COMPONENT WAFER PROCESSING PROCESS

Abstract

Component wafer processing method for a component wafer (1) in which a component layer (3) forming components (6) is layered on a base element (2) and in which each of the components (6) is formed in a respective area on a front face (4) which is subdivided by several crosswise arranged roads (5), the method comprising: a protective layer formation step to form a protective layer (12) covering the front side (4) of the component wafer (1); a mask formation step, after performing the protective layer formation step, applying a laser beam (36) along the roads (5) and forming a mask (13) having grooves (131) extending along the roads (5) in the protective layer (12); a component layer plasma etching step, after the mask formation step has been performed, of performing plasma etching on the component layer (3) of the component wafer (1) by component layer gas (581) through the mask (13), wherein in the component layer plasma etching step etch grooves (14) which do not reach an upper surface of the base element (2) are formed in the component layer (3), and a remaining section (141) of the component layer (3) is formed on a lower side of each of the etch grooves; and a base element plasma etching step, after the component layer plasma etching step has been performed, of performing plasma etching on the base element (2) by base element gas (582) through the mask (13).

Description

TECHNICAL BACKGROUND Area of ​​the invention

[0001] The present invention relates to a component wafer processing method. Description of the related technique

[0002] In recent years, hybrid interconnection has been developed in connection with the higher integration of electronic components. This method involves connecting electrodes formed on the front faces of components. Because hybrid interconnection connects the front faces of the components, the adhesion of foreign matter to these front faces could lead to connection failures.

[0003] Therefore, a method for singulating the wafer into individual components, for example by plasma etching, is being investigated as a method for singulating the wafer into components that are to be subjected to hybrid joining (see, for example, the Japanese patent application JP 2018-98318A).

[0004] US 2022 / 0199411A1 concerns a manufacturing process for electronic component chips. PRESENTATION OF THE INVENTION

[0005] In the wafer processing method described in the Japanese patent application JP 2018-98 318 A, a front face of a component wafer is covered with water-soluble plastic, and a laser beam is applied, removing a protective layer and a component layer along roads and forming a mask that is used at the time of plasma etching.

[0006] However, when laser processing grooves are formed by laser beam application, contaminant particles from the component layer are formed at the edges of the laser processing grooves. These contaminant particles extend in such a way that they protrude upwards from an upper surface of the component layer, posing a problem during subsequent hybrid bonding of the components.

[0007] Accordingly, an objective of the present invention is to provide a component wafer processing method which can inhibit dirt particles from protruding from an upper surface of a component layer.

[0008] According to one aspect of the present invention, a component wafer processing method is provided for a component wafer in which a component layer, which forms components, is layered on a base element, and in which each of the components is formed in a respective region on a front face divided by several crosswise arranged roads, the method comprising: a protective layer formation step to form a protective layer covering the front face of the component wafer, a mask formation step, after performing the protective layer formation step, applying a laser beam along the roads and forming a mask having grooves extending along the roads in the protective layer, and a component layer plasma etching step after the mask formation step has been performed.a plasma etching step on the component layer of the component wafer by component layer gas through the mask and a base element plasma etching step, after the component layer plasma etching step has been performed, a plasma etching step on the base element by base element gas through the mask.

[0009] In the component layer plasma etching step, etch grooves that do not reach the upper surface of the base element are formed in the component layer, and a remaining portion of the component layer is formed on the lower side of each of the etch grooves. Preferably, the component wafer processing method further comprises a laser processing step, performed after the component layer plasma etching step but before the base layer plasma etching step, in which a laser beam is applied to the remaining portion of the component layer and laser processing grooves are formed that divide the remaining portion and reach the base element.Preferably, the groove width of each of the laser processing grooves is designed to be narrower than the groove width of each of the etching grooves, and the depth of each of the etching grooves is set to such a depth that dirt particles formed in the laser processing step do not protrude from an upper surface of the component layer.

[0010] The present invention creates an effect such that it prevents dirt particles from protruding from an upper surface of a component layer.

