JP2021129000A - Wafer processing method - Google Patents

Abstract

To provide a wafer processing method in which the occurrence of cracking of a TAIKO wafer can be suppressed in forming a metal layer.SOLUTION: In the present embodiment, a protective member 105 formed on a wafer 100 in a protective member forming step is also used in steps from a grinding step to an annular processing step. Thus, in the state where the wafer 100 is reinforced and protected by the protective member 105, the steps from the grinding step to the annular processing step can be carried out. Accordingly, the occurrence of cracking of the wafer 100 can be suppressed in forming the metal layer 113.SELECTED DRAWING: Figure 3

Description

The present invention relates to a wafer processing method.

As disclosed in Patent Document 1, the TAIKO wafer is formed by grinding a central portion of a disk-shaped wafer, has a concave portion in the central portion, and has an annular convex portion around the central portion. .. In the technique described in this document, the opposite surface of the recess of the TAIKO wafer is attracted and held by an electrostatic chuck in the vacuum chamber, and a metal layer is formed on the bottom surface of the recess in the vacuum chamber.

Japanese Unexamined Patent Publication No. 2007-019461

In the TAIKO wafer, the recess is thinned to have a thickness of 150 μm or less by grinding a wafer having a thickness of about 700 μm. Therefore, the thickness changes abruptly at the boundary between the concave portion and the annular convex portion. When such a TAIKO wafer is attracted and held by an electrostatic chuck to form a metal layer on the bottom surface of the recess, the TAIKO wafer may crack at the boundary between the recess and the annular convex portion.
As a cause of this cracking, for example, the facts shown in the following (1) to (4) can be considered.

(1) In a TAIKO wafer, the boundary between the bottom surface of the recess and the annular convex portion, which has been ground and thinned by grinding to form the recess, may lose a slight flatness. Since the electrostatic chuck sucks the opposite surface (lower surface) of the bottom surface of the concave portion of the TAIKO wafer with a strong suction force by the flat suction surface, the boundary between the concave portion and the annular convex portion of the uneven TAIKO wafer is broken by the suction. ..

(2) The TAIKO wafer has a strong suction surface with strong adsorption force in a state where fine film debris on the inner wall of the vacuum chamber falls on the upper surface of the electrostatic chuck and is sandwiched between the upper surface of the electrostatic chuck and the lower surface of the TAIKO wafer. The TAIKO wafer is cracked by being attracted to.

(3) After forming the metal layer or the like, the TAIKO wafer is pushed up by a push-up pin in order to separate the TAIKO wafer from the suction surface of the electrostatic chuck. The impact of this push-up causes the TAIKO wafer to crack.

(4) The protective tape attached to the TAIKO wafer to form the recess is peeled off before the metal layer is formed. The protective tape is attached with a strong adhesive force to prevent the ingress of grinding water during grinding. A strong force is applied to the TAIKO wafer to peel off the protective tape having a strong adhesive force, and the TAIKO wafer is cracked.
Further, since the boundary between the thinned portion and the non-thinned portion of the TAIKO wafer is generated, an impact is applied at the time of tape peeling, and the TAIKO wafer is cracked.

Therefore, an object of the present invention is to prevent the TAIKO wafer from cracking during the formation of the metal layer.

The wafer processing method (the present processing method) according to the present invention is a wafer processing method in which a plurality of devices are formed in a region defined by a street on one surface, and the wafer is processed on one surface of the wafer. A protective member forming step of forming a protective member by covering the entire surface with a heat-resistant resin, and a concave portion and an annular convex portion along the outer periphery of the concave portion are formed by grinding the center of the other surface of the wafer. After the grinding step, the metal layer forming step of holding the wafer by the electrostatic chuck via the protective member and forming the metal layer on the bottom surface of the recess in the vacuum chamber, and the metal layer forming step, the said. A holding step of protecting the surface of the metal layer of the wafer with a dying tape and holding the wafer by a dying table via the dying tape, and along the outer periphery of the bottom surface of the wafer held by the dying table. From the protective member side, an annular processing step of performing an annular division process on the protective member and the wafer, and an annular convex portion removing step of removing the annular convex portion from the wafer after the annular processing step. After the annular convex portion removing step, the protective member removing step of removing the protective member from the wafer, and after the protective member removing step, the wafer is fragmented by cutting the wafer along the street. The protective member formed on the wafer in the protective member forming step is also used in the steps from the grinding step to the annular processing step.

