KR102575445B1 - Method of packing a die - Google Patents

Abstract

In the die packing method, a cassette in which wafers in which a plurality of dies are individualized is stored is loaded, and a wafer drawn from the cassette is placed on an expanding unit. Then, the wafer is aligned, and a die is picked up from the aligned wafer. The sides of the picked-up die are imaged to determine the good quality of the die, and the die determined to be good is inserted into a pocket formed on a reel tape, and the die drawn into the pocket is sealed.

Description

Die packing method {METHOD OF PACKING A DIE}

Embodiments of the present invention relate to a method for packaging a die. More specifically, embodiments of the present invention relate to a die packaging method for picking up individualized dies from a wafer, inspecting the picked dies, and packing the dies determined to be good products.

Recently, with the development and use of multifunctional and highly advanced electronic devices such as smart phones, semiconductor chips used in electronic devices tend to be more miniaturized and slimmer. Representatively used semiconductor chips are individually diced or sawed parts from wafers.

Here, a silicon wafer is generally used as the wafer. A silicon wafer is a thin silicon plate that forms the base of an integrated circuit of an electronic device. After making a high-purity single-crystal silicon called an ingot, the ingot is sliced thinly to make a disk-shaped intermediate workpiece. Wafers are finally manufactured through various post-processing processes such as etching and polishing of intermediate workpieces.

Crystal defects that affect yield and quality occur in the manufacturing process of these wafers. Since the crystal defects generated in this way affect the yield and quality of wafers as described above, it is necessary to visually inspect the presence or absence of crystal defects. In addition, after the visual inspection for crystal defects on the outside of the wafer is completed, the wafer that is found to be a genuine (defective) product requires an electrical inspection in order to be practically used in an electronic device.

A circuit element may be implemented on the wafer and may be singulated into one die.

The die may be accommodated in a pocket formed on the reel tape and packed. At this time, the dies are visually inspected and classified into good and bad dies, and only the dies determined to be good are accommodated in the pocket.

To visually inspect the dies, a vision inspection process of imaging the dies using a camera may be performed.

In the vision inspection process, cracks occurring inside the dies must be detected. However, when cracks formed inside the dies are minute, there is a problem in that they are not easily detected.

Embodiments of the present invention provide a die packaging method capable of packaging only good products among the dies by easily detecting micro cracks generated inside the dies.

In the die packaging method according to embodiments of the present invention, a cassette in which wafers in which a plurality of individual dies are stored is loaded, and a wafer drawn from the cassette is placed on an expanding unit. Then, the wafer is aligned, and a die is picked up from the aligned wafer. The sides of the picked-up die are imaged to determine the good quality of the die, and the die determined to be good is inserted into a pocket formed on a reel tape, and the die drawn into the pocket is sealed.

In one embodiment of the present invention, the step of imaging the sides of the picked-up die may use near infrared (NIR) light having a wavelength range of 1,000 to 1,100 nm.

In one embodiment of the present invention, in order to determine the good quality of the die, images of the side parts may be synthesized.

In one embodiment of the present invention. It is possible to determine the good quality of the die by taking an image of the back side of the die.

In the die packaging method according to the embodiments of the present invention as described above, after picking up a die from the aligned wafer, it is possible to determine the quality of the die by taking images of the sides of the picked up die. As a result, it is possible to more effectively check the presence or absence of cracks formed inside the die.

In particular, by imaging the side of the die using near infrared (NIR) light having a wavelength range of 1,000 to 1,100 nm, light can effectively transmit through the silicon layer provided inside the die and excellent sensitivity can be secured.

1 is a block diagram for explaining a die packaging apparatus according to an embodiment of the present invention.
2 is a perspective view of a wafer inspected in the die packaging apparatus according to the present invention.
FIG. 3 is a perspective view for explaining the die packaging apparatus of FIG. 1 .
4 is a flowchart illustrating a die packing method according to an embodiment of the present invention.
5 is a graph showing light transmittance and CCD sensitivity for each wavelength.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention does not have to be configured as limited to the embodiments described below and may be embodied in various other forms. The following examples are not provided to fully complete the present invention, but rather to fully convey the scope of the present invention to those skilled in the art.

In the embodiments of the present invention, when one element is described as being disposed on or connected to another element, the element may be directly disposed on or connected to the other element, and other elements may be interposed therebetween. It could be. Alternatively, when an element is described as being directly disposed on or connected to another element, there cannot be another element between them. The terms first, second, third, etc. may be used to describe various items such as various elements, compositions, regions, layers and/or parts, but the items are not limited by these terms. will not

Technical terms used in the embodiments of the present invention are only used for the purpose of describing specific embodiments, and are not intended to limit the present invention. In addition, unless otherwise limited, all terms including technical and scientific terms have the same meaning as can be understood by those skilled in the art having ordinary knowledge in the technical field of the present invention. The above terms, such as those defined in conventional dictionaries, shall be construed to have a meaning consistent with their meaning in the context of the relevant art and description of the present invention, unless expressly defined, ideally or excessively outwardly intuition. will not be interpreted.

