JP2003068832A - Dicing tape and its using method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a semiconductor chip against damage at the time of spreading a dicing tape or picking up the semiconductor chip following to dicing even if a wafer is made thin. SOLUTION: A dicing tape 1 is provided with through holes 2 of microdiameter over the entire surface thereof. When a wafer 3 pasted to the dicing tape 1 is diced into semiconductor chips 3a and then the dicing tape 1 is spread, diameters of the through holes 2 are enlarged because the dicing tape 1 is spread in all directions. Consequently, air spreads through the enlarged through holes 2 to the rear sides of the semiconductor chips 3a and adhesion between the semiconductor chips 3a and the dicing tape 1 is relaxed thus facilitating stripping of the semiconductor chips 3a from the dicing tape 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dicing tape which is attached to the back surface of a wafer to hold the wafer in a dicing process for cutting the wafer into semiconductor chips and a method of using the dicing tape. Specifically, by providing a minute through-hole on the entire surface of the dicing tape, air is allowed to enter the back surface of the semiconductor chip from the through-hole when the dicing tape is stretched, thereby promoting separation of the semiconductor chip from the dicing tape. Even if the semiconductor chip is thinner than the current state, the semiconductor chip is prevented from being damaged when peeled from the dicing tape after dicing.

[0002]

2. Description of the Related Art In a dicing process for cutting a wafer into semiconductor chips, a dicing tape is used to hold the wafer. FIG. 9 is a perspective view showing a conventional dicing tape.

The conventional dicing tape 11 is a smooth tape having an adhesive layer on one surface, and is usually supplied in the form of a long product wound in a roll. FIG. 10 is a perspective view showing a usage state of a conventional dicing tape. The dicing tape 11 has a wafer 12 attached to one surface thereof, the dicing tape 11 attached with the wafer 12 is attached to a ring-shaped frame 13, and the dicing tape 11 is cut according to the shape of the frame 13. It is used as it is.

The wafer 12 held by the dicing tape 11 is cut into semiconductor chips by a dicing device (not shown). When the cutting of the wafer 12 is completed, the dicing tape 11 is extended to increase the distance between the semiconductor chips, and then the semiconductor chips are picked up.

FIG. 11 is a perspective view showing an outline of a mechanism for picking up a semiconductor chip. Dicing tape 11
A needle elevating mechanism 14 is provided on the back surface side of the needle 14a, and the needle 14a projects according to the position of the semiconductor chip 12a to be picked up. Also, the suction collet 15
Is attached to a robot hand or the like (not shown), sucks and holds the semiconductor chip 12a pushed up by the needle 14a, and conveys it to another place.

As a result, the semiconductor chip 12a is pushed up together with the dicing tape 11 by the needle 14a from the back surface side of the dicing tape 11, and the suction collet 1 is used.
The semiconductor chip 12a is peeled from the dicing tape 11 and picked up by positioning 5 on the corresponding semiconductor chip 12a and lifting the semiconductor chip 12a in a sucked state.

[0007]

The current wafer has a thickness of about 400 μm, and if the thickness is about this, the dicing tape is stretched or the semiconductor chip is cracked or cracked at the time of picking up the semiconductor chip thereafter. There will be no obstacles such as

However, as the thickness of the wafer becomes thinner in order to make the semiconductor chip thinner, when the dicing tape is stretched, the semiconductor chip itself is pulled by the stretching of the dicing tape and cracked, or when dicing at the time of pickup. There was a problem of losing the adhesive strength of the tape and breaking it.

The present invention has been made in order to solve such a problem, and even a thin semiconductor chip is prevented from being damaged when the dicing tape is stretched or picked up from the dicing tape, and a method of using the dicing tape. The purpose is to provide.

[0010]

In order to solve the above-mentioned problems, the dicing tape according to the present invention comprises an adhesive layer provided on one surface of a flexible sheet-shaped substrate,
In a dicing process for cutting a wafer into semiconductor chips, a dicing tape to be attached to the back surface of the wafer has a plurality of small micro-holes penetrating from the surface of the base material to the surface of the adhesive layer on at least the entire surface of the portion where the wafer is attached. A through hole is provided.

