through the opening, so that the first surface S1 is in contact with the adhesive layer of the first tape 30. In this way, the substrate 10 is held by the dicing frame 20.

[0029] (2-2) Scribing Step S110 (FIG. 4B) In the scribing step S110, the processing device 50 forms a scribe line SL on the second surface S2.

[0030] In this step, the processing device 50 uses the scribing wheel 52 to form a plurality of scribe lines SL in a grid pattern on the second surface S2.

[0031] The scribing wheel 52 is a disk-shaped member whose outer peripheral edge is formed into a triangular shape in cross section and functions as a cutting edge. The scribing wheel 52 is rotatably held in a holder (not shown) with its rotation axis aligned horizontally. The processing device 50 controls the holder to move the scribing wheel 52 at a predetermined speed with its cutting edge in contact with the second surface S2 with a predetermined contact load, thereby forming the scribe line SL.

[0032] The contact load of the scribing wheel 52 is equal to or greater than 1 N and equal to or less than 10 N. The moving speed of the scribing wheel 52 is equal to or greater than 100 mm / sec and equal to or less than 300 mm / sec.

[0033] (2-3) Second Tape Attachment Step S120 (FIG. 4(c)) In the second tape attachment step S120, the processing device 50 attaches a second tape 40 to the second surface S2 and the surface of the dicing frame 20 opposite to the first tape 30. The second tape 40 is an ultraviolet-curable dicing tape having an ultraviolet-curable adhesive layer (not shown) formed on a base material (not shown).

[0034] In this step, the processing device 50 attaches the second tape 40 so that the adhesive layer is in contact with the second surface S2 of the substrate 10. At this time, the adhesive layer of the second tape 40 is attached to the surface of the dicing frame 20 opposite the first tape 30 at the peripheral portion, and is also attached to the first tape 30 at the ring-shaped joint portion 20a that surrounds the periphery of the substrate 10.

[0035] The base material of the second tape 40 is a film made of, for example, polyvinyl chloride (PVC), polyolefin (PO), polyethylene (PE), or the like. The adhesive layer of the second tape 40 is formed of an acrylic adhesive or the like. The adhesive strength of the second tape 40 is preferably 1.0 N / 20 mm or more. The thickness of the second tape 40 is 50 μm or more and 180 μm or less.

[0036] When this step is completed, the processing device 50 turns the dicing frame 20 upside down so that the first surface S1 of the substrate 10 faces upward.

[0037] (2-4) Breaking Step S130 ((d) of FIG. 4) In the breaking step S130, the processing device 50 divides the substrate 10 along the scribe line SL. More specifically, in this step, the processing device 50 pushes the breaking bar 53 toward the table 51 from the first surface S1 side to bend the breaking bar 53, thereby dividing the substrate 10 sandwiched between the first tape 30 and the second tape 40 along the scribe line SL.

[0038] When the amount of bending of the substrate 10 exceeds a certain amount, the substrate 10 is broken along the scribe lines SL. The processing device 50 breaks the substrate 10 along all of the scribe lines SL. As a result, the rectangular chips 100 are separated from the substrate 10 while being sandwiched between the first tape 30 and the second tape 40.

[0039] The cutting edge angle of the break bar 53 is 10° or more and 90° or less. In the present embodiment in which the brittle material layer 11 is made of silicon carbide, the cutting edge angle of the break bar 53 may be 10° or more and 90° or less. The cutting edge radius of the break bar 53 is 5 μm or more and 100 μm or less. In the present embodiment in which the brittle material layer 11 is made of silicon carbide, the cutting edge radius of the break bar 53 is 10 μm or more and 100 μm or less. The pushing amount of the break bar 53 is 30 μm or more and 200 μm or less.

[0040] (2-5) First Tape Peeling Step S140 (FIG. 4(e)) In the first tape peeling step S140, the processing device 50 peels the first tape 30 from the first surface S1 of the substrate 10 and the dicing frame 20.

[0041] (2-6) Second Surface Side Ultraviolet Light Irradiation Step S150 ((f) of FIG. 4) In the second surface side ultraviolet light irradiation step S150, the processing device 50 irradiates the second tape 40 with ultraviolet light UV from the second surface S2 side. More specifically, in this step, the processing device 50 irradiates the substrate 10 and the second tape 40 with ultraviolet light UV from below using an ultraviolet light irradiation device (not shown). This reduces the adhesive strength of the pressure-sensitive adhesive layer of the second tape 40.

