JP2019033177A - Manufacturing method and manufacturing device for semiconductor element - Google Patents

Abstract

To provide a manufacturing method of a semiconductor element capable of dividing a semiconductor substrate by stably forming a crack in an intended direction, and preventing a foreign matter from being scattered onto the semiconductor element around a laser irradiation portion due to irradiation of laser beam.SOLUTION: There is provided a method for manufacturing a semiconductor element by dividing a semiconductor substrate formed with a semiconductor element, which includes: a process of preparing the semiconductor substrate having a front surface and a rear surface, which is formed with the semiconductor element on the front surface; a process of preparing a sheet having an adhesive material on one surface; a process of adhering the sheet to the front surface by using the adhesive material; a process of pressing the front surface, and applying mechanical bending to the semiconductor substrate; a process of irradiating the front surface with a laser beam to evaporate a material of the semiconductor substrate, and pressurizing the front surface by an evaporating pressure generated by an increase in a volume of the material between the sheet and the semiconductor substrate; and a process of dividing the semiconductor substrate by the mechanical bending and the evaporating pressure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for manufacturing a semiconductor element, and more particularly, to a method and apparatus for dividing a semiconductor substrate into individual semiconductor elements.

  Conventionally, as a method of dividing a semiconductor substrate on which a plurality of semiconductor elements are formed into individual semiconductor elements, a groove serving as a starting point of division is formed by scoring, and then stress is applied in the direction of expanding the groove. A method of bending was implemented. However, such a mechanical processing method requires a two-step process such as scoring and three-point bending, which has a problem of increasing processing costs. For this reason, instead of the mechanical division method, a division method using laser irradiation has been proposed (for example, see Patent Document 1).

JP 2012-24816 A

  Patent Document 1 discloses a method of dividing a semiconductor substrate (forming a crack) by irradiating the semiconductor substrate with a short pulse laser beam at a predetermined interval along a planned division line while performing three-point bending on the semiconductor substrate. It is disclosed. However, the impact caused by irradiation with the short pulse laser beam does not act only on the intended dividing direction, but also acts in other directions. Therefore, a crack may occur in an unintended direction. For this reason, in the method of Patent Document 1, the crack is not stably formed in the intended direction. Further, the method of irradiating the semiconductor substrate with laser light has a problem that a foreign matter is scattered on the semiconductor element around the irradiated portion and the semiconductor element is contaminated, thereby causing a defect. Therefore, there is a problem that the manufacturing yield of the semiconductor element is lowered due to these causes.

  The present invention has been made for the purpose of solving the above-described problems. The semiconductor substrate is divided by stably forming a crack in an intended direction, and foreign matter is irradiated around the laser irradiated portion by laser light irradiation. It is an object of the present invention to provide a method for manufacturing a semiconductor element capable of preventing scattering on the semiconductor element.

Therefore, the present invention provides a method for manufacturing a semiconductor element by dividing a semiconductor substrate on which the semiconductor element is formed. This method
Preparing a semiconductor substrate having a front surface and a back surface, and a semiconductor element formed on the front surface;
Preparing a sheet having an adhesive on one side;
A process of adhering a sheet to the surface using an adhesive;
Pressing the surface and subjecting the semiconductor substrate to mechanical bending;
A process of irradiating the surface with laser light to evaporate the material of the semiconductor substrate, and pressurizing the surface with the evaporating pressure generated by the increase in the volume of the material between the sheet and the semiconductor substrate, including mechanical bending and evaporating pressure Dividing the semiconductor substrate.

  According to the present invention, tensile stress can be efficiently generated by laser irradiation, a crack can be stably formed, and the semiconductor substrate can be divided. Furthermore, according to the present invention in which the semiconductor substrate is covered with a sheet, it is possible to prevent foreign matter from being scattered on the semiconductor element around the laser irradiated portion by the irradiation of the laser beam. Therefore, according to the present invention, a high manufacturing yield of semiconductor elements can be obtained.

It is a perspective view which shows an example of the apparatus for manufacturing the semiconductor element which concerns on Embodiment 1 of this invention. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the evaporation pressure confinement using a sheet | seat. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the evaporation pressure confinement using a sheet | seat. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the evaporation pressure confinement using a sheet | seat. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement using a sheet | seat, and mechanical bending provision. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement using a sheet | seat, and mechanical bending provision. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement using a sheet | seat, and mechanical bending provision. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement, mechanical bending provision, and also the light absorption in an epitaxial layer. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement, mechanical bending provision, and also the light absorption in an epitaxial layer. It is sectional drawing explaining the division | segmentation principle of the semiconductor substrate by the combination of evaporation pressure confinement, mechanical bending provision, and also the light absorption in an epitaxial layer. FIG. 5 is a cross-sectional view showing a specific example in which the presser blade has a cylindrical shape and causes a plurality of breaks at a time. It is sectional drawing which shows the specific example which produces a several fracture | rupture at once with a some presser blade and three or more receiving blades. It is sectional drawing which shows the specific example which produces a mechanical bending by 4-point bending. It is sectional drawing explaining the effect | action of the evaporation pressure when the contact interface of a semiconductor substrate and a sheet | seat is not adhere | attached. It is sectional drawing explaining the effect | action of the evaporation pressure when the contact interface of a semiconductor substrate and a sheet | seat is adhere | attached. It is a detailed perspective view of the manufacturing apparatus of FIG. It is a detailed perspective view of the manufacturing apparatus in which the pressing blade has an opening. It is sectional drawing which shows the division | segmentation principle of the manufacturing method of the semiconductor element which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the division | segmentation principle of the manufacturing method of the semiconductor element which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the division | segmentation principle of the manufacturing method of the semiconductor element which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the division | segmentation principle of the manufacturing method of the semiconductor element which concerns on Embodiment 2 of this invention.

