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CN-116277553-B - Method for compensating position error of wafer cutting blade

CN116277553BCN 116277553 BCN116277553 BCN 116277553BCN-116277553-B

Abstract

A method for compensating a positional error of a dicing blade of a wafer includes placing a wafer frame, to which a dicing tape is attached and on which a wafer to be diced is attached, onto a chuck, cutting a notch on a dicing tape blank area of a periphery of the wafer with the dicing blade, moving a blade alignment distance by a moving part, to which the dicing blade is attached, such that a camera is moved above the notch, determining a deviation distance between a center line of the notch and an alignment line in a lens of the camera, and re-determining a value of the blade alignment distance according to the deviation distance. According to the invention, the cost of chip manufacture can be greatly reduced, and the dicing efficiency of the wafer is remarkably improved.

Inventors

  • LIU AN
  • PENG RUIBO

Assignees

  • 英特尔产品（成都）有限公司
  • 英特尔公司

Dates

Publication Date
20260505
Application Date
20230321

Claims (8)

  1. 1. A method for compensating for positional errors of a wafer dicing blade detachably mounted to a moving part (9) of a wafer dicing machine (1) and for dicing a wafer placed on a suction cup (5) of the wafer dicing machine (1), the moving part (9) being movably arranged on a graduated screw (7) of the wafer dicing machine (1), a camera (11) being further mounted on the moving part (9), a blade alignment distance (H) being spaced between a center line (11 c) of the camera (11) and a center line (13 c) of the dicing blade (13), the method comprising: placing a wafer frame (3) to which a dicing tape is attached and on which a wafer (17) to be diced is attached, onto the suction cup (5); Cutting a notch (K) on a cutting tape blank area (B) at the periphery of the wafer (17) by using the cutting blade; -moving the moving part (9) by the blade alignment distance (H) such that the camera (11) is moved above the cut (K); determining a deviation distance between a center line of the cutout (K) and an alignment line in a lens of the camera, and The value of the blade alignment distance (H) is redetermined as a function of the offset distance.
  2. 2. The method for compensating for a positional error of a wafer dicing blade according to claim 1, characterized in that redefining the value of the blade alignment distance (H) from the offset distance comprises: Inputting the deviation distance as a compensation value into a control system of the cutting machine, and The value of the blade alignment distance (H) is redetermined based on the compensation value.
  3. 3. The method for compensating for positional errors of a wafer dicing blade according to claim 1, wherein determining the offset distance comprises: Adjusting the position of the lens of the camera such that an alignment line (S) in the lens is aligned with the center line of the cutout, and determining the moving distance of the lens of the camera as the offset distance.
  4. 4. A method for compensating for positional errors of a wafer dicing blade according to claim 3, characterized in that aligning an alignment line (S) in the lens with a center line of the kerf comprises: so that the movable lines (M1, M2) of the camera lens, which are symmetrically located on both sides of the alignment line (S) and parallel to the alignment line (S), are aligned with both edges of the slit (K).
  5. 5. The method for compensating for positional errors of a wafer dicing blade according to claim 1, wherein determining the offset distance comprises: the center line of the cutout is automatically determined using machine vision and the offset distance between the center line of the cutout and an alignment line in the lens of the camera is calculated.
  6. 6. The method for compensating for positional errors of a wafer dicing blade according to claim 1, wherein the camera is arranged to automatically focus according to a distance from a lens of the camera to an upper surface of the dicing tape such that a focal point of the camera is located exactly on the upper surface of the dicing tape.
  7. 7. The method for compensating for positional errors of a wafer dicing blade according to claim 1, wherein the offset distance is determined in a region of 80-90% of the entire length of the kerf near the kerf ends.
  8. 8. The method for compensating for positional errors of a wafer dicing blade according to claim 1, wherein the method is performed after each replacement of the dicing blade.

