JPH1074718A - Semiconductor polishing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a semiconductor wafer from being broken due to the mixing of a foreign substance in the wafer in a polishing system for polishing the rear side of the semiconductor wafer with a plurality of circuits, such as ICs, formed on the surface side. SOLUTION: In a semiconductor wafer polishing system having at least a protective tape pasting process, in which a protective tape 4 is pasted on the surface of a semiconductor wafer 2, and a polishing process, in which the rear of the wafer pasted with the tape 4 after the protective tape pasting process is polished, a tape etching process (10 to 16) for inspecting the presence and absence of a foreign substance 17 on the side, where is pasted with the protective tape, of the wafer 2 is provided between the above protective tape pasting process and the polishing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing system for polishing a back surface of a semiconductor wafer having a plurality of circuits, such as ICs, formed on the front surface.

[0002]

2. Description of the Related Art In general, a semiconductor wafer having such a circuit formed thereon is polished thinly in order to enhance a heat radiation effect or the like before being cut into dice by a dicing device for each circuit.

In order to polish the semiconductor wafer, since a circuit is formed on the surface of the semiconductor wafer, a protective tape is adhered to this surface, and the surface on which the protective tape is adhered is polished. The semiconductor wafer is thinly finished by being brought into contact with a chuck table of the apparatus to be suction-supported and polishing the back side of the semiconductor wafer by a polishing grindstone of a polishing apparatus.

[0004]

However, although the interior of a factory that handles semiconductor wafers is a highly-cleaned clean room, it is still inevitable that hair or some dust is present. Chips may be generated when cutting after attaching the protective tape. Such foreign matter such as hair or chips may enter between the protective tape and the surface of the semiconductor wafer or adhere to the surface of the protective tape in the protective tape attaching step.

After the protective tape is adhered to the semiconductor wafer, the semiconductor wafer is transferred to a polishing step in a state in which the foreign matter such as the hair or the chips remains attached, and the semiconductor wafer to which the protective tape is adhered is attached. Will be placed on the chuck table of the polishing apparatus, and when a pressing force is applied by polishing, the flatness is impaired due to the presence of the foreign matter, and the pressing is locally concentrated.
A semiconductor wafer breaks due to shearing force in part,
There is a problem to say.

As described above, the conventional semiconductor wafer polishing system has a problem to be solved in preventing cracking of the semiconductor wafer caused by entry of foreign matter such as hair or chips of a protective tape.

[0007]

The gist of the present invention for solving the above problems of the semiconductor wafer polishing system according to the present invention is to provide a protective tape attaching step of attaching a protective tape to the surface of a semiconductor wafer, and the protective tape attaching step. A polishing step of polishing the back surface of the semiconductor wafer to which the protective tape has been attached after the attaching step, and a semiconductor wafer polishing system having at least, between the protective tape attaching step and the polishing step, the semiconductor wafer That is, a tape check step for inspecting the presence or absence of foreign matter on the side where the protective tape is attached is provided.

The checking means in the tape checking step includes an optical means, an image pickup means for taking in an image via the optical means, converting the image into an electric signal, and outputting the electric signal, and inputting the output of the image pickup means into a numerical value and outputting it. A / D conversion means,
An image processing means for inputting the output of the D conversion means and binarizing the output, and a determination means for inputting the output from the image means to determine the presence / absence of a foreign substance; The checking means in (1) is provided in an attaching device in a protective tape attaching process or a polishing device in a polishing process, or exists independently; in the tape checking process, a semiconductor wafer placed on an inspection table Irradiation is performed from the oblique direction to the side where the protective tape is adhered by the illumination device for inspection.

According to the semiconductor wafer polishing system of the present invention, before moving to the polishing step, it is detected whether or not foreign matter is attached to the protective tape side of the semiconductor wafer.
If foreign matter is attached, it can be determined and removed from the transfer line to the polishing process as foreign matter present,
In the polishing step, only the semiconductor wafer to which the foreign matter is not attached is transferred, so that the semiconductor wafer can be prevented from being broken by the foreign matter.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a semiconductor wafer polishing system according to the present invention will be described in detail with reference to the drawings. First, the semiconductor wafer 1 to be polished
As shown in FIG. 1, the semiconductor wafer 1 has a disk shape with a plurality of circuits 2 such as ICs formed on the front surface thereof. When polishing the back surface of the semiconductor wafer 1, a protective tape is attached to the front surface. Be worn.

In this protective tape attaching step, as shown in FIGS. 2 to 5, an attaching device A is used, and the semiconductor wafer 1 is placed on the chuck table 3 of the attaching device A.
The semiconductor wafer 1 is placed with its front side on which circuits 2 such as ICs are formed facing up.

