TWI622096B - Fabrication method of semiconductor piece - Google Patents

Abstract

A method for manufacturing a semiconductor article includes forming a groove having a first groove portion and a second groove portion, and the second groove portion is a groove portion formed to communicate with a lower portion of the first groove portion. And extends downward at a steeper angle than the angle of the first groove portion, the groove has a shape in which no corner portion exists between the first groove portion and the second groove portion, and the groove is positioned on the front side and borrowed Formed by dry etching; attaching a holding member including an adhesive layer to the front surface with a groove formed on the front surface; thinning the substrate from the rear surface of the substrate in a state where the holding member is attached; and after thinning, Remove the holding member from the front.

Description

Manufacturing method of semiconductor object

The invention relates to a method for manufacturing a semiconductor object.

A cutting method has been proposed in which a first groove is formed on the front surface of a sapphire substrate by a first blade, and then a second groove is formed on the back surface by a second blade that is deeper and wider than the first groove. , Thereby increasing the yield without reducing the number of wafers that can be obtained from one substrate (JP-A-2003-124151). In addition, a method has been proposed to form a trench from the front side of the wafer to the middle of the wafer by laser, and then use the laser to grind the wafer from the back side to the position where the trench formed by the laser is reached, thereby making it possible to The number of semiconductor elements formed in a wafer is increased (JP-A-2009-88252).

The invention provides a method for manufacturing a semiconductor article that can easily prevent an adhesive layer from remaining on the front surface of a semiconductor substrate and prevent damage to the semiconductor article.

(1) A method for manufacturing a semiconductor article, comprising: forming a groove having a first groove portion, a width of the first groove portion gradually narrowing from a front surface of the substrate toward a rear surface of the substrate; and Two groove portions are groove portions formed to communicate with the lower portion of the first groove portion, and extend toward the lower portion at a steeper angle than the angle of the first groove portion. A groove portion and the second There is no shape of a corner portion between the groove portions, the groove is positioned on the front surface and is formed by dry etching; a holding member including an adhesive layer is attached to the front surface, and the front surface is formed with the A groove; in a state where the holding member is attached, thinning the substrate from the back surface of the substrate; and removing the holding member from the front surface after thinning the substrate.

(2) A method for manufacturing a semiconductor article, comprising: forming a groove having a first groove portion whose width gradually narrows from a front surface of the substrate toward a rear surface of the substrate; and Two groove portions are groove portions formed to communicate with the lower portion of the first groove portion and extend downward at an angle steeper than the angle of the first groove portion. There is no shape of a corner portion between the groove portion and the second groove portion. The groove is positioned on the front surface and is formed by dry etching. A holding member including an adhesive layer is attached to the front surface, and the front surface is formed. Having the groove on the front surface; forming a groove on the back surface using a cutting member that rotates from the back surface of the substrate toward the groove on the front surface with the holding member attached; and After the groove on the back surface, the holding member is removed from the front surface.

(3) The method for manufacturing a semiconductor article according to item (1) or (2), further comprising: the step of forming the trench on the front surface is performed as follows: by the dry etching, The width of the groove on the front side gradually narrows toward the back side. The etching strength starts to form the groove on the front side, and the groove on the front side is formed. In the meantime, the flow rate of the gas for forming the protective film contained in the etching gas used for the dry etching is switched from the first flow rate to the first flow rate within a range in which the flow rate of the gas for forming the protection film is not stopped. A second flow with a small flow.

(4) The method for manufacturing a semiconductor article according to item (1) or (2), further comprising: forming the trench on the front surface in the following manner: by the dry etching to The width of the groove on the front side gradually narrows toward the back side. The etching strength starts to form the groove on the front side, and during the groove formation on the front side, it will be included in the dry etching. The flow rate of the gas for forming the protective film in the etching gas is switched from the first flow rate to a second flow rate greater than the first flow rate.

(5) The method for manufacturing a semiconductor article according to the item (1) or (2), wherein the second groove portion has a width that is not wider than a width of a lowermost portion of the first groove portion and extends downward shape.

(6) The method for manufacturing a semiconductor article according to the item (1) or (2), wherein a depth of the first groove portion is deeper than a depth to which the adhesive layer enters, and the second groove The portion has a shape that becomes wider toward the lower portion than the width of the lowermost portion of the first groove portion.

According to the above-mentioned items (1) and (2), as compared with the case where the trench is formed on the front surface under a single etching condition, it is possible to easily prevent the adhesive layer from remaining on the front surface of the semiconductor substrate and prevent the semiconductor damage.

According to the above-mentioned items (3) and (4), as compared with a case where the flow rate of the gas is not switched during the grooves formed on the front surface, the prevention of the adhesive layer can be easily achieved. Remains on the front surface of the semiconductor substrate and prevents damage to the semiconductor object.

According to the above item (5), compared with the structure including the second groove portion having a width larger than the width of the lowermost portion of the first groove portion, when the adhesive layer enters the second groove portion, It is possible to prevent the adhesive layer from remaining on the front surface of the semiconductor substrate.

According to the above item (6), the area on the back surface of the semiconductor object after dicing can be reduced compared with a case where the trench on the front surface has a shape in which the width of the trench gradually narrows toward the lower portion of the trench.

100‧‧‧Light-emitting element

120‧‧‧ cutting area (cutting line)

130‧‧‧Photoresist pattern

140‧‧‧micro groove

160‧‧‧Tape

162‧‧‧ tape base member

164‧‧‧Adhesive layer

164a‧‧‧Adhesive layer

164b‧‧‧Adhesive layer

165, 166‧‧‧Adhesive layer

170‧‧‧Groove

180, 200‧‧‧ UV

190‧‧‧Tape

192‧‧‧ tape base member

194‧‧‧Adhesive layer

210‧‧‧Semiconductor wafer (semiconductor object)

220‧‧‧Fixed components

230‧‧‧Circuit Board

300‧‧‧ cutting knife

400, 410‧‧‧ micro groove

402, 404, 412, 412a, 414, 414a

500, 510, 520, 530, 540‧‧‧ micro groove

502, 504, 512, 514, 522, 524, 542, 542a, 544, 544a

532, 534‧‧‧‧First groove section, side

532a, 534a‧‧‧Second groove section, side

600‧‧‧Photoresist

610‧‧‧ opening

620‧‧‧Groove

630‧‧‧protective film

800‧‧‧step

FIG. 1 is a flowchart showing an example of a manufacturing procedure of a semiconductor article according to an example of the present invention.

2 (A) to (D) are schematic cross-sectional views of a semiconductor substrate in a manufacturing process of a semiconductor article according to an example of the present invention.

3 (A) to (E) are schematic cross-sectional views of a semiconductor substrate in a manufacturing process of a semiconductor article according to an example of the present invention.

FIG. 4 is a schematic plan view of a semiconductor substrate (wafer) at the time of completion of circuit formation.

FIG. 5 is a cross-sectional view showing a half cut performed by a cutting blade in detail.

6 is a cross-sectional view showing a residual adhesive layer when the tape for dicing is removed from the front surface of the substrate.

FIG. 7 is a micro-groove according to an example of the present invention, FIGS. 7 (A) and 7 (B) are cross-sectional views showing the shape of a first micro-groove, and FIGS. 7 (C) and 7 (D) It is sectional drawing which shows the shape of a 2nd microgroove.

FIG. 8 is a micro-groove according to a comparative example, and FIGS. 8 (A) and 8 (B) show an inverted cone shape 8 (C) and FIG. 8 (D) are cross-sectional views showing micro-grooves in a vertical shape.

FIG. 9 is a micro-groove of another comparative example, FIG. 9 (A) is a cross-sectional view showing only a micro-groove in a forward tapered shape, and FIG. 9 (B) and FIG. A cross-sectional view of a micro-groove formed separately from the vertical shape.

10 (A) to (D) are schematic process cross-sectional views illustrating a method of manufacturing a micro-groove according to an example of the present invention.

11 (A) is a cross-sectional view showing a stepped portion formed in a semiconductor wafer, FIG. 11 (B) is a view showing a load applied to the stepped portion when cutting by a dicing blade, and FIG. 11 (C) It is a view showing the damage of the step portion.