  In each drawing of the present specification, the same reference numeral indicates the same or substantially the same element. Further, in this specification, “crack” is defined as a surface of a portion where a bond between atoms of a semiconductor substrate is broken and separated. If there is no possibility of confusion, the line of intersection between the crack and the surface of the semiconductor substrate may be referred to as a crack.

Embodiment 1 FIG.
<Manufacturing equipment>
FIG. 1 is a perspective view showing an example of an apparatus for manufacturing a semiconductor element according to the first embodiment of the present invention, the whole being represented by 100. FIG. In FIG. 1, a semiconductor substrate 20 to be divided, which is placed on the manufacturing apparatus 100 and has a first main surface (front surface) and a second main surface (back surface), is attached to the surface of the semiconductor substrate 20. A sheet 25 is shown. One or more semiconductor elements are formed on the surface of the semiconductor substrate 20. The semiconductor substrate 20 is typically divided using the manufacturing apparatus 100 along the planned dividing line 30 existing between the semiconductor elements.

  In the example illustrated in FIG. 1, the manufacturing apparatus 100 includes a base 1 and two receiving blades 2 attached on the base 1. Instead, the manufacturing apparatus 100 may include a receiving blade stage (not shown) mounted on the base 1, and the receiving blade 2 may be mounted on the receiving blade stage. Here, for easy understanding, the direction perpendicular to the upper surface of the base 1 is defined as the Z axis (the downward in the vertical direction is positive), and the two axes orthogonal to each other within the upper surface of the base 1 are the X axis and the Y axis. And The receiving blade 2 has a prismatic shape whose longitudinal direction is parallel to the X axis. The two receiving blades 2 have the same shape, and are arranged at the same position in the X direction and apart from each other in the Y direction.

  Furthermore, the manufacturing apparatus 100 includes a pressing blade 4 that applies a mechanical bending force to the semiconductor substrate 20 together with the receiving blade 2 above the receiving blade 2 (the negative side in the Z-axis direction). The presser blade 4 has a substantially triangular prism shape whose longitudinal direction is parallel to the X axis and has a side or surface that functions as a blade on the lower side. The presser blade 4 is arranged such that the position in the Y direction is between the positions in the Y direction of the two receiving blades 2. In this way, the semiconductor substrate 20 is placed between the two receiving blades 2 and the pressing blade 4 and the pressing blade 4 is pressed downward. As a result, the semiconductor substrate 20 can be given a three-point bend with the pressing blade as the load point and the receiving blade as the support point, and the semiconductor substrate 20 can be given a mechanical bend whose upper side is a valley.

  In the present specification, the receiving blade 2 and the pressing blade 4 may be referred to as “mechanical bending imparting means” or simply “bending imparting means”.

  In the first embodiment, the semiconductor substrate 20 is irradiated with the laser light L on the valley side of the bent semiconductor substrate 20 in addition to the mechanical bending. The laser beam L is applied to the semiconductor substrate 20 from the side of the sheet 25 as viewed from the semiconductor substrate 20 through the pressing blade 4 and the sheet 25 on the semiconductor substrate 20. Therefore, the presser blade 4 and the sheet 25 need to be made of a material that transmits the laser light L. The material of the presser blade 4 is preferably glass or acrylic. When glass is used as the material of the presser blade 4, there is an advantage that it is excellent in durability, for example, is not easily deformed against a bending load and is not easily damaged. When acrylic is used, there is an advantage that it can be easily processed.

  Instead of being a material that transmits the laser light L, the pressing blade 4 may have a structure having an opening 4H in a portion that should be an optical path of the laser light L (see FIG. 10). In this case, the material of the pressing blade 4 can be a metal. This is advantageous because the metal can be easily processed and has high durability.

  Referring again to FIG. 1, the manufacturing apparatus 100 includes laser irradiation means 10 for irradiating the semiconductor substrate 20 with the laser light L. The laser irradiation means 10 includes a laser light source 11 that emits laser light L and a mirror 12. The laser light source 11 is, for example, a YAG pulse laser. The laser light L emitted from the laser light source 11 is reflected by the mirror 12 and travels in the direction of the semiconductor substrate 20 to be divided. Further, the laser irradiation means 10 includes cylindrical lenses 14 and 16 and an objective lens 18. The laser light L reflected by the mirror 12 is incident on the cylindrical lens 14, subsequently passes through the cylindrical lens 16, and travels toward the objective lens 18 in the direction of the semiconductor substrate 20 to be divided.

