News Column

Patent Issued for Method for Manufacturing Semiconductor Chips from a Semiconductor Wafer

July 23, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent by the inventors Jarry, Vincent (La Membrolle sur Choisille, FR); Hougron, Patrick (Parcay Meslay, FR); Touzet, Dominique (Savigne Sous le Lude, FR); Mendez, Jose (Hommes, FR), filed on March 4, 2013, was published online on July 8, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8772134 is assigned to STMicroelectronics (Tours) SAS (Tours, FR).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The present invention relates to a method for manufacturing semiconductor chips from a semiconductor wafer.

"The manufacturing of semiconductor chips especially comprises steps during which components and interconnect metallizations are formed inside and on top of a semiconductor wafer, followed by a step during which the wafer is cut into individual chips, for example, by means of a saw. Various individual chip testing steps are generally provided after the cutting.

"FIGS. 1A, 1B and 2A, 2B schematically illustrate steps of a method for cutting a semiconductor wafer 10 into individual chips by means of a saw. FIGS. 1A and 2A are top views and FIGS. 1B and 2B respectively are cross-section views along planes B-B of FIGS. 1A and 2A.

"FIGS. 1A and 1B illustrate an initial step in which wafer 10 is arranged on a surface of an adhesive film 12 stretched on a support frame 14. Generally, wafer 10 has an approximately round shape and frame 14 has a round inner contour with a diameter greater than the diameter of wafer 10. In this example, the outer contour of frame 14 has a generally approximately square shape with rounded corners and comprises location notches 16.

"The specific shape of frame 14, and more specifically of its outer contour, enables to accurately position the wafer in a processing machine, for example, a sawing machine. In a given production line, frame 14 generally is an element of standard shape and dimension, used at various steps of the manufacturing during which the wafer should be maintained on a support. Thus, the various machines of a given manufacturing line are provided to receive a type of support frame 14, of given shape and dimensions.

"FIGS. 2A and 2B illustrate the actual operation of cutting of wafer 10 into individual chips 18. The cutting is conventionally performed by means of a circular saw (not shown) running through the wafer along a grid of lines and columns. The cutting is performed across the entire thickness of the wafer and stops in the upper portion of adhesive film 12, without however cutting this film. It should be noted that, in practice, a semiconductor wafer comprises a much greater number of elementary chips 18 than what has been shown. It should be noted that generally, the semiconductor wafer is not perfectly circular but has a flat side, not shown, enabling to align all wafers in the same way with respect to frame 14.

"After the wafer has been cut, the individual chips remain on frame 14, and other manufacturing steps may be provided, during which the cut wafer is processed in machines capable of receiving frame 14. Such steps for example are a visual inspection of the chips, a probe test, a marking of defective chips, etc. Adhesive film 12 especially enables chips 18 to remain in place during these steps and during subsequent transportations of frame 14.

"In some cases, the user or the customer desires to receive the cut chips to assemble them in various electronic devices. The chips are then shipped on the support frame 14 on which they have been cut. On reception of the chips, the test and/or inspection steps may be implemented again by using equipment capable of receiving frame 14. The actual mounting of the chips, for example, their mounting on printed circuit boards, is also carried out by means of machines capable of receiving frame 14.

"The different manufacturers and users of semiconductor chips do not necessarily use the same support frame standards. Now, generally, given equipment is equipped to receive frames of a single standard. Accordingly, in such a production system, a manufacturer of semiconductor chips using a given type of frame can only sell his production to users equipped to receive this type of frame.

"FIGS. 3 and 4 are top views schematically showing, respectively, a frame 34 and a frame 44, corresponding to two standards much used in the art to support wafers having a 20-cm diameter (approximately 8 inches), that is, standard FF-108 and standard FF-105. Frames 34 and 44 have approximately identical general shapes but different dimensions. The general shapes of frames 34 and 44 are similar. Frame 44 has dimensions slightly smaller than the dimensions of frame 34, and in particular outer dimensions smaller than the outer dimensions of frame 34 but greater than the inner diameter of frame 34. In this example, the inner diameter of frame 44 is slightly smaller than the inner diameter of frame 34. The difference in outer dimensions especially results in that the machines capable of receiving frame 34 are not capable of receiving frame 44, and conversely.