[0011] The above and other objects, features and advantages of the present invention and the manner of its realization will become clearer, and the invention itself will best be understood by studying the following description and the attached claims with reference to the attached drawings, which show some preferred embodiments of the invention. SHORT FIGURE DESCRIPTION Fig. Figure 1 is a perspective view showing an example of a workpiece to be machined by a component wafer machining process according to a first embodiment of the present invention; Fig. Figure 2 is a flowchart illustrating the sequence of the component wafer processing process according to the first embodiment; Fig. Figure 3 is a perspective view that schematically depicts a state in which a ribbon is attached to the back side of a component wafer and an annular frame is attached to an outer edge section of the ribbon in a protective layer formation step of the process. Fig. 2 is attached to the component wafer processing process shown; Fig. 4 is a schematic cross-sectional side view representing a state in which a water-soluble plastic is applied to an entire front face of the component wafer during the protective layer formation step of the process. Fig. 2 is applied using the component wafer processing method shown; Fig. 5 is a cross-sectional view that schematically represents a part of the component wafer which has a protective layer applied to its front face in the protective layer formation step of the process described in Fig. 2 is designed as a component wafer processing process shown; Fig. 6 is a schematic cross-sectional side view, showing a mask formation step of the in Fig. 2 represents the component wafer processing process shown; Fig. 7 is a cross-sectional view that schematically represents a part of the component wafer, which includes the mask formation step of the in Fig. has undergone the component wafer processing process shown in section 2; Fig. Figure 8 is a cross-sectional view that schematically represents an embodiment of a plasma etching device, which includes a component layer plasma etching step and a base element plasma etching step of the [description of the device]. Fig. 2 performs the component wafer processing process shown; Fig. Figure 9 is a cross-sectional view of a portion of the device wafer, schematically illustrating the device-layer plasma etching step of the process described in Figure 9. Fig. 2 represents the component wafer processing process shown; Fig. Figure 10 is a cross-sectional view of a portion of the component wafer, schematically illustrating the base element plasma etching step of the process described in Figure 10. Fig. 2 represents the component wafer processing process shown; Fig. 11 is a cross-sectional view that schematically represents a portion of the component wafer, which includes a mask removal step of the in Fig. has undergone the component wafer processing process shown in section 2; Fig. Figure 12 is a flowchart that represents a sequence of the component wafer processing method according to a second embodiment of the present invention; Fig. Figure 13 is a cross-sectional view of a portion of the device wafer, schematically illustrating the device layer plasma etching step of the process described in Figure 13. Fig. 12 represents the component wafer processing process shown; Fig. Figure 14 is a cross-sectional view of a portion of the component wafer, schematically illustrating a laser processing step of the process. Fig. 12 represents the component wafer processing process shown; Fig. Figure 15 is a cross-sectional view that schematically represents a part of the component wafer that undergoes the laser processing step of the in Fig. has undergone the component wafer processing process shown in section 12; and Fig. Figure 16 is a cross-sectional view of a portion of the component wafer, schematically illustrating the base element plasma etching step of the process described in Figure 16. Fig. 12 represents the component wafer processing process shown. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0012] Embodiments of the present invention are described in detail below with reference to the drawings. The details described in the following exemplary embodiments do not limit the present invention in any way. Furthermore, the components described below include those that are readily conceivable to a person skilled in the art and those that are essentially identical. In addition, the embodiments described below can be combined with one another in a suitable manner. Moreover, various omissions, substitutions, or modifications of the embodiment can be carried out within the scope that does not deviate from the basic concept of the present invention.

[0013] A component wafer processing method according to a first embodiment of the present invention is described with reference to the drawings. Fig. Figure 1 is a perspective view showing an example of a workpiece being machined using the component wafer machining process according to the first embodiment. Fig. Figure 2 is a flowchart that illustrates the sequence of the component wafer processing process according to the first embodiment.

[0014] The component wafer processing method according to the first embodiment is a component wafer processing method for a Fig. 1. Component wafer 1 shown. In the first embodiment, the component wafer 1 is a wafer such as a semiconductor wafer, which has a base element 2 made of silicon or the like and in which a component layer 3 is layered on the base element 2. As shown in Fig. As shown in Figure 1, the component wafer 1 has components 6 which are formed in the areas of a front face 4 which are delimited in a grid pattern by several crosswise arranged roads 5.

[0015] Each of the components 6 is, for example, an integrated circuit element such as an integrated circuit (IC) or a large-scale integration (LSI) circuit, or a memory (semiconductor memory component). In the first embodiment, the component layer 3, for example, comprises several dielectric films made of SiO2 and stacked on top of each other, as well as a circuit layer made of conductive metal and arranged between the dielectric films.

[0016] The component 6 is configured such that the dielectric intermediate films and the circuit layer of component layer 3 are stacked on top of each other. Note that in the sections 5, component layer 3 consists only of the dielectric intermediate films. Furthermore, the component 6 has unillustrated electrodes formed on its front face. Each electrode is flat and, in the first embodiment, is preferably positioned flush with the front face of the component 6. The electrode comprises a conductive metal, such as a copper alloy, and is used to connect the component 6 of the component wafer 1 to a component of another wafer or a component chip.

[0017] Specifically, in the first embodiment, the component wafer 1 is a wafer in which a component from another wafer or a component from a component chip is mounted onto the component 6, and the electrodes of the component 6 are connected to the electrodes of the component from the other wafer or the component of the respective component chip. As described above, in the first embodiment, the component wafer 1 to be processed is a wafer that is essentially to be subjected to so-called hybrid bonding. However, the wafer to which the present invention is applicable is not limited to a wafer that is to be subjected to hybrid bonding.

[0018] The component wafer processing method according to the first embodiment is a method for dividing the component wafer 1 into individual component chips 10 along the roads 5. Note that each of the component chips 10 has a part of the base element 2 and the component 6 attached to the base element 2.

[0019] The device wafer processing method according to the first embodiment is a method for dividing the device wafer 1 into device chips 10 by plasma etching, i.e., a method for dividing the device wafer 1 into device chips 10 by what is essentially referred to as plasma dividing. As in Fig. Figure 2 shows that the component wafer processing method according to the first embodiment comprises a protective layer formation step 1001, a mask formation step 1002, a component layer plasma etching step 1003, a base element plasma etching step 1004 and a mask removal step 1005. (Protective layer formation step)

[0020] Fig. Figure 3 is a perspective view that schematically depicts a state in which a tape is attached to the back side of a component wafer and an annular frame is attached to an outer edge section of the tape in a protective layer formation step of the process. Fig. 2 is attached to the component wafer processing process shown. Fig. 4 is a schematic cross-sectional side view representing a state in which water-soluble plastic is applied to an entire front face of the component wafer during the protective layer formation step of the process. Fig. The component wafer processing process shown in section 2 is applied. Fig. 5 is a cross-sectional view that schematically represents a part of the component wafer which has a protective layer applied to its front side in the protective layer formation step of the process. Fig. The component layer 3 is formed according to the wafer processing method shown in section 2. It should be noted that the component layer 3 is in Fig. 4 is not shown.