The shape of the cross section perpendicular to the traveling direction of the laser light L before being emitted from the laser light source 11 and incident on the cylindrical lens 14 is a perfect circle. The focal length of the cylindrical lens 14 is f _C1 , and the focal length of the cylindrical lens 16 is f _C2 (| f _C1 |> | f _C2 |). Here, it is defined that the focal length is negative when the lens is a concave lens. When the cylindrical lenses 14 and 16 are arranged such that the distance between the lenses becomes D _C = f _C1 + f _C2 , the laser light L becomes a parallel light beam, and the cross section perpendicular to the traveling direction has a short diameter of 1 and a long diameter of 1. / E times (here, e = | f _C1 |). In the first embodiment, the cylindrical lenses 14 and 16 are arranged so that the minor axis is parallel to the X axis and the major axis is parallel to the Y axis. In this specification, e may be referred to as an ellipticity ratio. In the case where the cylindrical lenses 14 and 16 are not provided, the shape of the cross section perpendicular to the traveling direction of the laser light L remains a perfect circle, and this case can be interpreted as an ellipticity ratio e = 1.

  The light that has passed through the cylindrical lens 16 is then incident on the objective lens 18 and is focused on the focused spot L2. When the cylindrical lenses 14 and 16 are installed as described above, the condensing spot L2 has an elliptical shape whose major axis is parallel to the X axis and whose major axis is e times the minor axis. By making the condensing spot L2 into an elliptical shape, a crack along the major axis direction of the ellipse is easily formed.

  The manufacturing apparatus 100 preferably includes a lens barrel (not shown) that integrally holds the cylindrical lenses 14 and 16 and the objective lens 18. The mirror 12 is preferably held by a mirror holder (not shown). In order to adjust both the position of the laser beam L and the laser beam direction, it is more preferable that the manufacturing apparatus 100 has a plurality of sets of mirrors 12 and mirror holders. The configuration in which the manufacturing apparatus 100 includes the mirror 12 has been described above, but the configuration may be such that the laser beam from the laser light source 11 is directly incident on the cylindrical lens 14 without the mirror 12.

  Furthermore, the manufacturing apparatus 100 includes positioning means (not shown) for irradiating a desired position with laser light and dividing the semiconductor substrate 20 at the desired position.

  For example, the positioning means includes a receiving blade stage that supports the receiving blade 2. The receiving blade stage preferably has a mechanism for adjusting the interval between the receiving blades 2. Further, the positioning means includes a pressing blade stage that moves the pressing blade 4 in the Z direction, for example. In order to change the manufacturing conditions according to various restrictions and conditions such as the material and size of the semiconductor substrate 20, the pressing blade stage further has a mechanism for adjusting the rotation of the pressing blade 4 around the Y axis (the inclination of the pressing blade). It is preferable to have. Further, the positioning means includes a work stage for performing, for example, XY movement of the semiconductor substrate 20 and rotation around the Z axis. Specifically, after the sheet 25 is attached to the semiconductor substrate 20, the sheet 25 (and the semiconductor substrate 20) is further attached to the ring. Next, a ring is attached to the work stage, and the work stage performs XY movement of the ring and rotation around the Z axis. The receiving blade stage, the presser blade stage, and the work stage are more preferably electric stages in order to improve production efficiency.

  The manufacturing apparatus 100 may include an upper unit support member (not shown) that supports the laser irradiation unit 10 and the pressing blade stage. The receiving blade stage, the work stage and the upper unit support material are fixed on the base 1.

  In the above description, the work stage for moving the semiconductor substrate 20 has been described as means for moving the relative position between the semiconductor substrate 20 and the condensing point L1, but the first embodiment is not limited to this, and the galvano is not limited thereto. A known optical system that can adjust the position of the condensing point L1, such as a scan mirror, may be used.

  In general, the semiconductor substrate 20 is composed of a lug 20a that is a peripheral area that is not used as a semiconductor element, and an element 20b on which a semiconductor element is provided. The position of the laser beam L is adjusted by the positioning means of the manufacturing apparatus 100 so that only the ear portion 20a is irradiated. By adjusting in this way, there is an adverse effect such as thermal damage to the element portion 20b due to the irradiation of the laser light L, or defects due to scattering of foreign materials such as semiconductor materials scattered by the irradiation of the laser light L on the element portion 20b. Can be prevented.

  Furthermore, the manufacturing apparatus 100 includes a control unit that cooperatively controls the laser irradiation unit 10, the receiving blade 2, the pressing blade 4, and the positioning unit.

<Manufacturing process>
The method for manufacturing a semiconductor element according to the first embodiment of the present invention is performed by the following steps 1 to 8.

