An individual integrated circuit or chip is generally formed from a larger structure known as a semiconductor wafer. Each semiconductor wafer has a plurality of integrated circuits arranged in rows and columns. Typically, the wafer is sawn or “diced” into rectangularly shaped discrete integrated circuits along two mutually perpendicular sets of parallel lines or “streets” lying between each of the rows and columns thereof.
The description herein is made with reference to the drawings, wherein like reference numerals are generally utilized to refer to like elements throughout, and wherein the various structures are not necessarily drawn to scale. In the following description, for purposes of explanation, numerous specific details are set forth in order to facilitate understanding. It may be evident, however, to one of ordinary skill in the art, that one or more aspects described herein may be practiced with a lesser degree of these specific details. In other instances, known structures and devices are shown in block diagram form to facilitate understanding.
In the process of singulation or dicing of a semiconductor wafer, a number of rectangular regions are sectioned on the surface of a semiconductor wafer by streets that are arranged in a lattice form, and a semiconductor circuit is arranged in each of the rectangular regions. The semiconductor wafer is separated along the streets into individual rectangular regions to obtain semiconductor chips. A cutting machine used for separating the semiconductor wafer along the streets typically involves dicing with a rotating blade or a laser beam. Dicing saw blades can be in the form of an annular disc that is either clamped between the flanges of a hub or built on a hub that accurately positions the thin flexible saw blade which carries diamond particles as the abrasive material.
Although saw singulation works well, continuing advancements in the semiconductor industry have tested the limitations of saw singulation. One such advancement is the increase in wafer size. Singulation of a larger area utiziling current techniques involves the use of single or dual dicing blades or a single laser head, row by row, in sequence. A blade of a wafer saw or a laser beam is passed through the surface of the semiconductor wafer by moving either the blade or beam relative to the wafer or the table of the saw and the wafer relative to a stationary blade or beam, or a combination of both. The blade or beam cuts precisely along each street, returning back over the wafer while the wafer is laterally indexed to the next cutting location. Once all cuts associatd with mutually parallel streets having one orientation are complete, either the blade is rotated 90° relative to the wafer or the wafer is rotated 90°, and cuts are made through streets in a direction perpendicular to the initial direction of cut. This results in a time-consuming process.
In a conventional process, a singulation blade is generally operated at a rotational (spindle) speed of 20,000 rotations per minute (RPM), and a table speed of two inches per second (IPS). These speeds are typical of a conventional “Disco” type singulation machine. As is commonly understood in the art, the table speed measures the (linear) speed of the blade moving along a molded strip during singulation of the molded strip, whereas the spindle speed approximates the rotational speed of the blade (about its axis), as the blade cuts through the molded strip.
The relatively slow conventional speeds are used in the art to reduce blade overheating, to preserve blade life, and to reduce the number of defects in the singulated product. As mentioned above, speeding up the singulation process is beneficial to improve throughput and thereby reduce costs associated with semiconductor manufacturing.
Accordingly, the present disclosure is directed to an apparatus for the singulation of a semiconductor wafer. In some embodiments the disclosed apparatus comprises a plurality of cutting devices. The cutting devices may comprise at least two dicing blades or laser modules. The cutting devices are operable to dice a semiconductor wafer across an entire circumferential edge of the wafer, thereby eliminating the necessity for dicing single rows or streets in sequence, increasing throughput and decreasing processing time.
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During operation of the dicing saws 106, dicing blade 110 of the dicing saw 106 is passed through a surface of the semiconductor wafer 103 by movement of the wafer 103 in wafer feed direction 118, while dicing saws 106 remain in a static position. Dicing blades 110 will concurrently cut wafer 103 to produce multiple cutting lines 114 simultaneously in parallel across an entire circumferential edge 105 of wafer surface. In one embodiment, semiconductor wafer 103 can then be rotated 90° and cuts are made in a second direction perpendicular to the first direction of the cutting lines 114. In another embodiment, dicing saws 106 can be rotated 90° by movement arm suspended by support (not shown) holding dicing saws 106 from above.
Distance between cutting lines 114 may be adjusted to account for variable sizes of circuits arranged on the semiconductor wafer 103. Dicing saws 106 are moveable in an axial direction to adjust distance between cutting lines 114. In this manner, wafer 103 may be diced to provide circuits of all the same size, or various size circuits may be cut on the same wafer 103.
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A further embodiment of the singulation apparatus disclosed herein is illustrated in
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At step 902 a semiconductor wafer is arranged on a support surface configured to hold wafer. Support surface may be moveable in order to move wafer during dicing process.
At step 904, a plurality of cutting devices is assembled to dice the semiconductor wafer. The cutting devices may comprise at least two dicing blades or laser modules. Cutting devices are moveable in an axial direction along the circumferential edge of the semiconductor wafer.
At 906, cutting devices are moved relative to the semiconductor wafer on the support surface relative to the support surface, or the support surface holding the wafer is moved while cutting devices remain stationary. Dicing of the semiconductor wafer into individual chips by formation of multiple concurrent cutting lines then proceeds at step 908.
It will be appreciated that equivalent alterations and/or modifications may occur to one of ordinary skill in the art based upon a reading and/or understanding of the specification and annexed drawings. The disclosure herein includes all such modifications and alterations and is generally not intended to be limited thereby. In addition, while a particular feature or aspect may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features and/or aspects of other implementations as may be desired. Furthermore, to the extent that the terms “includes”, “having”, “has”, “with”, and/or variants thereof are used herein, such terms are intended to be inclusive in meaning—like “comprising.” Also, “exemplary” is merely meant to mean an example, rather than the best. It is also to be appreciated that features, layers and/or elements depicted herein are illustrated with particular dimensions and/or orientations relative to one another for purposes of simplicity and ease of understanding, and that the actual dimensions and/or orientations may differ substantially from that illustrated herein.
Therefore, the disclosure relates to An apparatus for the singulation of a semiconductor wafer including a semiconductor substrate support. A plurality of cutting devices are provided to concurrently cut a surface of the semiconductor wafer to form multiple cutting lines.
In another embodiment, the disclosure relates to a method for the singulation of a semiconductor wafer. The method comprises supporting a semiconductor wafer on a support surface. The method further comprises providing a plurality of cutting devices and cutting the semiconductor wafer with the plurality of cutting devices, the cutting devices operable to form multiple concurrent cutting lines on a surface of the semiconductor wafer.
In a still further embodiment, the disclosure relates to an apparatus for the singulation of a semiconductor wafer. The apparatus comprises at least two cutting devices, the cutting devices comprising dicing blades or laser modules and being operable to perform the concurrent dicing of the wafer in a direction across a complete circumferential edge of the wafer.