[0021] The protective layer formation step 1001 is a step for forming a protective layer 12 that covers the entire front face 4 of the device wafer 1. In the protective layer formation step 1001 according to the first embodiment, as described in Fig. Figure 3 shows a central section of a circular plate-shaped strip 8, which has a larger diameter than the component wafer 1, attached to a rear side 7 of the component wafer 1, and an annular frame 9, which has a larger inner diameter than the outer diameter of the component wafer 1, is attached to an outer edge section of the strip 8.Note that in the first embodiment, the tape 8 is either an adhesive tape comprising a base material made of a non-adherent but flexible plastic and an adhesive layer layered on the base material made of an adhesive and flexible plastic, wherein the adhesive layer is attached to the component on the component wafer 1 and the ring frame 9, or a film comprising no adhesive and made only of the base material, which is a thermoreversible plastic, which is thermocompression bonded to the component wafer 1 and the ring frame 9.

[0022] In the protective layer formation step 1001 according to the first embodiment, a Fig. 4 Protective layer coating device 20, as shown, holds the back side 7 of the component wafer 1 via the belt 8 on a holding surface 22 of a holding table 21, holds the back side 7 of the component wafer 1 via the belt 8 under suction on the holding surface 22 and clamps the ring frame 9 by clamps 23 which are provided around the holding table 21. In the protective layer formation step 1001 according to the first embodiment, as shown in Fig. As shown in Figure 4, the protective coating device 20 applies water-soluble plastic 11 in liquid form to the center of the front face 4 of the component wafer 1 from a nozzle 24 located on an upper side of the component wafer 1 while rotating the rotary table 21 about its axis. The water-soluble plastic 11 applied to the front face 4 of the component wafer 1 then spreads towards an outer edge of the component wafer 1 due to the centrifugal force generated by the rotation of the rotary table 21 and covers the entire front face 4 of the component wafer 1.

[0023] In this way, in the protective layer formation step 1001 according to the first embodiment, the water-soluble plastic 11 is applied to the component wafer 1, which is held on the rotary table 21 and rotates about its axis, by feeding and applying the water-soluble plastic 11, a process essentially described as rotational coating. In the protective layer formation step 1001 according to the first embodiment, the water-soluble plastic 11 is dried and the protective layer 12 is formed, which covers the entire front face 4 of the component wafer 1, as shown in Fig. 5 shown.

[0024] It should be noted that in the first embodiment, the water-soluble plastic 11 comprises, for example, a water-soluble plastic such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP). Furthermore, the protective layer 12 formed from the water-soluble plastic 11 exhibits resistance to the component gas 581, which is converted into plasma gas and used in the component layer plasma etching step 1003, and to the base element gas 582, which is converted into plasma gas and used in the base element plasma etching step 1004. Furthermore, according to the first embodiment, the water-soluble plastic 11 has light-absorbing materials distributed therein that absorb a laser beam 36 with a wavelength of 355 nm, which is applied in the mask formation step 1002. However, it is not necessary for the water-soluble plastic 11 according to the present invention to have light-absorbing materials.For example, soot or phthalocyanine is used as a light-absorbing material.

[0025] The protective layer 12, which is formed on the entire front face 4 of the component wafer 1 by drying the water-soluble plastic 11, is made of the water-soluble plastic 11 described above, and thus the protective layer 12 is made of a material that has resistance to the component layer gas 581, which has been converted into plasma gas and is used in the component layer plasma etching step 1003, and to the base element gas 582, which has been converted into plasma gas and is used in the base element plasma etching step 1004, and is designed to have a uniform thickness that has resistance to the gas 581 and the gas 582, which have each been converted into plasma gas. (Mask training step)

[0026] Fig. 6 is a schematic cross-sectional side view, showing the mask formation step of the in Fig. 2 represents the component wafer processing process shown. Fig. 7 is a cross-sectional view that schematically represents a part of the component wafer that undergoes the mask formation step of the process. Fig. 2 has undergone the component wafer processing process shown. Note that component layer 3 in the illustration in Fig. 6 was omitted. Mask training step 1002 consists of, after performing the protective layer training step 1001, using the laser beam 36 (shown in Fig. 6) to apply along the roads 5 and in the protective layer 12 a mask 13 (shown in Fig. 7) to form a groove or opening 131 (shown in Fig. 7) is formed, which extends along road 5.

[0027] In the mask training step 1002 according to the first embodiment, a Fig. The laser processing device 30, as shown in Figure 6, holds the back side 7 of the component wafer 1 over the belt 8 on a holding surface 32 of a clamping table 31 under suction and clamps the annular frame 9 by clamps 37 provided around the clamping table 31. In the mask formation step 1002 according to the first embodiment, the laser processing device 30 acquires an image of the front side 4 of the component wafer 1 by means of an imaging camera and performs an alignment of the positions of the surfaces 5 of the component wafer 1 and a condenser lens 34 of a laser beam application unit 33.