For example, the method for manufacturing a semiconductor article according to the present invention is applied to a method of dividing (cutting) a member having a substrate shape (for example, a semiconductor wafer formed with a plurality of semiconductor elements) and a method of manufacturing each semiconductor article (semiconductor wafer). method. The semiconductor element formed on the substrate is not limited to a specific element, and may include a light emitting element, an active element, a passive element, and the like. In a preferred aspect, the manufacturing method according to the present invention may be applied to a method of taking out a semiconductor object including a light emitting element from a substrate, and the light emitting element may be, for example, a surface emitting semiconductor laser, a light emitting diode, or a light emitting gate. Fluid, etc. One semiconductor article may include a single light emitting element, and may include a plurality of light emitting elements arranged in an array. In addition, a semiconductor article may include a driving circuit that drives one light emitting element or a plurality of light emitting elements. The substrate may be composed of, for example, silicon, SiC, compound semiconductor, sapphire, or the like. However, the substrate is not limited thereto, and a substrate including at least one semiconductor (hereinafter, may be collectively referred to as a semiconductor substrate) may be a substrate formed of other materials. In a preferred aspect, the substrate is A semiconductor substrate in which a light-emitting element such as a surface-emitting semiconductor laser or a light-emitting diode is formed on the semiconductor substrate, and the semiconductor substrate is composed of a group III-V compound such as GaAs.

In the following description, a method of taking out each semiconductor object (semiconductor wafer) from a semiconductor substrate on which a plurality of light emitting elements are formed will be described with reference to the drawings. It is worth noting that the scale or shape of the drawings is emphasized to help understand the characteristics of the present invention, and the scale or shape of the drawings need not be the same as the scale or shape of the actual device.

[Example]

FIG. 1 is a flowchart showing an example of a manufacturing procedure of a semiconductor article according to an example of the present invention. As shown in FIG. 1, the method for manufacturing a semiconductor object according to this example includes a step (S100) of forming a light emitting element, a step of forming a photoresist pattern (S102), and a step of forming a micro trench on a front surface of a semiconductor substrate (S104). Step of removing the photoresist pattern (S106), step of attaching a tape for dicing on the front surface of the semiconductor substrate (S108), step of half-cutting the back of the semiconductor substrate (S110), tape for dicing A step of applying ultraviolet light (UV) and attaching an adhesive tape for extension to the back surface of the semiconductor substrate (S112), a step of removing the adhesive tape for cutting and applying an ultraviolet light for the adhesive tape for extension (S114), and picking up A semiconductor object (semiconductor wafer), and a step of die-mounting (S116) and the like on a circuit board. The cross-sectional views of the semiconductor substrate shown in FIGS. 2 (A) to 2 (D) and 3 (A) to 3 (E) correspond to each of steps S100 to S116.

As shown in FIG. 2 (A), in the step (S100) of forming a light-emitting element, a plurality of light-emitting elements 100 are formed on the front surface of a semiconductor substrate W made of, for example, GaAs. The light-emitting element 100 is, for example, a surface-emitting semiconductor laser, a light-emitting diode, Light gate fluid. It is worth noting that in FIG. 2 (A), one area is shown as the light-emitting element 100, but the light-emitting element 100 shows an element included in a semiconductor object after cutting, and not only in the area of one light-emitting element 100 One light emitting element can be formed, and multiple light emitting elements or other circuit elements can be formed.

FIG. 4 is a plan view showing an example of the semiconductor substrate W when the step of forming a light emitting element is completed. For convenience of description, only the light emitting element 100 located in the middle portion in FIG. 4 is shown. On the front surface of the semiconductor substrate W, a plurality of light emitting elements 100 are formed in an array form in a matrix direction. The planar area of the single light emitting element 100 is a substantially rectangular shape, and the light emitting elements 100 are spaced apart from each other in a lattice shape using a cutting area 120 defined by a cutting line or the like having a constant interval S.

If the formation of the light emitting element is completed, a photoresist pattern is formed on the front surface of the semiconductor substrate W (S102). As shown in FIG. 2 (B), the photoresist pattern 130 is produced in such a manner that a cutting region 120 defined by a cutting line or the like on the front surface of the semiconductor substrate W is exposed. The photoresist process is used to produce the photoresist pattern 130.

Subsequently, a fine trench is formed on the front surface of the semiconductor substrate W (S104). As shown in FIG. 2 (C), a micro trench having a constant depth is formed on the front surface of the semiconductor substrate W using the photoresist pattern 130 as a mask (hereinafter, for convenience of description, it is referred to as a micro trench or trench on the front surface) Slot) 140. The trench may be formed by, for example, dry etching, and preferably, the trench is formed by an anisotropic plasma etching method (reactive ion etching method) as an anisotropic dry etching. The width Sa of the micro trench 140 is substantially the same as the width of the opening formed in the photoresist pattern 130, and the width Sa of the micro trench 140 is, for example, several μm to several ten μm. Preferably, the width Sa is about 3 μm to about 15 μm. In addition, the depth of the micro trench 140 is, for example, about 10 μm to about 100 μm, and the depth is formed at least deeper than the depth of a functional element such as a light emitting element. Preferably, micro groove The depth of the groove 140 is about 30 μm to about 80 μm. If the micro-grooves 140 are formed by a commonly used cutting blade, the interval S between the cutting regions 120 is the sum of the margin width taking into account the width of the groove and the amount of pitching of the cutting blade, and the interval S becomes as large as about 40 μm to about 80 μm. Meanwhile, in the case where the micro-trench 140 is formed in the semiconductor program, not only the width of the trench is narrow, but also the marginal width for cutting can become narrower than that in the case where a dicing blade is used. That is, the interval S between the dicing regions 120 can be reduced. For this reason, the number of semiconductor objects obtained can be increased by arranging the light emitting elements on the wafer in a high density manner. The “front side” in this example indicates the surface side where a functional element such as a light-emitting element is formed, and the “back side” indicates the surface side opposite to the “front side”.

Subsequently, the photoresist pattern is removed (S106). As shown in FIG. 2 (D), if the photoresist pattern 130 is removed from the front surface of the semiconductor substrate, the micro-grooves 140 formed along the cutting region 120 are exposed on the front surface. The shape of the micro trench 140 will be described in detail below.

Subsequently, a UV-curable tape for dicing is attached (S108). As shown in FIG. 3 (A), an adhesive tape 160 for dicing having an adhesive layer is attached to the light emitting element side. Subsequently, a half-cut is performed along the micro-groove 140 from the back surface of the substrate by a dicing blade (S110). In order to position the cutting blade, a method of arranging an infrared camera above the back surface of the substrate and directly sensing the micro-groove 140 through the transmissive substrate can be used. Method or other known methods. As shown in FIG. 3 (B), by positioning, half cutting is performed by a dicing blade, and a groove 170 is formed on the back surface of the semiconductor substrate. The trench 170 has a depth reaching the micro trench 140 formed on the front surface of the semiconductor substrate. Here, the micro-groove 140 is formed with a narrower width than the groove 170 formed on the back surface by a dicing blade, but this is due to the following factors: If the micro-groove 140 is formed with a narrower width than the groove 170 on the back surface, Compared with the case where the semiconductor substrate is cut only by a dicing blade, the number of semiconductor objects that can be obtained from one wafer is increased. As shown in FIG. 2 (C), if a micro trench having a width of about several μm to about ten μm is formed from the front surface to the back surface of a semiconductor substrate, it is not necessary to form a trench on the back surface using a dicing blade, but It is not easy to have a micro-groove with such a depth. Therefore, as shown in FIG. 3 (B), a half cut formed from the back surface by a cutter is combined.

Subsequently, ultraviolet light (UV) is applied to the tape for cutting, and the tape for extension is also attached (S112). As shown in FIG. 3 (C), ultraviolet light 180 is applied to the tape 160 for cutting, and the adhesive layer is cured. Then, an adhesive tape 190 for expansion is attached to the back surface of the semiconductor substrate.

Subsequently, the tape for cutting is removed, and ultraviolet light is applied to the tape for extension (S114). As shown in FIG. 3 (D), the tape 160 for dicing is removed from the front surface of the semiconductor substrate. Further, ultraviolet light 200 is applied to the tape 190 for expansion on the back surface of the substrate, and the adhesive layer is cured. The tape 190 for expansion is elastic to the base member, and the tape extends in such a manner that the cut semiconductor object can be easily picked up after dicing, thereby expanding the interval between the light emitting diodes.