In this processing method, an ultraviolet curable resin may be used as the resin.

In the present processing method, the protective member forming step is to spread the liquid resin over the entire surface of the one surface of the wafer, and to apply an external stimulus to the liquid resin to cure the liquid resin. May include.

Alternatively, in the present processing method, the protective member forming step involves arranging the sheet-shaped resin on one surface of the wafer and applying heat to the sheet-shaped resin to bring it into close contact with the wafer. It may be included. The wafer processing method according to claim 1.

Further, in the present processing method, the protective member removing step is performed by injecting air from the outside of the outer circumference of the protective member toward the outer circumference of the protective member to bring the protective member and one surface of the wafer together. It may include intervening air in between to blow off the protective member and remove it from the wafer.

In this processing method, the protective member formed on the wafer in the protective member forming step is also used in the steps from the grinding step to the annular machining step. Thereby, the steps from the grinding step to the annular processing step can be carried out in a state where the wafer is reinforced and protected by the protective member. Therefore, it is possible to prevent the wafer from cracking when the metal layer is formed.

It is a perspective view which shows the structure of a wafer. It is explanatory drawing which shows the protection member forming process. It is explanatory drawing which shows the protection member forming process. It is explanatory drawing which shows the grinding process. It is explanatory drawing which shows the grinding process. It is explanatory drawing which shows the metal layer formation process. It is explanatory drawing which shows the metal layer formation process. It is a perspective view which shows the structure of a work set. It is explanatory drawing which shows the holding process. It is explanatory drawing which shows the annular processing process. It is explanatory drawing which shows the annular processing process. It is explanatory drawing which shows the annular convex part removal process. It is explanatory drawing which shows the annular convex part removal process. It is explanatory drawing which shows the protection member removal process. It is explanatory drawing which shows the protection member removal process. It is explanatory drawing which shows the cutting process. It is explanatory drawing which shows the protection member forming process of another aspect. It is explanatory drawing which shows the protection member forming process of another aspect.

As shown in FIG. 1, the wafer 100, which is the processing target of the wafer processing method according to the present embodiment, is a disk-shaped semiconductor wafer. A grid-like street 102 is formed on the surface 101, which is one surface of the wafer 100. A plurality of devices 103 are formed in the area partitioned by the street 102. The back surface 104, which is the other surface of the wafer 100, does not have the device 103.

In this embodiment, the wafer 100 is divided to form a plurality of chips each including one device 103.
Therefore, in the present embodiment, the protective member forming step, the grinding step, the metal layer forming step, the holding step, the annular processing step, the annular convex portion removing step, the protective member removing step and the cutting step are carried out on the wafer 100. do.

(1) Protective member forming step In the protective member forming step, the protective member is formed by covering the entire surface 101 of the wafer 100 with a heat-resistant resin.

In this step, as shown in FIG. 2, the wafer 100 is set in the protective film forming apparatus 10. The protective film forming apparatus 10 includes a holding table 11 that holds the wafer 100 by the holding surface 14. The holding table 11 is formed in a disk shape smaller than the wafer 100. The holding surface 14 is formed of a porous material, and can hold the wafer 100 by suction by communicating with a suction source (not shown). The wafer 100 is held by the holding surface 14 of the holding table 11 so that the surface 101 faces upward.

Further, the protective film forming apparatus 10 is a liquid resin supply nozzle 12 for supplying the liquid resin 200 to the wafer 100 held on the holding table 11, and a rotation axis of the holding table 11, in a direction perpendicular to the holding surface 14. It includes an extending spindle 13. In this embodiment, the liquid resin 200 is a thermosetting resin.