Step 1: Adjustment is made so that the cutting edge direction of the receiving blade 2, the cutting edge direction of the presser blade 4, and the long axis direction of the focused spot L <b> 2 are parallel to the X axis.
Step 2: A sheet 25 is attached to the semiconductor substrate 20, and the sheet 25 is attached to a ring.
Step 3: The alignment of the semiconductor substrate 20, the receiving blade 2, and the presser blade 4 is adjusted by placing the ring on the work stage and detecting the edge or electrode pattern of the semiconductor substrate 20.
Step 4: The work stage is moved so that the pressing blade 4 hits directly above the planned dividing line 30 on the semiconductor substrate 20.
Step 5: The pressing blade 4 is moved (lowered) in the positive Z direction to apply a predetermined load to the semiconductor substrate 20 and mechanically bend the semiconductor substrate 20 to generate a tensile stress.
Step 6: The laser beam L is emitted from the laser light source 11 and irradiated onto the planned dividing line 30 of the semiconductor substrate 20 to divide the semiconductor substrate 20.
Step 7: The holding blade 4 is moved (raised) in the Z negative direction.
Step 8: Steps 4 to 7 are repeated until the division of all the division lines 30 on the semiconductor substrate 20 is completed.

  Preferably, the cleavage direction of the semiconductor substrate 20 is made to coincide with the planned dividing line 30. Thereby, a crack can be formed and progressed more reliably. In addition, since the end face of the semiconductor element formed by division becomes a flat cleavage face, the end face can be used as a resonator mirror of a laser diode.

<Split principle>
The principle of dividing the semiconductor substrate 20 using the manufacturing apparatus 100 will be described with reference to FIGS. 2a to 2c are cross-sectional views illustrating the principle of dividing the semiconductor substrate 20 by evaporating pressure confinement using the sheet 25. FIG. The semiconductor substrate 20 is affixed under the sheet 25. The sheet 25 is made of a material that transmits the laser light L.

  As shown in FIG. 2a, when the laser beam L is condensed on the interface between the semiconductor substrate 20 and the sheet 25 by the lens described above, the semiconductor material near the focal point L1 absorbs the laser beam L and is heated. Evaporate. In general, since the volume of the evaporated semiconductor material is larger than the volume of the (solid) semiconductor material before evaporation, a force is generated that pushes the periphery of the evaporated portion outward. In this specification, this force is called “evaporation pressure”. Since the periphery of the condensing point L1 on the semiconductor substrate 20 is sealed by the sheet 25, the evaporated semiconductor material is confined around the condensing point L1 between the semiconductor substrate 20 and the sheet 25. Therefore, as shown in FIG. 2b, the evaporation pressure pushes the periphery of the condensing point L1 of the semiconductor substrate 20 downward (arrow A in FIG. 2b). As a result, bending strain is generated in the semiconductor substrate 20, and tensile stress (arrow B in FIG. 2b) is generated on the back surface of the semiconductor substrate 20 opposite to the surface on the condensing point L1 side. When the tensile stress exceeds the breaking strength of the semiconductor substrate 20, as shown in FIG. 2c, the semiconductor substrate 20 is cracked.

  When the semiconductor material evaporated using the sheet 25 is confined around the condensing point L1 between the semiconductor substrate 20 and the sheet 25 (when “evaporation pressure confinement” is performed), the force by which the evaporation pressure pushes the semiconductor substrate 20 When the evaporation pressure is not confined, the evaporation pressure is significantly larger than the force pushing the semiconductor substrate 20. This is because when the evaporation pressure confinement is not performed, the evaporated semiconductor material diffuses upward and does not generate a sufficient force to push the lower semiconductor substrate 20.

  3a to 3c are cross-sectional views illustrating the principle of dividing the semiconductor substrate 20 by a combination of evaporation pressure confinement using the sheet 25 and mechanical bending. As shown in FIG. 3A, the presser blade 4 and the two receiving blades 2 give the semiconductor substrate 20 a mechanical bend in which the sheet 25 side is a valley. In a state where mechanical bending is applied, the laser beam L is irradiated from the sheet 25 side. The tensile stress is promoted by adding not only bending strain due to evaporation pressure but also mechanical bending. Thereby, the division | segmentation by the laser beam L can be produced more reliably in a desired position.

  Furthermore, there is an advantage in using the pressing blade 4. Without the presser blade 4, the evaporation pressure deforms not only the semiconductor substrate 20 below the condensing point L1, but also the upper sheet 25. Therefore, the evaporation pressure is dispersed vertically, and the pressure applied to the lower semiconductor substrate 20 is small. On the other hand, if there is the pressing blade 4 and the pressing blade 4 is in contact with the upper surface of the semiconductor substrate 20, the evaporation pressure cannot deform the sheet 25 on the condensing point L1. Therefore, the evaporation pressure is not dispersed upward, the pressure applied to the semiconductor substrate 20 is increased, and a crack can be more reliably formed at a desired position. For this reason, it is advantageous to use the pressing blade 4.

