WAFER PROCESSING PROCESS

Abstract

Wafer processing method comprising: a protective film provisioning step with a provision of a protective film (21) on the front face (11a) of a wafer (11) having a component area (11d) where a plurality of components (15) are formed, each having a bump, and a circumferential edge area (11e) surrounding the component area (11d) in the state in which the component area (11d) is covered with the protective film (21), and then bringing the protective film (21) into close contact without adhesive with the front face (11a) of the wafer (11) in order to follow the shape of the bump;a wafer unit formation step comprising applying a liquid resin (25), which is curable by an external stimulus, to the front side (11a) of the wafer (11) and then curing the liquid resin (25) by applying the external stimulus to form a protective element (27) that covers the protective film (21) and the peripheral edge region (11e) of the wafer (11), thereby forming a wafer unit constructed with the wafer (11), the protective film (21) and the protective element (27) in the state in which the front side (11a) of the wafer (11) is covered with the protective element (27); a grinding step comprising holding the protective element (27) of the wafer unit against a holding surface (44a) of a clamping table (44) and then grinding the rear side (11b) of the wafer (11) of the wafer unit to thereby to reduce the thickness of the wafer (11);and a peeling step involving peeling the protective element (27) and the protective film (21) from the wafer (11), which is reduced in thickness.;

Description

Background of the invention; Field of the invention

[0001] The present invention relates to a wafer processing method for use in grinding a wafer which has an unevenness on its front side. Description of the relevant state of the art

[0002] There are numerous instances where a wafer is processed for thinning before being subdivided into component chips to reduce the size and weight of each chip used in various electronic devices or similar applications. For example, the wafer can be thinned by grinding in such a way that it is held on a clamping table with the front face of the wafer, on which the components are formed, facing the top surface of the table, and a rotating grinding wheel is brought into contact with the back face of the wafer held on the table.

[0003] When grinding a wafer using such a method, a protective element is typically applied to the front side of the wafer (see, for example, the Japanese patent number Hei 10-50642). This prevents damage to the components formed on the front side of the wafer from grinding pressure applied during the process. For example, the protective element can be provided by an adhesive strip made of resin or a similar material, or by a relatively hard substrate. SUMMARY OF THE INVENTION

[0004] Often, an irregularity, such as contact bumps, is formed on the front side of the wafer, with the contact bumps serving as electrodes for each component. However, if such an irregularity is present on the front side of the wafer, the resulting height difference cannot be sufficiently reduced by the adhesive tape, so that the shape corresponding to the irregularity appears on the back side of the wafer after grinding.

[0005] This problem rarely arises when using a relatively hard substrate as a protective element. However, this substrate is bonded to the wafer using an adhesive, such as thermoplastic wax. Consequently, when removing the substrate from the wafer after grinding, an additional step is necessary, such as immersion in a solution or heating.

[0006] It is therefore an object of the present invention to provide a wafer processing method that can sufficiently reduce the influence of the unevenness present on the front side of the wafer when grinding the rear side of the wafer and can also eliminate the need for any additional process after grinding the wafer.

[0007] In accordance with one aspect of the present invention, a wafer processing method is provided which includes: a protective film provisioning step comprising providing a protective film to the front side of a wafer, which forms a component area where a plurality of components, each having a bump, is formed and which has a circumferential edge area surrounding the component area in the state in which the component area is covered with the protective film, and the protective film is then brought into close contact with the front side of the wafer to follow the shape of the bump;a wafer unit formation step comprising the application of a liquid resin, curable by an external stimulus, to the front face of the wafer, followed by the curing of the liquid resin by the application of the external stimulus to form a protective element covering the protective film and the peripheral edge region of the wafer, thereby forming a wafer unit consisting of the wafer, the protective film, and the protective element in the state where the front face of the wafer is covered with the protective element; a grinding step comprising holding the protective element of the wafer unit against a holding surface of a clamping table, followed by grinding the rear face of the wafer unit to reduce the thickness of the wafer; and a peeling step comprising peeling the protective element and the protective film from the wafer, which has been reduced in thickness.

[0008] Preferably, an edge section between the outer circumference of the wafer and the front side of the wafer is chamfered, and the front side of the wafer is covered with a protective element to enclose the edge section that is chamfered during the wafer unit formation step.

[0009] Preferably, the wafer unit formation step includes the steps of applying the liquid resin to a flat sheet, nextly pressing the wafer over the protective film against the liquid resin applied to the flat sheet, and nextly hardening the liquid resin by applying the external stimulus in order to fix the protective element to the wafer.