[0028] In mask training step 1002 according to the first embodiment, as in Fig. As shown in Figure 7, while the clamping table 31 and the laser beam application unit 33 are moved relative to each other along the roads 5, the laser processing device 30 fixes a focal point of the laser beam 36 on a front face of the protective layer 12 on each of the roads 5 and applies the laser beam 36, with a wavelength (for example, 355 nm) that can be absorbed by the protective layer 12 and emitted by a laser oscillator 35, to the protective layer 12 on each of the roads 5 in order to remove the protective layer 12 on each of the roads 5. In the mask formation step 1002 according to the first embodiment, the laser processing device 30 forms the grooves or openings 131 that extend along the roads 5 over the entire length of each of the roads 5 and forms the mask 13 in the protective layer 12 in which each of the Fig. The grooves or openings 131 shown in Figure 7 are formed. It should be noted that the roads 5 are exposed on the undersides of the grooves or openings 131.

[0029] It should be noted that in mask formation step 1002 according to the first embodiment, the protective layer 12 on the roads 5 is completely removed in the thickness direction by the laser processing device 30, but according to the present invention, the protective layer 12 can be left slightly at the bottom of the groove or the opening 131. It should be noted that the protective layer 12 that remains slightly at the bottom of the groove or opening 131 is etched and removed in the next component layer plasma etching step 1003. In this way, in mask formation step 1002 according to the present invention, the laser processing device 30 removes the protective layer 12 on each of the roads 5 and applies the laser beam 36 to the component wafer 1 under such processing conditions that the removal of the component layer 3 on each of the roads 5 is limited, thereby forming the mask 13 on the component wafer 1. (Plasma etching device)

[0030] Next, a plasma etching device 50 is described which performs the component layer plasma etching step 1003 and the base element plasma etching step 1004. Fig. Figure 8 is a cross-sectional view that schematically represents an embodiment of the plasma etching device, which performs the component layer plasma etching step and the base element plasma etching step of the [document / model]. Fig. The plasma etching device 50, as shown in 2, performs the component wafer processing process. Fig. Figure 8 shows a parallelepipedic chamber 51, a holding unit 52, an upper electrode 53 and a control device 55.

[0031] The chamber 51 has an internal processing area 511 in which plasma etching is performed. The chamber 51 is provided on one side wall 512 with a groove or opening 513 for loading and unloading the component wafer 1 and with an opening / closing door 514 for opening or closing the groove or opening 513. The opening / closing door 514 opens or closes the groove or opening 513 by being raised or lowered by an opening / closing mechanism 515, which may, for example, include an air cylinder.

[0032] Furthermore, the chamber 51 is provided with an opening 517 in a bottom wall 516. The opening 517 forms a connection between the inside and the outside of the chamber 51. The opening 517 is connected to a suction mechanism 510, such as a vacuum pump.

[0033] The holding unit 52 and the upper electrode 53 are arranged such that they face each other in the processing area 511 of the chamber 51. An upper surface of the holding unit 52 is a holding surface 524 for holding the component wafer 1 over the belt 8. Furthermore, the holding unit 52 is made of a conductive material and also functions as the lower electrode.

[0034] The holding unit 52 has a disc-shaped holding section 521 and a cylindrical support element 520, which projects downwards from a central part on a lower surface of the holding section 521. The support element 520 is inserted into a groove or opening 522 formed in the bottom wall 516 of the chamber 51. An annular insulating element 523 is arranged in the groove or opening 522 between the bottom wall 516 and the holding element 520, and the chamber 51 and the holding unit 52 are electrically insulated from each other. Furthermore, the holding unit 52 is connected to a high-frequency power source 56 located outside the chamber 51.

[0035] In the holding section 521 of the holding unit 52, an electrode 526 is provided, which is connected to a high-frequency current source (not shown). When electrical energy from the high-frequency energy source is applied to the electrode 526, a dielectric polarization phenomenon occurs between the holding surface 524 and the device wafer 1, and the holding unit 52 holds the device wafer 1 on the holding surface 524 by electrostatic attraction generated by polarization of charges.

[0036] Furthermore, a cooling channel 527 is formed within the holding section 521 and the support section 520 of the holding unit 52, in which a cooling fluid flows to cool the holding unit 52. Both ends of the cooling channel 527 are connected to a coolant circulation mechanism 528. When the coolant circulation mechanism 528 is actuated, a cooling fluid, e.g., water, circulates and flows in the cooling channel 527 and cools the holding unit 52.

[0037] The upper electrode 53 is made of a conductive material and has a disc-shaped gas ejection section 531 and a cylindrical support structure 530 that projects upwards from a central part on an upper surface of the gas ejection section 531. The support structure 530 is inserted into a groove or opening 532 formed in an upper wall 518 of the chamber 51. An annular insulating element 533 is arranged within the groove or opening 532 between the upper wall 518 and the support structure part 530, and the chamber 51 and the upper electrode 53 are electrically insulated from each other.

[0038] The upper electrode 53 is connected to a high-frequency current source 57 outside the chamber 51. A support arm of a lifting / lowering mechanism 534 is attached to an upper end section of the support section 530. The upper electrode 53 is raised and lowered by the lifting / lowering mechanism 534.

[0039] Several ejection openings 535 are provided on a lower surface of the gas ejection section 531. The ejection openings 535 are connected via a flow channel 536 formed in the gas ejection section 531 and the support structure 530 to a first gas supply source 58 and a second gas supply source 59 for the etching gas. The first gas supply source 58 delivers the gas 581 and the gas 582 from the ejection openings 535 through the flow channel 536 into the interior of the chamber 51. In the first embodiment, the first gas supply source 58 delivers a fluorine-based gas, namely the gas 581 and the gas 582, into the interior of the chamber 51 when the base element 2 of the component wafer 1 is made of silicon. The second gas supply source 59 supplies etching gas to the interior of the chamber 51 from the discharge openings 535 through the flow channel 536. In the first embodiment, the second gas supply source 59 delivers oxygen gas to the interior of the chamber 51.