The spindle 13 is arranged below the holding table 11 and is rotationally driven by a motor (not shown), for example, in the direction of arrow 301. As a result, the holding table 11 is rotated together with the spindle 13.

The liquid resin supply nozzle 12 communicates with a liquid resin supply source (not shown), and supplies the liquid resin 200 to the surface 101 of the wafer 100 which is held by the holding surface 14 and rotates together with the holding table 11 from above. As a result, the liquid resin 200 spreads over the entire surface 101 of the wafer 100.

Then, the liquid resin 200 is cured by applying an external stimulus to the liquid resin 200. In the present embodiment, the liquid resin 200 is cured by heating the liquid resin 200 with a heating device (not shown). As a result, as shown in FIG. 3, a protective member 105 made of a liquid resin 200 is formed on the surface 101 of the wafer 100 so as to cover the entire surface thereof.

The liquid resin 200 may be an ultraviolet curable resin. In this case, the liquid resin 200 contains, for example, a polyester resin as a main material and an acrylic resin as a diluent, and has a heat resistant temperature of about 200 degrees.

When an ultraviolet curable resin is used as the liquid resin 200, the liquid resin 200 is spread over the entire surface 101 of the wafer 100, and then the liquid resin 200 is irradiated with ultraviolet rays to form the protective member 105 on the surface 101.

(2) Grinding Step In the grinding step (TAIKO grinding step), a concave portion and an annular convex portion along the outer periphery of the concave portion are formed on the back surface 104 by grinding the center of the back surface 104 of the wafer 100.

In this step, as shown in FIG. 4, the wafer 100 on which the protective member 105 is formed is set in the grinding device 20. The grinding apparatus 20 includes a chuck table 21 that holds the wafer 100 by the holding surface 22. The holding surface 22 is formed of a porous material, and can hold the wafer 100 by suction by communicating with a suction source (not shown). The wafer 100 is held by the holding surface 22 of the chuck table 21 via the protective member 105 so that the back surface 104 faces upward.

Further, the grinding device 20 has a grinding means 23 for grinding the back surface 104 of the wafer 100 above the chuck table 21. The grinding means 23 includes a spindle 24 extending in a direction perpendicular to the holding surface 22, a mount 25 attached to the tip of the spindle 24, and a plurality of grinding wheels 26 arranged in an annular shape on the lower surface of the mount 25.

In the grinding step, the outer edge of the grinding wheel 26 is arranged inside the wafer 100 by a predetermined distance 401 with the grinding means 23 arranged above the wafer 100. In this state, the spindle 24 is rotationally driven by a motor (not shown), for example, as shown by an arrow 303, so that the mount 25 and the grinding wheel 26 attached to the lower end of the spindle 24 are rotated.

After that, the grinding means 23 is grounded downward toward the wafer 100 held on the holding surface 22. Further, the chuck table 21 is rotated by a drive source (not shown). As a result, the rotating grinding wheel 26 comes into contact with the back surface 104 of the wafer 100 held on the holding surface 22 of the rotating chuck table 21, and the back surface 104 is ground.

In this grinding, the outer edge of the grinding wheel 26 is arranged inside the outer circumference of the wafer 100 by a predetermined distance 401. Therefore, the grinding wheel 26 grinds the center of the back surface 104 of the wafer 100. As a result, as shown in FIG. 5, a recess (circular recess) 110 having a bottom surface 111 is formed on the back surface 104 of the wafer 100. Further, an annular convex portion 112 is formed along the outer circumference of the concave portion 110.

By forming the concave portion 110 and the annular convex portion 112 on the back surface 104 of the wafer 100 in this way, the wafer 100 can be made into a TAIKO wafer. That is, the wafer 100 whose center is thinned is reinforced by the annular convex portion 112 on the outer circumference. Therefore, for example, it is possible to prevent the wafer 100 from being damaged when the wafer 100 is conveyed to an apparatus that forms a metal layer on the bottom surface 111 of the recess 110.

