CUTTING METHOD

Abstract

Cutting method for cutting a workpiece (1) in the form of a plate along an intended cutting line (5), wherein the cutting method comprises: Forming a reshaped area (7) in the workpiece (1) along the intended cutting line (5) by applying a laser beam (L) while positioning a condensation point (P) in the workpiece (1); and after forming the transformed area (7) in the workpiece (1), cutting the workpiece (1) along the intended cutting line (5), wherein, during the cutting of the workpiece (1), a dry etching process is carried out from a front surface (3) towards a rear surface (4) of the workpiece (1), while the workpiece (1) is fixed at least under its own weight or by suction on a support element (202) to form a groove (9) from the front surface (3) to reach the rear surface (4) of the workpiece (1), where a halogen-based etching gas is used for the dry etching process during cutting, wherein a material for the workpiece (1) comprises at least one made of silicon, tungsten, titanium, titanium nitride and molybdenum, and wherein, when cutting the workpiece (1), the dry etching process is carried out using a plasma-free chlorine trifluoride gas as a halogen-based etching gas at a pressure of not less than 10 Pa and not more than 90 kPa (abs) and at a temperature of not less than one boiling point of each fluoride in the material and less than 200°C.

Description

Scope of the invention

[0001] The present invention relates to cutting methods, in particular to a cutting method for cutting a workpiece in the form of a plate along an intended cutting line. State of the art

[0002] There is a well-known processing method for using a laser beam to position a condensation point in a workpiece in the form of a plate, thereby creating a transformed area, and then performing an etching process on this transformed area. This processing method is described, for example, in the Japanese patent application with publication number JP 2004-359 475 A (PTL 1). In the processing method described in this publication, a wet etching process is used as the etching process for the transformed area. Citation list for patent literature

[0003] PTL 1: Japanese patent application, publication number: JP 2004-359475A

[0004] Methods for cutting and etching semiconductor substrates are known from US 2016 / 0 307 851 A1 and US 2006 / 0 032 833 A1. US 2005 / 0 287 846 A1 relates to a method for manufacturing an integrated circuit chip comprising an etching step of a metal film. WO 2011 / 112 823 A2 describes manufacturing methods for semiconductor devices comprising the removal of an oxide layer by etching. Summary of the invention: Technical problem

[0005] A cutting process is conceivable in which a workpiece, such as a semiconductor substrate, is cut using the processing method described in the preceding publication. In this case, it is conceivable that the semiconductor substrate is cut and separated by an expandable tape. When the semiconductor substrate is cut and separated by the expandable tape, surface roughness and cracks occur in the chips, leading to a reduction in the mechanical strength of the chips. Another problem is that if the strength of the interface between the chips exceeds the strength of the adhesive surface of the expandable tape during the expansion of the semiconductor substrate by the expandable tape, the chips will exhibit defective shapes.

[0006] When the chips to be formed from the semiconductor substrate are small, it is advantageous to use a dry etching process, which, unlike wet etching, can be manufactured using microfabrication. In a conventional dry etching process, the etching gas reacts with a base material and an adhesive used to bond an expandable ribbon. During this reaction, the expandable ribbon undergoes both chemical and thermal changes, resulting in expansion and contraction. This deformation creates external stress on the semiconductor substrate, leading to unintended cutting and fragmentation. Furthermore, a reaction byproduct of the etching gas and expandable ribbon adheres to the device, resulting in a cleaning process.The reaction between the etching gas and the expandable tape can only be avoided by lowering the etching gas pressure and the processing temperature, which means that a practically applicable etching rate cannot be guaranteed.