The dicing tape according to the present invention described above is attached to the back surface of the wafer. The wafer to which the dicing tape is attached is cut into individual semiconductor chips in the dicing process. Then, when the dicing process is completed, the dicing tape is stretched to form a gap between the semiconductor chips to facilitate pickup.

Since the dicing tape is provided with a plurality of minute through holes, the through holes are expanded by stretching the dicing tape. As a result, air enters the contact points between the dicing tape and the semiconductor chips through the through holes, and the adhesion between the dicing tape and the semiconductor chips is relaxed. Therefore, the semiconductor chip can be easily picked up, and even a thin semiconductor chip is not damaged.

Further, the method of using the dicing tape according to the present invention is a dicing step of cutting a wafer into semiconductor chips, and in the method of using the dicing tape which is attached to the back surface of the wafer, at least the entire surface of the portion to which the wafer is attached is used. , A wafer is attached to a dicing tape having a plurality of minute through holes, the wafer is diced, and then the through holes are expanded by stretching the dicing tape, and air is passed from the through holes to the back surface of the semiconductor chip. Is to take in.

In the above-described method of using the dicing tape according to the present invention, the through hole is expanded by stretching the dicing tape, and the air entering the through hole relaxes the adhesion of the dicing tape to the semiconductor chip. As a result, the semiconductor chip can be easily picked up, and even a thin semiconductor chip is not damaged.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a dicing tape of the present invention will be described below with reference to the drawings. That is, FIG. 1 is an explanatory view showing the dicing tape of the present embodiment,
FIG. 1A is a plan view of the dicing tape, and FIG. 1B is a sectional view of a main part of the dicing tape.

The dicing tape 1 of the present embodiment is provided with minute through holes 2 on the entire surface thereof, so that air is taken in from the through holes 2 when the wafer is stretched after dicing, and the semiconductor chip is peeled off. To prevent the damage.

The dicing tape 1 has a pressure-sensitive adhesive layer 1b provided on one surface of a transparent and flexible substrate 1a. The pressure-sensitive adhesive layer 1b is formed by applying a UV-curable pressure-sensitive adhesive to the base material 1a, for example. This UV-curable pressure-sensitive adhesive has the property that when it is irradiated with UV rays, it cures and weakens its adhesive strength.

The dicing tape 1 is provided with a plurality of through holes 2. The through hole 2 has a circular shape with a minute diameter and is provided over the entire surface of the dicing tape 1. The through hole 2 penetrates the pressure-sensitive adhesive layer 1b of the dicing tape 1 and penetrates from the front surface to the back surface of the dicing tape 1.

FIG. 2 is a perspective view showing a usage state of the dicing tape of this embodiment. The wafer 3 is attached to the dicing tape 1. Then, the dicing tape 1 to which the wafer 3 is attached is attached to the ring-shaped frame 4. At this time, wafer 3
The dicing tape 1 is attached to the frame 4 so that is located substantially in the center of the frame 4, and the dicing tape 1 is cut in accordance with the shape of the frame 4.

Since the dicing tape 1 is provided with a plurality of through holes 2 as described in FIG. 1, when the dicing tape 1 is attached to the wafer 3, the through holes 2 are formed on the entire back surface of the wafer 3. To exist. And
The wafer 3 held on the dicing tape 1 is cut into semiconductor chips 3a by a dicing device (not shown).

FIG. 3 shows the through hole 2 and the semiconductor chip 3 described above.
It is explanatory drawing which shows the relationship of a. The wafer 3 attached to the dicing tape 1 as shown in FIG. 2 is cut into the size of the semiconductor chip 3a by a dicing device (not shown). Note that in FIG. 3, the size of the semiconductor chip 3a is shown in a range surrounded by a two-dot chain line. And
The diameter and pitch of the through holes 2 are determined so that, for example, about 30 through holes 2 are present on the back surface of the semiconductor chip 3a.

