Device manufacturing methods

Abstract

To provide a manufacturing method of a device capable of realizing a novel process for manufacturing a device formed only of a device layer.SOLUTION: A manufacturing method of a device comprises: a wafer preparation step 1001 of preparing a wafer with a base material, a laser beam adsorption layer laminated on the base material, and a device layer in which a device is formed in a region which is divided with a plurality of division schedule lines crossed on an upper surface of the laser beam adsorption layer; a device layer division step 1002 of forming a division groove for dividing at least the device layer into individual devices along the division schedule line; and a lift off step 1004 of radiating a laser beam of a wavelength adsorbed by the laser beam adsorption layer after an implementation of the device layer division step 1002, and lifting-off the devices from the base material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a device. [Background technology]

[0002] As electronic devices become thinner, devices are also required to be thinned to 100 μm or less. For example, a technology is widely adopted that thins only the area of ​​the wafer that corresponds to the device, leaving the outer periphery thick to prevent damage during handling (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-5621 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there is a type of wafer known as an SOI (Silicon on Insulator) wafer, in which an insulating layer called a BOX layer (Buried Oxide Layer) made of SiO2 is formed on a substrate such as silicon, and a device layer including a rewiring layer that constitutes the device is formed on top of that.

[0005] In recent years, there has been a demand for further thinning of devices by completely removing the base material such as silicon of the SOI wafer to leave devices consisting of only the device layer.

[0006] An object of the present invention is to provide a method for manufacturing a device that can realize a novel process for manufacturing a device consisting of only a device layer. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a device manufacturing method of the present invention is a device manufacturing method comprising: a wafer preparation step of preparing a wafer including a substrate, a laser beam absorption layer laminated on the substrate, and a device layer in which devices are formed in regions partitioned by a plurality of planned division lines intersecting on an upper surface of the laser beam absorption layer; a device layer dividing step of forming division grooves along the planned division lines to divide at least the device layer into individual devices; a transfer member disposing step, after the device layer dividing step, of applying an adhesive whose adhesive strength decreases when an external stimulus is applied to a surface of the device layer, and attaching a transfer member to the adhesive to dispose the transfer member on the surface of the device layer; and a lift-off step, after the transfer member disposing step, of irradiating a laser beam having a wavelength absorbed by the laser beam absorption layer from the substrate side, and lifting off the devices from the substrate. The device layer is formed on the upper surface of the laser beam absorption layer. 2 an insulating layer made of silicon, a silicon layer made of silicon formed on the insulating layer, and a rewiring layer formed on the silicon layer. It is characterized by:

[0008] The device manufacturing method may further include a device pick-up step of, after the lift-off step, applying an external stimulus to the adhesive to reduce the adhesive strength of the adhesive, and then picking up the devices one by one from the transfer member. 。 [Effects of the Invention]

[0009] The present invention has the effect of realizing a novel process for manufacturing a device consisting of only a device layer. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a wafer to be processed in a device manufacturing method according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the wafer shown in FIG. [Figure 3] FIG. 3 is a flowchart showing the flow of the method for manufacturing the device according to the first embodiment. [Figure 4]FIG. 4 is a perspective view schematically showing a device layer dividing step in the method for manufacturing the device shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view schematically showing the wafer after the device layer dividing step in the method for manufacturing the device shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view schematically showing the wafer after the transfer member disposing step in the device manufacturing method shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a state in which a laser beam is irradiated in the lift-off step of the method for manufacturing the device shown in FIG. [Figure 8] FIG. 8 is a plan view showing the locus of the focal point of a laser beam in the lift-off step of the method for manufacturing the device shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a state in which the substrate is removed in the lift-off step of the method for manufacturing the device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0012] [Embodiment 1] A device manufacturing method according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of a wafer to be processed in the device manufacturing method according to the first embodiment. Fig. 2 is a cross-sectional view of the wafer shown in Fig. 1. Fig. 3 is a flowchart showing the flow of the device manufacturing method according to the first embodiment.

[0013] The device manufacturing method according to the first embodiment is a method for processing a wafer 1 shown in Fig. 1. The wafer 1 to be processed in the device manufacturing method according to the first embodiment is a wafer such as a disk-shaped semiconductor wafer that includes a base material 2, a laser beam absorption layer 3 stacked on the base material 2, and a device layer 4 provided on an upper surface 31 of the laser beam absorption layer 3, as shown in Figs. 1 and 2.