Subsequently, the diced semiconductor object is picked up and mounted on a wafer (S116). As shown in FIG. 3 (E), the semiconductor wafer (semiconductor article) 210 picked up from the tape 190 for expansion is mounted on the circuit board 230 via a fixing member 220 such as a conductive adhesive (such as an adhesive or solder).

Subsequently, the half cutting by the cutting blade will be described in detail. FIG. 5 shows a state where the enlarged cross-sectional view is turned upside down when half cutting is performed by a cutting blade as shown in FIG. 3 (B). FIG. 3 illustrates the light emitting element 100 formed on the front surface of the substrate in an emphasized manner. However, FIG. 5 does not clearly show the light emitting element 100 on the front surface of the substrate, but The light emitting element 100 is formed on the front surface of the substrate in the same manner as in FIG. 3.

As shown in FIG. 5, the semiconductor substrate W is cut along the micro-groove 140 from the back surface while the dicing blade 300 is rotated, so that the dicing blade 300 forms a groove 170 in the semiconductor substrate W. The cutting blade 300 is, for example, a disc-shaped cutting member. Here, an example in which the tip portion of the cutting blade has a constant thickness is shown, but the cutting blade may have a tapered tip portion. The groove 170 (notch width) formed by the cutting blade 300 has a width substantially the same as the thickness of the cutting blade 300, and the groove 170 is made to a depth communicating with the micro-groove 140. Outside the semiconductor substrate W, the dicing blade 300 is positioned in a direction parallel to the rear surface of the semiconductor substrate W. In addition, as the dicing blade 300 moves by a predetermined amount in the direction Y perpendicular to the back surface of the semiconductor substrate W, a step is formed in a coupling portion of the groove 170 and the micro-groove 140 to form a stepped portion 800, and the micro-groove 140 uses the semiconductor substrate The thickness direction of W is positioned so as to have a predetermined thickness T in the Y direction. Then, after the dicing blade 300 is positioned outside the semiconductor substrate W, while the dicing blade 300 rotates, at least one of the dicing blade 300 and the semiconductor substrate W is moved in a direction parallel to the back surface of the semiconductor substrate W, thereby causing A trench 170 is formed in the substrate W. The step portion 800 is a portion located between the step formed in the coupling portion of the trench 170 and the micro-groove 140 and the front surface of the semiconductor substrate W, that is, the step portion 800 is formed by the width of the trench 170 and the micro-groove. The difference between the widths of 140 forms part of the s-step shape.

When the half cutting performed by the cutting blade 300 is performed, the tape 160 for cutting is attached to the front surface of the substrate. The tape 160 for cutting includes a tape base member 162 and an adhesive layer 164 laminated on the tape base member. The adhesive layer 164 composed of an ultraviolet curable resin has a constant viscosity or viscosity characteristic before being applied with ultraviolet light, and has a characteristic of curing when being applied with ultraviolet light and losing the adhesive property. Sex. For this reason, when the adhesive tape 160 for dicing is attached, the adhesive layer 164 is adhered to the front surface of the substrate including the micro-grooves 140 and the substrate is held in such a manner that the diced semiconductor objects are not separated after dicing .

In the cutting line A2 of FIG. 5, while the semiconductor substrate W is being cut, the vibration B and the cutting pressure P are caused to pass through the groove 170 by the rotation of the cutting blade 300 or the relative movement between the cutting blade 300 and the semiconductor substrate W. The inner wall is applied to the semiconductor substrate W. If the semiconductor substrate W is pressed in the Y direction by the cutting pressure P, the adhesive layer 164 having a viscosity flows into the micro trench 140. In addition, as the vibration B is transmitted to the vicinity of the micro-groove 140, the flow of the adhesive layer 164 is promoted. In addition, during the cutting by the cutter 300, the cutting water (jet stream) mixed with the cutting powder is supplied to the groove 170, and the pressure P1 is applied in a direction in which the micro groove 140 expands due to the cutting water, thereby further promoting adhesion. Entry of agent layer 164. As a result, if the micro-grooves do not have a forward tapered shape according to the present example (to be described later), there are cases where, for example, the adhesive layer 164 enters a micro-groove having a width of about 5 μm at an entry depth of about 10 μm. 140 in. Therefore, in this example, even if the trench width on the front side is made narrower than the trench width on the back side due to, for example, an increase in the number of obtained semiconductor objects, if the method of manufacturing a semiconductor object is performed by The cutting member is rotated to form the grooves on the back surface, and the number of semiconductor objects obtained is also slightly reduced. Therefore, a micro-groove in a forward tapered shape is formed (to be described later).

During the cutting of the cutting line A2 adjacent to the cutting line A1 line, in the cutting line A1 where the cutting is completed, pressure is applied to the microgroove 140 in such a manner that the microgroove 140 becomes narrow in the width direction. Therefore, it should be considered that Yes, the adhesive layer 164 entering the micro-groove 140 may easily further enter the micro-groove 140. In the cutting line A3 on the opposite side, the adhesive layer 164 has just adhered before cutting, so it should be It is considered that the amount of the adhesive layer 164 entering the micro-groove 140 is relatively reduced.

If the half cutting by the cutting blade 300 is completed, the tape 190 for extension is attached to the back of the substrate, and then, the ultraviolet light 180 is applied to the tape 160 for cutting. The adhesive layer 164 to which ultraviolet light is applied is cured, and the adhesive force of the adhesive layer 164 is lost (FIG. 3 (C)). Subsequently, the tape for dicing is removed from the front side of the substrate. FIG. 6 is a cross-sectional view showing a remaining portion of the adhesive layer when the tape for cutting is removed. The expansion tape 190 attached to the back surface of the substrate includes an adhesive tape base member 192 and an adhesive layer 194 laminated on the adhesive tape base member. The cut semiconductor object is held by the adhesive layer 194.

When the adhesive tape 160 for dicing is removed from the front surface of the substrate, the adhesive layer 164a entering the micro-groove 140 enters a deeper position. Therefore, there is a case where a part of the adhesive layer 164a is not sufficiently covered by ultraviolet light. It was irradiated without curing. Because the uncured adhesive layer 164a is tacky, when the adhesive layer 164a is removed from the front surface of the substrate, the uncured adhesive layer 164a is cut off, and the adhesive layer 164a remains in the micro-groove 140, or It may remain in a state of being reattached to the front surface of the substrate. In addition, even in a cured state, the adhesive layer 164a penetrates deep into the narrow micro-grooves, and therefore, the adhesive layer 164a may remain in a tearing manner due to pressure during removal. If the remaining adhesive layer 164b is reattached to the front surface of the light emitting element, the light amount of the light emitting element is reduced, the light emitting element becomes defective, and the yield is reduced. In addition, even in the semiconductor wafer other than the light emitting element, the adhesive layer 164b remains, and therefore other harmful effects such as a failure judged by the appearance inspection of the wafer occur. For this reason, it is not preferable that the adhesive layers 164a and 164b remain on the front surface of the substrate when the tape for cutting is removed. In this example, as the shape of the micro-grooves formed on the front surface of the substrate changes to a forward tapered shape (To be described later), it is possible to prevent the adhesive layer from remaining in micro-grooves or the like on the front surface of the substrate when the tape for dicing is removed.

There are many cases in which if a plurality of light emitting elements 100 are formed in a mesa shape, the light emitting element 100 forms a convex portion, a concave portion is formed between the light emitting element 100 and another light emitting element 100, and a micro groove is formed. 140 is mainly formed in the concave portion. In the foregoing configuration, the adhesive layer 164 is attached not only to the protruding portion but also to the entrance portion of the micro-groove 140, so a configuration is considered in which the cutting water mixed with the cutting powder does not invade the front surface of the substrate. However, in order to follow the adhesive layer 164 located at the entry portion of the micro-groove 140, the adhesive tape for cutting is required to have the adhesive layer 164 with a sufficient thickness, and therefore, the adhesive layer 164 easily and deeply enters the micro-groove. 140 in. Therefore, under the condition that the adhesive layer 164 easily and deeply enters the micro-groove 140, a forward-tapered micro-groove according to this example is applied (to be described later), and therefore, the adhesive layer 164 Residues can get better results.