Here, the dicing tape 1 is required to have adhesiveness capable of holding the wafer 3 during dicing of the wafer 3. Providing the through holes 2 in the dicing tape 1 reduces the contact area with the wafer 3. Therefore, the number of the through holes 2 existing on the back surface of the semiconductor chip 3a is not limited to the above-mentioned example, and the size of the semiconductor chip 3a, the securing of the contact area for preventing the adhesiveness from being unnecessarily reduced, and the like are taken into consideration. Is set.

FIG. 4 is a perspective view showing the supply state of the dicing tape of this embodiment. The dicing tape 1 is
It is supplied in the form of a long product having a predetermined width rolled into a roll. There are several diameters of the wafer 3 handled in the dicing process, such as 6 inches, 8 inches, or 12 inches. The dicing tape 1 is provided with through-holes 2 on its entire surface so as to accommodate the wafers 3 having different diameters.

An apparatus (not shown) for attaching the dicing tape 1 to the wafer 3 has a mechanism for cutting the dicing tape 1 set on the frame 4 into a predetermined size. Therefore, by providing the through holes 2 on the entire surface of the dicing tape 1, the through holes 2 can be present on the entire back surface of the wafer 3 regardless of the size of the wafer 3. Further, as shown in FIG. 3, if the diameter of the through holes 2 is smaller than the size of the semiconductor chip 3a and the pitch is narrow, the wafer 3 may be placed at any position on the dicing tape 1 before cutting shown in FIG. Even if they are attached, the through holes 2 are evenly present under all the semiconductor chips 3a.

The method of using the dicing tape of this embodiment will be described below. In the dicing process of the wafer 3, first, as shown in FIG. 2, the dicing tape 1 is attached to the back surface of the wafer 3, and the dicing tape 1 to which the wafer 3 is attached is attached to the frame 4.

Then, the wafer 3 is cut into the size of the semiconductor chip 3a by a dicing device (not shown). When the cutting of the wafer 3 is completed, the dicing tape 1 is stretched. FIG. 5 is an explanatory view showing the operation of stretching the dicing tape 1, and FIG. 5 (a) shows a state before stretching.
FIG. 5B shows the state after stretching.

Below the dicing tape 1 attached to the frame 4, the diameter of the wafer 3 is larger than that of the wafer 3, and
A table 5 having a predetermined size smaller than the inner diameter of the frame 4 is provided. The table 5 is configured to move up and down by a drive mechanism (not shown).

Then, with the frame 4 held, as shown in FIG. 5B, the table 5 is raised to push up the portion of the dicing tape 1 to which the wafer 3 is attached from the back surface thereof. As a result, the dicing tape 1 is stretched in all directions. Then, by extending the dicing tape 1 in all directions, the intervals between the semiconductor chips 3a adjacent to each other on the dicing tape 1 also increase.

FIG. 6 is a sectional view showing the state of the dicing tape before and after stretching. FIG. 6A shows the state before stretching and FIG. 6B shows the state after stretching. As shown in FIG. 6A, when the wafer 3 is cut, the wafer 3 is fully cut. When the wafer 3 is fully cut, the dicing tape 1 also has a break in the middle,
Not shown here.

When the dicing tape 1 is pushed up on the table 5 as shown in FIG. 5 (b), the dicing tape 1 is stretched in all directions. Then, as the dicing tape 1 is stretched in all directions, as shown in FIG. 6B, the intervals between the adjacent semiconductor chips 3a on the dicing tape 1 also increase.

When the dicing tape 1 is stretched in all directions, the diameter of the through hole 2 also becomes large. Then, air enters the back surface of the semiconductor chip 3a through the through hole 2 having the larger diameter, and the adhesion between the semiconductor chip 3a and the dicing tape 1 is relaxed.

After the dicing tape 1 is stretched, the back surface of the dicing tape 1 is irradiated with ultraviolet rays to cure the ultraviolet-curable adhesive constituting the adhesive layer 1b shown in FIG. 1 to weaken its adhesive strength.