Embodiments of the present invention are described with reference to schematic illustrations of idealized embodiments of the present invention. Accordingly, variations from the shapes of the illustrations, eg, variations in manufacturing methods and/or tolerances, are fully foreseeable. Accordingly, embodiments of the present invention are not to be described as being limited to specific shapes of regions illustrated as diagrams, but to include variations in shapes, and elements described in the drawings are purely schematic and their shapes is not intended to describe the exact shape of the elements, nor is it intended to limit the scope of the present invention.

1 is a block diagram for explaining a die packaging apparatus according to an embodiment of the present invention. 2 is a perspective view of a wafer inspected in the die packaging apparatus according to the present invention. FIG. 3 is a perspective view for explaining the die packaging apparatus of FIG. 1 .

Referring to FIGS. 1 to 3 , the die packing apparatus according to an embodiment of the present invention visually inspects the appearance of each of a plurality of dies 4 individualized from a wafer 1 .

As shown in FIG. 2 , the wafer 1 includes a wafer ring 2 , an adhesive member 3 and a plurality of dies 4 . The wafer ring 2 supports a plurality of semiconductor dies 4 , and in particular supports an adhesive member 3 that adheres and supports the plurality of semiconductor dies 4 .

The die packaging apparatus 100 includes a cassette unit 105, an expanding unit 110, a pick-up unit 170, a vision unit 160, and a loading unit ( 120) and a control unit 150.

The cassette unit 130 supports a cassette accommodating a plurality of wafers 1 . In the cassette, slots are formed in which a plurality of wafers 1 can be stacked in the vertical direction.

The cassette unit 105 includes a gripper (not shown). The gripper may hold the wafer W accommodated in the cassette and transfer it to the expanding unit 110 . The gripper may perform horizontal movement, and for this purpose, a servo motor, a cylinder, or the like may be used.

The expanding unit 110 is disposed adjacent to the cassette unit 105. The expanding unit 110 supports a wafer. A wafer W diced into a plurality of dies 4 is placed on the expanding unit 110 .

The expanding unit 110 expands a space between the plurality of dies 4 . For example, the expanding unit 110 expands the gap between the plurality of dies 4 by holding the wafer ring 2 and expanding the adhesive member 3 supported on the wafer ring 2. . In this way, the gap between the plurality of dies 4 is expanded according to the expansion of the adhesive member 3 according to the operation of the expanding unit 110, so that the individual dies 4 can be easily picked up.

The pickup unit 170 is disposed between the expanding unit 110 and the loading unit 120 . The pickup unit 170 moves the dies 4 between the expanding unit 110 and the loading unit 120 . As an embodiment of the present invention, the pickup unit 170 includes a first pickup unit 172 and a second pickup unit 174 .

The first pickup unit 172 transfers the die from the expanding unit 110 to the second pickup unit 150 . The first pickup unit 172 rotates in the vertical direction. The first pick-up unit 172 includes a plurality of first pickers provided to be able to move up and down in a radial direction based on a rotation center. Accordingly, the dies may be picked up from the expanding unit 110 by rotating the first pick-up part 172 and moving the first pickers included in the first pick-up part 172 .

In addition, each of the first pickers may invert the dies 4 by rotating the first pick-up unit 172 by 180 degrees. For example, when the first pickup unit 172 picks up the die 4 from the adhesive member in the expanding unit 110, the rear surface of the die 4 may be exposed downward. Thereafter, when the first pick-up part 172 is rotated 180 degrees, the rear surface of the die 4 may be exposed upward.

The second pickup unit 174 is disposed above the first pickup unit 172 . The second pickup unit 174 receives the die 4 from the first pickup unit 172 . The second pick-up unit 174 is rotatably provided in a horizontal direction and includes a disk-shaped body and second pickers movable downward on an outer circumference of the body.

The loading unit 180 includes a reel tape rewinded in a reel format on a tape having pockets. The dies 4 may be accommodated inside the pocket. Meanwhile, the dies accommodated in the pocket may be sealed with a sealing tape.

The loading unit 180 independently receives a plurality of dies 4 classified into genuine products and defective products from the expanding unit 110 .

The vision unit 160 vision inspects the plurality of dies 4 transferred from the expanding unit 110 to the loading unit 180 . The vision unit 160, as an embodiment of the present invention, includes a first camera unit 161, a second camera unit 162, and a third camera unit 163.