  Once the starting crack is formed, the bending stress imparted by the receiving blade 2 and the pressing blade 4 is concentrated on the tip of the crack, so that the crack develops in the crossing direction (X direction) of the pressing blade 4. Therefore, by irradiating only one point on the peripheral edge of the semiconductor substrate 20 with the laser light L, it is possible to split the semiconductor substrate 20 by causing cracks to propagate along a desired planned dividing line.

  4a to 4c are cross-sectional views illustrating the principle of dividing the semiconductor substrate 20 by a combination of the above evaporative pressure confinement, mechanical bending, and further absorption in the epitaxial layer. 4A to 4C, the semiconductor substrate 20 includes a substrate layer 21 and an epitaxial layer 22 that is a semiconductor layer formed on one main surface side of the substrate layer 21. The material of the epitaxial layer 22 is different from the material of the substrate layer 21. The semiconductor substrate 20 is placed on the manufacturing apparatus 100 with the epitaxial layer 22 on the positive side in the Z-axis direction (lower side in the figure).

The wavelength λ of the laser light L is selected to be longer than the wavelength λ _S corresponding to the absorption edge of the material of the substrate layer 21 and shorter than the wavelength λ _E corresponding to the absorption edge of the material of the epitaxial layer 22. As shown in FIG. 4a, the laser beam L is irradiated from the substrate layer 21 side. Since the wavelength λ of the laser light L is longer than λ _S , one-photon absorption does not occur in the substrate layer 21, but multiphoton absorption (such as two-photon absorption) can occur. By considering the absorption coefficient of the substrate layer 21 with respect to the wavelength λ and appropriately setting the power of the laser light L or a condensing optical system such as a lens, a part of the energy of the laser light L is absorbed near the condensing point L1. The remainder can be configured to pass through the substrate layer 21 and be absorbed by the epitaxial layer 22. With this configuration, as shown in FIG. 4b, not only the bending strain and mechanical bending due to the evaporation pressure in the vicinity of the condensing point L1, but also the epitaxial layer 22 itself absorbs and evaporates to cause a breakage point ( C) of FIG. 4b occurs. Thereby, the division | segmentation by the laser beam L can be produced more reliably.

  In general, an epitaxial layer in a semiconductor substrate is composed of a plurality of layers made of different materials such as a quantum well layer and a contact layer in order to provide a function such as laser oscillation. In this specification, the wavelength corresponding to the absorption edge of the epitaxial layer refers to the longest wavelength among the wavelengths corresponding to the absorption edges of a plurality of materials constituting the epitaxial layer.

As an example, the material of the substrate layer 21 of the semiconductor substrate 20 is InP (indium phosphide). The wavelength (band gap wavelength) λ _S corresponding to the InP absorption edge is 919 nm. The epitaxial layer 22 is composed of, for example, a plurality of InGaAsP mixed crystal layers. Of these, 1670 nm of the contact layer InGaAs having the longest wavelength corresponding to the absorption edge can be considered as the wavelength λ _E corresponding to the absorption edge of the epitaxial layer 22. The laser light source 11 is, for example, a YAG pulse laser. The oscillation wavelength λ = 1064 nm of the YAG laser is longer than λ _s = 919 nm of InP of the substrate layer 21 and shorter than λ _E = 1670 nm of the epitaxial layer 22. Since λ _S <λ <2λ _S , the laser light L is absorbed by InP almost only by two-photon absorption. Since the two-photon absorption coefficient of InP for 1064 nm is 0.35 cm / MW, for example, when the power density of the laser light L at the condensing point L1 is 100 MW / cm ² , the laser light is 10 μm in the thickness direction of the substrate layer 21. 3.5% of the energy of L will be absorbed.

  In the above description, the mechanical bending imparting means is composed of the two prismatic receiving blades 2 and the one triangular prism-shaped pressing blade 4, but only one break at a time has been described. The form 1 is not limited to this. For example, as shown in FIG. 5, the presser blade 4 may have a cylindrical shape whose central axis is parallel to the X axis, and may be configured to cause a plurality of breaks at a time. In another example, as shown in FIG. 6, the plurality of pressing blades 4 and the three or more receiving blades 2 may be configured to be able to cause a plurality of breaks at a time. Further, a resin film (separator) (not shown) is provided between the semiconductor substrate 20 and the receiving blade 2 in order to prevent the receiving blade 2 and the semiconductor substrate 20 from coming into direct contact and scratching the semiconductor substrate 20. Also good.

  Furthermore, the mechanical bending imparting means is not limited to the above-described three-point bending. For example, as shown in FIG. 7, a processing method by four-point bending may be employed. Specifically, the semiconductor substrate 20 is mechanically bent by four-point bending with the pressing blade 4 as a load point and the receiving blade 2 as a supporting point. In a state where mechanical bending is applied, the laser beam L is irradiated from the sheet 25 side. In the four-point bending configuration, it is not necessary for the laser light L to pass through the pressing blade 4, and therefore the material of the pressing blade 4 can be a material such as a metal that can be easily processed. The use of a metal for the presser blade 4 has an advantage that the metal is excellent in durability and easy to process.