By providing the through holes 2 in the dicing tape 1 as described above, the through holes 2 expand and air enters when the dicing tape 1 is stretched, and the adhesion between the dicing tape 1 and the wafer 3a is relaxed. To be done. Then, by using an ultraviolet curable adhesive, the adhesive force of the adhesive is weakened by the irradiation of ultraviolet rays. As a result, the semiconductor chip 3a can be easily peeled from the dicing tape 1.

Next, the semiconductor chips 3a are picked up one by one. FIG. 7 is a perspective view showing an outline of a mechanism for picking up a semiconductor chip. A needle elevating mechanism 6 is provided on the back surface side of the dicing tape 1, and the needle 6a projects according to the position of the semiconductor chip 3a to be picked up. The suction collet 7 is attached to a robot hand or the like (not shown), sucks and holds the semiconductor chip 3a pushed up by the needle 6a, and conveys it to another place.

As a result, the semiconductor chip 3a is pushed up together with the dicing tape 1 by the needle 6a from the back surface side of the dicing tape 1, and the suction collet 7 is positioned on the corresponding semiconductor chip 3a.
The semiconductor chip 3a is peeled off from the dicing tape 1 and picked up by lifting it while sucking.

When the dicing tape 1 is stretched, a horizontal force is applied to stretch the semiconductor chip 3a in all directions because the dicing tape 1 is attached to the semiconductor chip 3a.

When the semiconductor chip 3a is pushed up by the needle 6a or when the suction collet 7 is used to suck and lift the semiconductor chip 3a, the dicing tape 1 is used.
Since it is attached to a, a force to pull the semiconductor chip 3a downward is applied.

As described above, in this embodiment, the through hole 2 is provided over the entire surface of the dicing tape 1,
When the dicing tape 1 is stretched, the through hole 2 expands to allow air to enter, and the adhesion of the dicing tape 1 to the semiconductor chip 3a is relaxed. Further, by using an ultraviolet curable adhesive for the adhesive layer 1b of the dicing tape 1, the adhesive force of the adhesive is lowered by the irradiation of ultraviolet rays after stretching.

Therefore, when the dicing tape 1 is stretched or when the semiconductor chip 3a is to be lifted, the peeling of the semiconductor chip 3a from the dicing tape 1 is promoted, and the semiconductor chip 3a has a force that may cause damage. It does not hang. As a result, even if the semiconductor chip 3a is thin, it will not be damaged when the dicing tape 1 is stretched or pushed up by the needle.

By providing the through hole 2 over the entire surface of the dicing tape 1, the dicing tape 1 can be easily stretched. That is, when the dicing tape 1 is stretched, the portion of the dicing tape 1 to which the wafer 3 is attached is pushed up by the table 5 from the back surface thereof while holding the frame 4 as described with reference to FIG. Therefore, the amount of expansion differs between the portion near the center of the dicing tape 1 and the peripheral portion.

As described above, when the dicing tape 1 is easily stretched by providing the through holes 2 in the dicing tape 1, the dicing tape 1 is easily stretched uniformly. As a result, variations in the arrangement of the semiconductor chips 3a on the dicing tape 1 can be eliminated. In this way, when the variation in the arrangement of the semiconductor chips 3a is eliminated, the control when positioning the suction collet 7 on each semiconductor chip 3a becomes easy.

Further, in the entire area of the dicing tape 1, the intervals between the adjacent semiconductor chips 3a are spread substantially uniformly, and when the semiconductor chips 3a are pushed up by the needle, the adjacent semiconductor chips 3a are affected. Can be prevented in all areas.

Further, in general, the table 5 for stretching the dicing tape 1 has a built-in heater for keeping the surface thereof at a predetermined temperature in order to promote the stretching. Normally, the temperature of the table 5 is about 50 ° C., and the heat is used to warm the dicing tape 1 to accelerate the stretching.

In the above-mentioned dicing tape 1 of this embodiment, since the through holes 2 are provided on the entire surface of the dicing tape 1, the stretching is promoted. Therefore, the stretching is further promoted by performing the stretching at a predetermined temperature. It Further, even when the temperature of the table 5 is lowered, the dicing tape 1 of the present embodiment is easier to stretch as compared with the conventional dicing tape.