(3) Metal Layer Forming Step In the metal layer forming step, a metal layer is formed on the bottom surface 111 of the recess 110 formed on the back surface 104 of the wafer 100.
In this step, as shown in FIG. 6, the wafer 100 on which the concave portion 110 and the annular convex portion 112 are formed is set in the vacuum film forming apparatus 30.

In the reduced pressure film forming apparatus 30, an electrostatic chuck 32 is provided inside a chamber 31 which is a vacuum chamber. The electrostatic chuck 32 holds the wafer 100 via the protective member 105 in an electrostatic manner. A sputter source 34 made of metal is arranged above the electrostatic chuck 32 at a position facing the electrostatic chuck 32 in a state of being supported by the exciting member 33. A high frequency power supply 35 is connected to the sputter source 34.

Further, a sputter gas introduction port 36 is provided on one side of the chamber 31. Through the sputter gas introduction port 36, a sputter gas such as argon gas is introduced into the chamber 31 as shown by an arrow 305. On the other side of the chamber 31, a decompression port 37 communicating with a decompression source (not shown) is provided.

In the vacuum film forming apparatus 30, the wafer 100 is electrostatically held by the electrostatic chuck 32 via the protective member 105, so that the bottom surface 111 of the recess 110 of the wafer 100 faces the sputter source 34. Further, the annular convex portion 112 of the wafer 100 is masked (not shown).

Then, the sputter source 34 which is magnetized by the excitation member 33, from the high frequency power source 35, for example with addition of a high frequency power of about 13.56 MHz, via a vacuum port 37, the inside of the chamber ^31, 10 -2 Pa to 10 ^The pressure is reduced to about -4 Pa, and the sputter gas is further introduced from the spatter gas introduction port 36.

As a result, plasma is generated, ions in the plasma collide with the sputtering source 34, metal particles are ejected, and the ejected metal particles are deposited on the bottom surface 111 of the recess 110 of the wafer 100. In this way, as shown in FIG. 7, the metal layer 113 is formed on the bottom surface 111 of the recess 110. The metal layer 113 has a thickness of, for example, about 30 to 60 nm.
In this metal layer forming step, the metal layer 113 may be formed on the bottom surface 111 of the recess 110 of the wafer 100 by using thin film deposition, CVD, or the like.

After that, the protective member 105 formed on the wafer 100 is pushed up from below by a lift pin (not shown) provided on the electrostatic chuck 32. As a result, the protective member 105 and the wafer 100 are removed from the electrostatic chuck 32.

(4) Holding step The holding step is carried out after the metal layer forming step. In the holding step, first, as shown in FIG. 8, the dicing tape 122 is attached to the back surface 104 side, which is the surface of the wafer 100 on which the metal layer 113 is formed. Further, the ring frame 121 is attached to the outer circumference of the dicing tape 122.

As a result, the wafer 100 is integrated with the ring frame 121 via the dicing tape 122 in a state where the protective member 105 is exposed. As a result, the work set 120 including the wafer 100, the dicing tape 122 and the ring frame 121 is formed. Further, the surface of the metal layer 113 formed on the bottom surface 111 of the recess 110 of the wafer 100 is protected by the dicing tape 122.

After that, the work set 120 including the wafer 100 is set in the cutting device 40 as shown in FIG. The cutting device 40 includes a dicing table 41 that holds the wafer 100 by the holding surface 42 via the dicing tape 122. The holding surface 42 is formed of a porous material, and can hold the wafer 100 by suction by communicating with a suction source (not shown).

Further, around the dicing table 41, a clamp 43 for holding the ring frame 121 of the work set 120 is provided. The work set 120 is held on the dicing table 41 by the holding surface 42 and the clamp 43.

