JP2001024010A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for preventing cracks from being developed in a semiconductor device, when a piece of semiconductor element is flaked from a UV-curing type adhesive tape. SOLUTION: In a manufacturing method, a semiconductor wafer is separated into a plurality of semiconductor elements 11. When the semiconductor element laminated on a UV-curing type adhesive tape 16 is flaked and picked up, only a UV irradiation area of a UV lamp 12 is adjusted to the size of a wafer, and only a bonding part between the semiconductor element and the adhesive tape is selectively cured with UV under atmospheric air. In this case, the adhesion of the adhesive face between each semiconductor element and the adhesive tape is decreased, while areas other than the laminated face of each semiconductor element are not subjected to UV irradiation. At the same time, since areas other than the dicing groove part and the stuck face of each semiconductor element are exposed to oxygen in the atmospheric air, they are insufficiently hardened or are not cured through UV beam but remain in a flexible state. Then, ease of flaking of the semiconductor element can be improved, when it is picked up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method of separating a semiconductor wafer attached to a UV-curable adhesive tape into individual pieces, and
The present invention relates to a step of irradiating and curing an adhesive tape to reduce adhesiveness and to pick up (peel) each semiconductor element from the adhesive tape.

[0002]

2. Description of the Related Art Conventionally, when a groove is formed along a dicing line or a chip dividing line of a semiconductor wafer and the back surface is ground to be separated into individual pieces, a UV-curable adhesive is applied to the pattern forming surface of the semiconductor wafer. The tape is stuck and protected. During this time, the protective tape was peeled off, and a dicing tape was stuck on the back surface of the wafer. When each semiconductor element (chip) is picked up, the entire surface of the adhesive tape is irradiated with UV in a state where oxygen is not contained in a nitrogen atmosphere or the like, thereby curing the UV adhesive and bonding the semiconductor element. Has reduced sex. Thereafter, expansion (stretching of the adhesive tape) is performed, and each semiconductor element is picked up (peeled) from the adhesive tape in a state where the adhesiveness is reduced. Further, even when the singulated semiconductor elements are transferred to another adhesive tape, after the transfer, the adhesiveness of the adhesive tape is reduced and picked up in the same UV irradiation area and irradiation atmosphere as described above. .

FIGS. 9 to 11 are for describing in detail the above-described conventional method for manufacturing a semiconductor device. FIG. 9 shows a UV irradiation step, FIG. 10 shows a state after UV irradiation, and FIG. 11B shows a pickup step, and FIG. 11B shows one semiconductor element in FIG. 11A in an enlarged manner. 9 to 11, reference numeral 1 denotes a singulated semiconductor device, 2 denotes a UV lamp for UV irradiation, 3 denotes a light shielding material for UV light, 4 denotes a cover, 5 denotes a wafer ring, 6
Is a UV-curable adhesive tape, 7 is a jig for stretching the tape, 8 is a replacement part for exposing the adhesive tape 6 to a nitrogen atmosphere by replacing the inside of the cover 4 with nitrogen or the like.

As shown in FIG. 9, the individualized semiconductor element 1 is attached to the UV adhesive side of a UV-curable adhesive tape 6, and the semiconductor element 1 and the adhesive tape 6 are bonded together. It is housed in the replacement unit 8 while being held by the wafer ring 5. Nitrogen or the like is introduced into the substitution section 8 at the time of UV irradiation, and the air inside is substituted with nitrogen. Further, UV irradiation is performed on the entire surface of the adhesive tape 6 by the UV lamp 2 from the back surface side of the adhesive tape 6 to cure the UV adhesive, thereby reducing the adhesiveness between the semiconductor element 1 and the adhesive tape 6. . Since the UV irradiation is performed in a nitrogen atmosphere, the curing of the UV adhesive is promoted.

Thereafter, as shown in FIG. 10, the adhesive tape 6 to which the semiconductor element 1 is attached is taken out while being held by the wafer ring 5, and as shown in FIG. And the adhesive tape 6 is stretched. Then, in this state, the pins are pushed up from the back side, and the individual semiconductor elements 1 are separated from the adhesive tape 6 and picked up.