[0007] The present invention was made with regard to the above problem, and one objective of the present invention is to provide a cutting method by which a workpiece can be cut along an intended cutting line without an expandable belt. Solution to the problem

[0008] A cutting method for cutting a workpiece in the form of a plate along an intended cutting line according to claim 1 is provided. Advantageous effects of the invention

[0009] According to the cutting method of the present invention, a workpiece can be cut along an intended cutting line without an expandable belt. Brief description of the drawings Fig. Figure 1 is a schematic top view of a workpiece in a cutting process according to an embodiment of the present invention. Fig. 2 is a sectional view along line II-II in Fig. 1. Fig. Figure 3 is a schematic configuration diagram of a laser processing device for use in the formation of transformed areas in the cutting process according to the embodiment of the present invention. Fig. Figure 4 is a schematic top view of the workpiece in which the transformed areas are to be formed in the cutting process according to the embodiment of the present invention. Fig. 5 is a section view along line VV in Fig. 4. Fig. Figure 6 is a schematic top view of the workpiece after laser processing in the cutting process according to the embodiment of the present invention. Fig. 7 is a sectional view along line VII-VII in Fig. 6. Fig. 8 is a sectional view along line VIII-VIII in Fig. 6. Fig. Figure 9 is a schematic top view of the workpiece after the transformed areas have been formed in the cutting process according to the embodiment of the present invention. Fig. Figure 10 is a sectional view along line XX in Fig. 9. Fig. Figure 11 is a schematic configuration diagram of an etching device for use in the formation of grooves in the cutting process according to the embodiment of the present invention. Fig. Figure 12 is a schematic top view of the workpiece after the grooves have been formed in the cutting process according to the embodiment of the present invention. Fig. 13 is a sectional view along line XIII-XIII in Fig. 12. Fig. Figure 14 is an enlarged sectional view of area A in Fig. 10. Fig. Figure 15 is an enlarged sectional view illustrating an initial dry etching process, which is shown in Fig. 10 was carried out in area A. Fig. Figure 16 is an enlarged sectional view illustrating the workpiece located in area A in Fig. 10 was cut. Fig. Figure 17 is a schematic top view of the workpiece after division. Fig. 18 is a sectional view along the line XVIII-XVIII in Fig. 27. Fig. Figure 19 is a schematic sectional view of a TEG formation area in the workpiece after laser processing in the cutting process according to the embodiment of the present invention. Fig. Figure 20 is an enlarged sectional view showing a dry etching process at the TEG formation area in Fig. 19 is illustrated. Detailed description of embodiments of the invention

[0010] A cutting method according to an embodiment of the present invention is described below with reference to the drawings. Unless otherwise specified, the same elements are designated by the same symbols and their description is not repeated.

[0011] With reference to the Fig. 1 and Fig. 2, a workpiece 1 is prepared for the cutting process according to the embodiment of the present invention. As in the Fig. 1 and Fig. As shown in Figure 2, workpiece 1 is, for example, a semiconductor substrate. The following describes the case in which workpiece 1 is a semiconductor substrate.

[0012] The semiconductor substrate, referred to as workpiece 1, is configured to have an essentially disk-like shape. Workpiece 1 (semiconductor substrate) has an orientation surface 2 on its outer circumference. For example, workpiece 1 (semiconductor substrate) is a silicon (Si) wafer.

[0013] A plurality of functional devices (not shown) are intended to be placed on a front surface 3 of the workpiece (semiconductor substrate) 1. In other words, the workpiece (semiconductor substrate) 1 comprises a substrate body and the plurality of functional devices arranged on a front surface of the substrate body. The functional devices are, for example, semiconductor operating layers formed by crystal growth, light-receiving devices such as photodiodes, light-emitting devices such as laser diodes, or circuit elements formed as a circuit. The multiple functional devices are intended to be arranged in a matrix in directions parallel and perpendicular to the orientation surface 2 of the semiconductor substrate.

[0014] With reference to the Fig. Sections 3 to 10 describe the formation of a transformed area in the cutting process according to the embodiment of the present invention. First, a laser processing device 100 for use in the formation of the transformed area is described.

[0015] As in Fig. As shown in Figure 3, the laser processing device 100 comprises: a laser source 101 for generating pulse oscillation of a laser beam (processing laser beam) L; a dichroic mirror 103 configured to change the orientation of an optical axis of the laser beam L by 90°; and a condenser lens 105 for focusing the laser beam L. The laser processing device 100 also comprises: a support table 107 for supporting the workpiece (semiconductor substrate) 1, which is irradiated with the laser beam L focused by the condenser lens 105; a stage 111 for moving the support table 107 in the X, Y, and Z directions; a laser source controller 102 for controlling the laser source 101 to adjust the output, pulse width, and the like of the laser beam L; and a stage controller 115 for controlling the movement of the stage 111.

[0016] In this laser processing device 100, the laser beam L emitted by the laser source 101 is reoriented by 90° in the orientation of its optical axis by the dichroic mirror 103 and focused by the condenser lens 105 onto the workpiece (semiconductor substrate) 1 arranged on the support table 107. At the same time, the stage 111 is moved, causing the workpiece (semiconductor substrate) 1 to move relative to the laser beam L along a predetermined cutting line. As a result, a reshaped area is formed in the workpiece (semiconductor substrate) 1 along a predetermined cutting line 5, which serves as the starting point for the cutting. This reshaped area is described in detail below.

[0017] As in Fig. As shown in Figure 4, the workpiece (semiconductor substrate) 1 is in the form of a plate with an intended cutting line 5 along which the workpiece (semiconductor substrate) 1 is to be cut. The intended cutting line 5 is an imaginary line extending linearly. When forming the transformed area within the workpiece 1, the laser beam L is directed relative to the intended cutting line 5 (namely in the direction of an arrow A in Figure 4). Fig. 4) moves while a condensation point P is positioned within the workpiece (semiconductor substrate), as in Fig. 5 shown. Consequently, as shown in the Fig. Figures 6 to 8 show a transformed area 7 within the workpiece (semiconductor substrate) 1 formed along the intended cutting line 5, and the transformed area 7 formed along the intended cutting line 5 serves as a cutting start point area 8.

[0018] It should be noted that the condensation point P is the point where the laser beam L is focused. The intended cutting line 5 may be curved rather than linear, or a line actually drawn on the front surface 3 of the workpiece 1, rather than the imaginary line. The transformed area 7 may be solid or segmented. The transformed area 7 should only be formed within the workpiece 1. Cracks may originate from the transformed area 7, and the cracks and the transformed area 7 may be exposed on an outer surface (front, back, or circumferential) of the workpiece 1.

[0019] The transformed region 7 refers to a region whose density, refractive index, mechanical strength, or other physical properties have been altered compared to those of a surrounding region. Examples include a melt processing region, a crack region, a dielectric breakdown region, a region with a changed refractive index, and also a region exhibiting a mixture of these regions.

[0020] With renewed reference to Fig. 3 The workpiece (semiconductor substrate) 1 is mounted on the support table 107 of the laser processing device 100. Then, with the front surface 3 of the workpiece (semiconductor substrate) 1 as the laser beam entry surface, the laser beam L is applied while the condensation point P is positioned within the workpiece (semiconductor substrate) 1, and the condensation point P is scanned by moving the support table 107 along the intended cutting lines 5, which are arranged in a grid pattern to extend through adjacent functional devices. Additionally, the condensation point P is scanned on the intended cutting line 5 along a thickness direction of the workpiece (semiconductor substrate) 1.

[0021] As a result, as in Fig. Figure 9 shows transformed regions 7 formed in a lattice pattern within the workpiece (semiconductor substrate) 1. Each transformed region 7 extends within the workpiece (semiconductor substrate) 1 from the front surface 3 to a back surface 4 of the workpiece (semiconductor substrate) 1, as shown in Fig. 10 shown. In other words, the transformed area 7 is formed in the thickness direction of the workpiece (semiconductor substrate) 1.

