Wafer chuck for laser beam type wafer dicing device

Abstract

To provide a wafer chuck for a laser beam type wafer dicing which reduces a contact area between an upper surface of a chuck and a dicing tape, and a method.SOLUTION: In a laser beam type wafer dicing device 100, a chuck 120 includes a wafer supporting plate 122 which includes an upper surface 122A for holding a wafer 140 arranged on a dicing tape 160. The upper surface 122A includes a topographically structured front surface region 124. The topographically structured front surface region 124 is partially or completely overlapped with a wafer edge part 142 when the wafer 140 arranged on the dicing tape 160 is arranged on the upper surface 122A. The topographically structured front surface region 124 reduces the contact area between the upper surface 122A and the dicing tape 160.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to the field of wafer handling, and more particularly, to a wafer chuck and method for laser beam wafer dicing.

Background Art

[0002] One particular process in wafer handling involves mounting a wafer on a dicing tape and using a laser beam wafer dicing apparatus to divide the wafer into dice. More specifically, a wafer mounted on a dicing tape is placed on the upper surface of a wafer support plate of a wafer chuck, and a laser beam is used to cut the wafer into dice as it passes over the wafer.

[0003] The problem is that the dicing tape that holds the wafer during the cutting process (die separation) may adhere to the wafer support plate of the wafer chuck in the area outside the wafer edge (i.e., the area where the laser beam hits the tape directly). This can cause chuck contamination due to tape residues adhering to the chuck's wafer support plate, and can also cause further difficulties, namely die-to-die collisions (die knocking), i.e., when the tape is lifted with the cut wafers on it, the already cut dice may collide with each other, or the tape may adhere too strongly to the chuck and it becomes impossible to lift the tape at all. The process of chuck contamination is self-reinforcing, and in addition, the upper surface of the chuck may be directly damaged by the laser beam in the overcut area.

[0004] Conventionally, chemical cleaning and high-temperature cleaning of the chuck are used to remove tape residues from the chuck's support plate. This is typically performed about once a day and is very costly.

[0005] Another approach to avoid this difficulty is to use dicing tape specifically suited for laser dicing. This is extremely demanding, as subsequent processes must be precisely aligned with the new dicing tape. Therefore, using a different dicing tape would necessitate many changes to subsequent processes.

[0006] A third possibility is to stop the laser beam before reaching the wafer edge, thereby damping the wafer in the wafer edge region of the backend (BE) where the dicing tape is deployed. However, this is also impractical from a practical standpoint because damping the wafer edge in the BE would result in unacceptable particle contamination at that stage of the procedure (e.g., during the BE pick-and-place process). [Overview of the project] [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a chuck for a laser beam wafer dicing apparatus includes a wafer support plate having a top surface for holding a wafer placed on a dicing tape. The top surface includes a topographically structured surface region which partially or completely overlaps the wafer edge when the wafer placed on the dicing tape is positioned on the top surface. The topographically structured surface region reduces the contact area between the top surface and the dicing tape.

[0008] According to another aspect of the present disclosure, a laser beam wafer dicing apparatus includes a chuck as described above. The laser beam wafer dicing apparatus further includes a laser unit for generating a laser beam configured to cut the wafer into a die as it passes over the wafer.

[0009] According to another aspect of the present disclosure, a method for dicing a wafer includes placing the wafer on the upper surface of a wafer support plate of a chuck. A dicing tape is placed between the upper surface and the wafer. The upper surface includes a topographically structured surface region that overlaps with the wafer edge, and the topographically structured surface region reduces the contact area between the upper surface and the dicing tape. The wafer is cut into dies by passing a laser beam over the wafer. The dicing tape is lifted from the upper surface together with the die.