[0040] The control unit 55 controls the components of the plasma etching device 50 and causes the plasma etching device 50 to perform plasma etching on the component wafer 1. It should be noted that the control unit 55 is a computer comprising an arithmetic processing unit with a microprocessor, e.g., a central processing unit (CPU), a storage unit with memory, e.g., a random access memory (ROM) or a working memory (RAM), and an input / output interface. The arithmetic processing unit of the control unit 55 performs arithmetic operations according to a computer program stored in the storage unit and outputs control signals to the components of the plasma etching device 50 via the input / output interface.

[0041] Furthermore, the control device 55 is connected to a display unit, designed as a liquid crystal display element or the like, which displays various types of information, images, and the like, and to an input unit used by an operator to register and edit content information and the like. The input unit has at least one touch panel provided on the display unit or an external input device such as a keyboard. (Device layer plasma etching step)

[0042] Fig. Figure 9 is a cross-sectional view of a portion of the device wafer, schematically illustrating the device layer plasma etching step of the process described in Figure 9. Fig. Figure 2 represents the component wafer processing process shown. The component layer plasma etching step 1003 is a step in which, after the mask formation step 1002, plasma etching is carried out on the component layer 3 of the component wafer 1 through the mask 13 using the component layer gas 581 (which corresponds to the etching gas) that has been converted into plasma gas.

[0043] In the component layer plasma etching step 1003 according to the first embodiment, the plasma etching device 50 raises the upper electrode 53 by means of the lifting / lowering mechanism 534 and then lowers the opening / closing door 514 by means of the opening / closing mechanism 515 in a state in which a frame clamping plate 542 is raised by a lifting / lowering mechanism to open the groove or opening 513.

[0044] In the component layer plasma etching step 1003, the plasma etching device 50 causes a feeder unit (not shown) to load the component wafer 1, in which the mask 13 was formed in the mask formation step 1002, into the interior of the processing step 511 and to place the back side 7 of the component wafer 1 onto the holding surface 524 of the holding unit 52 via the belt 8. In component layer plasma etching step 1003, the plasma etching device 50 causes the high-frequency current source to apply an electric current to the electrode 526 and holds the back side 7 of the component wafer 1 against the holding surface 524 via the belt 8.

[0045] In the component layer plasma etching step 1003, the plasma etching device 50 causes the opening / closing mechanism 515 to raise the opening / closing door 514 and close the groove or opening 513, and actuates the extraction mechanism 510 to reduce the pressure inside the chamber 51 and create a vacuum (low-pressure) condition in the processing area 511. The plasma etching device 50 also actuates the coolant circulation mechanism 528 to circulate the cooling fluid, for example, water, within the cooling channel 527, thereby preventing an irregular temperature rise in the holding unit 52.In the component layer plasma etching step 1003, the plasma etching device 50 causes the lifting / lowering mechanism 534 to lower the upper electrode 53 and to adjust the distance between the lower surface of the upper electrode 53 and the component wafer 1 formed by the holding unit 52 to a predetermined interelectrode distance suitable for plasma etching.

[0046] In the component layer plasma etching step 1003, the plasma etching device 50 supplies the component layer gas 581 from the first gas supply source 58 at a predetermined flow rate and expels the component layer gas 581 from the plurality of openings 535 of the gas discharge section 531 towards the component wafer 1, which is held on the holding unit 52. In the component layer plasma etching step 1003, the plasma etching device 50, in a state in which the component layer gas 581 is supplied from the first etching gas supply source 58, applies high-frequency current, which generates and maintains plasma, from the high-frequency current source 57 to the upper electrode 53 and also applies high-frequency current for attracting ions from the high-frequency current source 56 to the holding unit 52, which serves as the lower electrode.

[0047] In the component layer plasma etching step 1003, the component layer gas 581, which is present in the space between the holding unit 52 and the upper electrode 53, is converted into plasma gas in the plasma etching device 50, and as described in Fig. As shown in Figure 9, the component layer gas 581, thus converted into plasma gas, is attracted to the side of the component wafer 1 and etches the front face 4 at the roads 5 exposed by the groove or opening 131 of the mask 13 on the component wafer 1 (subjecting it to what is essentially called plasma etching). In the component layer plasma etching step 1003, the plasma etching device 50 forms etch grooves 14 (in Fig. (9 shown) in the component layer 3 at the roads 5 and causes the etch grooves 14 to move towards the back side 7 of the component wafer 1. In this way, in the component layer plasma etching step 1003 according to the first embodiment, plasma etching is carried out on the component layer 3 of the component wafer 1 through the mask 13.

[0048] It should be noted that in the first embodiment, in the case where the component layer 3 on the surface 5 is formed from SiO2, a fluorine-based gas, such as CF4, is used as the component layer gas 581, but according to the present invention, C4F8 could alternatively be used. In the component layer plasma etching step 1003 according to the first embodiment, a predetermined time is preset in the plasma etching device 50 to subject the component layer 3 of the component wafer 1 to plasma etching, according to the thickness of the component layer 3 of the component wafer 1.