"It would be desirable for a manufacturer having equipment capable of receiving frame 34 to be able to sell his production to a user having equipment capable of receiving frame 44 (smaller than frame 34) without for one or the other of the manufacturer and of the user to have to modify his machines."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "Thus, an embodiment provides a method for manufacturing semiconductor chips from a semiconductor wafer, which overcomes at least some of the disadvantages of existing methods.

"An embodiment provides such a method capable of producing, in a production line capable of processing semiconductor wafers arranged on a frame of a first type, semiconductor chips arranged on a support frame of a second type having smaller outer dimensions than the frame of the first type.

"An embodiment provides such a method which is easy to implement.

"Thus, an embodiment provides a method for manufacturing semiconductor chips from a semiconductor wafer, comprising the steps of: fastening, on a first support frame, a second support frame having outer dimensions smaller than the outer dimensions of the first frame and greater than the inner dimensions of the first frame; arranging the wafer on a surface of a film stretched on the second frame; carrying out wafer processing operations by using equipment capable of receiving the first frame; separating the second frame from the first frame and removing the first frame; and carrying out wafer processing operations by using equipment capable of receiving the second frame.

"According to an embodiment, the processing operations in equipment compatible with the first frame comprise a step during which the wafer is cut into semiconductor chips and at least one semiconductor chip test step.

"According to an embodiment, the processing operations in equipment compatible with the second frame comprise a step of assembly of the semiconductor chips in electronic devices.

"According to an embodiment, the first frame comprises, on the side of a surface, guiding and fastening means capable of receiving the second frame, these means being contained, in top view, within the outer contour of the first frame.

"According to an embodiment, the outer and inner contours of the first frame respectively have a square general shape with rounded corners and a circular shape.

"According to an embodiment, the guiding and fastening means comprise: three guide rails fastened in the vicinity of three sides of the square forming the outer contour of the first frame, these guide rails delimiting a space inside of which the second frame is capable of being inserted; and a removable lug capable of being fastened in the vicinity of the fourth side of the square forming the outer contour of the first frame.

"According to an embodiment, the step during which the second frame is fastened to the first frame comprises the operations of: removing the removable lug from the first frame; inserting the second frame between the guide rails of the first frame; and fastening the removable lug to the first frame.

"According to an embodiment, the separation step comprises the operations of: removing the removable lug from the first frame; and removing the second frame from the guide rails of the first frame.

"Another embodiment provides a support frame for a semiconductor wafer, comprising, on the side of a surface, fastening means capable of receiving a second frame of outer dimensions respectively smaller than and greater than the outer and inner dimensions of the support frame, these means being contained, in top view, within the outer contour of the support frame.

"According to an embodiment, this support frame has an outer contour of generally square shape with rounded corners and a circular inner contour, said means comprising: three guide rails fastened in the vicinity of three sides of the square forming the outer contour of the support frame, these guide rails delimiting a space inside of which the second frame is capable of being inserted; and a removable lug capable of being fastened in the vicinity of the fourth side of the support frame.

"The foregoing and other objects, features, and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings."

URL and more information on this patent, see: Jarry, Vincent; Hougron, Patrick; Touzet, Dominique; Mendez, Jose. Method for Manufacturing Semiconductor Chips from a Semiconductor Wafer. U.S. Patent Number 8772134, filed March 4, 2013, and published online on July 8, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8772134.PN.&OS=PN/8772134RS=PN/8772134

Keywords for this news article include: Semiconductor, STMicroelectronics.

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Source: Electronics Newsweekly


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