Workpiece processing method

Abstract

To provide a technology for forming necessary amount of necessary type of layer film on a necessary part of a wafer surface, and enabling optimal surface treatment for each wafer.SOLUTION: A workpiece processing method for a workpiece such as wafer in which a plurality of devices are divided by scheduled division lines, forms a layer of any component at any position on the workpiece surface using a position-controllable discharge nozzle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for processing a workpiece such as a wafer on which a plurality of devices are partitioned by planned dividing lines. [Background technology]

[0002] Conventionally, in the field of semiconductor wafer manufacturing, it is known to form a resin film on the wafer surface for the purposes of protecting devices formed on the wafer surface from damage and contamination and for the purposes of preventing film peeling, known as delamination.

[0003] In addition, with regard to the technology of cutting a wafer using a cutting blade, as shown in, for example, Patent Document 1, a so-called dressing is known in which the cutting blade is appropriately sharpened using a dresser board or the like. Specifically, in dicing a wafer using a cutting blade, the cutting is performed along the intended division line by a rotating cutting blade, and the wafer is divided into individual devices. If the wafer is continuously cut by the cutting blade, the cutting performance of the cutting blade is reduced due to the abrasive grains being dropped, clogged, or worn out. In order to recover this reduced cutting performance, the cutting blade is sharpened by cutting the cutting blade into the dresser board.

[0004] In relation to this, for example, Patent Document 2 discloses a method of providing a dress board holding means for holding a dress board beside a holding means for holding a workpiece. Also, for example, Patent Document 2 describes a method of using an adhesive tape for holding a workpiece, in which abrasive grains are mixed into the adhesive tape, and the adhesive tape is given a dressing function for a cutting blade. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2006-218571 [Patent Document 2] Patent Publication No. 07-283171 [Patent Document 3] Patent Publication No. 08-088202 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional methods for forming a resin film uniformly on the wafer surface were unable to form different types of films depending on the required locations on the wafer, and were also forced to form films in unnecessary locations.

[0007] On the other hand, with regard to dressing, in the method of using an abrasive tape as described in Patent Document 3, dressing is constantly performed while the workpiece is being cut, which results in excessive sharpening of the cutting blade, leading to a deterioration in processing quality and increased wear on the cutting blade.

[0008] Furthermore, in the method of using abrasive tape as described in Patent Document 3, the type and amount of abrasive grains and the type of adhesive tape must be appropriately selected depending on the cutting blade and type of workpiece to be used, and abrasive tape must be prepared for each combination.

[0009] In view of the above problems, the present invention provides a technique for forming a layer film of a required type in a required amount at a required location on a wafer surface, thereby enabling optimal surface treatment for each wafer. [Means for solving the problem]

[0010] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0011] According to one aspect of the present invention, there is provided a method for processing a workpiece such as a wafer on which a plurality of devices are partitioned by planned dividing lines, the method comprising the steps of: forming a layer of any component at any position on the surface of the workpiece using a position-controllable discharge nozzle.

[0012] According to one aspect of the present invention, the method includes an adhesive layer forming step of forming an adhesive layer on the back surface of a workpiece, an abrasive layer laminating step of laminating an abrasive layer on the adhesive layer, an attachment step of attaching the surface on which the abrasive layer is laminated to an adhesive tape, and a dividing step of cutting the workpiece by cutting the workpiece while cutting with a cutting blade from the front surface side of the workpiece to the abrasive layer.

[0013] According to one aspect of the present invention, the method includes an adhesive layer forming step of forming an adhesive layer on the surface of a workpiece, an abrasive layer stacking step of stacking an abrasive layer on the adhesive layer, an attachment step of attaching the surface on which the abrasive layer is stacked to an adhesive tape, and a dividing step of cutting the workpiece by cutting the workpiece with a cutting blade while cutting from the back side of the workpiece to the abrasive layer.