[0049] In the component layer plasma etching step 1003, the plasma etching device 50 applies radio frequency energy to the holding unit 52 and the upper electrode 53 while supplying and removing the component layer gas 581 for a predetermined period of time, as shown in Fig. As shown in Figure 9, the exposed component layer 3 is completely removed from the groove or opening 131 of the mask 13 at road 5, thereby dividing the component layer 3 of the component wafer 1 along the groove or opening 131, i.e., the etch groove 14. In other words, in the component layer plasma etching step 1003, the plasma etching device 50 removes the component layer 3 at each road 5 of the component wafer 1 over its entire length. (Basic element plasma etching step)

[0050] Fig. Figure 10 is a cross-sectional view of a portion of the device wafer, schematically illustrating the base element layer plasma etching step of the process described in Figure 10. Fig. Figure 2 illustrates the component wafer processing process. The base element plasma etching step 1004 is a step in which, after the execution of the component layer plasma etching step 1003, plasma etching of the base element 2 of the component wafer 1 is carried out through the mask 13 with the base element gas 582 (which corresponds to an etching gas) that has been converted into plasma gas.

[0051] In the base element plasma etching step 1004, the plasma etching device 50 supplies the base element gas 582 from the first gas supply source 58 at a predetermined flow rate and directs the base element gas 582 from the multiple discharge openings 535 of the gas discharge section 531 onto the component wafer 1 held by the holding unit 52. In the base element plasma etching step 1004, while the base element gas 582 is being supplied for etching from the first gas supply source 58, the plasma etching device 50 applies high-frequency current, which generates and maintains plasma at the upper electrode 53 from the high-frequency current source 57, and applies high-frequency current from the high-frequency current source 56 to the holding unit 52, which serves as the lower electrode, to attract ions.

[0052] In the base element plasma etching step 1004, the base element gas 582, which is present in the space between the holding unit 52 and the upper electrode 53, is converted into plasma gas in the plasma etching device 50, and as described in Fig. As shown in Figure 10, the base element gas 582, which is thus converted into plasma gas, is attracted to the side of the device wafer 1 and etches the bottom of the etch groove 14, which is exposed by the groove or opening 131 of the mask 13 of the device wafer 1, i.e., the base element 2 (subjecting it to what is essentially called plasma etching). In the base element plasma etching step 1004, the plasma etching device 50 causes the etch groove 14 to move toward the rear side 7 of the device wafer 1. As described above, in the base element plasma etching step 1004 according to the first embodiment, the plasma etching on the base element 2 of the device wafer 1 is carried out through the mask 13.

[0053] Note that in the first embodiment, if the base element 2 is made of silicon, the base element gas 582 to be used is a fluorine-based gas such as SF6, C4F8, or CF4, but the base element gas 582 is not limited to such gas types. Furthermore, in the base element plasma etching step 1004 according to the first embodiment, the plasma etching device 50 performs plasma etching on the base element 2 of the device wafer 1 according to the Bosch method, in which plasma etching by supplying SF6 and the deposition of a protective layer on an inner surface and the like of the etch groove 14 by supplying C4F8 are repeated alternately. According to the present invention, however, the plasma etching could be carried out by supplying a single type of etching gas.

[0054] In base element plasma etching step 1004, a predetermined time duration is preset in the plasma etching device 50 to perform plasma etching on the base element 2 of the device wafer 1 according to the thickness of the base element 2 of the device wafer 1. In base element plasma etching step 1004, the plasma etching device 50 applies high-frequency current to the holding unit 52 and the upper electrode 53 while supplying and removing the base element gas 582 for a predetermined time duration, as described in Fig. Figure 10 shows the base element 2, which is fully exposed by the groove or opening 131 of the mask 13 at road 5, thereby dividing the component wafer 1 along the groove or opening 131, i.e., the etch groove 14, into individual component chips 10. More precisely, in the base element plasma etching step 1004, each of the etch grooves 14 is caused to penetrate the component wafer 1 along the entire length of each of the roads 5. (Mask removal step)

[0055] Fig. Figure 11 is a cross-sectional view that schematically represents a portion of the component wafer, which includes the mask removal step of the process described in Fig. The component wafer processing process shown in Figure 2 has been carried out. The mask removal step 1005 is a step in which, after the base element plasma etching step 1004 has been performed, the mask 13 is removed from the front face 4 of the component wafer 1.

[0056] In mask removal step 1005 according to the first embodiment, a cleaning device (not shown) places the back side 7 of the component wafer 1 over the belt 8 onto a holding surface of a rotary table, holds the back side 7 of the component wafer 1 against the holding surface by suction over the belt 8, and clamps the ring frame 9 by clamps provided around the rotary table. In mask removal step 1005 according to the first embodiment, the cleaning device feeds a cleaning fluid, for example purified water, to the center of the front side 4 of the component wafer 1 from a nozzle arranged on the top of the component wafer 1 while the rotary table rotates about its axis. The cleaning water supplied to the front side 4 of the component wafer 1 then flows towards the outer edge of the component wafer 1 due to the centrifugal force generated by the rotation of the rotary table and washes, as shown in Fig. Figure 11 shows the mask 13 from the front side 4 of the component wafer 1.

[0057] In this way, in mask removal step 1005 according to the first embodiment, the cleaning of the component wafer 1, essentially described as rotary cleaning, is carried out by supplying a cleaning fluid to the component 1, which is held on the rotary table and rotates about its axis. In mask removal step 1005 according to the first embodiment, the component wafer 1 is dried, and the component wafer processing process is terminated.