[0010] The elements in the drawings are not necessarily to scale with respect to each other. Similar reference numerals indicate corresponding similar parts. Features of the various embodiments shown can be combined insofar as they do not exclude each other, and / or can be selectively omitted unless explicitly stated to be necessary. Embodiments are illustrated in the drawings and described illustratively in the following description. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of an example of a laser beam wafer dicing apparatus. [Figure 2] Figure 2A is a schematic plan view of the top surface of the wafer support plate of an exemplary chuck for a laser beam wafer dicing apparatus, Figure 2B is a schematic perspective view of an exemplary portion of the topographically structured surface area shown in Figure 2A, and Figure 2C is a schematic plan view of an exemplary portion of the topographically structured surface area shown in Figure 2B. [Figure 3] This is a schematic cross-sectional view of an example wafer support plate for an exemplary chuck, showing the surface roughness and surface flatness of the support plate surface. [Figure 4] This is a flowchart illustrating an exemplary method for dicing a wafer. [Modes for carrying out the invention]

[0012] When used herein, adjacent layers or elements depicted are not necessarily in direct contact with each other; that is, there may be elements or layers interposed between such layers or elements. However, according to this disclosure, adjacent layers or elements depicted are, in particular, in direct contact with each other, i.e., there are no elements or layers interposed between these layers or elements.

[0013] The terms “above” or “below” in relation to a portion, element, or material layer formed, located, arranged, positioned, or installed “above” or “below” a surface may be used herein to mean that the portion, element, or material layer is located “directly above” or “directly below” the suggested surface, for example, in direct contact (e.g., installed, formed, positioned, arranged, installed, etc.). However, the terms “above” or “below” as used in relation to a portion, element, or material layer formed, located, arranged, or installed “above” or “below” a surface may be used to mean that the portion, element, or material layer is located “indirectly above” or “indirectly below” the suggested surface, for example, that one or more additional portions, elements, or layers are positioned between the suggested surface and the portion, element, or material layer.

[0014] Referring to Figure 1, the laser beam wafer dicing apparatus 100, hereafter referred to as wafer dicing apparatus 100, may include a chuck 120 and a laser unit 180 for generating a laser beam 182.

[0015] As is well known in the art, a chuck is a device configured to support a wafer during various stages of wafer processing. Typically, a chuck is designed according to the wafer processing performed on the wafer while the wafer is held by the chuck. Below, we consider a chuck 120 designed to support a wafer during laser beam wafer dicing. Such a chuck 120 is also referred to in the art as a "dicing chuck".

[0016] Figure 1 shows a part of such a wafer dicing apparatus 100, namely the chuck 120 and the laser unit 180. The wafer dicing apparatus 100 may further include a mechanism (not shown) for supporting the chuck 120 and a mechanism (not shown) to which the laser unit 180 is attached. These mechanisms allow the laser unit 180 to be moved relative to the chuck 120 in the lateral direction (X and / or Y direction) and the Z direction (i.e., a direction perpendicular to the plane defined by the X and Y directions, where the Y direction is perpendicular to the paper plane).

[0017] The chuck 120 includes a wafer support plate 122 having an upper surface 122A and a lower surface 122B opposite to the upper surface 122A. Typically, the chuck 120 includes additional plates (e.g., a chuck base plate and / or a chuck vacuum plate) positioned beneath the wafer support plate 122. Such plates that provide mechanical stability and / or vacuum functionality to the chuck 120 are not shown in Figure 1. In other words, Figure 1 shows only the upper plate of the chuck 120, i.e., only the wafer support plate 122.

[0018] For example, the wafer support plate 122 may include or consist of glass, such as quartz glass, or another material, such as a metal material (e.g., stainless steel) or polycarbonate.

[0019] During the operation of the wafer dicing apparatus 100, the wafer 140 is placed on the upper surface 122A of the wafer support plate 122 and held by the upper surface 122A of the wafer support plate 122. The wafer 140 is mounted on the dicing tape 160. That is, the dicing tape 160 has a lower surface that can directly contact the upper surface 122A of the wafer support plate 122 and an upper surface that can directly contact and adhere to the lower surface of the wafer 140. In other words, the dicing tape 160 is positioned between the upper surface 122A of the wafer support plate 122 and the wafer 140.

[0020] The dicing tape 160 can be attached to the dicing frame 170. The dicing frame 170 is used as a tool to transport and mount the dicing tape 160 together with the mounted wafer 140. During the process of dicing the wafer 140, the dicing frame 170 can be fixed to the chuck 120 by detachable connecting means (e.g., clamp connections or screw connections (not shown)). That is, the wafer support plate 122 and the dicing tape 160 are in a fixed positional relationship during the operation of the wafer dicing apparatus 100.