<Sheet>
Next, the sheet 25 will be described in more detail. As described above, the semiconductor substrate 20 and the sheet 25 are in contact with each other. When this contact interface is not adhered, as shown in FIG. 8a, the sheet 25 is peeled off from the semiconductor substrate 20 by the evaporation pressure generated by the evaporation of the semiconductor substrate 20 by the irradiation of the laser beam L, and the evaporation pressure is changed in the lateral direction. In order to escape, the pressure acting downward in the evaporation pressure is reduced. Accordingly, the tensile stress is also reduced. Therefore, the sheet 25 is composed of a sheet base material 26 and an adhesive material 27. As shown in FIG. 8b, when there is an adhesive 27 at the interface between the semiconductor substrate 20 and the sheet 25, the peeling of the sheet 25 from the semiconductor substrate 20 is suppressed, and the pressure acting on the lower side of the evaporation pressure, Accordingly, the tensile stress increases. In this way, cracks can be more reliably formed by using the adhesive material 27.

  Furthermore, the use of the adhesive material 27 can suppress a range in which the material of the semiconductor substrate 20 is scattered by evaporation, and thus a defect due to the scattering of foreign matter on the element portion 20b (FIG. 1) of the semiconductor substrate 20. Can be reduced.

  FIG. 9 is a perspective view showing details of the vicinity of the receiving blade 2 and the pressing blade 4 of the manufacturing apparatus 100 according to the first embodiment. FIG. 10 shows a case where the pressing blade 4 of FIG. 9 has an opening 4H in a portion that should become the optical path of the laser light L. In this case, the presser blade 4 can be made of a material such as metal that can be easily processed. The use of a metal for the presser blade 4 has an advantage that the metal is excellent in durability and easy to process.

  9 and 10, the semiconductor substrate 20 attached to the sheet 25 is placed between the pressing blade 4 and the two receiving blades 2. As a result of diligent research, the inventor has found that when the element portion 20b is adhered to the sheet 25 by the adhesive material 27, the semiconductor substrate 20 receives stress from the sheet 25 in a direction parallel to the interface (in-plane direction), It has been found that the crack that has developed from 20a tends to bend. Further, in order to obtain the effect of increasing the crack forming action by the adhesive material 27, it is sufficient that the adhesive material 27 is in a region of the sheet 25 that is in contact with the ear portion 20 a of the semiconductor substrate 20. Therefore, it is preferable that the sheet 25 has the adhesive material 27 only in a region in contact with the ear portion 20a of the semiconductor substrate 20.

  The material of the sheet base material 26 of the sheet 25 is, for example, polyvinyl chloride. Polyvinyl chloride transmits light having a wavelength of 1064 nm and can be easily deformed or extended when the semiconductor substrate 20 is peeled off and collected from the sheet base material 26 after division. preferable.

  As described above, according to the first embodiment, by attaching the sheet 25 to the semiconductor substrate 20, it is possible to increase the force by which the evaporation pressure pushes the semiconductor substrate 20 downward, and therefore, the tensile force is efficiently pulled. Stress can be generated. Further, in the first embodiment in which the laser beam L is irradiated in a state where mechanical bending is applied, the semiconductor substrate 20 is not only subjected to bending distortion due to evaporation pressure but also mechanical bending, and thus more reliably cracks. This can cause the semiconductor substrate 20 to be divided. Since cracks are likely to occur in the portion irradiated with the laser beam L, the semiconductor substrate 20 can be divided at a desired position by adjusting the irradiation position. Furthermore, this Embodiment 1 using the sheet | seat 25 can prevent a foreign material from scattering on the surrounding semiconductor element by irradiation of the laser beam L. FIG. Therefore, a high manufacturing yield of the semiconductor element can be obtained.

Embodiment 2. FIG.
11a to 11d are sectional views showing the division principle of the method for manufacturing a semiconductor device according to the second embodiment of the present invention. In the following description, differences from the first embodiment will be mainly described, and redundant description of other parts will be omitted in principle.

  In the second embodiment, the semiconductor element is manufactured using the manufacturing apparatus 100 as in the first embodiment, but the manufacturing process is different from that in the first embodiment. That is, the manufacturing method according to the second embodiment is performed by the following steps 1 to 9.

Step 1: Adjustment is made so that the cutting edge direction of the receiving blade 2, the cutting edge direction of the presser blade 4, and the long axis direction of the focused spot L <b> 2 are parallel to the X axis.
Step 2: A sheet 25 is attached to the semiconductor substrate 20, and the sheet 25 is attached to a ring.
Step 3: The alignment of the semiconductor substrate 20, the receiving blade 2, and the presser blade 4 is adjusted by placing the ring on the work stage and detecting the edge or electrode pattern of the semiconductor substrate 20.
Step 4: The work stage is moved so that the pressing blade 4 hits directly above the planned dividing line 30 on the semiconductor substrate 20.
Step 5: The pressing blade 4 is moved (lowered) in the positive Z direction to slightly apply a load to the semiconductor substrate 20.
Step 6: The laser light L is emitted from the laser light source 11 and irradiated onto the planned dividing line 30 of the semiconductor substrate 20.
Step 7: The pressing blade 4 is further lowered to divide the semiconductor substrate 20.
Step 8: The holding blade 4 is moved (raised) in the Z negative direction.
Step 9: Steps 4 to 8 are repeated until the division of all the division lines 30 on the semiconductor substrate 20 is completed.