[0014] In the first embodiment, the substrate 2 is made of silicon and is formed in a disk shape. The laser beam absorption layer 3 is made of resin, and in the first embodiment, is made of polyimide. The laser beam absorption layer 3 is laminated on the substrate 2 over the entire surface 21 of the substrate 2.

[0015] 1, in the device layer 4, devices 6 are formed in regions partitioned by a plurality of intersecting planned division lines 5. The devices 6 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), power devices, or MEMS (Micro Electro Mechanical Systems).

[0016] As shown in FIG. 2, the device layer 4 includes an insulating layer 7 formed on the upper surface 31 of the laser beam absorption layer 3, a silicon layer 8 formed on the insulating layer 7, and a redistribution layer 9 formed on the silicon layer 8. The insulating layer 7 is called a BOX layer (Buried Oxide Layer) made of SiO2. The silicon layer 8 is made of silicon. The redistribution layer 9 constitutes the device 6.

[0017] As described above, in the first embodiment, the wafer 1 is a so-called SOI (Silicon on Insulator) wafer in which the device layer 4 is formed on the upper surface 31 of the laser beam absorption layer 3. In the first embodiment, the base material 2 and the laser beam absorption layer 3 are removed from the wafer 1, and the wafer 1 is divided into individual devices 6 along the planned division lines 5. In the first embodiment, each of the divided devices 6 is composed of only the device layer 4, and has a thickness of about 10 μm.

[0018] The wafer 1 described above is manufactured, for example, by bonding together a silicon wafer in which a laser beam absorption layer 3 and an insulating layer 7 are laminated in this order on a base material 2, and a silicon wafer in which a redistribution layer 9 is laminated on a base material that will become a silicon layer 8. The wafer 1 is also manufactured, for example, by bonding together a silicon wafer in which a laser beam absorption layer 3 is laminated on a base material 2, and a silicon wafer in which an insulating layer 7 is laminated on one surface of a base material that will become a silicon layer 8 and a redistribution layer 9 is laminated on the other surface of the base material.

[0019] The device manufacturing method according to the first embodiment is a method of removing the base material 2 and the laser beam absorption layer 3 of the wafer 1 and dividing the wafer along the planned dividing lines 5 to manufacture individual devices 6. As shown in Fig. 3 , the device manufacturing method includes a wafer preparation step 1001, a device layer division step 1002, a transfer member arrangement step 1003, a lift-off step 1004, and a device pickup step 1005.

[0020] (Wafer preparation step) Wafer preparation step 1001 is a step for preparing a wafer having the above-described configuration. In wafer preparation step 1001, a wafer 1 having the above-described configuration is prepared.

[0021] (Device layer division step) Fig. 4 is a perspective view schematically showing a device layer dividing step in the method for manufacturing the device shown in Fig. 3. Fig. 5 is a cross-sectional view schematically showing the wafer after the device layer dividing step in the method for manufacturing the device shown in Fig. 3. In embodiment 1, the device layer dividing step 1002 is a step of forming dividing grooves 10 that divide at least the device layer 4 into individual devices 6 along the planned dividing lines 5.

[0022] In embodiment 1, in the device layer division step 1002, a known mounter adheres a disk-shaped tape 11 having a larger diameter than the wafer 1 to the back surface 22 behind the front surface 21 of the substrate 2 of the wafer 1, as shown in FIG. 4, and also adheres an annular frame 12 having an inner diameter larger than the outer diameter of the wafer 1 to the outer peripheral edge of the tape 11, thereby supporting the wafer 1 within the inner opening of the annular frame 12.

[0023] In the first embodiment, in the device layer dividing step 1002, the laser processing apparatus 50 suction-holds the back surface 22 side of the substrate 2 of the wafer 1 onto the holding surface 52 of the chuck table 51 via the tape 11. In the first embodiment, in the device layer dividing step 1002, the laser processing apparatus 50 sets the focal point 54 of the laser beam 53 at the device layer 4, and while moving the chuck table 51 relative to the laser beam applying unit 55 along the dividing lines 5, irradiates the wafer 1 with a laser beam 53 having a wavelength that is absorbed by the wafer 1 from the laser beam applying unit 55 onto the dividing lines 5 of the wafer 1, thereby performing ablation processing on the wafer 1.

