WO2005083763A1

WO2005083763A1 - Wafer transcription method

Info

Publication number: WO2005083763A1
Application number: PCT/JP2005/003146
Authority: WO
Inventors: Kinya Mochida; Mikio Komiyama; Kenichi Watanabe
Original assignee: Lintec Corporation
Priority date: 2004-03-01
Filing date: 2005-02-25
Publication date: 2005-09-09
Also published as: KR20060123462A; JP4768963B2; TWI354325B; JP2007220693A; TW200532786A; MY162177A; DE112005000448T5

Abstract

A wafer transcription method by which pick up is made possible by using a general purpose pick up apparatus. A wafer (1), of which a circuit side is fixed on a first frame (3) through a first adhesive sheet (2), is transcribed into a status where a side opposite to the circuit side is fixed on a second frame (6) through a second adhesive sheet (7) by the wafer transcription method. The wafer (1) fixed on the first frame (3) is permitted to abut on a transcription table (5) having a diameter larger than that of the wafer (1) but smaller than the inner diameter of the first frame (3), with the first adhesive sheet (2) at the bottom, then, the first frame (3) is pulled down, and under such conditions, the second frame (6) whereupon the second adhesive sheet (7) is stuck is arranged above the wafer (1). After sticking the second adhesive sheet (7) on the wafer (1), the first adhesive sheet (2) is peeled from the wafer (1), and the wafer (1) is transcribed on the second frame (6).

Description

Specification

Wafer transfer method

Technical field

The present invention relates to a wafer transfer method for transferring a framed semiconductor wafer (hereinafter simply referred to as “wafer”) fixed to a frame via an adhesive sheet to a state fixed to another frame. It is about.

Background art

[0002] For example, in a manufacturing process of a semiconductor device in an electronic industry or an optical industry, after a predetermined circuit pattern is formed on a surface of a wafer, the thickness of the wafer is reduced to be uniform, or when a circuit is formed. In order to remove the generated oxide film, the back surface of the wafer is ground (knock-grinded), and then the wafer is diced into circuits to obtain desired semiconductor chips (hereinafter simply referred to as “chips”). Manufacturing. Then, the chip is picked up in a subsequent pick-up step, the picked-up chip is die-bonded to a base such as a lead frame in the next die bonding step, and a desired semiconductor device is passed through subsequent steps such as molding. As if to manufacture.

[0003] In recent years, it has been desired to make a chip extremely thin as a semiconductor device. Under such circumstances, after the chip is made extremely thin, it is still separated into individual pieces (chips), which destroys a wafer. It has been difficult to carry them without any trouble and to perform processing such as dicing.

[0004] Therefore, since the wafer can be singulated without hardening any physical force on the wafer, the force of the dicing method by stealth dicing (registered trademark) is significantly larger than that of an extremely thin wafer. It is expected.

[0005] Stealth dicing involves irradiating the inside of a wafer with a focused laser beam and irradiating it with a laser beam, and modifying the focal point to form a weakened region, thereby forming a locus of the laser beam-irradiated focal point. This is a dicing method for cutting a wafer as a starting point (for example, see Patent Document 1). Stealth dicing of the wafer will only crack the modified area with very little force and will not cause unnecessary cracks in other parts. For this reason, compared to the normal dicing method in which cutting is performed by physical force, the processing of an extremely thin wafer is performed. Suitable for

[0006] However, even with the processing by stealth dicing, in order to carry out subsequent handling such as transfer of the wafer, the wafer is fixed to a ring-shaped frame via an adhesive sheet so as not to directly touch the wafer (chip). It was necessary to make the state of the work done.

[0007] By the way, when stealth dicing is performed, the laser beam irradiation is avoided by avoiding the transmission of a layer different from the material of the wafer body such as a circuit surface or an adhesive sheet as shown in FIG. Better to go. For this reason, the adhesive sheet is stuck on the circuit surface side, and the laser beam is irradiated from the back surface (ground surface) side of the wafer.

Patent Document 1: Japanese Patent No. 3408805

Disclosure of the invention

Problems to be solved by the invention

[0009] When picking up a chip while applying force, the chip recognition mechanism of a general-purpose pick-up device applies an adhesive sheet to the circuit surface side in order to recognize the position of the chip by detecting the circuit with a camera above the work force. An accurate positional relationship of the chips cannot be achieved with a worn work. Further, since the chip is pushed up with respect to the circuit surface, if a small amount of damage is given to the circuit, the following problem occurs.

[0010] The present invention has been made in view of the above problems, and transfers a state of a work in which an adhesive sheet is adhered to a circuit surface of a wafer to a state of a work in which an adhesive sheet is adhered to the back surface of a wafer. Accordingly, it is an object of the present invention to provide a method of transferring a wafer that can be picked up using a general-purpose pickup device. In particular, an object of the present invention is to provide a method of transferring a wafer that enables pick-up of a chip by a normal method from a work on which a wafer (chip) subjected to stealth dicing is fixed.

Means for solving the problem

[0011] In order to achieve the above object, the invention according to claim 1 is directed to a method in which a wafer having a circuit surface side fixed to a ring-shaped first frame via a first adhesive sheet is attached to a ring-shaped second frame. As a method for transferring a framed wafer in which a surface opposite to the circuit surface is fixed via a second adhesive sheet via a second adhesive sheet, a wafer fixed to the first frame is transferred to the wafer. Transfer table having a diameter larger than the diameter of the first frame and smaller than the inside diameter of the first frame After the first pressure-sensitive adhesive sheet is brought into contact with the first pressure-sensitive adhesive sheet downward, the first frame is pulled down, and in this state, the second pressure-sensitive adhesive sheet having the second pressure-sensitive adhesive sheet stuck thereon is above the wafer. 2 is disposed, and after attaching a second adhesive sheet to the wafer, the first adhesive sheet is peeled off from the eno, and the wafer is transferred to the second frame side. You.

[0012] The invention according to claim 2 is characterized in that, in the invention according to claim 1, the wafer is a wafer in which a dicing line is modified and weakened by irradiation with a laser beam.

The invention's effect

[0013] According to the wafer transfer method of the present invention, the work in which the adhesive sheet is adhered to the circuit surface of the wafer is transferred and becomes a normal work in which the adhesive sheet is adhered to the back surface of the wafer. The chip can be picked up using the pickup device. In particular, according to the wafer transfer method of the present invention, the transfer or processing of a wafer (chip) that has been subjected to stealth dicing or a fixed work can be performed. This can be performed more easily.

Brief Description of Drawings

FIG. 1 is a side sectional view showing a method of the present invention (a first work on which a wafer is reverse-mounted).

FIG. 2 is a side sectional view showing the method of the present invention (a step of setting a first work on a transfer table).

FIG. 3 is a side sectional view showing the method of the present invention (a step of pulling out the first frame).

FIG. 4 is a side sectional view showing the method of the present invention (a step of setting a second frame and a second pressure-sensitive adhesive sheet).

FIG. 5 is a side sectional view showing the method (transfer step) of the present invention.

FIG. 6 is a side sectional view showing the method (transfer step) of the present invention.

FIG. 7 is a side sectional view showing the method of the present invention (second work after transfer).

FIG. 8 is a side sectional view showing the wafer to which the surface protection tape has been attached.

FIG. 9 is a side sectional view showing a wafer back surface grinding (back grinding) step.

FIG. 10 is a side sectional view showing the configuration of another first work of the present invention. Explanation of reference numerals

1 Ueno

la chip

2 First adhesive sheet ten

3 First frame

5 Transfer table

6 Second frame

7 Second adhesive sheet

8 Sticking roller

9 rotating cannon

11 Adhesive sheet

Wl 1st work

W2 Second work

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 to FIG. 7 are side sectional views showing the method of the present invention in the order of steps.

FIG. 1 shows a configuration of a first work W1. The first work W1 is a ring-shaped first work W1 from a back surface of a wafer 1 stealth diced through a first adhesive sheet 2. It is constructed by integrating with frame 3 of 1.

Here, the wafer 1 is made extremely thin by grinding the back surface in the grinding step shown in FIG. The first work W1 is attached to the first adhesive sheet 2 on the circuit surface side of the extremely thin wafer 1 and is attached to the ring-shaped first frame 3 arranged around the wafer 1. It is constituted by sticking. In this state, the wafer 1 is reverse-mounted on the first adhesive sheet 2 with the circuit side down, and subsequently, the back surface (ground surface) side force is applied by a stealth dicing device (not shown) along the dicing line. It is irradiated. Then, the dicing line is modified and weakened by the irradiation of the laser beam, so that the wafer 1 can be divided into chips la with an extremely small force.

Thus, in the method of the present invention, as shown in FIG. 2, the first work W1 shown in FIG. It is placed on a disk-shaped transfer table 5 with the first adhesive sheet 2 facing down. Incidentally, the transfer table 5 may be provided with a suction fixing means (not shown).

Here, the diameter of the transfer table 5 is set to be larger than the diameter of the wafer 1 and smaller than the inner diameter of the first frame 3.

Next, from the state shown in FIG. 2, the first frame 3 is pulled down along the outer periphery of the transfer table 5 as shown in FIG. The first frame 3 is dropped for the purpose of preventing another second adhesive sheet 7 from adhering to the first adhesive sheet 2 in a transfer step described later. When the first frame 3 is withdrawn, the vacuum suction means is in the OFF state.

In the present embodiment, therefore, the dicing line of the wafer 1 is easily broken by stealth dicing by increasing the amount of pulling-down of the first frame 3 (brake). And singulated into multiple chips la (see Fig. 3). In this way, the first frame 3 can be dropped to separate the wafer 1 into chips la, and at the same time, the gap (calf) between the chips la can be expanded, and the subsequent expanding step in the pickup device can be omitted. Monkey

Thereafter, as shown in FIG. 4, a second frame 6 having a second adhesive sheet 7 adhered to the periphery thereof is set above the wafer 1 (a plurality of individual chips la). As shown in FIG. 5, the second pressure-sensitive adhesive sheet 7 is brought close to the back surface (upper surface) of the wafer 1 (the plurality of individual chips la) so as not to come into contact therewith. Then, the upper adhesive force of the second adhesive sheet 7 is moved in the direction of the arrow in FIG. 5 while rotating the application roller 8 to rotate the second adhesive tape 7 into the wafer 1 (a plurality of individual pieces). Affix to the back (top) of chip la).

[0025] As a method for attaching the second pressure-sensitive adhesive sheet 7, another method different from the above method may be used. For example, the second frame 6 is set around its periphery such that its upper surface is at the same height as the back surface (upper surface) of the chips la, and the second adhesive sheet 7 is placed together with the chips la in the second frame. It is OK to attach them all to frame 6!

When the transfer table 5 is provided with a suction fixing means, the first pressure-sensitive adhesive sheet 7 is attached to the wafer 1 (a plurality of individual chips la), Until the stage where the adhesive sheet 2 is released and the transfer is completed, this adsorption fixing means is turned on and the chip 1 is turned on. a can be prevented from shifting or falling off.

Next, as shown in FIG. 6, when the second frame 6 and the second adhesive sheet 7 fixed thereto are lifted upward, the wafer 1 (a plurality of individual chips la) is lifted. Then, the first pressure-sensitive adhesive sheet 2 is also released, adheres to the second pressure-sensitive adhesive sheet 7, and is transferred thereto. As a result, as shown in FIG. 7, the wafer 1 (the plurality of individual chips la) having the first adhesive sheet 2 adhered to the circuit surface thereof has the second surface on the back surface (ground surface) side as shown in FIG. The second adhesive sheet 7 is adhered, and the second work W2 is formed by integrally bonding the wafer 1 and the second frame 6 with the second adhesive sheet 7.