The first camera unit 161 is disposed on one side of the first pickup unit 172 . The first camera unit 161 checks the position of the die 4 seated on the expanding unit 110 . The first camera unit 161 may check whether the die is picked up by the first pickup unit 172 .

The second camera unit 162 is disposed on the other side of the first pickup unit 172 . The second camera unit 162 may inspect whether the die pickup of the first pickup unit 172 was successful and the appearance of the rear surface of the die.

In addition, the second camera unit 162 is disposed on one side of the first pickup unit 172 . The second camera unit 162 captures an image of the side of the die 4 . In this way, it is possible to check cracks inside the die using an image obtained by capturing the side surface of the die.

The third camera unit 163 may capture an image of whether or not the die is loaded into the pocket formed in the reel tape in the loading unit 180 .

The controller 150 is connected to the cassette unit 105 , the expanding unit 110 , the vision unit 170 , the pickup unit 170 and the loading unit 180 . The controller 150 transmits driving signals to each of the cassette unit 105, the expanding unit 110, the vision unit 170, the pickup unit 170, and the loading unit 180.

4 is a flowchart illustrating a die packing method according to an embodiment of the present invention.

Referring to FIGS. 1 and 4 , in the die packing method according to an embodiment of the present invention, a cassette in which individualized wafers of a plurality of dies are stored is loaded (S110). At this time, the cassette may be located in the cassette unit 105.

Next, the wafer taken out of the cassette is placed on the expanding unit 110 (S120). To this end, a gripper grips the wafer from the slot of the cassette and places it in the expanding unit 110 .

Then, the wafer is aligned (S130). To this end, a camera positioned above the expanding unit 110 may check the position of a die formed on the wafer.

Subsequently, a die is picked up from the aligned wafer (S140). In this case, after the first pickup unit 172 picks up the die from the wafer, it rotates 180 degrees along a vertical plane. Next, the second pickup unit 174 receives the inverted die from the first pickup unit 172 .

Subsequently, the quality of the die is determined by taking images of the sides of the picked-up die (S150). The second pickup unit 174 rotates along a horizontal plane. At this time, the vision unit 160 images the sides of the die, for example, four sides. Accordingly, by determining whether there is a crack inside the die, the die may be classified as a good product or a defective product.

The die judged to be good is inserted into a pocket formed on the reel tape (S160). In this case, the second pickup unit may drop the dies determined to be good products toward the pocket.

Subsequently, the die inserted into the pocket is sealed (S170). To this end, a process of laminating the sealing tape in a roll-to-roll manner so as to face the reel tape may be performed.

In one embodiment of the present invention, the step of imaging the sides of the picked-up die may use near infrared (NIR) light having a wavelength range of 1,000 to 1,100 nm.

5 is a graph showing light transmittance and CCD sensitivity for each wavelength.

Referring to FIG. 5 , near infrared (NIR) light having a wavelength range of 1,000 to 1,100 nm may have excellent light transmittance that effectively transmits through a silicon layer of a die. Furthermore, the plurality of camera units 161 , 162 , and 163 constituting the vision unit 160 may have excellent sensitivity to the NIR light.

In one embodiment of the present invention, in the step of determining the good quality of the die, images obtained by taking sides of the die are synthesized. In this way, it is possible to determine an inclined crack formed inside the die.

For example, when an image obtained by capturing only the rear surface of a die is obtained and a simple line shape is displayed, cracks may not be detected due to limitations in the resolution of the optical system. On the other hand, when an image obtained by synthesizing images of the side parts is used, it is possible to determine an inclined crack formed inside the die. This is because side images are synthesized for vertically extending cracks, so that cracks extending in the vertical direction can be effectively detected.

In the present invention. It is possible to determine the good quality of the die by taking an image of the back side of the die. For example, a vision inspection may be additionally performed on the existence, quantity, and shape of bumps formed on the rear surface of the die.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that there is

100: die packaging device 105: cassette unit
110: expanding unit 150: control unit
160: vision unit 170: pickup unit
180: loading unit

Claims (4)

loading a cassette in which wafers from which a plurality of dies are individualized are accommodated, into a cassette unit;
placing the wafer taken out from the cassette on an expanding unit;
aligning the wafer;
picking up a die from the aligned wafer;
determining the quality of the die by taking images of the sides of the picked-up die;
inserting the dies determined to be good products into a pocket formed on a reel tape; and
sealing a die retracted into the pocket;
The step of imaging the sides of the picked-up die uses near infrared (NIR) light having a wavelength range of 1,000 to 1,100 nm,
The step of determining the good quality of the die includes determining whether or not there is an oblique crack formed inside the die and extending in a vertical direction by synthesizing side images obtained by capturing the side portions. delete delete According to claim 1. The step of determining the good quality of the dies further comprises the step of determining the good quality of the dies by capturing an image of the rear surface of the dies in a picked-up state.

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