In addition, it should be considered that when the micro-grooves that are perpendicular to the front surface of the semiconductor substrate are formed, the adhesive layer 164 enters a deeper distance than the width of the micro-grooves (that is, the adhesive layer 164 is located in the micro-grooves). In the case where the shape of the adhesive layer 164a in the groove is vertically extended, as compared with the case where the shape of the adhesive layer 164a is not vertically extended, when the adhesive layer 164 is removed, the adhesive layer 164 is more likely to be applied to The pressure on the root of the adhesive layer 164a in the micro-groove tears and easily remains. Therefore, in a case where the forward tapered shape according to the present example is not applied, the width of the microgroove, the thickness of the adhesive layer 164, and the like are manufactured so that the shape of the adhesive layer 164a in the microgroove is vertically extended, apply According to the micro-grooves of a forward tapered shape according to this example (to be described later), a better effect can be obtained with respect to the residue of the adhesive layer 164.

Subsequently, the shape of a micro-groove according to an example of the present invention will be described. FIG. 7 (A) is a cross-sectional view showing the shape of a first micro-groove according to the present example, and FIG. 7 (B) is a view showing a process of performing an adhesive layer into the micro-groove of FIG. 7 (A). View of ultraviolet light.

As shown in FIG. 7 (A), the micro-groove 400 according to the present example includes side surfaces 402 and 404 (inclined to be referred to as a forward cone shape) in which the opening width Sa1 is narrowed from the opening width Sa1 on the front surface of the substrate to a depth D The width of the bottom Sa2 (Sa1> Sa2), and the sides 402 and 404 face each other in an inclined manner. That is, the micro trench 400 has a shape in which the width is gradually narrowed from the opening width Sa1 on the front surface of the semiconductor substrate W to the depth D. Further, the side surfaces 402 and 404 are not straight, but have a shape in which the lower side of the groove extends downward at a steep inclination angle compared to the upper side of the groove. During the formation of a trench (to be described in detail below), the shape of the trench is formed by switching the etching conditions. The opening width Sa1 is, for example, about several μm to about ten μm. In the case where a trench 170 deeper than a formation depth of a circuit such as a light emitting element is formed from the back surface, the depth D is formed so that the step portion 800 formed by the difference in width between the trench 170 and the micro trench 400 is not damaged. If the micro-grooves 400 are left, when the grooves 170 are formed from the rear surface of the substrate, the stepped portion 800 may be damaged by the pressure generated by the cutting blade 300, and therefore, a depth that is not damaged is required. At the same time, because the strength of the semiconductor substrate is weakened by the deep trenches, compared to the case where the semiconductor substrate W processed in the procedure after the micro trenches 140 are shallow, the case where the micro trenches 400 are too deep becomes difficult to handle. . Therefore, it is preferable that deeper formation is unnecessary. In addition, it is preferable that the micro-trench 400 is formed by anisotropic dry etching, and the inclination angles of the side surfaces 402 and 404 can be appropriately selected by changing the shape of the photoresist, the etching conditions, and the like. In the shape of FIG. 7 (A), a part (corner part) where the angle of the side of the groove suddenly changes is not located between the first groove part and the second part. The boundary portion between the groove portions is, therefore, the boundary between the first groove portion on the upper side and the second groove portion on the lower side is unclear. However, since the angles of the upper and lower side surfaces of the micro-groove 400 are different from each other, FIG. 7 (A) is an example of a groove (micro-groove) on the front side: the width of the groove is not larger than the first The width of the lowermost portion of the groove portion, and the groove includes a second groove portion extending downward at a steeper angle than the angle of the first groove portion. The first groove portion gradually narrows in width from the front surface to the back surface of the substrate. In the groove portion, the groove further includes a groove portion formed to communicate with the lowermost portion of the first groove portion.

As shown in FIG. 7 (B), a groove 170 having a cut width Sb formed by cutting by the cutter blade 300 is formed, and the groove 170 is connected to the micro groove 400. The width (notch width Sb) of the trench 170 is, for example, about 20 μm to about 60 μm. A part of the adhesive layer 164 enters the microconical groove 400 having a forward tapered shape due to pressure or vibration from, for example, pressing from the cutter 300, and after the adhesive tape for extension is attached, the substrate is irradiated with ultraviolet light 180 from the front surface于 切 的 的 160160。 Cutting tape 160. At this time, since the micro-groove 400 is made into a forward tapered shape, the ultraviolet light 180 is not blocked by the semiconductor substrate W and is sufficiently applied to the adhesive layer 164a in the micro-groove 400. Therefore, the micro-groove 400 is easily adhered. The agent layer 164a is cured. As a result, when the tape 160 for cutting is removed from the front surface of the substrate, even if the opening widths of the micro-grooves 400 are the same as each other, the adhesive layer 164a in the micro-grooves 400 is lost compared to the vertical shape of the micro-grooves 400 More adhesiveness makes the adhesive layer 164a easily separated from the front surface of the substrate and the micro-groove 400, and inhibits the adhesive layer from re-attaching to the front surface of the substrate. In addition, since the forward-tapered shape of the micro-groove 400 has an inclined groove shape, the adhesive layer 164a entering the micro-groove 400 is not cured even if it is pressed, as compared with the case of the vertical groove. It is also easy to leave and facilitate extraction.

FIG. 7 (C) is a sectional view showing the shape of a second micro-groove according to the present example. Face view. The second micro-groove 410 includes: groove portions of the side surfaces 412 and 414, the side surfaces 412 and 414 facing each other in a slanting manner in an advancing direction of the width Sa2 in the middle portion from the opening width Sa1 to the depth D of the front surface of the substrate; As well as the groove portions of the side surfaces 412a and 414a, the side surfaces 412a and 414a are substantially vertical from the width Sa2 to the bottom and face each other. That is, the second micro-groove 410 includes a first groove portion and a second groove portion. The width of the first groove portion gradually narrows from the front surface to the back surface of the substrate. In the lower communicating groove portion, the width of the second groove portion is not greater than the width of the lowermost portion of the first groove portion, and the second groove portion extends downward at a steeper angle than the angle of the first groove portion. . Then, during the formation of the trench, the shape is formed while the etching conditions are switched. In the same manner as in FIG. 7 (A), the shape of FIG. 7 (C) is a shape in which the angle of the side where the groove does not exist at the boundary portion between the first groove portion and the second groove portion suddenly changes Part (corner part). Preferably, when the tape 160 for cutting is attached, the depth D of the groove portion inclined by the side surfaces 412 and 414 is deeper than the depth to which the adhesive layer 164 enters. Since the depth of the groove portion deeper than the depth D is narrower than the groove width of the forward tapered shape, the ratio of the vibration of the tape used for cutting or the groove width due to pressure increases to be greater than the groove width of the forward tapered shape. . Therefore, when the adhesive layer 164 advances into the groove portion deeper than the depth D when the adhesive tape 160 for cutting is attached, the adhesive layer 164 enters a deeper portion of the groove due to vibration or pressure of the cutter. in. Therefore, it is preferable that, in a state where the tape 160 for cutting is attached, the depth D is deeper than the depth to which the adhesive layer 164 enters.

In addition, it is preferable that the depth D is a depth in which the adhesive layer 164 does not enter the groove portion deeper than the depth D after a groove is formed on the back surface by a dicing blade. Preferably, the depth D is 10 μm or more. This is due to the following factors: If the adhesive layer 164 enters the groove portion deeper than the depth D, the adhesive layer is more accommodating. Easy to remain when removed. Other conditions such as the depth of the entire micro-trench are the same as those of FIG. 7 (A). Here, as another example of FIG. 7 (C), the second groove portion of the second micro-groove 410 is under the condition that the depth D is 10 μm or more because the depth of the adhesive layer is within 10 μm. It may have a shape in which the width of the second groove portion gradually widens from the depth D toward the bottom of the second micro-groove 410.