  Steps 1 to 4 according to the second embodiment are the same as steps 1 to 4 according to the first embodiment, and only steps after step 5 are different.

  With reference to FIGS. 11a to 11d, the division principle of the method for manufacturing a semiconductor device according to the first embodiment will be described. As shown in FIG. 11a, the laser beam L is condensed and irradiated on the interface between the semiconductor substrate 20 and the sheet 25 (step 6). Then, as shown in FIG. 11b, the semiconductor material of the semiconductor substrate 20 evaporates, and an evaporation pressure (arrow A in FIG. 11b) is generated due to the increase in volume, and the surface opposite to the surface on the condensing point L1 side. Tensile stress (arrow B in FIG. 11b) is generated. When the tensile stress exceeds the breaking strength of the semiconductor substrate 20, as shown in FIG. 11c, the semiconductor substrate 20 is cracked. If there is no mechanical bending at the time of laser irradiation or if it is sufficiently small, this crack will not grow long and will be local in the vicinity of the focal point L1. Next, as shown in FIG. 11d, the receiving blade 2 and the presser blade 4 cause the semiconductor substrate 20 to be mechanically bent so that the sheet 25 side becomes a valley, thereby causing a crack to develop. In this way, the semiconductor substrate 20 can be divided along the planned dividing line 30 (not shown in FIG. 11d).

  The reason why a slight load is applied to the semiconductor substrate 20 in the step 5 is as follows. That is, when the semiconductor substrate 20 is irradiated with the laser light L, the volume increases due to evaporation of the semiconductor material of the semiconductor substrate 20 and an evaporation pressure is generated. When there is no step of applying a slight load as in step 5, this evaporation pressure deforms not only the semiconductor substrate 20 below the condensing point L1 but also the upper sheet 25. Therefore, the evaporation pressure is dispersed vertically, and the pressure applied to the lower semiconductor substrate 20 is small. On the other hand, when a slight load is applied to the semiconductor substrate 20 in the step 5, the evaporation pressure generated by the laser light L irradiation in the next step 6 may deform the sheet 25 above the condensing point L1. Can not. Therefore, the evaporation pressure does not disperse upward, and the pressure applied to the semiconductor substrate 20 increases, so that cracks can be formed more efficiently. For this reason, it is advantageous to apply a slight load to the semiconductor substrate 20 in step 5.

  Depending on various conditions such as the material of the semiconductor substrate 20, there may be a case where a crack can be sufficiently formed without a step of applying a slight load. For example, when the semiconductor substrate 20 has the epitaxial layer 22, it becomes easy to form a crack without a step of applying a slight load. If a crack can be formed sufficiently, step 5 may be omitted. If step 5 is omitted, it is not necessary to irradiate the semiconductor substrate 20 with the laser beam L through the pressing blade 4, so that the pressing blade 4 does not need to transmit the laser beam L. Therefore, the presser blade 4 can be formed of a material that can be easily processed, such as metal.

  In the first embodiment, the laser irradiation is performed in a state where mechanical bending is applied, so that the formation and development of a crack start point occur simultaneously. In the second embodiment, the crack is generated by irradiating the laser beam L. After being generated, a mechanical bend is applied to develop the crack. In the first embodiment, at the time of preliminary mechanical bending, care must be taken so that the semiconductor substrate 20 is not divided at an undesired location starting from scratches, chips, or foreign matter on the semiconductor substrate 20. In No. 2, since the irradiation location of the laser beam L is the starting point of the division, there is no possibility of division at an undesirable location.

  Further, in the first embodiment, since it is necessary not to be divided only by mechanical bending, the allowable range of parameters such as mechanical bending load, indentation amount, or indentation speed is narrow. There is no such restriction, and the allowable range of parameters is wide. For example, in the second embodiment, after irradiating the semiconductor substrate 20 with the laser light L, the presser blade 4 is brought into contact with the semiconductor substrate 20 by applying the force of the presser blade 4 by the large pressing speed of the presser blade 4. be able to. By doing so, the semiconductor substrate 20 may be divided at a desired position, or a smoother dividing surface may be formed. Therefore, in the second embodiment, the parameters can be adjusted over a wide range in accordance with the material or thickness of the semiconductor substrate 20, so that the room for optimizing the division process is widened.