[0042] (2-7) Pick-up step S160 ((g) of FIG. 4) In the pick-up step S160, the processing device 50 removes the divided chips 100 from the second tape 40. Although not shown, at this time, the processing device 50 may use a stage to slightly lift the substrate 10 and the second tape 40 upward from below the second tape 40, a process called expanding. This stretches the second tape 40 and slightly separates adjacent chips 100, allowing the processing device 50 to easily remove the chips 100 from the second tape 40.

[0043] (3) Substrate Processing Method According to the Prior Art Next, a substrate processing method according to the prior art will be described for comparison with the method of the present invention. FIG. 5 is a diagram showing the process flow of the substrate processing method according to the prior art. FIGS. 6A and 6B are cross-sectional views showing the substrate processing method according to the prior art. The substrate processing method according to the prior art includes a third tape application step S200, a scribing step S210, a protective film application step S220, a breaking step S230, a protective film peeling step S240, a first-side ultraviolet irradiation step S250, a fourth tape application step S260, a third tape peeling step S270, a second-side ultraviolet irradiation step S280, and a pick-up step S290. Detailed descriptions of configurations and steps similar to or corresponding to those of the method of the present invention will be omitted as appropriate.

[0044] In the substrate processing method according to the prior art, a third tape 70 is used in place of the first tape 30. The third tape 70 is an ultraviolet-curable dicing tape having an ultraviolet-curable adhesive layer (not shown) formed on a base material (not shown).

[0045] (3-1) Third Tape Attachment Step S200 ((a) of Figure 6A) Except for the fact that the third tape 70 is used instead of the first tape 30, the third tape attachment step S200 is the same as the first tape attachment step S100 of the method of the present invention, and therefore a detailed description of the third tape attachment step S200 will be omitted.

[0046] (3-2) Scribing Step S210 ((b) of FIG. 6A) Since this step is similar to the scribing step S110 of the method of the present invention, detailed description of the scribing step S210 will be omitted.

[0047] (3-3) Protective Film Attaching Step S220 ((c) of FIG. 6A) In the protective film attaching step S220, the processing device 50 attaches the protective film 60 to the second surface S2 and the first tape 30. At this time, the peripheral edge of the protective film 60 is attached to the first tape 30 at a ring-shaped joint portion 60a that surrounds the periphery of the substrate 10.

[0048] The protective film 60 is a film that prevents the second surface S2 from being damaged in the breaking step described below. The protective film 60 is a film made of a resin material that does not have an adhesive layer.

[0049] When this step is completed, the processing device 50 turns the dicing frame 20 upside down so that the first surface S1 of the substrate 10 faces upward.

[0050] (3-4) Breaking Step S230 ((d) of FIG. 6A) Since this step is similar to the breaking step S130 of the method of the present invention, detailed description of the breaking step S230 will be omitted.

[0051] (3-5) Protective Film Peeling Step S240 ((e) of FIG. 6A) In the protective film peeling step S240, the processing device 50 peels the protective film 60 from the second surface S2 of the substrate 10 and the dicing frame 20.

[0052] (3-6) First Surface Side Ultraviolet Ray Irradiation Step S250 ((f) of FIG. 6B) In the first surface side ultraviolet ray irradiation step S250, the processing device 50 irradiates the third tape 70 with ultraviolet rays UV from the first surface S1 side. More specifically, in this step, the processing device 50 uses an ultraviolet ray irradiation device (not shown) to irradiate the substrate 10 and the third tape 70 with ultraviolet rays UV from below. This reduces the adhesive strength of the pressure-sensitive adhesive layer of the third tape 70.

[0053] (3-7) Fourth Tape Attachment Step S260 ((g) in FIG. 6B) In the fourth tape attachment step S260, the processing device 50 attaches a fourth tape 80 to the second surface S2 and the surface of the dicing frame 20 opposite to the third tape 70. The fourth tape 80 is an ultraviolet-curable dicing tape having an ultraviolet-curable adhesive layer (not shown) formed on a base material (not shown).

[0054] When this step is completed, the processing device 50 turns the dicing frame 20 upside down so that the first surface S1 of the substrate 10 faces upward.

[0055] (3-8) Third Tape Peeling Step S270 ((h) in Figure 6B) Except for the fact that the third tape 70 is peeled off instead of the first tape 30, this is the same as the first tape peeling step S140 of the method of the present invention, and therefore a detailed description of the third tape peeling step S270 will be omitted.

[0056] (3-9) Second surface side ultraviolet irradiation step S280 ((i) in FIG. 6B) In the second surface side ultraviolet irradiation step S280, the processing device 50 irradiates the fourth tape 80 with ultraviolet rays UV from the second surface S2 side. More specifically, in this step, the processing device 50 uses an ultraviolet irradiation device (not shown) to irradiate the substrate 10 and the fourth tape 80 with ultraviolet rays UV from below. This reduces the adhesive strength of the adhesive layer of the fourth tape 80.