(5) Circular Processing Step In the annular processing step (annular groove forming step), the outer periphery of the bottom surface 111 of the concave portion 110 of the wafer 100 held on the dicing table 41, that is, along the boundary between the concave portion 110 and the annular convex portion 112. From the side of the protective member 105, the protective member 105 and the wafer 100 are subjected to an annular division process (circle cut).

As shown in FIG. 9, a dicing table spindle 44 extending in a direction perpendicular to the holding surface 42 is provided on the lower surface of the dicing table 41. The dicing table spindle 44 rotates the dicing table 41 by being driven by a motor (not shown).

A cutting mechanism 45 is arranged above the dicing table 41. The cutting mechanism 45 includes a blade spindle 46 extending in the horizontal direction parallel to the holding surface 42, and a cutting blade 47 provided at the tip of the blade spindle 46 extending parallel to the surface perpendicular to the holding surface 42.

In the annular processing step, the cutting blade 47 is arranged on the boundary between the concave portion 110 and the annular convex portion 112 in the wafer 100 held on the dicing table 41. Then, as shown in FIG. 10, the dicing table spindle 44 rotates the dicing table 41 as shown by, for example, arrow 307. Further, the blade spindle 46 lowers the cutting mechanism 45 toward the wafer 100 held on the holding surface 42 while rotating the cutting blade 47 as shown by, for example, arrow 309.

As a result, the protective member 105 and the wafer 100 are subjected to annular division processing from the side of the protective member 105 along the boundary between the concave portion 110 and the annular convex portion 112. By such division processing, as shown in FIG. 11, a division groove 125 is formed along the boundary between the concave portion 110 and the annular convex portion 112, and the annular convex portion 112 is cut from the wafer 100.

(6) Annular convex portion removing step The annular convex portion removing step is carried out after the annular processing step. In the annular convex portion removing step, the annular convex portion 112 is removed from the wafer 100.

In this step, as shown in FIG. 12, the transport means 48 is arranged above the dicing table 41 holding the wafer 100 in which the dividing groove 125 is formed. The transport means 48 includes a base 49 extending in the horizontal direction and a pair of lower support portions 50 provided at both ends of the base 49 and extending in the vertical direction. Further, the transport means 48 includes a vertical moving means 51 that moves the base 49 and the lower support portion 50 in the vertical direction, and a horizontal moving means 52 that moves the base 49, the lower support portion 50, and the vertical moving means 51 in the horizontal direction. I have.

In the transport means 48, the vertical movement means 51 causes the base 49, the lower support portion 50, and the vertical movement means 51 to be arranged in the horizontal direction so that the pair of lower support portions 50 are arranged above the annular convex portion 112 in the wafer 100. Move to. After that, the base 49 and the lower support portion 50 are lowered by the vertical moving means 51, and the hook-shaped tip of the lower support portion 50 supports the lower surface of the annular convex portion 112 from the outside. In this state, the base 49 and the lower support portion 50 are moved upward by the vertical moving means 51. As a result, as shown in FIG. 13, the annular convex portion 112 is removed from the wafer 100.

(7) Protective member removing step The protective member removing step is carried out after the annular convex portion removing step. In the protective member removing step, the protective member 105 is removed from the wafer 100.

In this step, as shown in FIG. 14, the air injection device 55 is arranged on the outer side of the wafer 100 and the protective member 105 held on the holding surface 42 of the dicing table 41 in a state where the annular convex portion 112 is removed. Will be done. The air injection device 55 includes an air injection nozzle 56 and an air supply source 57 that communicates with the air injection nozzle 56.

The air injection device 55 injects air from the outside of the outer circumference of the protective member 105 toward the outer circumference of the protective member 105 by using the air injection nozzle 56. As a result, the air injection device 55 intervenes air between the protective member 105 and the back surface 104 of the wafer 100 to blow off the protective member 105 and remove the protective member 105 from the wafer 100, as shown in FIG. do.

(8) Cutting step The cutting step is carried out after the protective member removing step. In the cutting step, the wafer 100 is fragmented by cutting the wafer 100 along the street 102 (see FIG. 1).