Here, if the micro-groove is deeply formed into a forward tapered shape as shown in FIG. 7 (A), it is necessary to expand the opening Sa1. In addition, if the micro-groove 400 is deeply formed into a forward-only cone shape while the opening portion Sa1 is narrowed, the tapered angle becomes a steep angle, and therefore, the adhesive layer 164 is likely to remain in the micro-groove 400. Meanwhile, in the shape of FIG. 7 (C), the width of the opening portion Sa1 is maintained to a width at which the adhesive layer can remain in the microgrooves, and microgrooves having a desired depth are easily formed. If a micro-groove having a desired depth can be formed, compared with a case where the depth of the micro-groove is shallow, when a groove 170 having a width wider than that of the micro-groove 410 is formed from the back surface, the step portion can be prevented from being damaged .

In addition, when a micro-trench perpendicular to the front surface of the semiconductor substrate is formed, in a case where the adhesive layer 164 enters a deeper distance than the width of the micro-trench (that is, the adhesive of the adhesive layer 164 in the micro-trench) When the shape of the layer 164a is vertically extended, compared with the case where the shape of the adhesive layer 164a is not vertically extended, when the adhesive layer 164 is removed, the adhesive layer 164 is The pressure on the root of the adhesive layer 164a is liable to remain. Therefore, it is preferable that if it is assumed that a vertical micro-groove is formed, the entry portion of the micro-groove has a forward tapered shape such that, for example, as shown in FIG. 7 (C), the width of the micro-groove or the adhesive layer 164 The shape of the adhesive layer 164a entering the micro-grooves is vertically extended under manufacturing conditions such as the thickness of the metal layer. That is, the grooves in a portion located lower than the groove portion of the forward tapered shape The width of the portion is narrower than the depth to which the adhesive layer enters when the entire micro-groove 410 is formed with the groove width. If the entering portion of the groove has a forward tapered shape, the adhesive layer is targeted for the adhesive layer. The residue of 164 can get better results.

As shown in FIG. 7 (D), if the groove 170 having a cut width Sb is formed by cutting the micro groove of FIG. 7 (C) by means of the cutter 300, the groove 170 is connected to the micro groove 410. In the same manner as in FIG. 7 (B), a portion 164a of the adhesive layer 164 enters the micro-groove 410, but if the depth D of the forward-tapered groove portion (side surfaces 412 and 414) of the micro-groove 410 is formed To be deeper than the depth to which the adhesive layer 164a enters, the adhesive layer 164a in the micro-groove 410 is sufficiently irradiated with ultraviolet light and is easily cured. For this reason, when the tape for cutting is removed, it is possible to prevent the adhesive layer from remaining in the micro-grooves 410 or on the front surface of the substrate. In addition, because the side surface of the micro-groove 410 is inclined, even when the adhesive layer 164a that is pressed into the micro-groove 410 is not cured, the adhesive layer is easy to leave and promote extraction.

Thus, according to the present example, since the micro-grooves 400 and 410 constitute a groove portion including a forward-tapered shape and the width of at least the front opening of the substrate is narrowed toward the bottom in the forward-tapered shape, In comparison, even if the adhesive layer of the tape used for dicing enters the micro-grooves, the entire adhesive layer in the micro-grooves is applied with ultraviolet light to cause the adhesive layer to lose its adhesiveness and cure the adhesive layer. In addition, since the tapered shape is formed, as compared with the case where the tapered shape is not formed, the adhesive layer is prevented from being cut off when the tape for cutting is removed, and it is easy to form the microgroove and the front surface of the substrate by integral molding. Perform removal. Further, in the same manner as the shape of FIG. 9 (A) (which will be described later), because not only the sides of the micro-grooves are straight, but also the sides of the lower side have a steeper angle than the sides of the upper side. Therefore, even under the condition that the widths of the openings of the micro-grooves are the same as each other, the shape is formed more than the shape shown in FIG. 9 (A). Deep trench. If a deeper groove can be formed, when the groove 170 is formed on the back surface, the step portion 800 is difficult to be damaged by the pressure caused by the cutting blade. Therefore, when the shape of FIG. 9 (A) is compared with the shape of FIG. 7 (A) or FIG. 7 (C), the shape of FIG. 7 (A) or FIG. 7 (C) is easy to obtain the following effects: preventing the adhesive Remains of the layer and prevents damage to the step.

In addition, all the drawings of FIGS. 7 (A) to 7 (D) show a shape in which the opening width Sa1 on the front surface of the substrate is narrower than the width of the groove 170, but this is because if the opening width Sa1 on the front surface of the substrate is built The structure is narrower than the width of the trench 170, and the number of obtained semiconductor objects can be increased compared with the method of cutting with the width of the trench 170. Here, in general, in order to increase the number of semiconductor objects obtained, trenches on the front surface are formed by an anisotropic etching method (by which a trench having a narrow width and a vertical shape is easily formed). Than grooves on the front surface formed by an isotropic etching method or a dicing blade. However, if an anisotropic etching method is simply used to form a narrow and vertical trench shape, this method is not preferable from the viewpoint of the adhesive layer remaining. At the same time, if the residue of the adhesive layer is noticed, compared with the trench on the front surface formed by anisotropic dry etching in which the trench has a narrow and vertical shape, the trench is not vertical and is formed by anisotropy. The openings of the micro trenches formed by the isotropic etching method or the like are better, but the narrow and deep trenches are not formed by the isotropic etching method. Therefore, in this example, even if microgrooves having the shapes shown in FIGS. 7 (A) to 7 (D) are formed by anisotropic dry etching, the number of semiconductor objects obtained can be increased and the adhesive layer can be prevented. Residual.

8 (A) and 8 (B) are comparative examples when the micro-grooves are formed into an inverted cone shape. As shown in FIG. 8 (A), the micro-groove 500 has sides 502 and 504, where the width Sa2 at the bottom is larger than the opening width Sa1, and the sides 502 and 504 face each other and It's inclined. The micro-groove 500 is made into a so-called inverted cone shape. In this way, in the case of using an isotropic etching method or even an anisotropic dry etching, by setting the flow rate of a gas (Cl2, etc.) for etching included in the etching gas and the protection for forming a protective sidewall The shape of the wider side of the bottom side is formed by balancing the flow rate of the gas (C4F8, etc.) of the membrane to form an inverted cone shape. As shown in FIG. 8 (B), when a part 164a of the adhesive layer 164 enters the inverted-cone-shaped micro-groove 500, the opening of the opening width Sa1 becomes narrow, and therefore, a part of the ultraviolet light 180 is easily caught by the semiconductor substrate W. It is shielded so that ultraviolet light is not sufficiently applied to the peripheral portion 165 (filled portion in the drawing) of the adhesive layer 164a, and a large amount of uncured adhesive layer 165 is liable to remain. Therefore, compared with the case of a forward tapered shape, when the tape for cutting is removed, the adhesive layer 165 having stickiness is easily cut off and remains in the micro-grooves, or reattaches to the front surface of the substrate, and the like. In addition, since it has an inverted cone shape, the adhesive layer 164 that is pressed into the micro-grooves 500 and hardly hardens exists in a smooth manner.

8 (C) and 8 (D) are comparative examples when the micro-grooves are formed in a vertical shape. As shown in FIG. 8 (C), the micro-groove 510 includes side surfaces 512 and 514, the side surfaces 512 and 514 are perpendicular to the opening width Sa1 of the front surface of the substrate and face each other, and the micro-groove 510 is made into a so-called vertical shape Trench. The shape is formed by using commonly used anisotropic dry etching. As shown in FIG. 8 (D), since the adhesive layer 164a that has entered into the microgroove 510 in a vertical shape penetrates deeper into the width Sa1 of the microgroove, compared with the case of a forward tapered shape, The entire adhesive layer 164a is not sufficiently irradiated with the ultraviolet light 180, and a part of the adhesive layer 166 of the peripheral portion of the adhesive layer 164a is easily uncured. The uncured adhesive layer 166 is smaller than the inverted tapered adhesive layer 165 of FIG. 8 (A), but when the tape for cutting is removed, the adhesive layer 166 may remain in the micro-grooves 510 or may reattach To the front surface of the substrate.