[0057] (3-10) Pick-up step S290 ((j) in Figure 6B) Except for the fact that the fourth tape 80 is used instead of the second tape 40, the pickup step S290 is the same as the pickup step S160 of the method of the present invention, so a detailed explanation of the pickup step S290 will be omitted.

[0058] (4) Features The method of the present invention divides the substrate 10 to cut out a plurality of chips 100. The method of the present invention includes the steps of: applying a first tape 30 having weak adhesiveness to the first surface S1 of the substrate 10 (first tape applying step S100); forming a scribe line SL on the second surface S2 of the substrate 10, which is the surface opposite to the first surface S1 (scribing step S110); applying a second tape 40 containing an ultraviolet-curable adhesive to the second surface S2 (second tape applying step S120); dividing the substrate 10 along the scribe line SL (breaking step S130); and removing the divided chips 100 from the second tape 40 (pickup step S160).

[0059] In the method of the present invention, the second tape 40 is applied to the second surface S2 before the breaking step S130, in which the substrate 10 is divided along the scribe lines SL, thereby suppressing damage to the substrate 10 during the breaking step S130. Furthermore, in the method of the present invention, the second tape 40 is not removed during the pick-up step S160, in which the divided chips 100 are removed, but is used to secure the substrate 10. This eliminates the need for the protective film application step S220, the protective film peeling step S240, the fourth tape application step S260, and the second surface side ultraviolet irradiation step S280, which were performed in the conventional substrate processing method. Therefore, this substrate processing method suppresses damage to the substrate 10 during the breaking step S130 while also suppressing increases in the manufacturing cost of the substrate 10.

[0060] Furthermore, in the method of the present invention, second tape 40 having an adhesive layer is attached to second surface S2 in second tape attachment step S120, so that foreign matter such as dust generated in the scribing step or the like adheres to the adhesive layer on second surface S2 and is removed. Therefore, according to the present invention, adhesion of foreign matter to chip 100 is also suppressed.

[0061] (5) Modifications (5-1) Modification A The material of the brittle material layer 11 is not limited to silicon carbide. Other examples of the material of the brittle material layer 11 include single crystal materials, polycrystalline materials (ceramics, etc.), and glass. Examples of single crystal materials include single crystal silicon (Si), gallium nitride (GaN), gallium arsenide (GaAs), sapphire, and quartz. Examples of ceramics include low-temperature fired ceramics and high-temperature fired ceramics.

[0062] In addition to or instead of the metal layer 12, the substrate 10 may have attached to or contain on its surface or inside a layer such as a thin film that is not a brittle material (e.g., a resin layer) or a semiconductor material.

[0063] (5-2) Modification B In the breaking step S130, the processing device 50 may bend the substrate 10 along the scribe line SL by a three-point support bending method. In the breaking step S130 using the three-point support bending method, the pushing amount of the breaking bar 53 is 30 μm or more and 200 μm or less.

[0064] (5-3) Modification C In the method of the present invention, all steps may be performed in one apparatus such as the processing apparatus 50, or some steps may be performed in different apparatuses.

[0065] (5-4) Modification D The first tape 30 may have a weak adhesive strength of 0.01 N / 20 mm or more and less than 1.5 N / 20 mm during the scribing step S110. The method of the present invention may further include an adhesive strength reducing step of reducing the adhesive strength of the first tape before the scribing step S110.

[0066] 2. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as necessary.

[0067] The present invention can be widely applied to substrate processing in which a substrate is divided to cut out a plurality of chips.

[0068] 10: Substrate 30: First tape 40: Second tape 100: Chip S1: First surface S2: Second surface SL: Scribe line UV: Ultraviolet light

Claims

1. A substrate processing method for cutting a substrate into a plurality of chips, comprising the steps of: attaching a first tape containing a weakly adhesive to a first surface of the substrate; forming a scribe line on a second surface of the substrate opposite to the first surface; attaching a second tape containing an ultraviolet-curable adhesive to the second surface; dividing the substrate along the scribe lines; and removing the divided chips from the second tape.

2. The substrate processing method according to claim 1, wherein the adhesive contained in the first tape has an adhesive strength of 0.01 N / 20 mm or more and 1.5 N / 20 mm or less.

3. The substrate processing method according to claim 1 or 2, wherein the substrate is made of a single crystal material.

4. The substrate processing method according to claim 1 or 2, wherein the substrate is made of glass.

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