[0014] According to one aspect of the present invention, the cutting blade is formed by fixing abrasive grains with a binder, and in the abrasive grain stacking step, the abrasive agent for forming the abrasive grain layer is selected based on at least one of the size of the abrasive grains contained in the cutting blade, the type of binder, and the type of the workpiece. Effect of the Invention

[0015] The present invention provides the following advantages. That is, according to one aspect of the present invention, it is possible to form a layer of any component with any thickness at any position on the surface of a wafer, which is a workpiece, by using a position-controllable discharge nozzle. Furthermore, since the layer to be formed is not uniform but can be designed for each wafer, it is possible to individually perform the surface treatment required for each wafer. [Brief description of the drawings]

[0016] [Figure 1] 1A to 1C are diagrams showing an embodiment of a method for processing a workpiece according to the present invention; [Diagram 2]1A is a diagram showing an example of forming an abrasive layer on a part of the dividing line, and FIG. 1B is a diagram showing an example of forming an abrasive layer on the outer peripheral edge of a wafer. [Diagram 3] FIG. 2 is a diagram showing the procedure of the first embodiment. [Figure 4] 11A and 11B are diagrams showing cross-sectional views of a cut portion in a dividing step. [Diagram 5] FIG. 4 is a diagram showing a pickup state in the first embodiment. [Figure 6] FIG. 11 is a diagram showing the procedure of the second embodiment. [Figure 7] 11A and 11B are diagrams showing cross-sectional views of a cut portion in a dividing step. [Figure 8] FIG. 11 is a diagram showing a pickup state in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a method for processing a workpiece according to the present invention. As shown in Fig. 1, a wafer W, which is an example of a workpiece, is configured as a semiconductor device wafer and has a front surface Wa and a back surface Wb. A plurality of devices D are formed on the front surface Wa, and each device D is partitioned by a grid-like planned dividing line S. The workpiece is not particularly limited and may be one on which devices are formed as shown in Fig. 1, or one on which devices are not formed.

[0018] Then, with the back surface Wb of the wafer W exposed upward, an adhesive 12 is applied from an adhesive layer nozzle 10 connected to an adhesive supply source 16 to form an adhesive layer 14 on the back surface Wb. This adhesive layer 14 is for adhering an abrasive layer to be formed later.

[0019] The adhesive 12 for constituting the adhesive layer 14 is not particularly limited, but is selected to be one that can hold the abrasive layer 24, which is to be laminated later, in an attached state, and that exhibits suitable performance for picking up the chips and peeling them off from the adhesive 12 after the wafer W is later diced to form chips.

[0020] For example, by using a UV-curable adhesive 12, the chips can be peeled off at the boundary between the adhesive layer 14 and the back surface Wb of the wafer W by irradiating UV light during later pick-up. Since abrasive grains are difficult to transmit UV light, if UV curing is difficult due to the density or arrangement of the abrasive grain layer, a separate adhesive layer such as a thermal peeling layer may be used. Also, an adhesive layer that simply exhibits adhesive properties may be used.

[0021] Next, an abrasive agent 22 containing abrasive grains is discharged from a discharge nozzle 20 onto the surface 14a of the adhesive layer 14, and an abrasive layer 24 is formed on the surface 14a. At this time, due to the presence of the adhesive layer 14, the abrasive layer 24 does not come into contact with the back surface Wb of the wafer W, and damage to the back surface Wb of the wafer W by the abrasive agent can be prevented.

[0022] The discharge nozzle 20 is connected to an abrasive supply source 30 and is configured to be able to continuously discharge abrasive grains. The discharge nozzle 20 is also connected to an arm 32 whose position is controlled, and a motor 36 that operates the arm 32 is automatically controlled by a control device 34, whereby the position and height of the discharge port of the discharge nozzle 20 are controlled.

[0023] The specific position control of the discharge nozzle 20 by the control device 34 can be arbitrarily set by the operator. As a result, for example, as shown in Fig. 2(A), by discharging the abrasive agent at some of the planned dividing lines S, an abrasive layer 24 can be formed at these locations, or as shown in Fig. 2(B), an abrasive layer 25 can be formed on the outer periphery of the wafer W. Of course, the present invention is not limited to these examples, and an abrasive layer can be formed at any location on the wafer W.