Description

Method for compensating position error of wafer cutting blade Technical Field The present invention relates to the fabrication of chips, and more particularly to a method for compensating for positional errors of a wafer dicing blade dicing a wafer into individual dies. Background In the chip manufacturing process, it is necessary to adhere dicing tape to a wafer frame (also called a chip ring), then attach a wafer to the dicing tape, and then dice the wafer into individual dies by a wafer dicing machine in a dicing step. Fig. 1 schematically shows a part of a wafer cutter in a simplified view, the wafer cutter 1 includes a chuck 5 for supporting a wafer frame 3 to which a wafer is attached, a lead screw 7 provided with graduations above the chuck 5, and a moving part 9 movably provided on the lead screw 7, a camera 11 and a rotary cutting blade 13 are mounted on the moving part 9, and a distance between a center line 11c of the camera 11 and a center line 13c of the rotary cutting blade 13 is referred to as a blade alignment distance H. When dicing a wafer, the alignment lines in the lens of the camera 11 are aligned with feature points on the wafer, then the dicing machine control system controls the moving part 9 to move along the lead screw 7 by the alignment distance H so that the blade center line 13c is aligned with the dicing line on the wafer and dicing the wafer along the dicing line, then the moving part 9 continues to move along the lead screw 7 by the same distance as the die width (this distance is also referred to as the die pitch) and dicing the wafer along another dicing line until dicing is completed for the entire wafer along the direction parallel to the dicing line. Since the cutting blade 13 is a consumable, it needs to be replaced in time after a period of use. After the replacement of the dicing blade, there is inevitably a certain error in the position of the newly mounted dicing blade, so that the blade alignment distance H varies, and thus, the positional error of the dicing blade needs to be compensated for after each replacement of the dicing blade, which would otherwise cause the dicing blade center line to be misaligned with the dicing line on the wafer, so that the wafer is erroneously diced, thereby damaging the wafer or the obtained die. Existing methods for compensating for the positional error of a wafer dicing blade apply a bare silicon wafer (optical sheet) to a wafer frame by means of dicing tape, then manually place the wafer frame with the attached bare silicon wafer on a chuck of a dicing machine, then cut a slit on the bare silicon wafer with a newly replaced dicing blade, and move a camera toward the slit by an alignment distance H, then manually move the position of the camera such that the alignment line in the camera lens is aligned with the center line of the slit and measure the camera manually move distance, then input the camera manually move distance as a compensation value to a control system, so that the control system then re-determines the alignment distance H of the dicing blade on the basis of taking the compensation value into consideration. And finally, taking the bare silicon wafer out of the cutting machine after washing the bare silicon wafer, thereby completing the compensation or adjustment of the position error of the wafer cutting blade. Since the dicing blade is a consumable item and the positional error of the wafer dicing blade needs to be compensated or adjusted every time the dicing blade is replaced, this results in the need to use many bare silicon wafers, and the accessing and alignment adjustment process of the bare silicon wafers are performed by manual operation, which not only results in significant cost improvement but also greatly reduces production efficiency. Accordingly, there is a need for improvements in existing methods for compensating for positional errors of wafer dicing blades. Disclosure of Invention The present invention aims to overcome at least one of the above-mentioned drawbacks of the prior art by proposing an improved method for compensating for position errors of a wafer dicing blade. According to the present invention, there is provided a method for compensating a positional error of a wafer dicing blade detachably mounted to a moving part of a wafer dicing machine for dicing a wafer placed on a suction cup of the wafer dicing machine, the moving part being movably provided on a graduated screw of the wafer dicing machine, a camera being further mounted on the moving part, a blade alignment distance being spaced between a center line of the camera and a center line of the dicing blade, the method comprising: Placing a wafer frame to which a dicing tape is attached and on which a wafer to be diced is attached, onto the chuck; Cutting a notch on a blank area of the dicing tape at the periphery of the wafer by using the dicing blade; moving the moving portion by the blade alignment distance such that the camera