The attaching device A includes a supply roller 5 on which a protective tape 4 with an adhesive is wound, a winding roller 6 for winding the protective tape 4 drawn from the supply roller, and a semiconductor device comprising And a sticking roller 7 for sticking by pressing against the wafer 1, and the protective tape 4 pulled out from the supply roller 5 with the adhesive surface downward.
Is pressed against the surface of the semiconductor wafer 1 by the bonding roller 7 between the winding roller 6 and the surface of the semiconductor wafer 1 by rolling the bonding roller 7 in the direction of arrow a. The protection tape 4 is stuck.

Further, the sticking device A is provided with a cutting means for the bonded protective tape 4, and the cutting means moves up and down as shown by arrow b and moves in the direction shown by arrow c. It comprises a rotating support shaft 8, a laterally protruding cutter holding member 8a attached to the tip of the support shaft 8, and a cutter 9 attached to the cutter holding member 8a.

Then, as shown in FIG. 3, the sticking roller 7 is retracted from above the semiconductor wafer 1 to another place,
The support member 8 is lowered to a predetermined position, the cutter 9 is pierced into the protective tape 4, and the support member 8 is rotated once in the direction of arrow c and pulled up.

Thus, as shown in FIG. 4A, the protective tape 4a adhered to the front side of the semiconductor wafer 1 placed on the chuck table 3, the supply roller 5 and the winding roller 6, and Then, the protective tape 4 is cut and separated, and as shown in FIG. 4B, a hole 4b is formed in the protective tape 4 after the protective tape 4a is cut off.

Thereafter, the supply roller 5 and the take-up roller 6 are rotated to move the protective tape 4 in the take-up direction to prepare for the next application, and as shown in FIG. Is attached to the front side of the semiconductor wafer 1,
It is taken out from the chuck table 3 and transferred to the next tape check step.

As shown in FIG. 6, the configuration of the inspection apparatus B in the tape check step is as follows: an illuminator 10 serving as an inspection illumination means for irradiating the surface of the semiconductor wafer 1 from an oblique direction.
And an optical unit 11 having an eyepiece and the like, for example, CC
Imaging means 12 including a D camera and the like, and A / D conversion means 1
3, an image processing means 14, a determining means 15 for determining the presence or absence of a foreign substance, and a monitor 16 for displaying an image.

The semiconductor wafer 1 transferred to the tape check step is placed on a chuck table 3a and is irradiated obliquely by the illuminator 10 so that, for example, foreign matter adheres to the protective tape 4a of the semiconductor wafer 1. In the case where the foreign matter or the foreign matter has entered between the surface of the wafer and the protective tape 4a, the foreign matter and the shadow of the foreign matter are enlarged and largely appear. Alternatively, it is converted into a binary signal of 1.

The image processing means 14 comprises, for example, 256
X256 pixels are binarized, and the presence of a small foreign substance of, for example, 10 to 20 μm can be extracted as a numerical value of 0 or 1.

Then, the determining means 15 determines whether or not foreign matter is attached to the semiconductor wafer 1,
If it is determined that foreign matter is present, the semiconductor wafer 1 is removed and transferred to another route, for example, a foreign matter removing step. Further, the semiconductor wafer 1 determined to have no foreign matter
Is transferred to the next polishing step.

The semiconductor wafer 1 transferred to the foreign matter removing step is transferred again to the tape check step after the foreign matter is removed, and when the foreign matter is removed by the foreign matter removal, it is determined that there is no foreign matter, and the next polishing step is performed. The semiconductor wafer 1 is transferred. If foreign matter is present between the semiconductor wafer 1 and the protective tape 4, the tape is peeled off, the foreign matter is removed, and then the tape is transferred to a tape attaching step where a new tape is attached. Transferred to the process.

In particular, the monitor 16 is provided with
2. The image of the front side of the semiconductor wafer 1 captured by the step 2, ie, the side on which the protective tape 4 is adhered, is displayed, and foreign materials 17 such as chips of the protective tape, dust in the air, and hair are visually recognized. It is.

Next, the semiconductor wafer 1 determined to be free of foreign matter is transferred to a polishing step and polished by the polishing apparatus C as shown in FIG.

The polishing apparatus C is a commonly used one. For example, a support member 19 provided upright on a work table 18 and a vertically movable movable member are provided on the support member 19. Shaft 2 protruding below the drive unit 20
0a, and the wheel 21
And a chuck table 23 provided on the work table 18 so as to face the grindstone 22.