[0022] With reference to the Fig. Sections 11 to 16 describe the formation of a groove 9 by cutting according to the embodiment of the present invention. First, an etching device 200 for use in forming the groove 9 is described.

[0023] As in Fig. As shown in Figure 11, the etching device 200 comprises a chamber 201, a stage (support element) 202, a manometer 203, a thermometer 204, a valve 205, a vacuum pump 206, a valve 207, a valve 208, a flow regulator 209, a first gas supply device 210, a valve 211, a flow regulator 212 and a second gas supply device 213.

[0024] In the etching apparatus 200, chamber 201 is configured to receive the workpiece (semiconductor substrate) 1 in which the transformed regions 7 have been formed. The workpiece (semiconductor substrate) 1 is placed on the platform 202 in chamber 201. The workpiece (semiconductor substrate) 1 is secured to the platform 202 by its own weight. The platform 202 may include a suction device 202a. In this case, the workpiece (semiconductor substrate) 1 is secured to the platform 202 by suction from the suction device 202a. The suction device 202a is, for example, an electrostatic clamping device or a vacuum clamping device. In other words, the workpiece (semiconductor substrate) 1 is secured to the platform 202 at least by its own weight or by suction. The platform 202 is configured to have an adjustable temperature.Stage 202 is heated with the workpiece (semiconductor substrate) 1 placed on it, thereby heating the workpiece (semiconductor substrate) 1 to a temperature equal to that of stage 202.

[0025] Chamber 201 is connected to manometer 203 for measuring the pressure in chamber 201. Stage 202 is connected to thermometer 204 for measuring the temperature of workpiece 1 based on the temperature of stage 202. Thermometer 204 is connected to stage 202 and measures the temperature of stage 202 in order to measure the temperature of workpiece 1 (semiconductor substrate), which has been heated to the same temperature as stage 202. Chamber 201 is connected to vacuum pump 206 via a pipeline and valve 205. Vacuum pump 206 is a turbomolecular pump or a mechanical booster pump.

[0026] Chamber 201 is connected to the first gas supply device 210 via a pipeline through valve 207, valve 208, and flow regulator 209. The first gas supply device 210 is configured to supply a first etching gas. Chamber 201 is also connected to the second gas supply device 213 via a pipeline through valve 207, valve 211, and flow regulator 212. The second gas supply device 213 is configured to supply an etching gas. The etching gas supplied by the second gas supply device can be identical to or different from the etching gas supplied by the first gas supply device. Valves 205, 207, 208, and 211 are, for example, electronic control valves. Flow regulators 209 and 212 are, for example, mass flow meters.

[0027] While in the Fig. 11. If the etching device 200 includes the second gas supply device 213 in addition to the first gas supply device 210, the etching device 200 can also include only the first gas supply device 210. In other words, the etching device 200 can include only one gas supply device. Alternatively, the etching device 200 can include three or more gas supply devices.

[0028] As in the Fig. 12 and Fig. As shown in Figure 13, a dry etching process is carried out in the etching device 200 from the front surface 3 to the back surface 4 of the workpiece (semiconductor substrate) 1. The dry etching process is an anisotropic dry etching process using a mixed gas of sulfur hexafluoride (SF6), octafluorocyclobutane (C4F8), and oxygen (O2). The front surface 3 of the workpiece (semiconductor substrate) 1 is etched. Here, the transformed region 7 in the workpiece (semiconductor substrate) 1, which consists, for example, of polycrystalline silicon, exhibits a higher etch rate than an untransformed region, which consists, for example, of monocrystalline silicon. Therefore, the groove 9 is formed in the front surface 3 of the workpiece (semiconductor substrate) 1 along the intended cutting line 5. The dry etching process can be carried out, for example, with a photoresist formed on the functional devices. This photoresist is removed after the dry etching process is complete.