Accordingly, in the second work W2 shown in FIG. 7, the wafer 1 (a plurality of individual chips la) is turned upside down by the transfer to the second adhesive sheet 7 so that the circuit surface thereof faces upward. In the subsequent pick-up process, the pattern on the circuit surface of the chip la can be easily recognized by the camera, and the position of the chip la can be accurately recognized based on that, and the pick-up device is mounted. The suction collet can face the chip la to be picked up without any deviation. This prevents the chip la from being picked up incorrectly.

The first pressure-sensitive adhesive sheet 2 and the second pressure-sensitive adhesive sheet 7 may each be a UV-curable pressure-sensitive adhesive sheet. If the first pressure-sensitive adhesive sheet 2 is a UV-curable pressure-sensitive adhesive sheet, the pressure-sensitive adhesive force can be controlled by irradiating ultraviolet rays, so that the wafer 1 (chip la) can be fixed and the second pressure-sensitive adhesive sheet 7 in the expanding step. The transfer to the computer can be performed without difficulty.

Further, if the second pressure-sensitive adhesive sheet 7 is a UV-curable pressure-sensitive adhesive sheet, both the fixing of the wafer 1 (chip la) and the pickup operation in the transfer step can be performed without difficulty.

[0031] When the first pressure-sensitive adhesive sheet 2 and the second pressure-sensitive adhesive sheet 7 are both UV-curable pressure-sensitive adhesive sheets, the same type of pressure-sensitive adhesive sheet can be used, which simplifies material management. I can do it. For such an ultraviolet-curable pressure-sensitive adhesive sheet, a dicing tape used in a normal dicing step-pickup step can be used as it is.

By the way, in the present embodiment, the back surface is subjected to stealth dicing, and the dicing line is Although the method of transferring a wafer in a state of being modified and weakened by the irradiation of each light beam has been described, the present invention relates to the transfer of wafers already singulated by dicing by another method. Is similarly applicable.

FIG. 8 to FIG. 10 show steps of preparing a work in which an adhesive sheet is adhered to a circuit surface of a wafer by a method different from stealth dicing.

In FIG. 8, the wafer 1 has a surface protection tape 4 for grinding the back surface of the wafer attached to the circuit surface side. The wafer 1 is mounted on a processing table of a back grinding device (not shown) with its back surface facing upward, and is ground to a predetermined thickness by a rotating gantry 9 of the back grinding device (FIG. 9).

Subsequently, the ring-shaped frame 3 is arranged on the outer periphery of the wafer 1, and the adhesive sheet 11 is collectively adhered to the frame 3 and the surface protection tape 4 side of the wafer 1. Further, the work (first work) W1 shown in FIG. 10 is formed by subjecting the wafer 1 to full-cut dicing.

[0036] The first work W1 thus prepared is separated from the adhesive sheet 11 together with the surface protection tape 4 by the transfer method of the present invention to separate the wafer 1 (a plurality of individual chips la). The transfer can be performed, and the structure of the second work W2 is the same as the work shown in FIG. This allows the chip la to be picked up by a general-purpose pickup device.

Industrial applicability

The present invention is particularly useful as a method for transferring an extremely thin backside dicing wafer in a process of manufacturing a semiconductor device in the electronics industry or the optical industry.

Claims

The scope of the claims

[1] A wafer with the circuit surface side fixed to the first ring-shaped frame via the first adhesive sheet, and a second adhesive sheet on the second ring-shaped frame opposite to the circuit surface side. A method of transferring a framed wafer to a fixed state via

The wafer fixed to the first frame was brought into contact with a transfer table having a diameter larger than the diameter of the wafer and smaller than the inner diameter of the first frame with the first adhesive sheet facing down. Thereafter, the first frame is pulled down, and in that state, the second frame on which the second adhesive sheet is adhered is arranged above the wafer, and a second adhesive sheet is attached to the wafer. A method of transferring a wafer, comprising: after adhering, peeling the first adhesive sheet from the wafer and transferring the wafer to a second frame side.

2. The wafer transfer method according to claim 1, wherein the wafer is a wafer whose dicing line is modified and weakened by irradiation with a laser beam.