[0024] 1, parameters such as the amount of abrasive discharged from the discharge nozzle 20 per unit time and the moving speed of the discharge nozzle 20 are controlled by a control device 34, and these parameters can be set arbitrarily by an operator. This allows the thickness of the abrasive layer 24 to be set arbitrarily. The thickness of the abrasive layer 24 can be set based on, for example, the cutting blade tip exposure amount, the thickness of the adhesive layer, and the thickness of the wafer.

[0025] The abrasive supplied from the abrasive supply source 30 is the raw material for the abrasive layer 24, and the abrasive required for each process is stored in the abrasive supply source 30. This makes it possible to form the abrasive layer 24 using an abrasive having any desired composition depending on the type of the wafer W, etc. The composition of the abrasive can be selected in association with the abrasive contained in the cutting blade, which will be described later, and can be selected based on, for example, the size (e.g., grain size) of the abrasive contained in the cutting blade and the type of bonding material.

[0026] In this way, it is possible to form a layer of any component with any thickness at any position on the surface of the wafer, which is the workpiece, by using a position-controllable discharge nozzle, as shown in Figure 1. Furthermore, the layer to be formed is not uniform, but can be designed for each wafer, so that the surface treatment required for each wafer can be individually performed.

[0027] In the example of Figure 1, the adhesive layer 14 is formed on the back surface Wb side of the wafer W, and the abrasive layer 24 is formed on the adhesive layer 14. However, the adhesive layer 14 may be formed on the front surface Wa side of the wafer W, and the abrasive layer 24 may be formed on the adhesive layer 14.

[0028] Next, an example of forming an abrasive layer and performing cutting using the method described above will be described. EXAMPLES

[0029] 3, devices D are formed on a surface Wa of a substrate of a wafer W, which is a workpiece, and lattice-shaped division lines S are set thereon, and the wafer W is to be cut along the division lines S to be individually divided into chips. A protective film for protecting the devices D is formed in advance on the surface Wa, and a protective layer may be formed by carrying out a protective layer forming step before forming an adhesive layer 14 described below.

[0030] For such a wafer W, first, an adhesive layer forming step is performed in which an adhesive layer 14 is formed on the back surface Wb of the wafer W. The front surface 14a of the adhesive layer 14 exhibits adhesiveness, and forms an adhesive surface that adheres and holds the abrasive layer 24 to be formed next. The adhesive layer 14 may be formed on the entire back surface Wb of the wafer W, or may be formed on only a partial area, similar to the abrasive layer 24.

[0031] 3, an abrasive layer stacking step is performed in which an abrasive layer 24 is stacked on the surface 14a of the adhesive layer 14 using a discharge nozzle 20. In this embodiment, a single linear abrasive layer 24 is formed along a part of the planned division line. Here, the abrasive layer 24 is in a state of being adhered to the surface 14a of the adhesive layer 14, and when the wafer W is inverted in the next bonding step, the abrasive layer 24 will not shift in position or fall off.

[0032] 3, a bonding step is performed in which the surface on which the abrasive layer 24 is laminated is bonded to an adhesive tape T. An annular frame F is also bonded to the adhesive tape T so as to surround the wafer W, thereby forming a wafer unit U.

[0033] At this time, the wafer W is turned over, and the adhesive layer 14 and the abrasive layer 24 formed on the back surface Wb of the wafer W are attached to the front surface Ta of the adhesive tape T. A glue layer is formed on the front surface Ta of the adhesive tape T, and the adhesive layer 14 and the abrasive layer 24 are attached to the front surface Ta. As a result, the front surface Wa of the wafer W is exposed.

[0034] Here, when the abrasive layer 24 is configured in a line shape as in this embodiment, it is considered that the abrasive layer 24 becomes uneven, and the cutting surface when cutting in the subsequent dividing step will not be flat. For this reason, it is preferable that the adhesive tape T sinks and fills the convex parts of the abrasive layer 24 as shown in Fig. 4, and for example, it is preferable to use a tape generally called a high bump tape.

[0035] 3, a dividing step is performed in which the wafer W is divided by cutting the wafer W with the cutting blade 51 while cutting from the front surface Wa side of the wafer W to the abrasive grain layer 24. The cutting blade 51 is rotated at high speed by a motor (not shown) provided in the cutting unit 50, and is formed into a disk shape by binding abrasive grains with a binder. During cutting, the cutting blade 51 is positioned at a predetermined height, and the wafer U is moved horizontally while being held by a holding table (not shown), thereby forming a cutting groove along the planned dividing line.