FIG. 9 (A) is a comparative example when the micro-groove 520 is formed into a forward tapered shape having only linear side faces 522 and 524. The shape is formed by, for example, using anisotropic dry etching, by setting the flow rate of a gas (Cl2, etc.) for etching included in the etching gas, and a gas (C4F8, etc.) for forming a protective film for protecting a sidewall. The balance between the flow is made into a forward cone shape. As shown in FIG. 9 (A), compared with the shape of FIG. 8 (A) or FIG. 8 (C), the adhesive layer 164a entering the micro-groove 520 in a forward tapered shape becomes the entire adhesive layer 164a easily. A state in which the ultraviolet light 180 is irradiated. Therefore, an uncured adhesive layer hardly occurs after the application of the ultraviolet light 180, and when the tape for cutting is removed, the adhesive layer hardly remains in the micro-grooves 520 or the front surface of the substrate, or hardly Reattach. However, in the shape of FIG. 9 (A), unlike the shape of FIG. 7 (A) or FIG. 7 (C), the side surfaces 522 and 524 of the micro-groove 520 are composed of side surfaces having a linear shape with a constant angle. Comparing the width Sa1 of the entry portion of the micro-trench under the same conditions, it is impossible to form a deeper trench than the trench of FIG. 7 (A) or FIG. 7 (C). As described above, in the case where a shallow trench is formed instead of a deep trench, when the trench 170 is formed on the back surface, the step portion 800 is easily damaged by the pressure generated by the cutting blade. Therefore, when the shape of FIG. 9 (A) is compared with the shape of FIG. 7 (A) or FIG. 7 (C), the shape of FIG. 7 (A) or FIG. 7 (C) is easy to obtain the following effects: preventing the adhesive Remains of the layer and prevents damage to the step.

In FIG. 9 (B), the micro-groove 530 includes: first groove portions 532 and 534, the width of which is gradually narrowed from the front surface to the back surface of the substrate; and second groove portions 532a and 534a, which are formed as A lower portion of a groove portion communicates, a width of the second groove portions 532a and 534a is not wider than a width of a lowermost portion of the first groove portion, and the second groove portions 532a and 534a are at an angle greater than that of the first groove portion Steeper angles extend downward. For example, a groove may be formed on the upper side corresponding to the first groove portion by an isotropic etching method. The groove portion is formed by forming a groove portion on the lower side corresponding to the second groove portion through anisotropic dry etching. In FIG. 9 (B), the entering portion of the micro-groove 530 has the same forward cone shape as the form in FIG. 9 (A), and therefore, compared with the shape of FIG. 8 (A) or FIG. 8 (C), The adhesive layer hardly remains in the micro-grooves 530 or on the front surface of the substrate. In addition, since a deeper groove can be formed even if the width Sa1 of the entry portion of the micro-trench 530 is the same as the width of the entry portion of FIG. 9 (A), the step portion is prevented compared to the shape of FIG. 9 (A). 800 damaged. However, in the shape of FIG. 9 (B), the micro-groove 530 has an edge on its side. In other words, there is a portion (corner portion) where the angle between the side surface 532 and the side surface 532a of the groove and the angle between the side surface 534 and the side surface 534a suddenly changes between the first groove portion and the second groove portion, Therefore, compared with the shape of FIG. 7 (A) or FIG. 7 (C), if the adhesive layer enters the second groove portion, the entire adhesive layer can hardly be irradiated with the ultraviolet light 180, and easily occurs. Uncured adhesive layer. In addition, since the angle between the side surface 532 and the side surface 532a and the angle between the side surface 534 and the side surface 534a suddenly change (corner portion), when the tape 160 for cutting is removed from the front surface of the substrate, The adhesive layer 164a of the two grooves is hooked to the corner and tears, so that the residue of the adhesive layer 164a is promoted. Therefore, if the shape of FIG. 9 (B) is compared with the shape of FIG. 7 (A) or FIG. 7 (C), the shape of FIG. 7 (A) or FIG. 7 (C) is easy to obtain the following effects: preventing the adhesive Remains of the layer and prevents damage to the step.

In FIG. 9 (C), the micro-groove 540 includes a first groove portion composed of side surfaces 542 and 544 and having a linear shape, and the width of the side surfaces 542 and 544 is gradually narrowed from the front surface to the back surface of the substrate; and The two groove portions are formed to communicate with a lower portion of the first groove portion, and are composed of side surfaces 542a and 544a extending downward in a substantially vertical shape. For example, the shape can be realized by using only a tip portion having an acute angle The top end portion of the divided cutting blade is used to form a portion corresponding to the first groove groove portion and a cutting blade having a thin thickness is used to form a portion corresponding to the second groove portion. Further, in the case of the shape of FIG. 9 (C), the micro-groove 540 has an edge located in a side surface thereof. That is, in the same manner as in the case of the shape of FIG. 9 (B) described above, there are portions (corner portions) where the angle between the side surface 542 and the side surface 542a of the groove and the angle between the side surface 544 and the side surface 544a suddenly change. ). Therefore, if the shape of FIG. 9 (C) is compared with the shape of FIG. 7 (A) or FIG. 7 (C), the shape of FIG. 7 (A) or FIG. 7 (C) is easy to obtain the following effects: preventing the adhesive Remains of the layer and prevents damage to the step.

Subsequently, a method of manufacturing a micro trench according to the present example will be described. FIG. 10 is a cross-sectional view showing the steps of a method of manufacturing a micro-groove shown in FIGS. 7 (A) and 7 (C). As shown in FIG. 10 (A), a photoresist 600 is applied to the front surface of the semiconductor substrate W (GaAs substrate) on which a plurality of light emitting elements are formed. The photoresist 600 is an i-line photoresist having a viscosity of, for example, 100 cpi and is formed in a thickness of about several μm. The opening 610 is formed in the photoresist 600 using a known step such as an i-line stepper or TMAH 2.38% developer. The opening 610 is formed so that the cutting area 120 shown in FIG. 2 (A) is exposed.

Subsequently, as shown in FIG. 10 (B), the semiconductor substrate W is anisotropically etched by forming a photoresist pattern 600 having an opening 610 as an etching mask. As an example, inductively coupled plasma (ICP) is used as a reactive ion etching (RIE) device. By adding a CF-based gas as an etching gas, a protective film 630 is formed on the sidewall of the trench 620 while being etched. The plasma using a reactive gas generates free radicals and ions, but the sidewalls of the trench 620 are only eroded by free radicals, and the bottom of the trench is easily etched by both free radicals and ions, thereby completing the isotropic Anisotropic etching. Here, the etching conditions such as the output of the etching device, the flow rate of the gas, or the time are adjusted, and the etching is performed under the condition that a groove having a forward cone shape is formed. For example, with The flow rate of the etching gas (Cl2, etc.) contained in the etching gas is increased, or the flow rate of the CF-based gas (C4F8, etc.), which is a gas for forming the sidewall protection film, is reduced, and the protection film 630 formed on the sidewall of the trench is changed. It is thin, and therefore, the angle of the sidewall of the trench with respect to the depth direction becomes steep (that is, becomes approximately a vertical angle). In contrast, as the flow rate of a gas (Cl2, etc.) for etching contained in the etching gas decreases, or the flow rate of a CF-based gas (C4F8, etc.) as a gas forming a sidewall protection film increases, the Since the protective film 630 becomes thick, the angle of the sidewall of the trench with respect to the depth direction becomes gentle. For example, as the etching conditions, the power of the inductively coupled plasma is 500W, the bias power is 50W, and the pressure is 3Pa. As the etching gas, Cl2 is 150sccm, BCl3 is 50sccm, C4F8 is 50sccm, and the substrate temperature is 20 ° C. The etching time is 20 minutes.

Subsequently, as shown in FIG. 10 (C), the etching conditions are switched so that the angle becomes steeper than the angle of the forward cone formed in FIG. 10 (B). For example, as the flow rate of the etching gas (Cl2, etc.) contained in the etching gas increases, or the flow rate of the CF-based gas (C4F8, etc.) as the gas for forming the side wall protective film decreases, the trench portion 640 is formed, and the trench The portion 640 has a steeper angle than the angle of the sidewall of the trench 620 formed in FIG. 10 (B). For example, as the etching conditions, the power of the inductively coupled plasma is 500W, the bias power is 50W, and the pressure is 3Pa. As the etching gas, Cl2 is 200sccm, BCl3 is 50sccm, C4F8 is 35sccm, and the substrate temperature is 20 ° C. The etching time is 20 minutes. If a micro trench is formed, the thickness of the sidewall protection film 630 on the bottom side of the trench tends to be thinner than the thickness of the sidewall protection film 630 on the upper side. Therefore, as the etching strength becomes stronger in the process, it adheres to the previously formed The sidewall protection film 630 on the bottom side of the trench is cut, and the sidewall is easily exposed. Therefore, the groove width of the bottom side of the previously formed groove becomes slightly and slowly widened, and the groove extends downward. with At this time, because the thick side wall protective film 630 is attached to the upper side of the previously formed trench, and if the etching conditions are extremely strong, the side wall protective film 630 is not cut off until the side wall is exposed, and the upper side of the trench (entering part) The shape of) is retained without change.

