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JP-7856035-B2 - Data processing device and laser processing device

JP7856035B2JP 7856035 B2JP7856035 B2JP 7856035B2JP-7856035-B2

Inventors

  • 傍島 駿介

Assignees

  • 株式会社デンソー

Dates

Publication Date
20260511
Application Date
20230328

Claims (11)

  1. A data processing device (74) that processes data in which features are arranged in a two-dimensional array, A processor (741) capable of executing computer program instructions, A memory (742) connected to the processor and storing the computer program commands, Equipped with, The processor reads and executes the computer program instructions stored in the memory, A first map is generated by assigning the aforementioned features to a two-dimensional coordinate system. A second map is generated that has parameters relating to the overall shape of the two-dimensional array of the aforementioned data and its position in the two-dimensional coordinate system, and shows the two-dimensional distribution of the feature quantities assumed to be precisely located in the two-dimensional coordinate system. We calculate an evaluation function whose value increases as the difference between the first map and the second map increases. The parameters in the second map are updated so that the evaluation function becomes smaller. Data processing device.
  2. The aforementioned external shape is circular, The aforementioned parameters include the center position and radius in the circular two-dimensional coordinate system. The data processing device according to claim 1.
  3. The aforementioned feature quantity is the transmittance of laser light in the semiconductor wafer (1). The data processing device according to claim 1.
  4. The second map is corrected based on the state of the semiconductor wafer during the measurement of the transmittance. The data processing device according to claim 3.
  5. The aforementioned state is one in which the measurement light (LM) for measuring the transmittance is irradiated onto the outer edge of the semiconductor wafer. The data processing device according to claim 4.
  6. The aforementioned state is one in which the outer edge of the semiconductor wafer is being held by the gripping device (711). The data processing device according to claim 4.
  7. A laser processing apparatus (4) that irradiates a laser beam from the surface (21) of a semiconductor ingot (2) to form a peel layer (23) to a predetermined depth corresponding to the thickness of a semiconductor wafer (1) from the surface, A transmittance measuring unit (7) measures the transmittance of the laser light in the semiconductor wafer obtained by peeling it off from the semiconductor ingot at the peeling layer, A control unit (8) sets the irradiation conditions for the laser light based on the transmittance measured by the transmittance measuring unit, Equipped with, The aforementioned transmittance measuring unit is A processor (741) capable of executing computer program instructions, A memory (742) connected to the processor and storing the computer program commands, Equipped with, The processor reads and executes the computer program instructions stored in the memory, A first map is generated by assigning the aforementioned transmittance measurements to a two-dimensional coordinate system. A second map is generated that has parameters relating to the external shape of the semiconductor wafer and its position in the two-dimensional coordinate system, and shows the two-dimensional distribution of transmittance assumed to be precisely positioned in the two-dimensional coordinate system. We calculate an evaluation function whose value increases as the difference between the first map and the second map increases. The parameters in the second map are updated so that the evaluation function becomes smaller. Laser processing equipment.
  8. The parameters include the center position and radius of the semiconductor wafer in the two-dimensional coordinate system. The laser processing apparatus according to claim 7.
  9. The second map is corrected based on the state of the semiconductor wafer during the measurement of the transmittance. The laser processing apparatus according to claim 7.
  10. The aforementioned state is one in which the measurement light (LM) for measuring the transmittance is irradiated onto the outer edge of the semiconductor wafer. The laser processing apparatus according to claim 9.
  11. The aforementioned state is one in which the outer edge of the semiconductor wafer is being held by the gripping device (711). The laser processing apparatus according to claim 9.

Description

This invention relates to a data processing device that processes data in which feature quantities are arranged in a two-dimensional array, and a laser processing device that irradiates laser light from the surface of a semiconductor ingot. Various laser processing techniques are known for irradiating semiconductor ingots or wafers with laser light. For example, Patent Document 1 describes a technique in which a laser beam with a wavelength transparent to single-crystal SiC is focused within a SiC ingot, and the SiC ingot is irradiated with the laser light to form a delamination layer on the cutting surface. The wafer is then peeled from the SiC ingot along the cutting surface where the delamination layer was formed. Incidentally, within a SiC ingot, there may be regions with different crystal structures, known as faceted regions. These faceted regions have a higher refractive index and higher energy absorption rate compared to non-faceted regions. Therefore, the position and quality of the delamination layer formed within the SiC ingot by laser irradiation become uneven, resulting in a step difference in the wafer between the faceted and non-faceted regions. Furthermore, in order to grind the wafer produced from the SiC ingot to the desired thickness, it is necessary to account for the step difference between the faceted and non-faceted regions, requiring a thicker delamination layer, which hinders sufficient efficiency. Therefore, the laser processing apparatus described in Patent Document 1 detects facet regions from the upper surface of a SiC ingot and sets the coordinates of the facet regions and non-facet regions. Specifically, such a laser processing apparatus is equipped with a facet region detection means. The facet region detection means has an imaging means that images the SiC ingot held on a holding table from above, and performs image processing such as binarization on the image of the SiC ingot captured by the imaging means to distinguish between facet regions and non-facet regions. Then, such a laser processing apparatus positions the focal point of a laser beam with a wavelength that is transparent to SiC at a depth corresponding to the thickness of the wafer to be processed, and processes and feeds the wafer while irradiating it with laser light to form a strip-shaped delamination layer. At this time, the energy of the laser beam irradiated onto the facet regions is increased, and the position of the focuser is raised. This makes it possible to produce a wafer without a step between the facet regions and non-facet regions. Japanese Patent Publication No. 2020-47619 This is a plan view showing the schematic configuration of a semiconductor wafer.Figure 1 is a schematic diagram illustrating the overview of a wafer manufacturing method for producing semiconductor wafers from semiconductor ingots.This is a plan view showing the schematic configuration of a laser processing apparatus according to one embodiment of the present invention.This figure shows the schematic configuration of the transmittance measurement unit shown in Figure 3.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a schematic diagram showing the operation overview of the data processing unit.Figure 3 is a flowchart illustrating the operation overview of the data processing unit.This table shows the effects of this embodiment. (Embodiment) The embodiments of the present invention will be described below with reference to the drawings. Note that various modifications applicable to a single embodiment may hinder understanding of that embodiment if they are inserted in the middle of the series of descriptions of that embodiment. Therefore, modifications will be described collectively after the series of descriptions of a single embodiment. (Structure of semiconductor wafers and semiconductor ingots) As shown in Figure 1, the semiconductor wafer 1 is formed in the shape of a thin plate with a substantially circular outer shape having an orientation flat 10. In Figure 1, the x, y, and z coordinates are set so that the x axis is parallel to the orientation flat 10 and the z axis is parallel to the thickness direction of the semiconductor wafer 1. The semiconductor wafer 1 has a faceted region RF, a non-faceted region RN, and a high-transmittance region RH. The non-faceted region RN is the region other than the faceted region RF. The high-transmittance region RH is a part of the non-faceted region RN that has a higher transmittance of laser light (i.e., processing light LP shown in Figure 2) than other parts. The faceted re