Then, the semiconductor wafer 1 transferred to the polishing step is placed on the chuck table 23 with the front side of the semiconductor wafer 1 to which the protective tape 4a is adhered facing down. Is done.

As is generally performed in this state, the wheel 21 is rotated by the drive unit 20, the chuck table 23 is also rotated, and the back side of the semiconductor wafer 1 is polished to make the semiconductor wafer 1 thin. Is what you do.
Thereafter, the semiconductor wafer 1 is diced for each circuit by a dicing apparatus.

As described above, since the tape check step is interposed before the polishing step, foreign matter is not mixed in the polishing step.
Only the semiconductor wafer 1 having no adhesion is transferred, so that the semiconductor wafer is not cracked by the foreign matter.

In the above embodiment, the tape checking step has been described as being independent of the protective tape attaching step and the polishing step.
For example, provided in the sticking device A in the protective tape sticking step,
It can be provided in the polishing apparatus C. Thereby, the process path can be shortened. in short,
The gist of the present invention resides in a system in which a tape check step is incorporated before the polishing step.

[0029]

As described above, the semiconductor wafer polishing system according to the present invention inspects the presence or absence of foreign matter on the side where the protective tape is attached to the semiconductor wafer between the protective tape attaching step and the polishing step. Since the tape check step is provided, the presence or absence of foreign matter is checked in advance, and an excellent effect that cracking of the semiconductor wafer in the polishing step is prevented is prevented.

In addition, by irradiating the semiconductor wafer mounted on the inspection table on the protective tape attaching side in the tape check step from an oblique direction with the inspection illuminating means, the shadow of the foreign matter is greatly enlarged. This has an excellent effect that foreign matter can be easily found and foreign matter can be eliminated with high accuracy.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor wafer.

FIG. 2 is an explanatory view showing a state in which a protective tape 4 is adhered to a surface of a semiconductor wafer 1 in a protective tape attaching step.

FIG. 3 is an explanatory view showing a state in which the protective tape attached to the semiconductor wafer is cut by a cutter in the protective tape attaching step.

FIG. 4 is an explanatory view (a) after cutting the protective tape in the protective tape attaching step, and an explanatory view (b) showing a state in which holes corresponding to the semiconductor wafer portion are formed in the protective tape.

FIG. 5 is an explanatory view showing a state in which the semiconductor wafer having the protective tape adhered to the surface is transferred to the next tape check step from the protective tape attaching step.

FIG. 6 is a schematic configuration diagram showing a configuration of a tape check step according to the present invention.

FIG. 7 is an explanatory view showing a state where a semiconductor wafer is thinly polished by a polishing apparatus in a polishing step.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Circuit of IC etc., 2 Semiconductor wafer, 3 Chuck table, 4 Protective tape, 4a Cut-off protective tape, 5 Supply roller, 6 Take-up roller, 7 Sticking roller, 8 Support member, 9 Cutter, 10 Illuminator, 1
Reference Signs List 1 optical means, 12 imaging means, 13 A / D conversion means, 14 image processing means, 15 determination means, 16 monitor, 17 foreign matter, 18 work table, 19 support member, 20 drive section, 20a rotation axis, 21 wheel,
22 whetstone, 23 chuck table, A sticking device,
B inspection device, C polishing device.

Claims (4)

[Claims] 1. A protective tape attaching step of attaching a protective tape to a surface of a semiconductor wafer, and a polishing step of polishing a back surface of the semiconductor wafer to which the protective tape is attached after the protective tape attaching step. In a semiconductor wafer polishing system having at least a tape check step for inspecting the presence or absence of foreign matter on the protective tape sticking side of the semiconductor wafer is provided between the protective tape sticking step and the polishing step. Polishing system for semiconductor wafers. 2. The checking means in the tape checking step,
An optical unit, an imaging unit that captures an image via the optical unit, converts the image into an electric signal, and outputs the signal, an A / D conversion unit that inputs an output of the imaging unit, quantifies the output, and outputs the numerical value, and an A / D conversion unit 2. An image processing means for inputting the output of the image processing unit and binarizing the output, and outputting the output, and determining means for inputting the output from the image processing unit and determining the presence or absence of a foreign substance. A polishing system for a semiconductor wafer as described in the above. 3. The checking means in the tape checking step is provided in a sticking device in the protective tape sticking step or a polishing device in the polishing step, or is present independently. Or a polishing system for a semiconductor wafer according to item 2. 4. The inspection device according to claim 1, wherein the semiconductor tape mounted on the inspection table in the tape check step is irradiated from an oblique direction to the protective tape sticking side by an inspection illumination means. Semiconductor wafer polishing system.