[0021] The dicing tape 160 is required to support each die after die splitting (i.e., after the wafer 140 is cut into multiple dies by passing a laser beam 182 over the wafer 140). After die splitting, the dicing tape 160 is lifted together with the dies from the upper surface 122A of the wafer support plate 122. Lifting the dicing tape 160 together with the dies from the upper surface 122A can be done by a mechanism (not shown) that provides relative movement between the wafer support plate 122 and the dicing frame 170 in the Z direction.

[0022] The laser unit 180 may be of any type suitable for laser dicing. In particular, for example, a UV (ultraviolet) laser, which is efficient for dividing the wafer 140 that requires high energy for laser dicing, or a green laser (e.g., 532 nm wavelength), or an IR (infrared) laser can be used. Further, a pulsed laser can be used for the division.

[0023] The wafer 140 can be made of any semiconductor material such as, for example, SiC, Si, GaN, etc. The wafer 140 can have a thickness of 20 μm or more or 40 μm or more or 100 μm or more. Depending on the semiconductor material and the thickness of the wafer, it is necessary to appropriately select the laser energy and / or the pulse length.

[0024] For example, SiC is a mechanically very durable and electrically efficient material. The mechanical properties of SiC are comparable to those of diamond. Further, in the back-end (BE) process, SiC dies are very sensitive, and this must be taken into account already at the wafer dicing stage.

[0025] To achieve a high yield, it is necessary to adjust the dicing process according to the thickness of the wafer, and the dicing process must ensure complete division and overcut at the wafer edge to ensure complete division of the wafer. In this overcut region OA (see FIG. 1), all the laser energy of the semiconductor dicing process is introduced into the dicing tape 160.

[0026] As a result, the dicing tape 160 may be altered or damaged by locally melting at the upper surface, the back surface, and inside the tape (e.g., the intermediate layer if provided) of the dicing tape 160.

[0027] Further consequences of the laser beam 182 extending beyond the wafer edge 142 include the possibility of localized damage (tip-out) to the upper surface 122A of the wafer support plate 122, and / or the possibility of locally melted dicing tape 160 adhering to the upper surface 122A of the wafer support plate 122. The latter effect causes contamination of the dicing chuck 120. Both effects on the upper surface 122A of the wafer support plate 122, namely damage and contamination, are self-reinforcing; that is, surface areas that are already damaged and / or already contaminated are more susceptible to further damage or contamination than undamaged surface areas.

[0028] As a result, automated wafer lifting from the wafer support plate 122 may become more difficult or cease to function after a relatively small number of wafer processing cycles 140. Contamination and damage (e.g., cut lines) on the upper surface 122A of the wafer support plate 122 increase with each wafer. Finally, the sticky wafer 140 must be manually removed from the chuck 120, which can lead to wafer scrap. In a worst-case scenario from a product reliability standpoint, even if wafer lifting (so-called de-chucking) is still possible, locally sticky dicing tape 160 may cause bending of the dicing tape 160. This can result in die knocking, which can induce cracks and chips in the die.

[0029] For example, the aforementioned problem becomes serious when cutting SiC wafers with a thickness of 100 μm or more.

[0030] To avoid or at least mitigate the above and other problems, the upper surface 122A of the wafer support plate 122 includes a topographically structured surface region 124. The structured surface region 124 partially or completely overlaps the wafer edge 142 when the wafer 140 mounted on the dicing tape 160 is placed on the upper surface 122A. The topographically structured surface region 124 reduces the contact area between the upper surface 122A and the dicing tape 160 in the vicinity of the wafer edge 142 (e.g., at least within the overcut region OA).

[0031] In other words, when cutting wafer 140 into a die, an overcut is applied to the wafer edge. The overcut region length OAL is the radial dimension of the overcut region OA (see Figure 1). The outer edge 124O of the topographically structured surface region 124 extends radially beyond the wafer edge 142 by at least (maximum) the overcut region length OAL.

[0032] The overcut region OA begins at the wafer edge 142. The radial length OAL of the overcut region OA is defined by parameters such as die size and wafer position tolerance. Therefore, different OALs can be used for different wafers. The topographically structured surface region 124 can be dimensionally set to perfectly overlap the overcut region OA for all OALs (and therefore for all die sizes intended to be manufactured on the chuck 120, for example), thereby ensuring that the dicing tape 160 is supported by the topographically structured surface region 124 regardless of where the (focused) laser beam 182 strikes the dicing tape 160.