[0010] Preferably, the protective film provisioning step includes the steps of pressing the protective film against the front side of the wafer under a reduced pressure and next applying atmospheric pressure to the protective film in order to bring the protective film into close contact with the front side of the wafer in order to follow the shape of the irregularity.

[0011] Preferably, the protective film deployment step includes the step of applying pressure to the protective film via a cushion in order to press the protective film against the front side of the wafer.

[0012] Preferably, the protective film deployment step includes the step of attaching a weight to the protective film via a pad, thereby pressing the protective film against the front face of the wafer. More preferably, the protective film deployment step includes the steps of attaching the weight to the protective film via the pad under atmospheric pressure and, next, loading the wafer into a vacuum chamber in the state in which the weight is attached to the wafer.

[0013] Preferably, the protective film provisioning step includes the steps of loading the wafer into a vacuum chamber in the state in which the component area is covered with the protective film, and next, using a pressure means belonging to the vacuum chamber to press the protective film against the front side of the wafer.

[0014] In the wafer processing method according to the present invention, the component area where the components, each exhibiting irregularities, are formed, is first covered with the protective film. The protective film is then brought into close contact with the component area to conform to the shape of the irregularity. Subsequently, the liquid resin, which is curable by an external stimulus, is applied to the front face of the wafer and then cured to form the protective element, which covers the protective film and the peripheral edge area. Consequently, the wafer assembly, consisting of the wafer, the protective film, and the protective element, is formed in such a way that the front face of the wafer is covered by the protective element over the protective film. Since the protective element has sufficient thickness, the influence of the irregularity formed on the front face of the wafer can be adequately reduced.

[0015] Furthermore, in the wafer processing method according to the present invention, the protective film is not adhered to the component area, but merely held in close contact with it. Accordingly, it is not necessary to perform a special process for removing the protective film, such as immersion in a solution or heating. This means that the protective film and the protective element can be easily peeled off the wafer. As described above, the influence of the unevenness present on the front side of the wafer can be sufficiently reduced during grinding of the back side of the wafer. Moreover, no additional process is necessary after grinding the wafer.

[0016] Furthermore, in the wafer processing process according to the present invention, the protective film and the peripheral edge region of the wafer are covered with the protective element, which is formed from a liquid resin curable by an external stimulus. This means that the protective element is fixed to the peripheral edge region of the wafer. Although the protective film, which does not have adhesion via an adhesive, is used, there is no possibility that the protective film and the protective element will be peeled off the wafer during grinding.

[0017] The above and other tasks, features and advantages of the present invention and the manner of its implementation will become clearer by studying the following description and attached claims with reference to the accompanying drawings, which show some preferred embodiments of the invention, and the invention itself will be best understood by this. List of characters Fig. 1A is a schematic perspective view showing one way of covering the front side of a wafer with a protective film; Fig. 1B is a schematic perspective view showing the state where the front side of the wafer is covered with the protective film; Fig. 2A is a schematic sectional view showing one way of pressing the protective film onto the front side of the wafer; Fig. 2B is a schematic sectional view showing one way of bringing the protective film into close contact with the front side of the wafer; Fig. 2C is a schematic sectional view showing the state in which the protective film is in close contact with the front side of the wafer; Fig. 3A is a schematic sectional view showing one way of pressing the wafer over the protective film against a liquid resin that has previously been applied to a sheet; Fig. Figure 3B is a schematic sectional view showing one way of curing the liquid resin to form a protective element, thereby attaching the protective element to the wafer; Fig. 3C is a schematic sectional view of a wafer unit formed by attaching the protective element to the wafer; Fig. 4A is a schematic sectional view showing one way of grinding the back of the wafer; Fig. 4B is a schematic sectional view showing the state where the back side of the wafer has been ground; Fig. Figure 5 is a schematic sectional view showing one way of peeling the protective film, the protective element and the sheet from the wafer; the Fig. 6A, Fig. 6B and Fig. Figure 6C are schematic sectional views representing a first modification of the protective film deployment step; and the Fig. 7A and Fig. Figure 7B shows schematic sectional views representing a second variation of the protective film deployment step. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0018] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. The wafer processing method in accordance with this preferred embodiment includes a protective film deployment step (see Fig. 1A, Fig. 1B, Fig. 2A, Fig. 2B and Fig. 2C), a wafer unit training step (see Fig. 3A, Fig. 3B and Fig. 3C), a grinding step (see Fig. 4A and Fig. 4B) and a peeling step (see Fig. 5) In the protective film provisioning step, a protective film, which has no adhesive strength, is brought into close contact with the front face of a wafer by means of an adhesive (glue) such that the protective film follows the uneven shape provided on the front face of the wafer. In the wafer unit formation step, the protective film is covered with a protective element formed from a liquid resin to form a wafer unit consisting of the wafer, the protective film, and the protective element. In the grinding step, the back side of the wafer is ground in the state in which the protective element of the wafer unit is held against a clamping surface of a worktable. In the peeling step, the protective element and the protective film are peeled from the wafer, which has been thinned by the grinding step. These steps of the wafer processing method in accordance with this preferred embodiment are now described in detail.