[0029] The dry etching process is carried out from the front surface 3 to the back surface 4 of the workpiece (semiconductor substrate) 1, while the workpiece (semiconductor substrate) 1 is fixed on stage 202, at least under its own weight or by suction, to form the groove 9 from the front surface 3 so that it reaches the back surface 4 of the workpiece (semiconductor substrate) 1.

[0030] The following refers to the Fig. The formation of groove 9 is described in detail in sections 14 to 16. Fig. 14 to 16 correspond to an area A, which is located in the Fig. 10 and Fig. 13 is enclosed by a dash-dot-dash line.

[0031] As in Fig. As shown in Figure 14, after the formation of the transformed region 7 in the workpiece (semiconductor substrate) 1, the workpiece (semiconductor substrate) 1 is processed along the line shown in Fig. The intended cutting line 5 shown in section 4 is cut. In other words, as shown in Fig. As shown in Figure 15, a dry etching process is carried out on the workpiece (semiconductor substrate) 1 from the front surface 3 to the back surface 4 of the workpiece (semiconductor substrate) 1. The front surface 3 of the workpiece (semiconductor substrate) 1 is etched by the dry etching process. Furthermore, the groove 9 is partially formed into the transformed area 7 from the front surface 3 to the back surface 4 of the workpiece (semiconductor substrate) 1.

[0032] As in Fig. As shown in Figure 16, the dry etching process continues to etch the front surface 3 of the workpiece (semiconductor substrate) 1. Furthermore, the groove 9 is formed from the front surface 3 so that it reaches the back surface 4 of the workpiece 1. In this way, the workpiece (semiconductor substrate) 1 is cut along the reshaped area 7. In the state shown in the Fig. 12 and Fig. As shown in Figure 13, the distance between the chips formed from the cut workpiece (semiconductor substrate) 1 is essentially zero.

[0033] Next, with reference to the Fig. 17 and Fig. 18, the cut workpiece (semiconductor substrate) is divided into chips. In other words, the distance between the chips is increased. In the Fig. 17 and Fig. In the state shown in Figure 18, the distance between the chips is maintained at a minimum prescribed distance. The distance between the chips should only be a distance suitable for the next step. After cutting, the workpiece (semiconductor substrate) 1 can be transferred to an expandable tape, which can then be expanded to divide the workpiece (semiconductor substrate) 1.

[0034] Next, etching gases for use in dry etching processes in the cutting process according to the embodiment of the present invention will be described in detail.

[0035] A halogen-based etching gas is used for each of the first and second dry etching processes. A halogen-based etching gas is used for each of the first through nth dry etching processes. The halogen-based etching gas is a plasmaless chlorine trifluoride gas (CIF3).

[0036] Next, the function and effect of the cutting method according to the embodiment of the present invention will be described. According to the cutting method in the embodiment of the present invention, after the formation of the transformed area 7 in the workpiece (semiconductor substrate) 1, the workpiece (semiconductor substrate) 1 is cut along the intended cutting line 5. The dry etching process is carried out from the front surface 3 to the rear surface 4 of the workpiece (semiconductor substrate) 1, while the workpiece (semiconductor substrate) 1 is fixed to stage 202, at least under its own weight or by suction, to form the groove 9 from the front surface 3 so that it reaches the rear surface 4 of the workpiece (semiconductor substrate) 1. This cuts the workpiece (semiconductor substrate) 1 along the intended cutting line 5.

[0037] Therefore, an expandable tape is not used to cut and separate the workpiece (semiconductor substrate) 1. This prevents the formation of surface roughness and cracks in the chips, which would otherwise lead to a reduction in the chips' mechanical strength. Since the strength of the bonding surface between the chips does not exceed the strength of the adhesive surface of the expandable tape, the formation of chip deformities is also prevented. Furthermore, a reaction between the etching gas, the base material, and the adhesive of the expandable tape is prevented, which would cause the expandable tape to undergo chemical and thermal changes and thus deform in an expanding and contracting manner.Accordingly, the application of an external stress to the workpiece (semiconductor substrate) 1 by this deformation, which leads to unintentional cutting and parting of the workpiece (semiconductor substrate) 1, can be prevented. Furthermore, since a reaction byproduct of etching gas and expandable tape does not adhere to the device, the need for a cleaning process is eliminated. Because the etching gas does not react with the expandable tape, it is unnecessary to reduce the etching gas pressure and processing temperature. This ensures a practically applicable etching rate.