[0033] The overcut area length (OAL) can be set to 1.5 mm or less. For example, OAL may be 0.3 mm, 0.6 mm, 0.9 mm, 1.2 mm, or 1.5 mm or more, or less.

[0034] The reduction in the contact area between the dicing tape 160 and the upper surface 122A of the wafer support plate 122 reduces contamination of the chuck, and therefore makes it possible to significantly extend the interval for cleaning the chuck.

[0035] The reduction in the contact area between the upper surface 122A and the dicing tape 160 reduces the probability of contamination and / or damage to the (remaining) upper surface 122A. For example, the reduction in contact area may be 30% or more, 50% or more, or 70% or more of the nominal area of ​​the topographically structured surface region 124. The greater the reduction in contact area, the lower the probability of contamination and / or surface damage to the upper surface 122A of the wafer support plate 122.

[0036] In some cases, the reduction in contact area may be 30% or less, 50% or less, or 70% or less of the nominal area of ​​the topographically structured surface region 124. The larger the contact area, the better the support for the dicing tape 160 in the overcut region OA.

[0037] Figure 2B shows an example of a structure that can be used, for example, for a topographically structured surface region 124. In this example, the structure includes, or consists of, an array of small pedestals or supports formed, for example, as cubes separated by grooves. Other possible shapes of such supports include tapered structures, such as conical or pyramidal shapes with truncated tops.

[0038] A topographically structured surface region 124 can be formed as a ring (see Figure 2A). The ring may have a circular inner edge 124I and / or a circular outer edge 124O.

[0039] In other examples, the inner edge 124I and / or outer edge 124O of a ring-shaped topographically structured surface region 124 may have a linear region 124L. In Figure 2A, the inner edge 124I of the ring is similar in shape to or in harmony with (e.g., coincident with) the wafer edge 142 (i.e., the contour of the wafer 140). For example, the wafer edge 142 may have a linear region, and therefore the inner edge 124I of the topographically structured surface region 124 may have a linear region 124L (e.g., a secant). The remaining portion of the inner edge 124I of the topographically structured surface region 124 may be rounded, and in particular may be circular, for example.

[0040] To ensure that the wafer edge 142 is always positioned on and laterally inward of the topographically structured surface region 124, and to allow for some positional tolerances while the wafer is placed on the chuck 120, the inner edge 124I of the topographically structured surface region 124 may have a radial dimension that is somewhat smaller than that of the wafer edge 142 along the entire circumferential extension of the inner edge 124I.

[0041] The width of the topographically structured surface region 124 (i.e., the radial distance between the inner edge 124I and the outer edge 124O) may be, for example, 4 mm, 6 mm, 8 mm, or 10 mm or more or less.

[0042] The wafer 140 may be, for example, a 6, 8, 10, or 12-inch wafer. For example, a 6-inch wafer 140 may have a contour as shown in Figure 2A, while an 8, 10, or 12-inch wafer typically has a circular shape, and therefore the inner edge 124I (and optionally the outer edge 124O) of the ring-shaped topographically structured surface region 124 may be circular in shape.

[0043] A 6-inch wafer 140 can have a diameter in the range of 149.75 to 150.25 mm. The diameter of the inner edge 124I of the topographically structured surface region 124 may be, for example, about 146 ± 0.2 mm. The diameter of the outer edge 124O of the topographically structured surface region 124 may be, for example, 154 ± 0.2 mm. The linear length of the 6-inch wafer 140 may be in the range of 46 to 49 mm. Therefore, the linear length LL of the linear region 124L of the inner edge 124I of the topographically structured surface region 124 may be in the range of 45 mm to 55 mm.

[0044] For an 8-inch wafer 140, the diameter of the inner edge 124I of the topographically structured surface region 124 may be, for example, about 196 ± 0.2 mm. The diameter of the outer edge 124O of the topographically structured surface region 124 may be, for example, 204 ± 0.2 mm. For a 12-inch wafer 140, the diameter of the inner edge 124I of the topographically structured surface region 124 may be, for example, about 296 ± 0.2 mm. The diameter of the outer edge 124O of the topographically structured surface region 124 may be, for example, 304 ± 0.2 mm. As described above, for 8-inch and 12-inch wafers 140, the topographically structured surface region 124 may have a perfectly circular inner edge 124I and / or outer edge 124O.