In this embodiment, the through hole 2
However, the shape is not limited to this. FIG. 8 is a plan view of an essential part showing a modified example of the through hole. The through hole 8 shown in FIG. 8 is formed by making a cross cut over the entire surface of the dicing tape 1.

The through hole 8 is closed before the dicing tape 1 is stretched, but when the dicing tape 1 is stretched to pick up the semiconductor chip 3a, the through hole 8 is formed.
Spread, and air enters from the through holes 8 to the back surface of the semiconductor chip 3a. Therefore, the adhesion of the dicing tape 1 to the semiconductor chip 3a is relaxed, and the semiconductor chip 3
It is possible to prevent the semiconductor chip 3a from being damaged during the pickup of a.

Further, in this embodiment, the through hole 2 is provided on the entire surface of the dicing tape 1 supplied by rolling the long product in a roll shape. However, only the portion corresponding to the size of the wafer 3 or The through hole 2 may be provided only in a portion corresponding to the size of the frame 4. That is, if the through hole 2 is provided in the above-mentioned portion of the dicing tape 1, the through hole 2 exists on the entire surface of the portion to which the wafer 2 is attached.

[0048]

As described above, according to the present invention, a dicing tape to which a wafer is attached is provided with a plurality of minute through holes in a dicing process for cutting a wafer into semiconductor chips.

Then, after dicing the wafer, the through hole is expanded by stretching the dicing tape,
Air is taken into the back surface of the semiconductor chip from this through hole.

As a result, air is introduced from the through holes into the contact points between the dicing tape and the semiconductor chip, the adhesion between the dicing tape and the semiconductor chip is relaxed, and the semiconductor chip can be easily picked up.

Therefore, even if the wafer becomes thin,
It is possible to prevent the semiconductor chip from being damaged when the dicing tape is stretched or when the semiconductor chip is picked up.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a dicing tape according to the present embodiment.

FIG. 2 is a perspective view showing a usage state of the dicing tape according to the present embodiment.

FIG. 3 is an explanatory diagram showing a relationship between a through hole and a semiconductor chip.

FIG. 4 is a perspective view showing a supply state of the dicing tape according to the present embodiment.

FIG. 5 is an explanatory diagram showing an operation of stretching the dicing tape.

FIG. 6 is a cross-sectional view of essential parts showing a state of the dicing tape before and after stretching.

FIG. 7 is a perspective view showing an outline of a mechanism for picking up a semiconductor chip.

FIG. 8 is a plan view of an essential part showing a modified example of a through hole.

FIG. 9 is a perspective view showing a conventional dicing tape.

FIG. 10 is a perspective view showing a usage state of a conventional dicing tape.

FIG. 11 is a perspective view schematically showing a mechanism for picking up a semiconductor chip.

[Explanation of symbols]

1 ... Dicing tape, 1a ... Base material, 1b ...
・ Adhesive layer, 2 ... Through hole, 3 ... Wafer, 3a
... Semiconductor chip, 4 ... Frame, 5 ... Table, 6a ... Needle, 7 ... Suction collet, 8
... Through holes

Claims (3)

[Claims] 1. A dicing tape which is provided on one surface of a flexible sheet-like base material with a pressure-sensitive adhesive layer, and which is attached to the back surface of the wafer in a dicing step of cutting the wafer into semiconductor chips, A dicing tape characterized in that a plurality of minute through holes penetrating from the surface of the base material to the surface of the pressure-sensitive adhesive layer are provided on at least the entire surface to which the wafer is attached. 2. The dicing tape according to claim 1, wherein the pressure-sensitive adhesive layer is made of a UV-curable pressure-sensitive adhesive. 3. A method of using a dicing tape attached to the back surface of a wafer in a dicing process for cutting a wafer into semiconductor chips, wherein a plurality of minute through holes are provided at least on the entire surface of the portion to which the wafer is attached. A wafer is attached to the dicing tape, the wafer is diced, and the through hole is expanded by stretching the dicing tape, and air is taken into the back surface of the semiconductor chip from the through hole. How to use dicing tape.