[0038] When the workpiece (semiconductor substrate) 1 is transferred to the expandable belt for division after cutting, the processing time is extended by the transfer step. However, the number of active species reacting with the reformed area 7 increases due to the increased etching gas pressure, thereby improving the etching rate. This can significantly reduce the etching time, thus shortening the overall processing time.

[0039] According to the cutting method in the embodiment of the present invention, a halogen-based etching gas is used for the dry etching process.

[0040] According to the cutting process in the embodiment of the present invention, a plasma-free chlorine trifluoride gas (CIF3) is used as the halogen-based etching gas.

[0041] Next, various variants of the cutting method according to the embodiment of the present invention will be described. A first variant of the cutting method according to the embodiment of the present invention will be described first. This first variant relates to the Fig. 19 and Fig. Referring to section 20, a TEG (Test Element Group) 10 can be formed on the intended cutting line of the workpiece (semiconductor substrate) 1. In this case, at least one of tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo) can be used as the material for the TEG 10. In other words, in this case, the workpiece (semiconductor substrate) 1 comprises the substrate body, the functional devices (not shown), and the TEG 10.

[0042] Therefore, the material for workpiece 1 comprises at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). In this case, during the cutting step of workpiece 1, the dry etching process is carried out using a plasma-free chlorine trifluoride (CIF3) gas as a halogen-based etching gas at a pressure of not less than 10 Pa and not more than 90 kPa (abs) and at a temperature of not less than the boiling point of each fluoride in the material and less than 200°C.

[0043] With renewed reference to Fig. 11 is the pressure in chamber 201. This temperature is the temperature of workpiece 1.

[0044] The pressure is set to no less than 10 Pa because the etch rate decreases due to a decrease in the etching reaction rate when the pressure is below 10 Pa. The pressure is also set to no less than 10 Pa because it takes time to reduce the pressure to less than 10 Pa using vacuum pump 206. Furthermore, the amount of any potential reaction byproduct discharged from groove 9 remains essentially unchanged when the pressure is set to less than 10 Pa compared to when the pressure is set to 10 Pa. Finally, a mechanical pressure booster pump, rather than a turbomolecular pump, can be used to set the pressure to 10 Pa. Finally, the pressure is set to no more than 90 kPa because it is difficult to set the pressure above 90 kPa in a vacuum device.Etching can be performed with plasmaless chlorine trifluoride (CIF3) gas over a pressure range of not less than 10 Pa and not more than 90 kPa (abs). Therefore, the pressure range is set to not less than 10 Pa and not more than 90 kPa (abs). Chlorine trifluoride (CIF3) gas can etch silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). Therefore, silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo) are used as the workpiece material. The temperature is set to not less than the boiling point of each fluoride in the material for workpiece 1, as this setting ensures the etch rate in each material. The temperature is set to less than 200°C because the maximum temperature during the dicing of the devices formed on workpiece 1 is 200°C.

[0045] In the first embodiment of the cutting process according to the present invention, the material for the workpiece 1 comprises at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). In this case, the dry etching process is carried out in the cutting step of the workpiece using a plasma-free chlorine trifluoride (CIF3) gas as a halogen-based etching gas at a pressure of not less than 10 Pa and not more than 90 kPa (abs) and at a temperature of not less than the boiling point of each fluoride in the material and less than 200°C. Consequently, the workpiece 1, which comprises at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo), can be etched.