[0058] According to the component wafer processing method of the first embodiment described above, the laser processing device 30 removes the protective layer 12 on each of the roads 5 in mask formation step 1002 and forms the mask 13 on the component wafer 1 by applying the laser beam 36 under such processing conditions that the removal of the component layer 3 on each of the roads 5 is prevented, thus inhibiting the formation of dirt particles protruding from the component layer 3 on the front face 4 of the component wafer 1 after mask formation step 1002. Furthermore, according to the component wafer processing method of the first embodiment, the component layer 3 is removed on each of the roads 5 in the component layer plasma etching step 1003.

[0059] Consequently, the component wafer processing method according to the first embodiment produces such an effect that dirt particles are prevented from protruding on the upper surface of the component layer 3 in each of the individual component chips 10.

[0060] Next, the component wafer processing method according to a second embodiment of the present invention will be described with reference to the drawings. Fig. Figure 12 is a flowchart that illustrates a sequence of the component wafer processing process according to the second embodiment. Fig. Figure 13 is a cross-sectional view of a portion of the device wafer, schematically illustrating the device layer plasma etching step of the process described in Figure 13. Fig. 12 represents the component wafer processing process shown. Fig. Figure 14 is a cross-sectional view of a portion of the component wafer, schematically illustrating a laser processing step of the process. Fig. 12 represents the component wafer processing process shown. Fig. Figure 15 is a cross-sectional view that schematically shows a portion of the component wafer undergoing the laser processing step of the process described in the article. Fig. was subjected to the component wafer processing process shown in section 12. Fig. Figure 16 is a cross-sectional view of a portion of the component wafer, schematically illustrating the base element layer plasma etching step within the process described in Fig. Figure 12 illustrates the component wafer processing process. Note that in the Fig. 12, Fig. 13, Fig. 14, Fig. 15 and Fig. 16 sections, identical to those of the first embodiment, are identified by identical reference numerals and their description is omitted.

[0061] The component wafer processing method according to the second embodiment is the same as that of the first embodiment, except that it includes the component layer plasma etching step 1003 and the base element plasma etching step 1004, which differ from those of the first embodiment, and furthermore includes a laser processing step 1010, as shown in Fig. Figure 12 shows that in the second embodiment, the protective layer formation step 1001 and the mask formation step 1002 are carried out in a similar manner to the first embodiment.

[0062] In the component layer plasma etching step 1003 of the component wafer processing method according to the second embodiment, the plasma etching device 50 applies high-frequency energy to the holding unit 52 and the upper electrode 53, while the component layer gas 581 is supplied for a second predetermined time period, which is shorter than the predetermined time period for removing the component layer 3 of the component wafer 1 over the entire thickness direction by the component layer gas 581 converted into plasma gas, plasma etching is carried out on the component wafer 1 through the mask 13 and thereby forms the etch groove 14 in the component layer 3 on each of the roads 5 of the component wafer 1.

[0063] In this way, the plasma etching device 50 forms the etch groove 14 in the device layer plasma etching step 1003 of the device wafer processing method according to the second embodiment in the device layer 3 on each of the roads 5, which does not reach the upper surface of the base element 2, i.e. the etch groove 14 in which the device layer 3 remains at its bottom, as in Fig. Figure 13 shows that in the component layer plasma etching step 1003 of the component wafer processing method according to the second embodiment, the plasma etching device 50 forms a remaining section 141 of the component layer 3 on the lower side of the etch groove 14, which is formed in the component layer 3 on each of the roads 5 of the component wafer 1.

[0064] The laser processing step 1010 is a step in which, after the component layer plasma etching step 1003 has been performed but before the base element plasma etching step 1004 is performed, a laser beam 62 (shown in Fig. 14) is applied to the remaining section 141 of the component layer 3 to divide the remaining section 141 and create a laser processing groove 15 (shown in Fig. 15) to form, which reaches the base element 2. In the laser processing step 1010 according to the second embodiment, a Fig. 14 The laser processing device 60 shown secures the back side 7 of the component wafer 1 to a holding surface of a clamping table via the belt 8 and clamps the ring-shaped frame 9 by means of clamps provided around the clamping table.

[0065] In laser processing step 1010 according to the second embodiment, the laser processing device 60 acquires an image of the front face 4 of the component wafer 1 with an imaging unit and aligns the positions of the etch grooves 14 formed in the tracks 5 of the component wafer 1 and a condenser lens of a laser beam application unit 61. In laser processing step 1010 according to the second embodiment, the laser processing device 60 sets the focal point of the laser beam 62 on a front face of the remaining section 141 at the bottom of the etch groove 14 while moving the clamping table and the laser beam application unit 61 relative to each other along the etch groove 14 formed in each of the tracks 5, and applies the laser beam 62, which has a wavelength absorbable by the component layer 3, to the bottom of each of the etch grooves 14 formed in the tracks 5.The laser processing device 60 removes the remaining section 141 at the bottom of each of the etch grooves 14 formed in the roads 5 and forms the laser processing groove 15, which divides the component layer 3 and reaches the base element 2 at the bottom of the remaining section 141 in order to divide the component layer 3 along the roads 5. It should be noted that the groove width 152 of the laser processing groove 15 is narrower than the groove width 142 of the etch groove 14.