[0036] 4 shows a cross section of the cut portion in the dividing step, and shows, from the bottom, the adhesive tape T, the abrasive layer 24, the adhesive layer 14, and the substrate Ws of the wafer W. Devices D are formed on the front surface Wa side of the wafer W. A dividing line S is set between adjacent devices D, and cutting is performed by cutting the wafer by cutting the cutting blade 51 along the dividing line S, forming a cut groove M1.

[0037] Of the multiple planned division lines S, the abrasive layer 24 is formed on some of the planned division lines S. For example, the abrasive layer 24 is formed on one of two planned division lines S. According to this example, dressing with the abrasive layer 24 is performed during one of the two traverse cuts.

[0038] Furthermore, by arranging the abrasive layer 24 at an appropriate position and interval as described above, the cutting blade 51 will not be over-sharpened due to excessive dressing, and by performing regular dressing, reduced cutting performance can be restored, making it possible to maintain processing quality.

[0039] In the above embodiment, a function of dressing the wafer W, which is the workpiece, is added, and further, this function can be added arbitrarily within a necessary range.

[0040] Furthermore, compared to dressing using abrasive grains mixed into adhesive tape, the above embodiment in which an abrasive layer is formed along the intended division line makes it possible to obtain the dressing effect with a smaller amount of abrasive grains, thereby reducing the cost of abrasive grains required for dressing.

[0041] In addition, since abrasive grains do not easily transmit UV light, there is concern that the UV-curable adhesive layer may not cure properly when picked up, but by arranging the abrasive grain layer only on the planned dividing lines, the abrasive grain layer is removed by dressing during cutting, leaving almost no residue. Therefore, there is no need to consider the adhesive layer curing poorly, and a UV-curable adhesive can be used.

[0042] The above embodiment shows a case where an abrasive layer 24 is provided at a portion of the intended division line S shown in FIG. 2(A), but the same effect can be obtained when an abrasive layer 25 is provided at the outer peripheral edge portion shown in FIG. 2(B).

[0043] After cutting has been performed along all of the planned division lines, as shown in FIG. 5, for example, UV light is irradiated from a UV lamp 61 to harden the UV-curable adhesive layer 14, and the chips C are peeled off and picked up at the boundary between the adhesive layer 14 and the back surface Wb of the wafer W (substrate Ws). EXAMPLES

[0044] 6, devices D are formed on a surface Wa of a substrate of a wafer W, which is a workpiece, and lattice-shaped division lines S are set thereon, and the wafer W is to be cut along the division lines S to be individually divided into chips. A protective film for protecting the devices D is formed in advance on the surface Wa, and a protective layer may be formed by carrying out a protective layer forming step before forming an adhesive layer 14 described below.

[0045] For such a wafer W, first, an adhesive layer forming step is performed in which an adhesive layer 14 is formed on the front surface Wa of the wafer W. The front surface 14a of the adhesive layer 14 exhibits adhesiveness, and forms an adhesive surface that adheres and holds the abrasive layer 24 that is formed next. The adhesive layer 14 may be formed on the entire front surface Wa of the wafer W, or may be formed on only a partial area, similar to the abrasive layer 24.

[0046] 6, an abrasive layer stacking step is performed in which an abrasive layer 24 is stacked on the surface 14a of the adhesive layer 14 using a discharge nozzle 20. In this embodiment, a single linear abrasive layer 24 is formed along a part of the planned division line. Here, the abrasive layer 24 is in a state of being adhered to the surface 14a of the adhesive layer 14, and when the wafer W is inverted in the next bonding step, the abrasive layer 24 will not shift in position or fall off.

[0047] 6, a bonding step is performed in which the surface on which the abrasive layer 24 is laminated is bonded to an adhesive tape T. An annular frame F is also bonded to the adhesive tape T so as to surround the wafer W, thereby forming a wafer unit U.