[0046] Next, a second variant of the cutting method according to the embodiment of the present invention is described. In this second variant, an insulating film can be formed on the intended cutting line of the workpiece. In this case, at least one of silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx) can be used as the material for the insulating film. It should be noted that the composition (x) of SiNx can vary around Si3N4, where x represents the ratio of the number of atoms (composition) that form a SiN compound according to the chemical formula. The value of x, for example, must not be less than 1.0 and not greater than 1.5. In this case, the workpiece (semiconductor substrate) comprises the substrate body, the functional devices, and the insulating film.

[0047] Therefore, the workpiece material can include at least one of silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). In this case, the first dry etching process and the second dry etching process can be performed during the workpiece cutting step using anhydrous hydrogen fluoride (HF) added to the halogen-based etching gas. The etching gas containing anhydrous hydrogen fluoride (HF), added to the halogen-based etching gas, can etch silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). For this reason, the etching gas includes anhydrous hydrogen fluoride (HF), which is added to the halogen-based etching gas.

[0048] In the second variant of the cutting process according to the embodiment of the present invention, the workpiece material can comprise at least one of silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). In this case, the dry etching process can be carried out in the cutting step of the workpiece using anhydrous hydrogen fluoride (HF), which is added to the halogen-based etching gas. Consequently, the workpiece 1, comprising at least one of silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx), can be etched.

[0049] In the multitude of plasma-free dry etching processes in the first variant and the second variant of the cutting process according to the embodiment of the present invention described above, the volume density of gas molecules can be varied within a range of not less than 10 times and not more than 10000 times compared to the volume density during a pressure reduction process immediately preceding each dry etching process.

[0050] Next, a third variant of the cutting process is described according to an example. In this third variant, a TEG and an insulating film can be formed on the intended cutting line of the workpiece. In this case, at least one of tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo) can be used as the material for the TEG, and at least one of silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx) can be used as the material for the insulating film.

[0051] Therefore, the workpiece material can include at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), molybdenum (Mo), silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). In this case, the dry etching process can be carried out in the workpiece cutting step using at least one of carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), methane trifluoride (CHF3), hydrogen fluoride (HF), and oxygen (O2) in a plasma state as the etching gas at a pressure of not less than 10 Pa and not more than 0.8 kPa (abs) and at a temperature of less than 200°C. This pressure is the pressure in the chamber. This temperature is the temperature of the workpiece.

[0052] Carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), methane trifluoride (CHF3), hydrogen fluoride (HF), and oxygen (O2) in the plasma state can etch silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), molybdenum (Mo), silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). For this reason, silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), molybdenum (Mo), silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx) are used as workpiece materials. The pressure is set to no more than 0.8 kPa (abs) because the maximum power in the remote plasma is achieved at a pressure of 0.8 kPa.

[0053] In the third variant of the cutting process, the workpiece material can include at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), molybdenum (Mo), silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon nitride (SiNx). In this case, the dry etching process can be carried out in the cutting step of the workpiece using at least one of carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), methane trifluoride (CHF3), hydrogen fluoride (HF), and oxygen (O2) in a plasma state as the etching gas at a pressure of not less than 10 Pa and not more than 0.8 kPa (abs) and at a temperature of less than 200°C. This allows the workpiece, which comprises at least one of silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), molybdenum (Mo), silicon dioxide (SiO2), silicon oxynitride (SiON) and silicon nitride (SiNx), to be etched.

[0054] Next, a fourth variant of the cutting process is described according to another example. In this fourth variant, an aluminum film and a TEG can be formed on the intended cutting line of the workpiece. In this case, aluminum (Al) can be used as the material for the aluminum film, and at least one of tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo) can be used as the material for the TEG.