  DESCRIPTION OF SYMBOLS 1 Base, 2 receiving blade, 4 presser blade, 4H opening, 10 Laser irradiation means, 11 Laser light source, 12 Mirror, 14 Cylindrical lens, 16 Cylindrical lens, 18 Objective lens, 20 Semiconductor substrate, 20a Ear part, 20b Element part, 21 substrate layer, 22 epitaxial layer, 25 sheet, 26 sheet base material, 27 adhesive material, 30 dividing line, 100 manufacturing apparatus.

Claims (11)

A method of manufacturing a semiconductor element by dividing a semiconductor substrate on which a semiconductor element is formed,
Preparing a semiconductor substrate having a front surface and a back surface, and a semiconductor element formed on the front surface;
Preparing a sheet having an adhesive on one side;
Adhering the sheet to the surface using the adhesive material;
Pressing the surface and subjecting the semiconductor substrate to mechanical bending;
Irradiating the surface with laser light to evaporate the material of the semiconductor substrate, and pressurizing the surface with an evaporation pressure generated by an increase in the volume of the material between the sheet and the semiconductor substrate, And a step of dividing the semiconductor substrate by the mechanical bending and the evaporation pressure. A method of manufacturing a semiconductor element by dividing a semiconductor substrate on which a semiconductor element is formed,
Preparing a semiconductor substrate having a front surface and a back surface, and a semiconductor element formed on the front surface;
Preparing a sheet having an adhesive on one side;
Adhering the sheet to the surface using the adhesive material;
Irradiating the surface with laser light to evaporate the material of the semiconductor substrate, and pressurizing the surface with an evaporation pressure generated by an increase in the volume of the material between the sheet and the semiconductor substrate, A step of causing a crack in the back surface of the semiconductor substrate by the laser light irradiation, the evaporation pressure, or both;
And a step of pressing the surface and mechanically bending the semiconductor substrate to develop the crack and dividing the semiconductor substrate. The mechanical bending is given so that the surface side of the semiconductor substrate to which the sheet is bonded becomes a trough,
The laser beam is irradiated from the surface side,
The manufacturing method according to claim 1, wherein the sheet is made of a material that transmits the laser beam. The mechanical bending is a three-point bending means in which one pressing blade that presses the front surface of the semiconductor substrate through the sheet is used as a load point and two receiving blades that receive the back surface of the semiconductor substrate are supporting points. Given by
The pressing blade is made of a material that transmits the laser light, or has a structure having an opening in the optical path of the laser light,
The manufacturing method according to claim 3, wherein the laser light passes through the pressing blade or the opening and the sheet and is applied to the semiconductor substrate. The mechanical bending is performed by a four-point bending means in which two pressing blades that press the front surface of the semiconductor substrate through the sheet are load points and two receiving blades that receive the back surface of the semiconductor substrate are supporting points. Given,
The manufacturing method according to claim 3, wherein the laser light is applied to the semiconductor substrate through the two pressing blades.   The manufacturing method according to claim 1, wherein the laser light is applied to a peripheral portion of the semiconductor substrate that does not have the semiconductor element.   The manufacturing method according to claim 6, wherein the adhesive material of the sheet is present only in a region in contact with the peripheral portion of the semiconductor substrate.   The manufacturing method according to claim 1, wherein a wavelength of the laser light is longer than a wavelength corresponding to an absorption edge of the semiconductor substrate. The semiconductor substrate has a substrate layer, and a semiconductor layer made of a semiconductor material different from the material of the substrate layer formed on the substrate layer,
The wavelength of the laser light is longer than the wavelength corresponding to the absorption edge of the substrate layer and shorter than the wavelength corresponding to the absorption edge of the semiconductor layer,
The manufacturing method according to claim 8, wherein the laser light is irradiated from the substrate layer side of the semiconductor substrate. A laser light source for supplying laser light;
And a receiving blade that receives the back surface of the semiconductor substrate, the receiving blade serving as a load point, and the receiving blade. Bending imparting means for mechanically bending the semiconductor substrate by means of three-point bending with a supporting point as a support point;
Laser irradiation means for condensing and irradiating the laser light on the semiconductor substrate,
An apparatus for manufacturing a semiconductor element by dividing the semiconductor substrate on which the semiconductor element is formed,
The said pressing blade consists of a material which permeate | transmits the said laser beam, or is a structure which has an opening in the optical path of the said laser beam, The manufacturing apparatus of the semiconductor element characterized by the above-mentioned. A laser light source for supplying laser light;
A semiconductor element having two pressing blades for pressing the front surface of the semiconductor substrate on which the semiconductor element is formed; and two receiving blades for receiving the back surface of the semiconductor substrate. Bending imparting means for mechanically bending the semiconductor substrate by means of four-point bending with a supporting point as a support point;
Laser irradiation means for condensing and irradiating the laser light on the semiconductor substrate,
An apparatus for manufacturing a semiconductor element by dividing the semiconductor substrate on which the semiconductor element is formed,
The apparatus for manufacturing a semiconductor element, wherein the laser irradiating means and the two pressing blades are arranged so that the laser light is irradiated to the semiconductor substrate through the two pressing blades.

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