[0045] As shown in Figures 2B and 2C, the topographically structured surface region 124 may include a structural pattern. The structural pattern may include an array of island-shaped supports 126. The array of island-shaped supports 126 may be a regular array, for example, as shown in Figures 2B and 2C.

[0046] The structural height of the structured pattern may be 0.01 mm or more, or 0.025 mm or more, or 0.05 mm or more. In the illustrated example, the structural height (or groove depth) is, for example, 0.06 mm. The structural height (i.e., groove depth) may be, for example, 0.2 mm or less, or 0.1 mm or less, or 0.07 mm or less.

[0047] The structural length SL of the structured pattern (i.e., the lateral dimension of the island-shaped support 126) may be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.6 mm or less. In the illustrated example, SL = 0.2 mm.

[0048] The structural spacing SS (i.e., groove width) between adjacent island-shaped support columns 126 may be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, or 0.3 mm or more, or less. In the illustrated example, SS = 0.2 mm.

[0049] In Figures 2B and 2C, the island-shaped support column 126 is exemplified as having a square cross-section, but other cross-sectional shapes such as circles or polygons (e.g., triangles, rectangles, pentagons, hexagons, etc.) are also possible.

[0050] In all examples, the structural pattern may be complementary to the grid pattern. For example, in Figures 2B and 2C, the grooves between the island-shaped supports 126 are formed as a square grid.

[0051] The topographically structured surface region 124 can communicate with the vacuum system of the chuck 120. Referring to Figure 2B, the vacuum groove 128 can intersect with the topographically structured surface region 124. For example, the vacuum groove 128 can extend radially. The vacuum groove 128 can have a depth greater than the depth of the groove between the island pillars 126 and / or a width less than the width of the groove between the island pillars 126.

[0052] In this way, the vacuum system of the chuck 120, configured to hold the dicing tape 160 to the upper surface 122A of the wafer support plate 122 by suction, is connected to a topographically structured surface region 124 and acts similarly on this portion of the wafer support plate 122. Another possibility other than the vacuum groove 128 is to use holes or openings (not shown) that open into grooves between island-shaped supports 126 to connect the vacuum system of the chuck 120 to the topographically structured surface region 124.

[0053] By using the above approach or other approaches, it becomes unnecessary to modify the vacuum supply system of chuck 120.

[0054] Since vacuum suction tends to pull the dicing tape 160 into the structural space (e.g., groove) between the island-shaped supports 126, it is necessary to limit the structural spacing SS (e.g., groove width) to avoid significant bending of the dicing tape 160 at and beyond the inner edge 124I of the topographically structured surface region 124.

[0055] Furthermore, the dimensions of the structural spacing SS may depend on the smallest available die size. More specifically, the structural spacing SS should be smaller than, for example, the smallest die size to avoid the smallest die being drawn into the groove.

[0056] Therefore, at least in the vicinity of the inner edge 124I of the topographically structured surface region 124 where dicing is performed, it may be beneficial to set the structural spacing SS to 0.2 mm or less or 0.15 mm or less.

[0057] Referring to Figure 3, the remaining portion of the upper surface 122A of the wafer support plate 122 can have low roughness and / or high flatness. More specifically, the upper surface 122A (and optionally the lower surface 122B) can have a roughness of 2.5 μm or less in the radially inner surface area of ​​the topographically structured surface area 124 and / or in the radially outer surface area of ​​the topographically structured surface area 124. In particular, the roughness may be in the range of 2.0 μm to 2.3 μm. Furthermore, the upper surface 122A (and optionally the lower surface 122B) of the wafer support plate 122 can have a flatness of 0.005 mm or less in the radially inner surface area of ​​the topographically structured surface area 124 and / or in the radially outer surface area of ​​the topographically structured surface area 124.

[0058] As already mentioned above, the wafer support plate 122 may be made of, for example, glass, such as quartz glass. In this case, structuring for forming the topographically structured surface region 124 can be carried out using a LIDE (laser-induced deep etching) process.

[0059] The diameter of the wafer support plate 122 may be, for example, about 220 mm. The thickness of the wafer support plate 122 may be, for example, about 10 mm.

[0060] Referring to Figure 4, the wafer dicing process may include, in S1, placing the wafer on the upper surface of the wafer support plate of the chuck, with a dicing tape placed between the upper surface and the wafer. The upper surface includes a topographically structured surface region that overlaps with the wafer edge. The topographically structured surface region reduces the contact area between the upper surface and the dicing tape.