[0019] In the wafer processing method according to this preferred embodiment, the protective film provisioning step is first carried out in such a way that a protective film, which has no adhesive force, is brought into close contact with the front face of a wafer by means of an adhesive agent, such that the protective film follows the uneven shape provided on the front face of the wafer. In particular, the front face of the wafer is first covered with a protective film, which has no adhesive layer, and the protective film is then brought into close contact with the front face of the wafer.

[0020] Fig. 1A is a schematic perspective view showing one way of covering the front side of a wafer. 11 with a protective film 21 shows, and Fig. 1B is a schematic perspective view showing the state in which the front side of the wafer is 11with the protective film 21 is covered. As in Fig. As shown in 1A, the wafer 11 a disc-shaped element with a front side 11a and a rear side 11b For example, the wafer 11 formed with silicon (Si). The wafer 11 has an outer circumference 11c on, with the edge between the outer circumference 11c and the front 11a is chamfered and the edge between the outer circumference 11c and the back 11b is also chamfered. The front side 11a of the wafer 11 is with a central component area 11d and a circumferential border area 11e built up, which covers the component area 11d surrounds the component area 11d is formed by a multitude of intersecting dividing lines (streets) 13subdivided to define a multitude of separate areas where a multitude of building elements are located. 15 , such as how integrated circuits (ICs) are formed. A multitude of contact bumps (unevenness) 17 , which serve as electrodes, are located on the front side of each component 15 provided for. For example, each contact bump 17 formed with solder. Although the wafer 11 In this preferred embodiment, the wafer is a disk-shaped element formed with silicon. 11 not limited to this material, this shape, this structure, this size, etc. For example, the wafer 11 They can be made with any other semiconductors, ceramics, resins, or metals. Likewise, the components are 15 and the contact bumps 17not limited to this type, quantity, shape, structure, size, arrangement, etc. For example, the contact bumps 17 They can be replaced by any structures (unevenness) with other functions. In other words, the contact bumps can be replaced. 17 from the front 11a of the wafer 11 omitted.

[0021] During the protective film application step, the component area 11d of the wafer 11 first with the protective film 21 covered. The protective film 21 It is a soft film, formed, for example, from resin. The protective film 21 is a circular element with a size (diameter) that corresponds to the size of the component area 11d corresponds. That is, the diameter of the protective film. 21 is smaller than the diameter of the wafer 11 The protective film 21It has no adhesive layer. Although not specifically limited to this, the thickness of the protective film is 21 For example, preferably set to approximately 30 to 150 µm. As in Fig. As shown in 1A, the protective film 21 on the front 11a of the wafer 11 placed in such a way that the outer perimeter of the protective film 21 with the outer perimeter of the component area 11d , that is, the boundary between the component area 11d and the circumferential border area 11e , agrees, so that the component area 11d of the wafer 11 completely with the protective film 21 is covered. In other words, the perimeter boundary area is 11e of the wafer 11 , as in Fig. 1B shown, exposed.

[0022] After covering the front side 11a (more precisely, the component sector) 11d ) of the wafer 11with the protective film 21 , the protective film 21 with the front side 11a of the wafer 11 brought into close contact in the following way. Fig. 2A is a schematic sectional view showing one way of pressing down the protective film. 21 to the front 11a of the wafer 11 represents. Fig. 2B is a schematic sectional view showing one way of bringing the protective film into close contact. 21 with the front side 11a of the wafer 11 represents. Fig. 2C is a schematic sectional view showing the state in which the protective film is 21 with the front side 11a of the wafer 11 is in close contact. In particular, a weight 4 , as in Fig. 2A shown, under ambient pressure over a cushion 2 , such as a foam, on the front side 11a of the wafer 11(more precisely, on the protective film) 21 , the front side 11a (covered) mounted to thereby protect the protective film 21 against the front side 11a of the wafer 11 to press. In other words, pressure is applied across the padding. 2 on the protective film 21 applied, thereby the protective film 21 against the front side 11a of the wafer 11 Pressing is involved. As a result, part of the protective film is removed. 21 with the front side 11a of the wafer 11 brought into contact.