However, in the above-described conventional technique, when the semiconductor element 1 is thinned, the adhesive tape 6 depends on the hardness of the adhesive after UV irradiation and the amount of expansion.
Due to the tension (hardness), a large force is required when the semiconductor element 1 is picked up (detached), and there is a problem that cracks occur frequently when the semiconductor element 1 is detached from the adhesive tape 6. In addition, when the semiconductor element 1 is thin at the time of expansion, warpage of 40 μm to 60 μm occurs as a single element as shown in FIG. 11B, and there is a problem that the position of the semiconductor element cannot be detected in the pickup device. .

[0007]

As described above, the conventional method of manufacturing a semiconductor device requires a large force when picking up a semiconductor element, and causes a problem that a crack is generated when the semiconductor element is separated from the adhesive tape. there were.

Further, when the adhesive tape is stretched prior to the pickup, if the semiconductor element is thin, warpage occurs, and there is a problem that the position of the semiconductor element cannot be detected in the pickup device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device capable of preventing a crack from being generated when an individualized semiconductor element is peeled off from an adhesive tape. An object of the present invention is to provide a method for manufacturing a device.

Another object of the present invention is to provide a method for stretching an adhesive tape prior to pickup.
It is an object of the present invention to provide a method of manufacturing a semiconductor device in which warpage can be suppressed even when the semiconductor element is thin, and the position of the semiconductor element can be easily detected in a pickup device.

[0011]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising forming a plurality of semiconductor elements by dividing a semiconductor wafer attached to a UV-curable adhesive tape. And selectively performing UV irradiation in the air on the adhesive tape in the region where the plurality of semiconductor elements are attached, and picking up the semiconductor elements by peeling them from the adhesive tape. And a process.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method comprising: attaching a singulated semiconductor element to a UV-curable adhesive tape; Characterized by comprising a step of selectively irradiating UV in the air to a region where is adhered, and a step of picking up the semiconductor element by peeling it from the adhesive tape.

According to a third aspect of the present invention, in the step of peeling and picking up the semiconductor element from the adhesive tape, the semiconductor device is picked up by setting an expanding amount of a pickup device to an extent to remove wrinkles of the adhesive tape. It is characterized by.

According to the first aspect of the present invention, the adhesive surface between each semiconductor element and the adhesive tape is cured by selective UV irradiation to lower the adhesiveness, and the bonding of each semiconductor element is performed. The region other than the surface is not irradiated with UV, and the dicing groove portion, and the region other than the surface to which each semiconductor element is attached are exposed to oxygen in the atmosphere. Maintains an uncured and flexible state. As described above, by controlling the adhesive strength, adhesive elasticity, and UV curing state of the adhesive tape, it is possible to improve the ease of peeling when the semiconductor element is picked up.

Further, according to the manufacturing method of the present invention, the adhesive surface between each semiconductor element and the adhesive tape is cured by selective UV irradiation, thereby deteriorating the adhesive property. The area other than the attachment surface is not irradiated with UV, and the area between the semiconductor elements and the area other than the attachment surface of each semiconductor element are exposed to oxygen in the atmosphere. Causes cure alienation and maintains an uncured and flexible state. As described above, by controlling the adhesive strength, the adhesive elasticity, and the UV curing state of the adhesive tape, it is possible to improve the ease of peeling when the semiconductor element is picked up.

According to a third aspect of the present invention, if the amount of expansion of the pickup device is set to such an extent that the wrinkles of the adhesive tape are removed, the warpage of the element alone can be reduced even if the semiconductor element is thin, and the element of the pickup device can be reduced. Position detection can be easily performed.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. According to the present invention, a semiconductor wafer is singulated into semiconductor elements and then picked up (separated).
To reduce the adhesiveness by curing the UV-curable adhesive tape to make it easier to perform, the area to be irradiated with UV is limited to the semiconductor element portion (wafer size) only, and other areas that are not adhered to the semiconductor element are Portions (outside the wafer size area) are masked so that UV light is not irradiated. The UV irradiation is performed in the atmosphere (the acrylic UV resin undergoes curing and alienation due to the presence of oxygen and maintains an uncured and flexible state).

1 to 3 are for explaining in detail a method of manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 1 shows a UV irradiation step, FIG. 2 shows a state after UV irradiation, and FIG. Reference numeral 3 denotes a pickup step. 1 to 3, reference numeral 11 denotes an individualized semiconductor element, 12 denotes a UV lamp for UV irradiation, 13 denotes a UV light shielding material, 15 denotes a wafer ring, 16 denotes a UV-curable adhesive tape, 17 Is a jig for stretching the tape.

As shown in FIG. 1, the singulated semiconductor element 11 is attached to the UV adhesive side of a UV-curable adhesive tape 16, and the semiconductor element 11 and the adhesive tape 16 are bonded to a wafer. It is held by a ring 15. A UV light shielding material 13 is provided on the back surface of the adhesive tape 16 to which the semiconductor element 11 is attached.
The light shielding material 13 is irradiated with UV light from the UV lamp 12 only to the semiconductor element portion (wafer size), and the other portion (outside the wafer size area) not bonded to the semiconductor element is not irradiated with UV light. And an opening substantially equal to the wafer size is formed. Then, UV light is applied to the adhesive tape 16 by the UV lamp 12 from the back surface side of the adhesive tape 16 through the opening of the light shielding material 13 to reduce the adhesiveness between the semiconductor element 11 and the adhesive tape 16. Like that. At the time of the UV irradiation, the atmosphere is performed in the air.

Thereafter, as shown in FIG. 2, the adhesive tape 16 is conveyed to the pickup device while being held by the wafer ring 15, and a tape stretching jig 17 as shown in FIG. The conductive tape 16 is stretched, and in this state, the individual semiconductor elements 11 are picked up (peeled). The amount of expansion when the adhesive tape 16 is stretched is about the degree of wrinkling of the adhesive tape 16 (0 to 0).
1.5 mm).

When UV irradiation is performed by the above method, the adhesive surface A between the semiconductor element 11 and the adhesive tape 16 is cured by UV as shown in FIG. 2, and the dicing groove B and the wafer size are adjusted. The out-of-area C is in a state where the UV curing is insufficient or the UV curing is not performed. That is,
The adhesive force, adhesive elasticity, and UV cured state of the adhesive tape 16 are as shown in the following (1) to (3), respectively.

(1) Adhesive strength: strong C>B> A weak (2) Adhesive elasticity: high A>B> C low (3) UV curing state: A (cured)> B (insufficient curing)>
C (no curing) By setting the physical properties of the adhesive tape 16 to such a state, the adhesive surface A with the semiconductor element 11, the dicing groove portion B, and the adhesive tape 16 outside the wafer size area C are obtained.
Of the semiconductor element 11 can be selectively changed so that the semiconductor element 11 can be easily peeled off when picked up.

In the conventional method of manufacturing a semiconductor device,
In FIG. 10, the adhesive surface A between the semiconductor element 1 and the adhesive tape 6, the dicing groove portion B, and the area C outside the wafer size are all in a state where UV curing has been performed, and the adhesive force and adhesive strength of the adhesive tape 6 The agent elastic modulus and the UV cured state are as shown in the following (4) to (6), respectively.

(4) Adhesive strength: strong C = B> A weak (5) Adhesive elasticity: high A> B = C low (6) UV curing state: A (cured)> B = C (insufficient curing) Next, the step of picking up the semiconductor element 11 from the adhesive tape 16 will be described in detail.

At the time of picking up the semiconductor element 11, as shown in FIG. 4, the semiconductor element (chip) 11 is pushed up from the back side of the adhesive tape 16 using a pin (pickup needle) 18, and is lifted from the adhesive tape 16. The semiconductor element 11 is peeled off. The pin 18 is housed in a pin folder 19, and the pin 18 projects from the pin folder 19 during pickup.
This step can be subdivided into (a) a step of peeling off the corner of the chip, (b) a step of peeling up to the position of the pin 18, and (c) a step of peeling the inside from the pin position.

In the above steps (a) to (c), the characteristics required for the adhesive tape 16 include, in the step (a), the opening of the corners and sides of the chip at an early stage,
In the steps (b) and (c), it is possible that the film is peeled off at once without being peeled off gradually. In particular, in the case of a thin chip 11 having a thickness of 50 μm or less,
A warping phenomenon occurs with the chip 11 attached to the adhesive tape 16 as shown in FIG. This warp increases as the push-up displacement of the pin 18 increases, and a large force is applied to the contact portion between the chip 11 and the pin 18, causing a crack.

Therefore, in the above-described embodiment, by lowering the adhesive force while securing the flexibility of the dicing groove portion B in the adhesive tape 16, the corner of the chip 11 can be prevented before the warpage of the chip 11 increases. The opening of the part (outer peripheral part) is made. That is, since the peeling angle of the adhesive tape 16 at the time of peeling becomes acute by maintaining the flexibility of the dicing groove portion B in the adhesive tape 16, the semiconductor element 11 is peeled from the adhesive tape 16 with a weak force (vector). it can. Further, if the chip 11 and the adhesive tape 16 start to peel off, the warpage of the chip 11 decreases and the contact area of the adhesive tape 16 also decreases, so that the force (peak load) applied to the chip 11 and the adhesive tape 16 at the time of peeling is reduced. Can be smaller.

In order to promote the opening (peeling of the corner portion), not only the adhesive strength but also the peeling angle of the adhesive tape 16 is important. As shown in FIG. 6, the separation is given by a force F applied when the pin 18 pushes up, and the separation proceeds by the force Fz in the Z direction of the force F. Since this force Fz is expressed as Fz = Fsin θ (0 ≦ θ ≦ 90 °), it is advantageous to increase sin θ for peeling, that is, it is effective to increase θ. As described above, by increasing the angle of the adhesive tape 16 at the time of peeling, peeling can be performed with a low load and in a short time.

In the above embodiment, the adhesive tape 1
6, the flexibility of the dicing groove portion B can be ensured, so that the angle of the adhesive tape 16 at the time of peeling can be increased, and this also facilitates peeling.

FIG. 7 shows the peeling characteristics under the UV irradiation conditions. The peak load and the peeling time when the entire surface of the adhesive tape 16 was subjected to UV irradiation in a nitrogen atmosphere. Peak load and peeling time when performing UV irradiation, peak load and peeling time when performing UV irradiation only on the wafer area of adhesive tape 16 in a nitrogen atmosphere, and wafer area of adhesive tape 16 in air Only the peak load and the peeling time when only the UV irradiation is performed are shown.

As is clear from FIG. 7, the peak load when UV irradiation is performed only on the wafer area of the adhesive tape 16 in the atmosphere is the lowest, and the peeling time is also short. Can be peeled off. In addition, since the peak load and the peeling time when UV irradiation is performed on the entire surface of the adhesive tape 16 in the atmosphere are lower than those of the others, for example, the entire surface of the adhesive tape 16 is adjusted according to conditions such as a thick chip 11. UV irradiation may be performed.

FIG. 8 shows the amount of chip warpage under the conditions of UV irradiation. The relationship between the amount of expansion (tape expansion) and the amount of chip warpage when UV irradiation is performed on the entire surface of the adhesive tape 16 in a nitrogen atmosphere. Relationship, relationship between the amount of expansion and the amount of chip warpage when UV irradiation is performed on the entire surface of the adhesive tape 16 in the atmosphere, and when the UV irradiation is performed only on the wafer area of the adhesive tape 16 in a nitrogen atmosphere. The relationship between the amount and the amount of chip warpage, and the relationship between the expanded amount and the amount of chip warpage when UV irradiation is performed only on the wafer area of the adhesive tape 16 in the atmosphere are shown.

As shown in FIG. 8, the chip warpage increases as the expand amount increases under any of the UV irradiation conditions, and the smaller the expand amount, the smaller the chip warp amount. In addition, when the UV irradiation is performed only on the wafer area of the adhesive tape 16 in the atmosphere, the amount of chip warpage can be minimized as compared with other UV irradiation conditions.