[0024] In the device layer dividing step 1002 of the first embodiment, the laser processing apparatus 50 performs ablation processing on the division lines 5 of the wafer 1 to form division grooves 10 that divide the device layer 4 into individual devices 6. In the device layer dividing step 1002 of the first embodiment, the laser processing apparatus 50 forms division grooves 10 on all of the division lines 5 of the wafer 1, as shown in FIG. 5. In the first embodiment, the division grooves 10 divide the device layer 4 and the laser beam absorption layer 3 into individual devices 6.

[0025] In the first embodiment, in the device layer dividing step 1002, the laser processing device 50 performs ablation processing on the dividing lines 5 of the wafer 1 to form the division grooves 10, but in the present invention, in the device layer dividing step 1002, the cutting device may cut a cutting blade into the dividing lines 5 of the device layer 4 of the wafer 1 to form the division grooves 10. Also, in the present invention, in the device layer dividing step 1002, the division grooves 10 may be formed by etching the dividing lines 5 of the device layer 4 of the wafer 1 by wet etching, dry etching, or the like.

[0026] (Step of disposing of relocation members) Fig. 6 is a cross-sectional view schematically showing the wafer after the transfer member providing step in the device manufacturing method shown in Fig. 3. The transfer member providing step 1003 is a step of providing a transfer member 13 on the surface 41 of the device layer 4 before the lift-off step 1004 is performed.

[0027] In the first embodiment, in the transfer member disposing step 1003, an adhesive 14 whose adhesive strength decreases when an external stimulus is applied is applied to the surface 41 of the device layer 4 of the wafer 1, and as shown in Fig. 6, the transfer member 13 is attached to the adhesive 14, and the transfer member 13 is disposed on the surface 21 of the device layer 4, and the tape 11 is peeled off from the back surface 32. Note that in the first embodiment, the application of the external stimulus is, for example, irradiation with ultraviolet light or heating.

[0028] In the first embodiment, the transfer member 13 is made of a hard material and is formed in a disk shape with the same diameter as the wafer 1. In the first embodiment, the transfer member 13 is made of glass.

[0029] In the present invention, the transfer member 13 may be formed by applying a liquid resin (ResiFlat (registered trademark) manufactured by Disco Corporation) to the surface 41 of the device layer 4 and then hardening the liquid resin. In the present invention, the transfer member 13 may be a surface protection tape made of a base material and an adhesive layer, or a disk-shaped plate made of a hard material such as metal, ceramics, or silicon that is disposed on the surface 41 of the device layer 4 via the adhesive 14.

[0030] (Lift-off step) Fig. 7 is a cross-sectional view schematically showing a state in which a laser beam is irradiated in the lift-off step of the method for manufacturing the device shown in Fig. 3. Fig. 8 is a plan view showing a trajectory of a focal point of a laser beam in the lift-off step of the method for manufacturing the device shown in Fig. 3. Fig. 9 is a cross-sectional view schematically showing a state in which a substrate is removed in the lift-off step of the method for manufacturing the device shown in Fig. 3.

[0031] In the lift-off step 1004, after the device layer dividing step 1002 is performed, a laser beam 73 having a wavelength that is absorbed by the laser beam absorption layer 3 is irradiated from the substrate 2 side, thereby lifting off the device 6 from the substrate 2. In the first embodiment, in the lift-off step 1004, the laser processing apparatus 70 opens the on-off valve 77 provided in the suction path 76, and sucks the holding surface 72 of the chuck table 71 with the suction source 78, so that the front surface 41 side of the device layer 4 of the wafer 1 is suction-held by the holding surface 72 of the chuck table 71 via the transfer member 13.

[0032] In the first embodiment, in the lift-off step 1004, the laser processing device 70 sets the focal point 74 on the laser beam absorbing layer 3 of the wafer 1 held on the chuck table 71, and as shown in FIG. 7 , a pulsed laser beam 73 that is transparent to the base material 2 and has a wavelength that is absorbed by the laser beam absorbing layer 3 is irradiated from the laser beam irradiation unit 75 onto the laser beam absorbing layer 3 from the base material 2 side of the wafer 1.

[0033] In the lift-off step 1004, as shown in FIG. 8, the laser processing apparatus 70 first positions the focal point 74 at the outermost edge of the wafer 1, i.e., the laser beam absorption layer 3, and then irradiates the wafer with the pulsed laser beam 73 while moving the focal point 74 of the laser beam 73 and the chuck table 71 relatively so that the focal point 74 moves from the outermost edge in the circumferential direction and along a spiral locus 79 gradually moving toward the center.