[0055] Therefore, the workpiece material can include at least one of aluminum (Al), silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). In this case, the dry etching process can be carried out during the workpiece cutting step using at least one of chlorine (Cl₂), hydrogen bromide (HBr), hydrogen chloride (HCl), and boron trichloride (BCl₃) in a plasma state as the etching gas at a pressure of not less than 10 Pa and not more than 0.8 kPa (abs) and a temperature of less than 200°C. This pressure is the pressure in the chamber. This temperature is the temperature of the workpiece.

[0056] Chlorine (Cl₂), hydrogen bromide (HBr), hydrogen chloride (HCl), and boron trichloride (BCl₃) in the plasma state can etch aluminum (Al), silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). For this reason, aluminum (Al), silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo) are used as materials for the workpiece.

[0057] In the fourth variant of the cutting process, the workpiece material comprises at least one of aluminum (Al), silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo). During the cutting step, the dry etching process can be carried out using at least one of chlorine (Cl₂), hydrogen bromide (HBr), hydrogen chloride (HCl), and boron trichloride (BCl₃) in the plasma state as the etching gas at a pressure of not less than 10 Pa and not more than 0.8 kPa (abs) and at a temperature of less than 200°C. This allows the workpiece, which comprises at least one of aluminum (Al), silicon (Si), tungsten (W), titanium (Ti), titanium nitride (TiN), and molybdenum (Mo), to be etched.

[0058] In the multitude of dry etching processes in the plasma removal in the third variation and the fourth variation of the cutting process, the pressure can be varied in a range of not less than 10% and not more than 100% compared to the pressure reduction process that immediately precedes each dry etching process.

[0059] In the case of a downstream plasma treatment, where a gas discharge chamber and a substrate-installed chamber are separated by a discharge pressure control valve, the pressure in the substrate-installed chamber can be varied in a range of at least 1 / 10 and at most 1 / 10000 of the pressure in the gas discharge chamber, while the discharge pressure is kept constant.

[0060] It is to be understood that the embodiments disclosed herein are in every respect illustrative and not limiting. The scope of the present invention is defined by the terms of the claims, not by the foregoing description, and is intended to include all modifications in meaning and scope that are equivalent to the terms of the claims. Explanation of the reference symbols

[0061] 1 Workpiece; 3 Front surface; 4 Back surface; 5 Intended cutting line; 7 Reshaped area; 9 Groove; 100 Laser processing device; 200 Etching device; 201 Chamber; 202 Stage; 203 Manometer; 204 Thermometer; 205, 207, 208, 211 Valve; 206 Vacuum pump; 209, 212 Flow regulator; 210 First gas supply device; 213 Second gas supply device.

Claims

[1] Cutting method for cutting a workpiece (1) in the form of a plate along an intended cutting line (5), the cutting method comprising: Forming a reformed region (7) in the workpiece (1) along the intended cutting line (5) by applying a laser beam (L) while positioning a condensation point (P) in the workpiece (1); and after forming the transformed area (7) in the workpiece (1), cutting the workpiece (1) along the intended cutting line (5), wherein, when cutting the workpiece (1), a dry etching process is carried out from a front surface (3) towards a rear surface (4) of the workpiece (1) while the workpiece (1) is fixed at least under its own weight or by suction on a support element (202) to form a groove (9) from the front surface (3) to reach the rear surface (4) of the workpiece (1), where a halogen-based etching gas is used for the dry etching process during cutting, wherein a material for the workpiece (1) comprises at least one of silicon, tungsten, titanium, titanium nitride and molybdenum, and wherein, in cutting the workpiece (1), the dry etching process is carried out using a plasma-free chlorine trifluoride gas as a halogen-based etching gas at a pressure of not less than 10 Pa and not more than 90 kPa (abs) and at a temperature of not less than a boiling point of each fluoride in the material and less than 200°C. [2] Cutting method according to claim 1, wherein the material for the workpiece (1) comprises at least one of silicon dioxide, silicon oxynitride and silicon nitride, and when cutting the workpiece (1) the dry etching process is carried out with anhydrous hydrogen fluoride, which is added to the halogen-based etching gas.

Images