[0023] Then the wafer 11 into a low-pressure chamber 6 loaded in the state in which the weight 4 , as in Fig. 2B shown on the wafer 11 is appropriate. The vacuum chamber 6 closes a case 6a , which has an upper opening of a size that allows the passage of the wafer 11allows, and a door 6b to close the top opening of the housing 6a one. The case 6a is via an air outlet pipe 8 and a valve 10 connected to a negative pressure source (not shown), wherein the air in the negative pressure chamber 6 through the air outlet pipe 8 is removed. Furthermore, an air intake pipe is... 12 and a valve 14 with the case 6a connected, with the outside air (atmosphere) passing through the air intake pipe 12 into the low-pressure chamber 6 is being vacuumed. A support table 16 to support the wafer 11 is in the case 6a provided. The support table 16 has a substantially flat upper surface which serves as a support surface 16a to support the wafer 11 serves as a support surface. 16a is equipped with a protruding guide section 16bfor positioning the wafer 11 equipped with a heating device 18 to heat up the protective film 21 is in the support table 16 installed. The door will be in operation. 6b opened first to access the wafer 11 through the top opening of the case 6a into the low-pressure chamber 6 to load in the state in which the weight 4 over the cushion 2 on the front side 11a of the wafer 11 is attached, which is with the protective film 21 is covered. After the wafer 11 on the support surface 16a of the support table 16 is supported so that he gets through the leadership section 16b once positioned, the door will 6b , as in Fig. 2B shown, closed and the valve 14 will be closed next. Furthermore, the valve will be closed. 10 opened to allow access to the interior of the vacuum chamber 6to evacuate. As a result, the protective film 21 due to the weight 4 under reduced pressure on the front side 11a of the wafer 11 pressed. Furthermore, the gas (air) that is between the front side 11a of the wafer 11 and the protective film 21 remains, removed.

[0024] After the interior of the low-pressure chamber 6 Once the area is sufficiently evacuated, the valve will open. 10 closed and next the valve 14 opened to allow outside air (atmosphere) into the interior of the low-pressure chamber 6 to introduce. As a result, atmospheric pressure is exerted on the protective film. 21 exercised, so that the protective film 21 with the front side 11a of the wafer 11 can be brought into close contact so that it takes the shape of the contact bumps 17 , as in Fig. 2C is shown below, which is on the front side.11a of the wafer 11 are provided for. When atmospheric pressure is applied to the protective film. 21 can the heating device 18 must be activated to remove the protective film 21 to heat it up and thereby soften it. In this case, the protective film can 21 with the wafer 11 to be brought into contact in a simpler way.

[0025] After the protective film provisioning step has been executed, the wafer unit training step is performed in such a way that the protective film 21 is covered with a protective element formed from a liquid resin to form a wafer unit that is connected to the wafer 11 , the protective film 21 and is built upon the protective element, with the front side 11a of the wafer 11 is covered with the protective element. Fig. Figure 3a is a schematic sectional view showing one way of pressing the wafer. 11 about the protective film 21 represents a liquid resin that has previously been applied to a sheet. Fig. 3B is a schematic sectional view showing one way of curing the liquid resin to form a protective element, thereby bonding the protective element to the wafer. 11 is attached. Fig. 3C is a schematic sectional view of a wafer unit, which is created by fixing the protective element to the wafer. 11 is trained. Fig. 3A and Fig. In 3B, some of the components are represented by a function block.

[0026] The wafer unit training step is carried out using a protective element fixation device. 22 executed, which in the Fig. 3A and Fig. 3B is shown. The protective element fixing device 22 closes a holding table24 to hold an essentially flat arch (supporting arch) 23 on, which is made, for example, of a resin. The upper surface of the holding table 24 has a circular cutout 24a formed, which has a diameter larger than that of the wafer 11 An ultraviolet light source 26 is inside the recess 24a provided. The upper end of the recess 24a is with a plate 28 covered, which is capable of transmitting at least some of the ultraviolet light emitted from the source of ultraviolet light 26 is emitted. A central part of the arc 23 is set up, through the plate 28 to be supported. One suction pass 24b to draw in a circumferential section of the bow 23 is in the holding table 24 trained. An end to the suction passage 24bopens to the upper surface around the recess 24a of the holding table 24 , and the other end of the suction passage 24b is via a valve 30 with a vacuum source 32 connected. By applying a vacuum through the vacuum source. 32 via the suction passage 24b on the circumferential section of the arc 23 , the bow 23 under suction force on the holding table 24 held. A wafer holding unit 34 to hold the wafer 11 Under suction power, it is above the holding table 24 planned. The wafer holding unit 34 is supported by a movement mechanism not shown. The wafer 11 is set up to work on a lower surface 34a the wafer holding unit 34 to be held under suction. The wafer holding unit 34 held wafers 11It can be moved in a vertical direction by activating the movement mechanism.