In this step, as shown in FIG. 16, the cutting mechanism 45 is arranged above the wafer 100 held on the holding surface 42 of the dicing table 41 with the protective member 105 removed.

In the cutting mechanism 45, the cutting blade 47 is arranged along the street 102 on the wafer 100. Then, the cutting blade 47 is rotated by the blade spindle 46 as shown by, for example, arrow 311. In this state, the cutting blade 47 is lowered until the lower end of the cutting blade 47 touches the dicing tape 122 of the work set 120, and then the cutting blade 47 is moved horizontally along the street 102 as shown by an arrow 313. Move. As a result, the wafer 100 can be cut along the street 102.

By cutting the wafer 100 along all the streets 102 in this way, the wafer 100 can be made into small pieces. By peeling the fragmented wafer 100 from the dicing tape 122, a plurality of chips including one device 103 (see FIG. 1) can be obtained.

As described above, in the present embodiment, the protective member 105 formed on the wafer 100 in the protective member forming step is also used in the steps from the grinding step to the annular processing step. Thereby, the steps from the grinding step to the annular processing step can be carried out in a state where the wafer 100 is reinforced and protected by the protective member 105. Therefore, it is possible to prevent the wafer 100 from cracking when the metal layer 113 is formed.

That is, in the present embodiment, in the metal layer forming step, the wafer 100 is attracted and held by the electrostatic chuck 32 (see FIG. 6) via the protective member 105. Therefore, even if the wafer 100 is slightly lost in flatness or the wafer 100 is adsorbed by the electrostatic chuck 32 with a strong adsorption force in the state where the film-deposited debris is present on the electrostatic chuck 32, it is protected. Since the wafer 100 is reinforced and protected by the member 105, it is possible to prevent the wafer 100 from cracking.

Further, when the wafer 100 is removed from the electrostatic chuck 32, the protective member 105 formed on the wafer 100 is pushed up by the lift pin. Therefore, it is possible to prevent the impact from the lift pin from being directly transmitted to the wafer 100, so that the wafer 100 is prevented from cracking.

Further, since the protective member 105 is formed, the wafer 100 is less likely to bend. Therefore, even when the center of the wafer 100 is pushed up by one lift pin, cracking of the wafer 100 due to bending can be suppressed.

Further, in the present embodiment, the protective member 105 can be removed from the wafer 100 by air injection from the air injection device 55, as shown in FIGS. 14 and 15.
That is, the adhesive strength of the protective member 105 is smaller than that of a general protective tape. Therefore, the protective member 105 can be easily removed (peeled) from the wafer 100 by injecting air. Therefore, when the protective member 105 is removed from the wafer 100, it is possible to avoid applying a strong force that causes cracks in the wafer 100 to the wafer 100. Further, since the protective member 105 can be removed in a short time, the work efficiency can be improved.

Further, in the present embodiment, after the metal layer 113 is formed on the wafer 100, an annular processing step is performed on the wafer 100 in which the protective member 105 is formed, and the concave portion 110 and the annular convex portion 112 are formed. A dividing groove 125 is formed along the boundary. That is, in the present embodiment, the annular convex portion 112 is cut from the wafer 100 together with the protective member 105 for suppressing the cracking of the wafer 100. Therefore, it is possible to reduce the chipping that may occur on the cut surface that is the outer periphery of the wafer 100 when the annular convex portion 112 is cut. As a result, it is possible to prevent the wafer 100 from cracking starting from the chipping formed on the outer periphery in the cutting step of cutting the wafer 100 into small pieces.