If the flow rate of the CF-based gas (C4F8, etc.) used to form the side wall protective film is reduced, it is preferable that the flow rate is reduced in a range where it is not completely stopped. This is because, if the gas for forming the side wall protective film is stopped, the etching strength becomes too large in the side wall direction, and a groove portion that becomes wider toward the lower portion of the micro groove is formed. In the case where the width of the groove portion is widened toward the lower portion of the micro-groove in this manner, if the adhesive layer 164a enters the groove portion, the entire adhesive layer 164a is irradiated with ultraviolet light 180, and the adhesive layer 164a is It is easy to remain in the same manner as in the case of FIG. 8 (A). As described above with reference to FIG. 5, if a groove is formed in the back surface of the substrate with respect to the micro groove by a rotating cutting member such as a dicing blade, the adhesive layer may enter a depth that exceeds an intended value, for example, an adhesive The layer enters a micro-trench with a width of about 5 μm to a depth of about 10 μm. Therefore, if there is no special reason for forming the groove portion that becomes wider toward the lower portion of the micro groove, the groove portion may not be formed from the viewpoint of preventing the adhesive layer from remaining. In addition, if the etching strength becomes too large in the side wall direction by stopping the gas used to form the side wall protective film or the like, the side wall protective film 630 may be cut until the side wall on the upper side (entering portion) of the trench is exposed. It is considered that this is because the concentration of the fresh etching gas on the side of the incoming portion is higher than that of the bottom of the micro trench. By doing so, the upper side of the trench is etched to become wider in the width direction, and the area where the element is formed may be affected in some cases. Therefore, it is preferable that the etching strength is switched within a range in which the upper side of the trench is not exposed.

After the formation of the micro-trench in FIG. 10 (C) is completed, the photoresist 600 is removed by oxygen ashing as shown in FIG. 10 (D). By doing this, The micro-grooves 400 and 410 shown in FIGS. 7 (A) and 7 (C) are obtained.

As described above, in the method of manufacturing a micro-groove according to the present example, the micro-groove is started to be formed at a first etching intensity that gradually narrows the width of the micro-groove in the depth direction. The dry etching conditions are switched to a second etching intensity that is stronger than the first etching intensity. The width of the entry portion of the trench on the front side extends downward without changing the width, and a micro trench is formed as follows: There is a portion where the groove width is widened from the front surface to the back surface of the substrate. Since the etching is performed at a first etching intensity that gradually narrows the width of the micro-grooves in the depth direction, micro-grooves are formed in a shape that prevents the micro-grooves from having the shape shown in FIG. 8 (A) and FIG. 8 (C). Residue of the adhesive layer 164a. In addition, during the formation of the micro-grooves, the strength of the dry etching is strengthened to the second etch strength, and the width of the entering portion of the micro-grooves is extended downward without changing the width under the second etch strength to form the grooves without the width. The microgrooves of the widened portion of the lower portion are formed as follows: the microgrooves are formed in FIG. 9 (C) and have no corner portions. In addition, even if the widths of the entering portions of the micro-grooves are the same as each other, deeper micro-grooves are formed compared to a forward tapered shape having only side surfaces formed in a linear shape in FIG. 9 (A).

The manufacturing method according to the present example described above is merely an example, and is not necessarily limited to the manufacturing steps shown in FIG. 10. For example, the opening 610 of the photoresist 600 formed in FIG. 10 (A) has an opening side perpendicular to the front surface of the substrate, but since it is easy to form the shape shown in FIG. 7 (A) or FIG. 7 (C), The shape may be such that the width of the opening gradually becomes wider from the front surface of the substrate toward the upper portion. If a photoresist of this shape is used, the etching range gradually widens from a portion where the photoresist is thin to a portion where the photoresist is thick, thereby easily forming a forward tapered shape. In addition, it is not necessary to switch the etching conditions only once, and if the etching intensity is gradually increased, it may be switched multiple times if necessary.

Subsequently, the width of the micro trench and the width of the trench on the back surface will be described. The difference between the steps results in damage. FIG. 11 (A) is a cross-sectional view when half cutting is performed with a cutter as shown in FIG. 3 (B), and FIG. 11 (B) is an enlarged view of a stepped portion shown in FIG. 11 (A), and FIG. 11 (C) shows the damage of the step portion.

As described above, a plurality of light emitting elements 100 are formed on the front surface of the semiconductor substrate W, and each light emitting element 100 is separated by a cutting area 120 defined by a cutting line or the like having a space S. It is assumed that micro-grooves 140 (vertical-shaped grooves shown in FIG. 8 (C)) having a width Sa are formed in the cutting region 120 by anisotropic dry etching. While the dicing blade 300 having the notch width Sb is rotated, the rear surface of the semiconductor substrate W is cut, and a trench 170 having a width substantially the same as the opening width Sb is formed in the semiconductor substrate W. Since the notch width Sb is larger than the width Sa of the micro trench 140, when the trench 170 is formed, due to the difference between the width Sb and the width Sa (that is, both the side surface of the micro trench 140 and the side surface of the trench 170 The difference between the positions of the cantilevered steps 800 having a thickness T is formed in the cutting region 120. If the center of the cutting blade 300 exactly matches the center of the micro-groove 140, the length extending in the horizontal direction of the stepped portion 800 becomes (Sb-Sa) / 2.

When cutting is performed by the cutting blade 300, the plane of the top end portion of the cutting blade 300 presses the semiconductor substrate W in the Y direction, so that a force F is applied to the stepped portion 800, and the pressure is concentrated on the corner portion C of the stepped portion 800. When the pressure applied to the corner portion C exceeds the fracture stress of the wafer, as shown in FIG. 11 (C), damage (stepping, cracking, warping, etc.) of the stepped portion 800 occurs. In particular, a compound semiconductor substrate such as a GaAs substrate has lower strength than a silicon substrate, and therefore, the stepped portion 800 is easily damaged. If the stepped portion 800 is damaged, the margin M for cutting the stepped portion 800 must be ensured, which means that the interval S of the cutting region 120 must be equal to or larger than the margin M, thereby reducing the obtained semiconductor article. quantity. Therefore, it is preferable to prevent the step portion 800 from being damaged.

If a cutting blade 300 having a predetermined thickness is used, as a factor that highly affects the pressure that damages the stepped portion 800, the following three items are mainly considered: first, the shape of the tip portion of the cutting blade; second, the thickness T of the stepped portion 800 And third, the size of the step of the step portion, that is, the positional shift amount between the micro-groove 140 and the groove 170. As described in this example, the micro-trench formation is started with a first etching intensity that gradually narrows the width of the micro-trench in the depth direction, and during the formation of the micro-trench, the dry etching conditions are switched to a ratio The first etching strength is strong at the second etching strength, and the width of the entry portion of the trench on the front side extends downward without changing the width, so that compared with the case where the micro-grooves are formed only by the first etching strength, Deeper micro trenches are formed. Therefore, the thickness T of the stepped portion 800 becomes thick. Therefore, even if the shape or positional shift amount of the tip end portion of the cutting blade is the same as each other, the step portion is prevented from being damaged.

