JP2015119068A - Processing method for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method for a wafer, by which the possibility of failure in die bonding step can be reduced.SOLUTION: A processing method for a wafer in which a device is formed in each of areas formed on the surface of the wafer and separated by a plurality of dividing lines intersecting one another comprises: a tape sticking step in which a dicing tape is stuck to the back of a wafer via a die bonding film; a holding step in which, after the tape sticking step, the wafer is held on a chuck table via the dicing tape; a cutting step in which the wafer held on the chuck table is cut from its surface to the dicing tape by a cutting blade, and separating grooves are formed for separating the wafer and the die bonding film by cutting them along the dividing lines and a heat emitting step in which after the cutting step, heat is applied along the cutting grooves and thereby a whisker-like burr of the die bonding film caused in the cutting step is melted to the minimum.

Description

  The present invention relates to a wafer processing method for dividing a wafer with a die bonding film to form a plurality of chips with a die bonding film.

  In a semiconductor device manufacturing process, a semiconductor wafer in which devices such as ICs and LSIs are formed in each region partitioned by a plurality of division lines formed in a lattice pattern on the surface is individually divided along the division lines. A semiconductor device is formed by dividing into devices.

  The divided semiconductor devices are die-bonded (adhered) to a metal substrate (lead frame), a tape substrate, or the like, and individual semiconductor chips are manufactured by dividing the metal substrate or the tape substrate. The semiconductor chip thus manufactured is widely used in various electronic devices such as mobile phones and personal computers.

  In order to die-bond a semiconductor device on a substrate, an adhesive such as solder, Au-Si eutectic, resin paste or the like is supplied to the semiconductor device mounting position on the substrate, and the semiconductor device is mounted thereon and bonded. The method is used.

  In recent years, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-182959, a sheet-like die bonding film called DAF (Die Attach Film) or DBF (Die Bond Film) is previously pasted on the back surface of a semiconductor wafer. The method of wearing is widely adopted.

  That is, by dividing the semiconductor wafer to which the DAF is bonded into individual chips, a semiconductor chip having the DAF attached to the back surface is formed. Thereafter, by bonding the semiconductor chip to the substrate via the DAF on the back surface of the semiconductor chip, there is an advantage that the adhesive used is minimized and the mounting area of the semiconductor chip can be minimized.

JP 2000-182959 A

  However, since DAF has a high ductility, when a semiconductor wafer to which DAF is bonded is cut with a cutting blade, there is a problem in that scissors-like burrs are generated in the cut DAF, causing disconnection during bonding.

  The present invention has been made in view of these points, and an object of the present invention is to provide a wafer processing method capable of reducing the risk of causing defects in the die bonding process.

According to the present invention, there is provided a wafer processing method in which devices are formed in respective regions defined by a plurality of intersecting division lines formed on a surface, and the wafer is diced on the back surface of the wafer via a die bonding film. A tape adhering step for adhering the tape, a holding step for holding the wafer on the chuck table via the dicing tape after performing the tape adhering step, and cutting from the surface of the wafer held on the chuck table Cutting the blade until reaching the dicing tape, cutting along the planned dividing line to form a dividing groove for dividing the wafer and the die bonding film, and after performing the cutting step, The die bonding fill generated in the cutting step by irradiating heat along the dividing groove A heat radiation step of melting reduction of whisker-like burrs,
A method for processing a wafer is provided.

  In the wafer processing method of the present invention, after the wafer is cut, a heat irradiation step of irradiating heat to the cut grooves formed by cutting is performed. By irradiating the dividing grooves with heat, the burrs in the die bonding film generated in the cutting step shrink and melt, reducing the risk that the burrs will reach the surface of the divided chip and adhere to the surface. It is possible to reduce the risk of occurrence of defects in the subsequent bonding process.

It is a surface side perspective view of a semiconductor wafer. It is a perspective view which shows a tape sticking step. It is a partial cross section side view which shows a holding | maintenance step. It is a partial cross section side view which shows a cutting step. It is a partial cross section side view which shows a heat irradiation step. It is a partial cross section side view which shows a pick-up step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a front side perspective view of a semiconductor wafer (hereinafter sometimes simply referred to as a wafer) 11.