[0027] In the wafer unit training step, a liquid resin is applied beforehand. 25 to the upper surface of the arch 23 applied, and the lower surface of the arch 23 will be, as in Fig. 3A shown, at the holding table 24 held. On the other hand, the back side 11b of the wafer 11 , as in Fig. 3A shown, on the lower surface 34a the wafer holding unit 34 held. Accordingly, the protective film is located 21 , the one with the front side 11a the wafer is kept in close contact with the liquid resin 25 opposite, which is on the arch 23 is applied. In this preferred embodiment, the liquid resin 25 an ultraviolet light curable resin that is capable of curing by ultraviolet light from a source 26to be cured by emitted ultraviolet light. For example, TEMPLOC (registered trademark), manufactured by Denka Company Ltd., can be used as the liquid resin. 25 can be used. Although in this preferred embodiment the liquid resin 25 previously on the upper surface of the arch 23 is applied and the bow 23 next at the holding table 24 when held, the bow 23 first at the holding table 24 be held and the liquid resin 25 next on the arch 23 be applied.

[0028] Then the wafer holding unit 34 lowered to the front side 11a of the wafer 11 about the protective film 21 against the liquid resin 25 , as in Fig. As shown in 3B, press. Accordingly, the liquid resin 25 in the radial direction of the wafer 11spreads and covers the protective film 21 and the circumferential border area 11e In this preferred embodiment, the amount of liquid resin 25 , which is on the bow 23 to be applied and the extent of a lowering of the wafer holding unit 34 so that the liquid resin 25 the chamfered edge between the outer circumference 11c and the front 11a of the wafer 11 covered. Afterwards, ultraviolet light is removed from the ultraviolet light source. 26 emitted to thereby increase the liquid resin 25 to harden. As a result, the liquid resin becomes 25 as a protective element 27 trained to apply the protective film 21 and the circumferential border area 11e , as in Fig. 3C shown, covered. The protective element 27 is on the front side 11a of the wafer 11fixed in order to form a wafer unit that is connected to the wafer 11 , the protective film 21 and the protective element 27 is constructed, with the front side 11a of the wafer 11 with the one on the bow 23 supported protective element 27 is covered. It should be noted that the chamfered edge is between the outer circumference. 11c and the front 11a of the wafer 11 in this preferred embodiment also through the protective element 27 is covered.

[0029] After executing the wafer unit training step, the grinding step is performed to clean the back side. 11b of the wafer 11 to grind. Fig. 4A is a schematic sectional view showing one way of grinding the back side. 11b of the wafer 11 represents, and Fig. 4B is a schematic sectional view showing the state in which the rear side 11b of the wafer 11 has been ground. The grinding step is carried out using a Fig. 4A shown grinding device 42 executed. The grinding device 42 closes a holding table (clamping table) 44 to hold the wafer 11 (Wafer unit) under suction. The holding table 44 It is connected to a rotary drive source (not shown), such as a motor, and configured to rotate about an axis that is substantially parallel to a vertical direction. A motion mechanism (not shown) is located beneath the holding table. 44 provided, and the holding table 44 This movement mechanism allows it to be moved horizontally. Part of the upper surface of the holding table 44 is used as a holding surface 44ato hold the bow 23 formed under suction force, which extends over the protective element 27 on the wafer 11 is fixed. The holding surface 44a is connected to a vacuum source (not shown) via a suction port (not shown). The suction port is located in the holding table. 44 formed. By applying a vacuum from the vacuum source to the holding surface. 44a , the wafer 11 over the arch 23 and the protective element 27 under suction force on the holding table 44 held.

[0030] The grinding device 42 Furthermore, it includes a grinding unit. 46 one that goes over the holding table 44 is intended. The grinding unit 46 includes a spindle housing (not shown) supported by a lifting mechanism (not shown). A spindle 48It is rotatably supported in the spindle housing. A disc-shaped bracket 50 is at the lower end of the spindle 48 attached. A grinding wheel 52 , which has essentially the same diameter as the bracket 50 , is on the lower surface of the bracket 50 attached. The grinding wheel 52 includes a wheel base 54 one made of a metal, such as stainless steel or aluminum. A variety of grinding elements. 56 is on the lower surface of the wheel base 54 It is attached so that it is arranged in a ring shape. A rotary drive source (not shown), such as a motor, is connected to the upper end (base end) of the spindle. 48 connected, so that the grinding wheel 52The wafer is rotated about an axis that is essentially parallel to a vertical direction by a force generated via the rotary drive source. A nozzle (not shown) is used to supply a grinding fluid, such as pure water, onto the wafer. 11 is inside or near the grinding unit 46 planned.

[0031] During the grinding step, the wafer 11 (Wafer unit) first at the holding table 44 the grinding device 42 held under suction. In particular, the bow 23 , which is over the protective element 27 on the wafer 11 is fixed, with the holding surface 44a of the holding table 44 brought into contact, and a vacuum from the vacuum source is applied to the holding surface. 44a applied. Accordingly, the wafer is 11 under suction force on the holding table 44 held in the state in which the rear side11b of the wafer 11 It is exposed upwards. Then the holding table 44 to a position below the grinding unit 46 moved. After that, both the holding table and the table are moved. 44 as well as the grinding wheel 52 , as in Fig. 4A shown, rotated, and the spindle housing (the spindle) 48 and the grinding wheel 52 ) is when an abrasive fluid is supplied to the rear side 11b of the wafer 11 lowered. A lowering speed (feed rate) of the spindle housing is set so that the lower surface of each grinding element is 56 on the back side 11b of the wafer 11 is attached. As a result, the rear side can be 11b of the wafer 11 They are ground down to reduce the thickness of the wafer. 11 to reduce. If the thickness of the wafer 11 to a predetermined thickness (finished thickness), as in Fig. As shown in 4B, the grinding step is reduced, and the grinding step is complete.

[0032] Although in this preferred embodiment the rear side 11b of the wafer 11 using the individual grinding unit 46 When grinding, two or more grinding units can be used to grind the wafer. 11 to sand. In this case, a rough sanding can first be carried out using sanding elements, each with large abrasive grains, and then a finish sanding can be carried out using sanding elements, each with smaller abrasive grains. In accordance with this sanding, the flatness of the back side can be improved. 11b Improvements can be made without significantly increasing the time required for grinding.

[0033] After the grinding step is performed, the peeling step is carried out to remove the protective film. 21, the protective element 27 and the bow 23 from the wafer 11 to subtract the amount that has been reduced in thickness. Fig. Figure 5 is a schematic sectional view showing one way of peeling off the protective film. 21 , of the protective element 27 and the bow 23 from the wafer 11 This represents the first step in the peeling process: a wafer holding unit. 62 prepared, which provides a holding surface 62a to hold the wafer 11 (at the arch) 23 fixed wafer unit) under suction force, and the rear side 11b of the wafer 11 is attached to the holding surface under suction force 62a the wafer holding unit 62 held. Then a peeling unit is used. 64 used to form an end section of the bow 23 to grasp. Then the wafer holding unit 62 and the puller unit 64 moved relative to each other to form the arc23 from the wafer 11 to separate. Accordingly, the protective film can be separated. 21 , the protective element 27 and the bow 23 , as in Fig. 5 shown as a unit of the wafer 11 be deducted.

[0034] In the wafer processing method in accordance with this preferred embodiment, the component area 11d , where the building elements 15 , each of which forms the contact bumps (unevenness) 17 exhibit, are trained, first with the protective film 21 covered, and the protective film 21 The next step will be the component area. 11d brought into close contact to form the shape of the contact bumps 17 to follow. Then the liquid resin, which can be cured by ultraviolet light (external stimulus), is used. 25 to the front 11a of the wafer 11 applied and then hardened to create the protective element 27to train that protects the protective film 21 and the circumferential border area 11e covered. Consequently, the wafer unit, which is connected to the wafer, is covered. 11 , the protective film 21 and the protective element 27 is constructed in the state in which the front side 11a of the wafer 11 with the protective element 27 about the protective film 21 is covered. Because the protective element 27 has sufficient thickness, the influence of the front side can be reduced. 11a of the wafer 11 The resulting unevenness is sufficiently reduced. Furthermore, the protective film adheres. 21 in the wafer processing process in accordance with this preferred embodiment not at the component area 11d on, but is merely in close contact with the component sector 11d Therefore, no special procedure is necessary to remove the protective film.21 to perform actions such as immersion in a solution or heating. That is to say, the protective film 21 and the protective element 27 can be easily removed from the wafer 11 can be peeled off. As described above, this can be done by sanding the back side. 11b of the wafer 11 the influence of unevenness, such as contact bumps 17 , which are on the front side 11a of the wafer 11 The existing residues are sufficiently reduced. Furthermore, no additional process is required after wafer grinding. 11 necessary. Furthermore, the protective film 21 and the circumferential border area 11e of the wafer 11 in the wafer processing process in accordance with this preferred embodiment with the protective element 27 covered with the liquid resin 25It is formed in a way that can be cured by ultraviolet light. That is to say, the protective element 27 is located at the perimeter edge 11e of the wafer 11 fixed. Although the protective film 21 , which does not exhibit adhesion through an adhesive (glue), it is accordingly unlikely or impossible that the protective film and the protective element will 27 during wafer grinding 11 from the wafer 11 can be deducted.