In the present embodiment, as shown in FIG. 2, in the protective member forming step, the protective member 105 is formed on the wafer 100 by using the liquid resin 200.
Instead, in the protective member forming step, as shown in FIG. 17, the sheet-shaped resin 130 made of a thermosetting resin is arranged on the surface 101 of the wafer 100, and heat is applied to the sheet-shaped resin 130. It may be configured to include being brought into close contact with the wafer 100. As shown in FIG. 18, the protective member 131 made of the sheet-shaped resin 130 can also be formed on the surface 101 of the wafer 100. Further, grains or pellets made of thermosetting resin are arranged on one surface so as to cover the surface 101 of the wafer 100, and heat is applied to the grains or pellets to bring them into close contact with the wafer to form a protective member 105. May be good.
The thermosetting resin forming the protective members 105 and 131 is formed of a polyolefin resin, a urethane resin, a chloride resin (vinyl chloride, vinylidene chloride, etc.), an acrylic resin, etc., and is used when forming a metal film. It has heat resistance and adhesive force (peeling property) that can be peeled off by air injection.
The removal of the protective member is not limited to air injection. A mixed liquid in which air and water are mixed may be injected from an air injection device. Further, mixed air in which powder is mixed with air may be injected.

10: Protective film forming device, 12: Liquid resin supply nozzle, 200: Liquid resin,
11: Holding table, 13: Spindle, 14: Holding surface,
20: Grinding device, 21: Chuck table, 22: Holding surface,
23: Grinding means, 24: Spindle, 25: Mount, 26: Grinding wheel,
30: Decompression film forming apparatus, 31: Chamber, 32: Electrostatic chuck,
33: Exciting member, 34: Spatter source, 35: High frequency power supply,
36: Sputter gas inlet, 37: Decompression port,
40: Cutting device, 41: Dicing table, 42: Holding surface, 43: Clamp,
44: Dicing table spindle,
45: Cutting mechanism, 46: Blade spindle, 47: Cutting blade,
48: Conveying means, 49: Substrate, 50: Lower support,
51: Vertical movement means, 52: Horizontal movement means,
55: Air injection device, 56: Air injection nozzle, 57: Air supply source,
100: Wafer, 101: Front side, 104: Back side,
102: Street, 103: Device, 105: Protective material,
110: concave part, 111: bottom surface, 112: annular convex part, 113: metal layer,
120: Workset, 121: Ring frame, 122: Dicing tape,
130: Sheet resin, 131: Protective member

Claims (5)

A method of processing a wafer in which a plurality of devices are formed in an area partitioned by a street on one surface.
A protective member forming step of forming a protective member by coating one surface of the wafer with a heat-resistant resin on the entire surface.
A grinding step of forming a recess and an annular protrusion along the outer circumference of the recess by grinding the center of the other surface of the wafer.
A metal layer forming step of holding the wafer by an electrostatic chuck via the protective member in a vacuum chamber and forming a metal layer on the bottom surface of the recess.
After the metal layer forming step, a holding step of protecting the surface of the metal layer of the wafer with a dicing tape and holding the wafer by a dicing table via the dicing tape.
An annular processing step of performing an annular division process on the protective member and the wafer from the protective member side along the outer circumference of the bottom surface of the wafer held on the dicing table.
After the annular processing step, an annular convex portion removing step of removing the annular convex portion from the wafer,
After the annular convex portion removing step, a protective member removing step of removing the protective member from the wafer, and a protective member removing step.
After the protective member removing step, the wafer is fragmented by cutting the wafer along the street.
The protective member formed on the wafer in the protective member forming step is also used in the steps from the grinding step to the annular processing step.
Wafer processing method. An ultraviolet curable resin is used as the resin.
The wafer processing method according to claim 1. The protective member forming step is
Spreading the liquid resin over the entire surface of the one surface of the wafer, and
The liquid resin is cured by applying an external stimulus to the liquid resin.
The wafer processing method according to claim 1. In the protective member forming step, the sheet-like resin is arranged on one surface of the wafer, and the protective member forming step is performed.
Including applying heat to the sheet-shaped resin to bring it into close contact with the wafer.
The wafer processing method according to claim 1. The protective member removing step is
By injecting air from the outside of the outer circumference of the protective member toward the outer circumference of the protective member, the air is intervened between the protective member and one surface of the wafer to blow off the protective member. Including removing from the wafer,
The wafer processing method according to claim 1.

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