[0034] The pulsed laser beam 73 has a wavelength that is transmissive to the substrate 2 but absorptive to the laser beam absorption layer 3. As a result, in the lift-off step 1004, the laser beam absorption layer 3 irradiated with the laser beam 73 is destroyed and gas is generated. In the lift-off step 1004 in the first embodiment, as shown in FIG. 9 , the substrate 2 is peeled off from the back surface 42 behind the front surface 41 of the device layer 4 of the wafer 1, i.e., from the insulating layer 7, thereby removing the substrate 2 from the device layer 4, i.e., from the devices 6. In the first embodiment, the wavelength of the laser beam 73 is 1064 nm.

[0035] (Device Pickup Step) The device pick-up step 1005 is a step of picking up the individual devices 6 from the transfer member 13 after the lift-off step 1004 is performed.

[0036] In the first embodiment, in the device pick-up step 1005, an external stimulus is applied to the adhesive 14 to reduce the adhesive strength of the adhesive 14. In the first embodiment, in the device pick-up step 1005, after the adhesive strength of the adhesive 14 is reduced, a picker (not shown) picks up the devices 6 one by one from the transfer member 13, for example, by suction-holding the devices 6.

[0037] In the present invention, in the device pick-up step 1005, tape or the like may be attached to the back side of the device layer 4, and the devices 6 may be transferred and then picked up. Also, in the present invention, in the device pick-up step 1005, the transfer member 13 may be divided into individual devices 6, and the devices 6 may be picked up together with the individualized transfer members 13.

[0038] The device manufacturing method according to the first embodiment described above includes the steps of: preparing, in a wafer preparation step 1001, a wafer 1 including a substrate 2, a laser beam absorbing layer 3 stacked on the substrate 2, and a device layer 4 having devices 6 formed in areas partitioned by a plurality of planned division lines 5 intersecting an upper surface 31 of the laser beam absorbing layer 3; dividing the device layer 4 in a device layer division step 1002; and then, in a lift-off step 1004, irradiating the substrate 2 with a laser beam 73 having a wavelength absorbed by the laser beam absorbing layer 3 from the substrate 2 side, thereby causing the laser beam 73 to be absorbed by the laser beam absorbing layer 3 and removing the substrate 2 from the back surface 42 of the device layer 4. After the lift-off step 1004, the wafer 1 is singulated into individual devices 6 consisting only of the device layer 4. As a result, the device manufacturing method according to the first embodiment has the effect of realizing a novel process for manufacturing devices 6 consisting only of the device layer 4.

[0039] The present invention is not limited to the above-described embodiments, etc. In other words, various modifications can be made without departing from the gist of the present invention. [Explanation of symbols]

[0040] 1 wafer 2 Base material 3. Laser beam absorption layer 4 Device Layer 5 Planned division line 6 Devices 10 dividing groove 13 Relocation parts 31 Top surface 41 Surface 73 Laser Beam 1001 Wafer Preparation Steps 1002 Device layer division step 1003 Relocation member placement step 1004 Lift-off Step 1005 Device Pickup Step

Claims

1. A method of manufacturing a device, comprising: a wafer preparation step of preparing a wafer including a substrate, a laser beam absorption layer laminated on the substrate, and a device layer in which devices are formed in regions defined by a plurality of planned division lines intersecting on an upper surface of the laser beam absorption layer; a device layer dividing step of forming dividing grooves along the dividing lines to divide at least only the device layer into individual devices; a transfer member disposing step in which, after the device layer dividing step is performed, an adhesive whose adhesive strength decreases when an external stimulus is applied to the surface of the device layer is applied, a transfer member is attached to the adhesive, and the transfer member is disposed on the surface of the device layer; a lift-off step of irradiating the device from the substrate with a laser beam having a wavelength that is absorbed by the laser beam absorption layer after the transfer member disposing step is performed, thereby lifting off the device from the substrate; The device layer includes an insulating layer made of SiO 2 formed on the upper surface of the laser beam absorption layer, a silicon layer made of silicon formed on the insulating layer, and a redistribution layer formed on the silicon layer.

2. 2. The device manufacturing method of claim 1, further comprising a device pickup step of, after performing the lift-off step, applying an external stimulus to the adhesive to reduce the adhesive strength of the adhesive, and then picking up the devices one by one from the transfer member.

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