[0061] As mentioned above, the reduction in contact area compared to the nominal surface area (i.e., total surface area) reduces the probability of surface damage and / or contamination of the chuck's support plate, and therefore extends the cleaning interval.

[0062] In S2, the wafer is cut into dies by passing a laser beam over it. The energy of the laser beam must be set according to the parameters of laser dicing, including in particular the wafer material, the wafer thickness, and (optionally) the thickness of the dicing tape. The dicing tape may be relatively thin (compared to dicing tape that would otherwise need to be used to avoid surface damage or contamination), and may have a thickness of, for example, 200 μm or less, 150 μm or less, or 100 μm or less.

[0063] In S3, the dicing tape is lifted from the upper surface of the wafer support plate of the chuck. Lifting the dicing tape can be achieved by moving the dicing frame 170 away from the chuck 120 (see Figure 1). As described above, the lifting procedure is greatly facilitated by providing a topographically structured surface region 124 on the upper surface 122A of the wafer support plate 122 of the chuck 120.

[0064] Examples The following embodiments relate to further aspects of the present disclosure:

[0065] In Example 1, the chuck for a laser beam wafer dicing apparatus includes a wafer support plate having a top surface for holding a wafer placed on a dicing tape. The top surface includes a topographically structured surface region that partially or completely overlaps the wafer edge when the wafer placed on the dicing tape is positioned on the top surface. The topographically structured surface region reduces the contact area between the top surface and the dicing tape.

[0066] In Example 2, the subject of Example 1 may optionally include the fact that the reduction in contact area is 30% or more, 50% or more, or 70% or more of the nominal area of ​​the topographically structured surface region.

[0067] In Example 3, the subject of Example 1 or 2 may optionally include the fact that the reduction in contact area is 30% or less, 50% or less, or 70% or less of the nominal area of ​​the topographically structured surface region.

[0068] In Example 4, the subject of any prior embodiment may optionally include the fact that the topographically structured surface region is formed as a ring.

[0069] In Example 5, the subject of any prior embodiment may optionally include a vacuum system in which a wafer support plate is configured to hold a dicing tape on its upper surface by suction, and a topographically structured surface region is in communication with the vacuum system.

[0070] In Example 6, the subject of any prior embodiment may optionally include a topographically structured surface region that includes a structural pattern having a structural height of 0.01 mm or more.

[0071] In Example 7, any subject of any prior embodiment may optionally include the fact that a topographically structured surface region includes a structural pattern having a structural length of 0.1 mm or more in one or any lateral direction.

[0072] In Example 8, the subject of any prior embodiment may optionally include the fact that the topographically structured surface region includes a structural pattern having a structural spacing of 0.15 mm or more in one or any lateral direction.

[0073] In Example 9, the subject of any one of Examples 6 to 8 may optionally include the fact that the structural pattern includes an array of island-shaped supports.

[0074] In Example 10, the subject matter of any one of Examples 6 to 9 may optionally include the fact that the structural pattern is complementary to the grid pattern.

[0075] Example 11 may optionally include the fact that the subject of any one of the preceding examples includes a surface region having a roughness of 2.5 μm or less radially inward of a topographically structured surface region.

[0076] In Example 12, any subject of any prior embodiment may optionally include the fact that the top surface includes a surface region having a flatness of 0.005 mm or less radially inward of the topographically structured surface region.

[0077] In Example 13, the subject of any prior embodiment may optionally include the fact that the wafer support plate is made of quartz glass.

[0078] Example 14 is a laser beam wafer dicing apparatus comprising a chuck described in any one of the prior embodiments and a laser unit for generating a laser beam configured to cut the wafer into a die as it passes over the wafer.

[0079] In Example 15, the subject of Example 14 can optionally include the fact that the laser unit includes a pulsed laser.

[0080] In Example 16, the subject matter of Example 14 or 15 may optionally include the fact that the laser unit includes a UV laser, a green laser, or an IR laser.

[0081] Example 17 is a method for dicing a wafer, which includes placing a wafer on the upper surface of a wafer support plate of a chuck, wherein a dicing tape is placed between the upper surface and the wafer, and the upper surface includes a topographically structured surface region that overlaps with the wafer edge, the topographically structured surface region reducing the contact area between the upper surface and the dicing tape, cutting the wafer into a die by passing a laser beam over the wafer, and lifting the dicing tape together with the die from the upper surface.