[0066] In laser processing step 1010, the remaining section 141 formed on the bottom of the etching groove 14 in each of the streets 5 is divided, as shown in Fig. Figure 15 shows dirt particles 151, which are formed by the component layer 3 and protrude from the bottom of the laser processing groove 15, at both edges of the laser processing groove 15 in its width direction. In the laser processing step 1010 according to the second embodiment, the laser processing device 60 forms the laser processing groove 15 at the bottom of each of the etching grooves 14 formed in the roads 5, which has a groove width 152 that is narrower than the groove width 142 of the etching groove 14, and which reaches the base element 2, and applies the laser beam 62 to the component wafer 1 under such processing conditions that a height 153 of the dirt particles 151 from the bottom of the etching groove 14 is less than a depth 143 of the etching groove 14 from the front face 4, in order to divide the component layer 3 at each of the roads 5 of the component wafer 1.As described above, in the second embodiment the groove width 152 of the laser processing groove 15 is narrower than the groove width 142 of the etching groove 14, and the depth 143 of the etching groove 14 is set to such a depth that the dirt particles 151 formed in the laser processing step 1010 do not protrude from the upper surface of the component layer 3 (i.e. the dirt particles 151 are prevented from protruding).

[0067] In the base element plasma etching step 1004 according to the second embodiment, the plasma etching device 50 performs an etching (essentially referred to as plasma etching) on ​​the base element 2, which is exposed at the bottom of the laser processing groove 15, by applying the base element gas 582, which has been converted into plasma gas, as shown in Fig.As shown in Figure 16, a second etch groove 16 is formed at the bottom of the laser processing groove 15 and causes the second etch groove 16 to move towards the rear side 7 of the component wafer 1. Note that in the base element plasma etching step 1004 according to the second embodiment, as in the first embodiment, the base element 2 of the component wafer 1 is plasma etched by the Bosch process and the base element 2 exposed by the laser processing groove 15 in each of the roads 5 is completely removed, so that the component wafer 1 is divided into individual component chips 10 along the laser processing groove 15, i.e., the second etch groove 16.

[0068] The component wafer processing method according to the second embodiment performs the mask removal step 1005 after the base element plasma etching step 1004 has been performed, as in the first embodiment.

[0069] According to the component wafer processing method of the second embodiment, the laser processing device 30 applies the laser beam 36 to form the mask 13 on the component wafer 1 in mask formation step 1002 and performs plasma etching on the component layer 3 at each of the roads 5 in component layer plasma etching step 1003. Similar to the first embodiment, the second embodiment therefore prevents dirt particles from protruding from the upper surface of the component layer 3 in the individual component chips 10.

[0070] Furthermore, although the device wafer processing method according to the second embodiment requires time to perform plasma etching on the device layer 3, the device layer plasma etching step 1003 performs the plasma etching until a center point of the device layer 3 is reached and the laser processing step 1010 divides the remaining section 141 by applying the laser beam 62, so that the processing time can be reduced compared to a case in which the plasma etching is performed on the entire thickness of the device layer 3.

[0071] Furthermore, in the component wafer processing method according to the second embodiment, the groove width 152 of the laser processing groove 15 formed in the remaining section 141 is narrower than the groove width 142 of the etching groove 14, and the contaminant particles 151 formed in the laser processing step 1010 are formed on the remaining section 141 of the component layer 3 at the bottom of the etching groove 14. Moreover, in the component wafer processing method according to the second embodiment, the depth 143 of the etching groove 14 is set such that it is greater than the height 153 of the contaminant particles 151. Consequently, the component wafer processing method according to the second embodiment can prevent the contaminant particles 151 formed in the laser processing step 1010 from protruding from the upper surface of the component layer 3.

[0072] It should be noted that the present invention is not limited to the embodiments mentioned above. That is to say, the present invention can be implemented with various modifications within a scope that does not deviate from the basic concept of the present invention. Within the scope of the present invention, the protective layer 12 could, for example, be a non-water-soluble layer such as a resist layer. In this case, the protective layer 12 is removed by ashing using oxygen gas, for example in mask removal step 1005.

Claims

[1] A component wafer processing method for a component wafer (1) in which a component layer (3) forming components (6) is layered on a base element (2) and in which each of the components (6) is formed in a respective area on a front face (4) which is subdivided by several crosswise arranged roads (5), the method comprising: a protective layer formation step to form a protective layer (12) covering the front side (4) of the component wafer (1); a mask formation step, after performing the protective layer formation step, applying a laser beam (36) along the roads (5) and forming a mask (13) having grooves (131) extending along the roads (5) in the protective layer (12); a component layer plasma etching step, after the mask formation step has been performed, of performing plasma etching on the component layer (3) of the component wafer (1) by component layer gas (581) through the mask (13), wherein in the component layer plasma etching step etch grooves (14) which do not reach an upper surface of the base element (2) are formed in the component layer (3), and a remaining section (141) of the component layer (3) is formed on a lower side of each of the etch grooves; and a base element plasma etching step, after the component layer plasma etching step has been performed, of performing plasma etching on the base element (2) by base element gas (582) through the mask (13). [2] Component wafer processing method according to claim 1, wherein The device wafer processing method further comprises a laser processing step, after the device layer plasma etching step has been performed but before the base layer plasma etching step is performed, of applying a laser beam (36) to the remaining section (141) of the device layer (3) and of forming laser processing grooves (15) that divide the remaining section (141) and reach the base element (2), and a groove width (152) of each of the laser processing grooves (15) is designed such that it is narrower than a groove width of each of the etching grooves, and a depth (143) of each of the etching grooves is set to such a depth that dirt particles (151) formed in the laser processing step do not protrude from an upper surface of the component layer (3).

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