Subsequently, application examples according to examples of the present invention will be described. In this application example, the groove 170 on the back surface according to the above-mentioned example is not formed, and the semiconductor substrate is polished from the back surface of the semiconductor substrate to the micro grooves on the front surface of the semiconductor substrate (back surface grinding), so that the semiconductor substrate is divided. . Specifically, instead of attaching the tape for cutting in step S108 of FIG. 1, the tape for back surface grinding is attached to the front surface of the substrate. The tape for cutting can be used as it is for the back grinding. Then, instead of the half cutting in step S110 of FIG. 1, the back surface grinding is performed until the micro grooves on the front surface. The back surface of the substrate is arranged in the same manner as seen in the half-cut, and for example, by moving the rotating magnet in a horizontal or vertical direction, the thickness of the entire substrate is thinned by back surface grinding until the micro grooves on the front surface are made. Until the groove is exposed. The subsequent steps may be the same as those of FIG. 1. If the strength of the substrate is reduced after back-grinding, only the peripheral portion of the substrate is not polished, so that the substrate can have Ribbed structure.

Here, in the back-grinding step, vibration or cutting pressure is applied to the adhesive layer of the tape for back-grinding via the inner wall of the micro-groove by the rotation of the magnet or the relative movement between the magnet and the semiconductor substrate. on. If the semiconductor substrate is pressed under the cutting pressure, an adhesive layer having a viscosity flows into the micro trench. In addition, as the vibration is transmitted to the vicinity of the micro-groove, the flow of the adhesive layer is promoted. In particular, if the micro-groove is a micro-groove having a width of about several μm to about a dozen μm, the adhesive layer easily and deeply enters the micro-groove, and if the width is equal to or less than 10 μm, The effect is more significant.

When the grinding by the magnet is completed, the tape for extension is attached to the back of the substrate, and the tape for back grinding is irradiated with ultraviolet light. The adhesive layer applied by the ultraviolet light is cured, the adhesive force of the adhesive layer disappears, and the adhesive tape for back surface grinding is removed from the front surface of the substrate. Here, as shown in FIG. 6, when the adhesive tape for back surface polishing is removed, the adhesive layer that has entered the micro-grooves on the surface side remains in the grooves or on the front surface of the substrate. Therefore, in order to prevent the adhesive layer from remaining when the tape for back surface grinding is removed, a micro-groove according to the example shown in FIGS. 7 and 10 may be applied. If the microgrooves of FIGS. 7 and 10 can be applied, not only the remaining adhesive layer is prevented, but deeper grooves are also formed, and the thickness of the semiconductor object after grinding can be easily ensured to ensure the strength of the semiconductor object.

In the example of the present application, the semiconductor substrate is polished from the rear surface of the semiconductor substrate to the micro-grooves on the front surface of the semiconductor substrate, and then the remaining portion is divided by applying a stress such as a tensile stress or a bending stress to the semiconductor substrate, thereby The semiconductor substrate can be divided.

Further, in the manufacturing method performed by the above-mentioned application example, During the trench on the front surface, the dry etching is switched to a second etching intensity that is stronger than the first etching intensity, and at the second etching intensity, the width of the entrance portion of the trench on the front surface does not widen and extends downward, And, a groove on the front surface can be formed without having a portion whose width becomes wider toward the lower portion of the groove. In this structure, an inverted tapered shape or the like where an adhesive layer easily remains is not formed, and therefore, even if the depth of penetration of the adhesive layer of the tape becomes deeper, the adhesive layer is prevented from remaining.

As described above, the preferred exemplary embodiment according to the present invention is described, but the present invention is not limited to the specific exemplary embodiment, and various modifications and changes can be made within the scope of the present invention described in the claims.

For example, the groove 170 on the back surface may be formed at a depth that reaches the vicinity of the micro groove on the front surface but does not communicate with the micro groove on the surface side. That is, in the step of forming the trench 170 on the back surface of FIG. 3 (B), a part of the thickness of the semiconductor substrate may form the trench 170 on the back surface. In this case, in a subsequent step, the semiconductor substrate may be divided by applying a stress such as a tensile stress or a bending stress to the semiconductor substrate, thereby dividing the remaining portion. In addition, if the first groove portion (the upper side of the micro groove on the front surface) has a forward tapered shape, the second groove portion (the micro groove on the front surface) is wider than the width of the lowermost portion of the first groove portion. The lower side of the groove) may have a wider width. For example, in the case where the depth to which the adhesive layer has entered is known in advance, the shape of the portion of the microgroove deeper than the depth to which the adhesive layer has entered may be a shape having a wider width in the depth direction. That is, the second groove portion may have a shape whose width becomes wider toward the lower portion than the width of the lowermost portion of the first groove portion. This is because if the width of the first groove portion is deeper than the depth to which the adhesive layer enters, even if the second groove portion has a shape that becomes wider in the depth direction, for example, an abnormality in which hardly any ultraviolet light is applied is promoted. . So, exactly, by having a shape that widens in the depth direction, The area of the back surface of the diced semiconductor article is reduced, and in the case where the semiconductor article is mounted on a circuit board or the like, the protruding or crawling-up of the adhesive member is prevented. When the flow rate of the gas for forming the protective film contained in the etching gas or the flow rate of the gas for etching is switched, the shape is formed by switching such that the etching intensity becomes stronger. In this case, it is preferable that the flow rate of the gas is switched within a range in which the corner portion is not formed in the side wall of the groove. It is not necessary that the micro-grooves on the front surface be formed only by the first groove portion and the second groove portion, and the lower portion of the second groove portion may include a third groove portion. In this case, the third groove portion may have a width larger than that of the second groove portion.

Further, the manufacturing method according to the present invention can be applied to a case where each element is cut from a substrate that does not include a semiconductor such as glass or a polymer.

The damage to be prevented by the present invention is not limited to the scope of loss, rupture, etc. that can be visually confirmed, but includes slightly preventing damage or slightly reducing the degree of damage regardless of the degree of prevention. In addition, preventing the residue of the adhesive layer does not mean completely preventing the residue, but includes slightly preventing the residue or slightly reducing the possible residue regardless of the degree of prevention. In addition, the microgrooves according to this example of FIGS. 7 and 10 are merely examples, and all types of methods formed by switching the etching strength can be used regardless of the shape or tilt angle of the microgrooves.

Claims (5)

A method for manufacturing a semiconductor article, comprising: a front side having a first groove portion and a second groove portion and forming a shape without a corner portion between the first groove portion and the second groove portion; In the step of trenching, the width of the first trench portion gradually narrows from the front surface to the back surface of the substrate, and the second trench portion is a trench portion formed in communication with the lower portion of the first trench portion and has a width. A direction that is wider than the lowermost width of the first groove portion; a step of adhering a holding member having an adhesive layer to the front surface on which the groove on the front side is formed; In the state, the step of thinning the substrate is started from the rear surface of the substrate; and the step of peeling the front surface from the holding member after the thinning the substrate. A method for manufacturing a semiconductor article, comprising: a front side having a first groove portion and a second groove portion and forming a shape without a corner portion between the first groove portion and the second groove portion; In the step of trenching, the width of the first trench portion gradually narrows from the front surface to the back surface of the substrate, and the second trench portion is a trench portion formed in communication with the lower portion of the first trench portion and has a width. A direction that is wider than the lowermost width of the first groove portion; a step of adhering a holding member having an adhesive layer to the front surface on which the groove on the front side is formed; A step of forming a groove on the back side by using a cutting member that rotates from the back surface of the substrate toward the groove on the front side in a state; and after forming the groove on the back side, peeling the front surface from the holding member A step of. For example, the method for manufacturing a semiconductor article according to claim 1 or 2, wherein the formation of the grooves on the front side is started by dry etching with an etching intensity that gradually narrows the width of the grooves on the front side toward the back surface, and During the formation of the trench on the front side, the flow rate of the protective film formation gas included in the etching gas used for the dry etching is within a range from which the flow rate of the protective film formation gas does not stop, from the first flow rate. The second flow rate smaller than the first flow rate is switched to form the groove on the front side. For example, the method for manufacturing a semiconductor article according to claim 1 or 2, wherein the formation of the grooves on the front side is started by dry etching with an etching intensity that gradually narrows the width of the grooves on the front side toward the back surface, and During the formation of the trench on the front side, the flow rate of the etching gas included in the etching gas used for the dry etching is switched from the first flow rate to a second flow rate greater than the first flow rate to form the front surface. Side groove. The method for manufacturing a semiconductor article according to claim 1 or 2, wherein the depth of the first groove portion is deeper than the depth to which the adhesive layer enters.