[0082] In Example 18, the subject of Example 17 can optionally further include applying an overcut to the wafer edge when cutting the wafer into a die, the wafer edge overcut length depending on the size of the die to be manufactured, and the topographically structured surface region protrudes radially beyond the wafer edge by at least the maximum overcut length.

[0083] In Example 19, the subject matter of Example 17 or 18 may optionally include the fact that the wafer is a SiC wafer.

[0084] In Example 20, the subject of any one of Examples 17 to 19 may optionally include the fact that the wafer has a thickness of 100 μm or more.

[0085] While specific embodiments have been illustrated and described herein, it will be understood by those skilled in the art that a wide variety of alternative and / or equivalent implementations may be used in place of the specific embodiments illustrated and described herein without departing from the scope of the invention. This application is intended to cover any adapted or modified forms of the specific embodiments described herein. Accordingly, the invention is intended to be limited only by the claims and their equivalents.

Claims

1. 1. A chuck for a laser beam wafer dicing apparatus, comprising: the chuck includes a wafer support plate having an upper surface for holding a wafer disposed on a dicing tape; the upper surface includes a topographically structured surface region; the topographically structured surface region partially or completely overlaps with a wafer edge when the wafer disposed on the dicing tape is placed on the upper surface; the topographically structured surface region reduces the contact area between the upper surface and the dicing tape; the topographically structured surface region includes a structure pattern including an array of island-like posts; Zipper.

2. the reduction in the contact area is 30% or more, or 50% or more, or 70% or more of the nominal area of the topographically structured surface region; 2. The chuck of claim 1.

3. the reduction in contact area is 30% or less, or 50% or less, or 70% or less of the nominal area of the topographically structured surface region; 2. The chuck of claim 1.

4. the topographically structured surface region is shaped as a ring; 2. The chuck of claim 1.

5. the wafer support plate includes a vacuum system configured to hold the dicing tape on the upper surface by suction; the topographically structured surface region is in communication with the vacuum system.

2. The chuck of claim 1.

6. The structure pattern has a structure height of 0.01 mm or more.

2. The chuck of claim 1.

7. The structure pattern has a structure length of 0.1 mm or more in one or any lateral direction.

2. The chuck of claim 1.

8. The structure pattern has a structure spacing of 0.15 mm or more in one or any lateral direction.

2. The chuck of claim 1.

9. the structural pattern is complementary to a grid pattern; 2. The chuck of claim 1.

10. the upper surface includes a surface region radially inward of the topographically structured surface region, the surface region having a roughness of 2.5 μm or less.

2. The chuck of claim 1.

11. the upper surface includes a surface region radially inward of the topographically structured surface region having a flatness of 0.005 mm or less.

2. The chuck of claim 1.

12. The wafer support plate is made of quartz glass. The chuck of claim 1.

13. A laser beam type wafer dicing apparatus, comprising: A chuck according to any one of claims 1 to 12; a laser unit for generating a laser beam configured to cut the wafer into dies as it passes over the wafer; A laser beam wafer dicing device comprising:

14. The laser unit includes a pulsed laser.

14. The laser beam wafer dicing device according to claim 13.

15. The laser unit includes a UV laser, a green laser, or an IR laser.

14. The laser beam wafer dicing device according to claim 13.

16. 1. A method of dicing a wafer, the method comprising: placing a wafer on an upper surface of a wafer support plate of a chuck; a dicing tape disposed between the upper surface and the wafer; the upper surface includes a topographically structured surface region that overlaps the wafer edge; the topographically structured surface region reduces the contact area between the upper surface and the dicing tape; the topographically structured surface region includes a structure pattern including an array of island-like posts; cutting the wafer into dies by passing a laser beam over the wafer; Lifting the dicing tape together with the die from the top surface; A method comprising:

17. The method further includes applying a wafer edge overcut when cutting the wafer into dies; the wafer edge overcut length is dependent on the size of the die to be manufactured; the topographically structured surface region protrudes radially beyond the wafer edge by at least a maximum overcut length; 17. The method of claim 16.

18. The wafer is a SiC wafer.

17. The method of claim 16.

19. The wafer has a thickness of 100 μm or more.

17. The method of claim 16.

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