[0035] The present invention is not limited to the preferred embodiment described above, but various modifications can be implemented. Although the liquid resin 25Whereas in the above preferred embodiment the liquid resin is curable by ultraviolet light, in the present invention, for example, any other type of liquid resin can be used which is curable by any other external stimulus (for example, heat) than ultraviolet light.

[0036] In this preferred embodiment, the protective element 27 by pressing down the wafer 11 about the protective film 21 to the one on the arch 23 applied liquid resin 25 on the wafer 11 fixed. As a variation, the liquid resin can be used. 25 on the wafer 11 and the protective film 21 be dripped to thereby protect the protective element 27 on the wafer 11 to fix it in place. In this case, the front side (exposed surface) of the protective element is fixed. 27preferably flattened (planarized) by using a flattening device or similar. By flattening the front side of the wafer 11 fixed protective element 27 can the back side 11b (Processing area) of the wafer 11 They can be flattened by grinding.

[0037] In the above preferred embodiment, the weight 4 over the cushion 2 on the front side 11a of the wafer 11 (more precisely, on the protective film) 21 , the front side 11a (covered) applied to thereby protect the protective film 21 against the front side 11a of the wafer 11 to press. Then the protective film will... 21 with the front side 11a of the wafer 11 brought into close contact. However, any other method can be used as a protective film deployment step.

[0038] The Fig. 6A, Fig. 6B and Fig. 6C represents a first modification of the protective film deployment step, wherein Fig. 6A is a schematic sectional view representing a state in which the front side 11a of the wafer 11 with the protective film 21 is covered, and the Fig. 6B and Fig. 6C schematic sectional views are showing one way of bringing the protective film into close contact. 21 with the front side 11a of the wafer 11 represent. In the protective film deployment step, in accordance with the first modification, the protective film is 21 , as in Fig. 6A shown, on the front side 11a of the wafer 11 (more precisely, in the component area) 11d ) in a manner similar to that of the preferred embodiment above. Consequently, the front side 11a of the wafer 11with the protective film 21 covered. Then the wafer 11 , as in Fig. 6B shown, into a low-pressure chamber 6 loaded.

[0039] As in Fig. Figure 6B shows the negative pressure chamber to be used in the first modification. 6 essentially constructed in the same way as that of the preferred embodiment above. However, the vacuum chamber to be used in the first modification excludes 6 a pressure unit (pressure medium) 72 to press down the protective film 21 to the wafer 11 one. The pressure unit 72 is on the inner wall surface of the door 6b provided. The pressure unit 72 has a surface as a pressure surface, which is attached to the support table 16 opposite, on, and a cushion 74 , such as a foam, is located on the lower surface of the pressure unit 72 provided for. If the door 6bin the closed state in which the wafer 11 at the support table 16 the low-pressure chamber 6 The protective film is placed 21 , the front side 11a of the wafer 11 covered, accordingly, as in the Fig. 6b and Fig. 6C is shown, by the pressure unit 72 over the cushion 74 against the wafer 11 pressed. Consequently, the protective film is removed. 21 against the front side 11a of the wafer 11 Pressed. As a result, part of the protective film is removed. 21 with the front side 11a of the wafer 11 brought into contact.

[0040] Then the valve 14 closed and next the valve will be 10 opened to allow access to the interior of the vacuum chamber 6 to evacuate. Accordingly, the protective film will be removed. 21 , as in Fig. 6C is shown, by the pressure unit 72 under reduced pressure against the front side 11a of the wafer 11 pressed. Furthermore, the gas (air) that is between the front side 11a of the wafer 11 and the protective film 21 remaining, removed. After the interior of the vacuum chamber 6 Once the area is sufficiently evacuated, the valve will open. 10 closed and the valve 14 The next thing opened is to allow outside air (atmosphere) into the interior of the low-pressure chamber. 6 to introduce. As a result, atmospheric pressure is exerted on the protective film. 21 applied so that the protective film 21 with the front side 11a of the wafer 11 can be brought into close contact in order to form the shape of the contact bumps 17 to follow, which is on the front side 11a of the wafer 11 are planned.