[0048] At this time, the wafer W is turned over, and the adhesive layer 14 and the abrasive layer 24 formed on the front surface Wa of the wafer W are attached to the front surface Ta of the adhesive tape T. A glue layer is formed on the front surface Ta of the adhesive tape T, and the adhesive layer 14 and the abrasive layer 24 are attached to the front surface Ta. As a result, the back surface Wb of the wafer W is exposed.

[0049] Here, when the abrasive layer 24 is configured in a line shape as in this embodiment, it is considered that the abrasive layer 24 becomes uneven, and the cutting surface when cutting in the subsequent dividing step will not be flat. For this reason, it is preferable that the adhesive tape T sinks and fills the convex parts of the abrasive layer 24 as shown in Fig. 7, and for example, it is preferable to use a tape generally called a high bump tape.

[0050] Next, as shown in FIG. 6, a dividing step is performed in which the wafer W is divided by cutting the wafer W with the cutting blade 51 cutting from the back surface Wb side of the wafer W to the abrasive layer 24.

[0051] 7 shows a cross section of the cut portion in the dividing step, and shows, from the bottom, the adhesive tape T, the abrasive layer 24, the adhesive layer 14, and the substrate Ws of the wafer W. Devices D are formed on the front surface Wa side of the wafer W. A dividing line S is set between adjacent devices D, and cutting is performed by cutting the wafer by cutting the cutting blade 51 along the dividing line S, forming a cut groove M2.

[0052] After cutting has been performed along all of the planned division lines, as shown in FIG. 8, for example, UV light is irradiated to harden the UV-curable adhesive layer 14, and the adhesive layer 14 is peeled off and picked up as chips C at the boundaries between the adhesive layer 14 and the surface Wa of the wafer W (substrate Ws) or the surface of the device D.

[0053] The same effects as those of Example 1 can be obtained in Example 2. In Example 2, since the adhesive layer 14 is formed on the front surface Wa side of the wafer W, if a protective layer forming step is performed in which a protective layer (not shown) is formed on the front surface Wa of the wafer W and the adhesive layer 14 is formed thereon, a step of inverting the wafer W is not required. [Explanation of symbols]

[0054] 10 Adhesive layer nozzle 12 Adhesive 14 Adhesive layer 14a surface 16 Adhesive Supply Source 20 Discharge nozzle 22 Abrasives 24 Abrasive layer 25 Abrasive layer 30 Abrasives Supply Source 32 Arm 34 Control device 36 Motor 51 Cutting blade 61 Lamp C-chip D Device F Annular frame S Division line T adhesive tape Ta surface U Wafer Unit W wafer Wa Surface Wb back side

Claims

1. A method for processing a workpiece such as a wafer in which a plurality of devices are partitioned by planned dividing lines, comprising the steps of: A method for processing a workpiece, comprising forming a layer of any component at any position on the surface of the workpiece by using a position-controllable discharge nozzle.

2. An adhesive layer forming step of forming an adhesive layer on the back surface of the workpiece; an abrasive grain laminating step of laminating an abrasive grain layer on the adhesive layer by using the method for treating a workpiece according to claim 1; a step of attaching the surface on which the abrasive layer is laminated to an adhesive tape; a dividing step of dividing the workpiece by cutting the workpiece with a cutting blade from the surface side of the workpiece to the abrasive grain layer; A method for cutting a workpiece, comprising:

3. An adhesive layer forming step of forming an adhesive layer on a surface of the workpiece; an abrasive grain laminating step of laminating an abrasive grain layer on the adhesive layer by using the method for treating a workpiece according to claim 1; a step of attaching the surface on which the abrasive layer is laminated to an adhesive tape; a dividing step of dividing the workpiece by cutting the workpiece with a cutting blade while cutting the workpiece from the back side to the abrasive grain layer; A method for cutting a workpiece, comprising:

4. The cutting blade is made of abrasive grains fixed with a binder, In the abrasive grain stacking step, The abrasive for forming the abrasive layer is Selection is made based on at least one of the size of the abrasive grains contained in the cutting blade, the type of the bonding material, and the type of the workpiece.

4. The method for cutting a workpiece according to claim 1, wherein the cutting surface is a surface of a workpiece.

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