As described above, by setting the UV irradiation area only to the contact surface between the semiconductor element 11 and the adhesive tape 16 and setting the UV irradiation atmosphere to the atmosphere, the adhesive elastic modulus of the adhesive tape 16 and the tape Since both the base materials have a soft elasticity, the peeling angle of the adhesive tape 16 at the time of peeling can be made acute, so that the semiconductor element 11 can be peeled from the adhesive tape 16 with a weak force (vector). Therefore, a thin and large chip can be picked up. Also,
In the pickup device, even when detecting the position of the semiconductor element before peeling, which is a problem particularly in the case of a thin thickness, the amount of expansion is suppressed to the extent of wrinkling of the tape, and other conditions (such as increasing the elasticity of the adhesive tape 16 by UV curing, etc.) ) Is optimized to prevent the adhesive tape 16 from becoming hard, so that warpage of the element alone can be reduced and position detection can be facilitated.

[0035]

As described above, according to the present invention, it is possible to obtain a method of manufacturing a semiconductor device which can prevent the occurrence of cracks when separating an individual semiconductor element from an adhesive tape.

In addition, when the adhesive tape is stretched prior to the pickup, warpage can be suppressed even if the semiconductor element is thin, and the position of the semiconductor element can be easily detected in the pickup device. A method is obtained.

[Brief description of the drawings]

FIG. 1 is a view for explaining a method for manufacturing a semiconductor device according to an embodiment of the present invention and showing a UV irradiation step.

FIG. 2 is a view for illustrating the method for manufacturing the semiconductor device according to the embodiment of the present invention, showing a state after UV irradiation.

FIG. 3 is a view for explaining the method for manufacturing the semiconductor device according to the embodiment of the present invention and showing a pickup step.

FIG. 4 is an enlarged cross-sectional view for explaining a semiconductor element pick-up step and at the time of chip peeling.

FIG. 5 is a view for explaining a semiconductor element pickup step and explaining warpage of the chip at the time of chip separation.

FIG. 6 is a view for explaining a semiconductor element pick-up step and explaining a peel angle at the time of chip peeling.

FIG. 7 is a graph showing a peeling property according to UV irradiation conditions and showing a relationship between a peak load and a peeling time under each UV irradiation condition.

FIG. 8 is a diagram showing the amount of chip warpage under UV irradiation conditions, and showing the relationship between the amount of expansion and the amount of chip warpage under each UV irradiation condition.

FIG. 9 is a view for explaining a conventional method for manufacturing a semiconductor device and showing a UV irradiation step.

FIG. 10 is a view for explaining a conventional method of manufacturing a semiconductor device, showing a state after UV irradiation.

11A and 11B are diagrams for explaining a conventional method of manufacturing a semiconductor device, in which FIG. 11A shows a pickup step, and FIG. 11B shows an enlarged view of one semiconductor element in FIG. .

[Explanation of symbols]

 Reference Signs List 11: semiconductor element, 12: UV lamp, 13: light shielding material for UV light, 15: wafer ring, 16: UV curable adhesive tape, 17: jig for extending tape, 18: pin, 19: pin folder.

Claims (3)

[Claims] 1. A step of forming a plurality of semiconductor elements by singulating a semiconductor wafer attached to a UV-curable adhesive tape, and a region of the adhesive tape to which the plurality of semiconductor elements are attached. A method of selectively irradiating UV light in the atmosphere, and a step of separating and picking up each semiconductor element from the adhesive tape. 2. A step of attaching the singulated semiconductor elements to a UV-curable adhesive tape, and selectively irradiating UV light to the region of the adhesive tape to which the semiconductor elements are attached in the air. Performing a semiconductor device from the adhesive tape and picking up the semiconductor element. 3. The step of peeling and picking up the semiconductor element from the adhesive tape, wherein the step of picking up is performed by setting an expanding amount of a pick-up device to such a degree as to remove wrinkles of the adhesive tape. Or a method for manufacturing a semiconductor device according to item 2.