[0041] The Fig. 7A and Fig. Figure 7B shows schematic sectional views illustrating a second variation of the protective film delivery step. In the protective film delivery step according to the second variation, a holding table is used. 82 with an upper surface as a holding surface 82a prepared, and the back side 11b of the wafer 11 is in that state at the holding surface 82a of the holding table 82 held in which the protective film 21 not on the front side 11a of the wafer 11 is appropriate. The construction of the holding table 82 is essentially the same as that of the holding table 44 A heating device 84 is in the holding table 82 installed. The protective film 21 is first applied to the lower surface of a sheet (detachment sheet) 29 held. Then the one through the bow lies 29 protective film held 21the front 11a (the component area) 11d ) of the wafer 11 opposite, and a roller 86 is used to cover the top surface of the bow 29 , as in Fig. 7A shows the rolling motion to press. At this point, the heating device can be... 84 must be activated to remove the protective film 21 to heat it up and thereby soften it. Accordingly, the protective film 21 so on the front side 11a of the wafer 11 appropriate that he cover the component area 11d covered. Consequently, the front side can 11a of the wafer 11 (more precisely, the component area) 11d ) with the protective film 21 be covered. Then the bow 29 , as in Fig. 7B shown, from the protective film 21 removed. This covering process using the roller. 86 can in the negative pressure chamber 6to be carried out. After covering the front side 11a (the component area) 11d ) of the wafer 11 with the protective film 21 will the protective film 21 with the front side 11a of the wafer 11 brought into contact in a similar manner to that of the preferred embodiment above or the first modification.

[0042] The present invention is not limited to the details of the preferred embodiments described above. The scope of protection of the invention is defined by the attached claims, and all modifications and variations that fall within the equivalent scope of protection of the claims are consequently included in the invention.

Claims

[1] Wafer processing processes, which include: a protective film deployment step comprising the deployment of a protective film to the front side of a wafer, comprising a component area where a plurality of components are formed, each having a bump, and a circumferential edge area surrounding the component area in the state where the component area is covered with the protective film, and then bringing the protective film into close contact with the front side of the wafer to follow the shape of the bump; a wafer unit formation step comprising the application of a liquid resin, which is curable by an external stimulus, to the front side of the wafer and then the curing of the liquid resin by applying the external stimulus to form a protective element that covers the protective film and the peripheral edge region of the wafer, thereby forming a wafer unit that is assembled with the wafer, the protective film and the protective element in the state in which the front side of the wafer is covered with the protective element; a grinding step involving holding the protective element of the wafer unit against a holding surface of a clamping table and then grinding the back side of the wafer of the wafer unit in order to reduce the thickness of the wafer; and a peeling step involving the removal of the protective element and the protective film from the wafer, which is reduced in thickness. [2] Wafer processing method according to claim 1, wherein an edge section between the outer circumference of the wafer and the front side of the wafer is chamfered; and the front side of the wafer is covered with the protective element in order to include the chamfered edge section in the wafer unit formation step. [3] Wafer processing method according to claim 1 or 2, wherein the wafer unit formation step includes the steps of applying the liquid resin to a flat sheet, nextly pressing the wafer over the protective film against the liquid resin applied to the flat sheet, and nextly curing the liquid resin by applying the external stimulus in order to fix the protective element to the wafer. [4] Wafer processing method according to one of the preceding claims, wherein the protective film provisioning step includes the steps of pressing the protective film against the front side of the wafer under a reduced pressure and next applying atmospheric pressure to the protective film in order to bring the protective film into close contact with the front side of the wafer in order to follow the shape of the unevenness. [5] Wafer processing method according to any of the preceding claims, wherein the protective film provisioning step includes the step of applying pressure via a cushion to the protective film in order to press the protective film against the front side of the wafer. [6] Wafer processing method according to any of the preceding claims, wherein the protective film provisioning step includes the step of applying a weight via a cushion to the protective film in order to press the protective film against the front side of the wafer. [7] Wafer processing method according to claim 6, wherein the protective film provisioning step includes the steps of attaching the weight via the pad to the protective film under atmospheric pressure and next loading the wafer into a vacuum chamber in the state in which the weight is attached to the wafer. [8] Wafer processing method according to one of the preceding claims, wherein the protective film provisioning step includes the steps of loading the wafer into a vacuum chamber in the state in which the component area is covered with the protective film, and next of using a pressure means belonging to the vacuum chamber to press the protective film against the front side of the wafer.

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