  The semiconductor wafer 11 is made of, for example, a silicon wafer having a thickness of 100 μm, and a plurality of division lines (streets) 13 are formed in a lattice shape on the surface 11 a and are partitioned by the plurality of division lines 13. Devices 15 such as IC and LSI are formed in each region. A notch 17 is formed on the outer periphery of the wafer 11 as a mark indicating the crystal orientation of the silicon wafer. Reference numeral 11 b denotes the back surface of the wafer 11.

  In the wafer processing method of the present invention, first, as shown in FIG. 2, the back surface of the wafer 11 is attached to a die bonding film 12 such as DAF, and the outer periphery of the die bonding film 12 is attached to an annular frame F. Affixed to the dicing tape T. That is, a tape adhering step for adhering the back surface 11b of the wafer 11 to the dicing tape T through the die bonding film 12 is performed.

  After performing the tape adhering step, as shown in FIG. 3, a holding step of sucking and holding the wafer 11 through the dicing tape T is performed by the chuck table 14 of the cutting device. The annular frame F is clamped and fixed by a clamp 16.

  Next, the wafer 11 held on the chuck table 14 is imaged by an imaging unit (not shown) of the cutting apparatus, and alignment is performed to detect the street 13 to be cut from the captured image by image processing such as pattern matching.

  After the alignment, as shown in FIG. 4, the cutting blade 20 mounted on the spindle 18 is rotated from the surface 11a of the wafer 11 to the dicing tape T while rotating at high speed in the direction of arrow A, and the chuck table By cutting and feeding 14, the cutting step of cutting along the scheduled dividing line 13 to form a dividing groove 19 for dividing the wafer 11 and the die bonding film 12 is performed.

  This cutting step is performed along all the division lines 13 that extend in the first direction while indexing and feeding the cutting blade 20, and then the chuck table 14 is rotated by 90 ° to be orthogonal to the first direction. The wafer 11 is divided into individual chips 21 each having a die bonding film 12 adhered to the back surface.

  Since the die bonding film 12 has high ductility, when the wafer 11 to which the die bonding film 12 is adhered is cut with the cutting blade 20, a bowl-shaped burr 22 is generated, and this burr 22 adheres to the surface of the chip 21. Sometimes. If the burrs 22 adhering to the surface of the chip 21 are left as they are, there is a problem of causing disconnection during chip 21 bonding.

  Therefore, in the present invention, as shown in FIG. 5, the wafer 11 is sucked and held by the chuck table 14A of the heat irradiation device via the dicing tape T, and the annular frame F is clamped and fixed by the clamp 16A.

  Then, heat is irradiated from the heater or the heat irradiation lamp 24 along the dividing groove 19 of the wafer 11 to reduce and melt the bowl-shaped burrs 22 of the die bonding film 12 generated in the cutting step, and from the surface of the chip 21. Completely removes the burrs 22 (thermal irradiation step).

  After the heat irradiation step, as shown in FIG. 6, the wafer 11 is sucked and held by the chuck table 14B of the pickup device via the dicing tape T, and the annular frame F is clamped and fixed by the clamp 16B. And the chip | tip 21 by which the film 12 for die bonding was stuck to the back surface by the pick-up collet 26 is picked up, and it accommodates in a chip | tip accommodation container.

  In the chip 21 manufactured by the wafer processing method of the present invention, the burrs 22 of the die bonding film 12 are reduced and removed from the surface of the chip 21 in the heat irradiation step. It is possible to reduce the risk of occurrence of defects such as disconnection.

11 Semiconductor Wafer 12 Die Bonding Films 14, 14A, 14B Chuck Table 19 Dividing Groove 20 Cutting Blade 22 Burr 24 Heat Irradiation Lamp 26 Pickup Collet

Claims (1)

A wafer processing method in which a device is formed in each region defined by a plurality of intersecting scheduled lines formed on a surface,
A tape attaching step of attaching a dicing tape to the back surface of the wafer via a die bonding film;
A holding step for holding the wafer on the chuck table via the dicing tape after performing the tape adhering step;
Cutting in which a cutting blade is cut from the surface of the wafer held on the chuck table to the dicing tape, and cut along the planned dividing line to form a dividing groove for dividing the wafer and the die bonding film. Steps,
After performing the cutting step, a heat irradiation step of radiating heat along the dividing groove to reduce and melt the bowl-shaped burrs of the die bonding film generated in the cutting step;
A wafer processing method characterized by comprising: