TWI777372B - Die transfer plate and die transfer method using thereof - Google Patents

Abstract

The present invention relates a die transfer plate and die transfer method using thereof. The die transfer plate of the present invention has a plurality of suckers, which allows simultaneously transferring and positioning a plurality of dies. The size of the suckers is in micro scale and thus the suckers are suitable for mass transferring micro-LED. The die transfer method of the present invention can use a plural of die transfer plates of the present invention to transfer dies onto a plural of boards, enhancing efficiency for transferring.

Description

Die removal chuck and method of die removal using the same

The present invention relates to a die-removing chuck and a die-removing method using the same. The die-removing chuck is particularly useful for mass transfer of Micro-LEDs.

Micro-LED is a micro-sized LED. Compared with traditional LED, each pixel of Micro-LED can independently adjust its brightness and address. It has considerable advantages in response speed, power consumption and durability. The backlight and color filter can directly provide excellent chroma and saturation with the three primary colors of red, blue and green. When the high-density arrangement is used as a display device, it can provide high-quality image quality. Recently, Micro-LEDs have been developed with flexible panel materials to make lighter and thinner displays for wearable devices or other curved displays.

However, Micro-LEDs have been faced with the problem of how to arrange huge and tiny sized dies on circuit boards or pads. Therefore, mass transfer and bonding are the key technologies of Micro-LED at present. Mass transfer and bonding requires a certain degree of high precision, and the yield is related to the cost of production capacity. Although the existing pick-and-place technology can sort a high-density array of dies onto a circuit board, it can only transfer a single die at a time, which is very time-consuming and energy-consuming in the process. Taking a 55-inch display as an example, 6.22 million Micro-LEDs must be placed on the panel to have high-resolution display pixels, which is quite labor-intensive and time-consuming.

In order to solve the defects of pick-and-place, many manufacturers in the market want to develop a technology that can transfer multiple dies at one time. However, in actual operation, there are problems such as die falling off and uneven arrangement when transferring die, which makes it difficult to improve the yield and production capacity of Micro-LED displays.

Therefore, the purpose of the present invention is to provide a chip removal chuck, which includes: a substrate; a plurality of magnetic suction heads arranged on one side of the substrate; wherein, the size of the plurality of magnetic suction heads is to be removed 40% to 85% of the grain size.

Further, the plurality of magnetic suction heads are arranged in a straight line or in an array.

Further, when the die-removing chuck removes the die, some of the plurality of magnetic suction heads have magnetic attraction, and some of the magnetic suction heads have a considerable distance from each other.

Further, an alignment mark is provided on the transparent substrate.

Further, the substrate is a transparent substrate.

Further, the die removing suction cup further includes a camera unit, which is arranged above the substrate and can be used for alignment of the suction cup and the wafer.

Further, the plurality of magnetic suction heads are formed by photo-etching.

An object of the present invention is to provide a method for removing die, the steps of which include: (a) providing at least one wafer formed by dicing to form a plurality of die, and each of the plurality of die has a magnetic attraction force ; (b) using at least one chip removal chuck of the present invention, using the plurality of magnetic suction heads to remove a portion of the plurality of chips to at least one carrier plate with magnetic attraction, and the magnetic force of the carrier plate is Attractive force > magnetic attractive force of the plurality of magnetic suction heads > magnetic attractive force of each of the plurality of die, so that the plurality of die of the portion can be transferred to the carrier by the plurality of magnetic suction heads; and (c ) Repeat this step (b) until the desired die transfer for the carrier is completed.

Further, there are at least three wafers in the step (a), and the colors of the three wafers are different.

Further, in the step (b), two die removal chucks are used for each of the wafers, and the two die removal chucks transfer a plurality of dies to the wafers disposed on the corresponding two sides of the wafer. carrier board.

Further, the wafer has at least one pair of alignment marks.

Compared with the prior art, the present invention has the following advantages:

1. The chip removal chuck of the present invention has a plurality of magnetic suction heads, and some of the suction heads with magnetic attraction are arranged in an array or linear order with equal spacing, and a plurality of chips can be transferred to the carrier and completed Arrangement to improve the efficiency and accuracy of removing die. In addition, the plurality of magnetic tips are completed by photo-etching, and the size is small, which is 40% to 85% of the size of the grains to be removed, so it can effectively align and reduce the alignment error during movement. To remove the MicroLED die.

2. The method for transferring die of the present invention can use a plurality of die transferring suction cups to simultaneously transfer the die to a plurality of carriers, thereby improving the process efficiency. In addition, by the magnetic attraction of the carrier > the magnetic attraction of the plurality of magnetic heads > the magnetic attraction of the magnetic attraction of the plurality of crystal grains, the stability of removing the crystal grains can be effectively improved, so that the The grains do not fall off during the removal process.

The detailed description and technical content of the present invention are described below with reference to the drawings. Furthermore, the drawings in the present invention are not necessarily drawn according to the actual scale for the convenience of description. These drawings and their scales are not intended to limit the scope of the present invention, and are described here in advance.

The term "comprise or include" as used herein means that in addition to the described components, steps, operational instructions and/or elements, one or more other components, steps, operational instructions and/or elements are not excluded Existing or appending elements. The term "about or approximately" as used means having an approximate or permissible margin of error to avoid illegal or improper use by unknown third parties of exact or absolute values disclosed herein. The word "a" means that the grammatical object of the article is one or more than one (eg, at least one).

In the present invention, the "carrier board" refers to a sheet-like object, such as a circuit board or a spacer, placed after a plurality of dies are removed. The size of the carrier board is based on the size of the display device to be prepared. Depends.

Please refer to FIGS. 1 to 3 , which are respectively a bottom view and a side view of the die removing chuck of the present invention, and a schematic diagram of a cut wafer.

As shown in FIGS. 1 and 2 , the die removal chuck T of the present invention includes a substrate S and a plurality of magnetic suction heads H, and the plurality of magnetic suction heads H are disposed on one side of the substrate S. , there are a plurality of non-magnetic suction heads H' between the magnetic suction heads H and the magnetic suction heads H, so that there is a considerable distance between the two magnetic suction heads H. For example, in Figure 1, the magnetic suction heads H represented by black With magnetic attraction, there are six non-magnetic tips H' represented by white between the two black magnetic tips H. Since there is a considerable distance between the two magnetic suction heads H, when sucking the die D, the magnetic attraction force between the magnetic suction heads H will not affect each other.

Since the carrier plate will eventually be made into a product component (such as a panel of a display device), the distance between the magnetic suction heads H is set according to the distance and number of dies D to be placed on the carrier plate, and can be set according to the The size of the wafer W and the size of the die D to be cut are adjusted, and the sum of the length of each die D on the carrier and the length of the distance between it and the next die D is the cut The multiple of the length of each die D on the wafer W and the sum of the length of the distance between it and the next die D. Specifically, as shown in FIG. 9 , the carriers P1 and P2 respectively have six die placement blocks P11 to P16 and P21 to P26. Each die placement block P11 to P16 and P21 to P26 needs to be placed The number of dies D is 25, and the array order is 5×5 (that is, 5 dies D need to be placed in the length and width respectively, and the length of each die D to be placed is 0.1 mm, and each The sum of the length of the die D and the distance between the next die D is 1 mm. It is set according to the distance and quantity of the die D to be placed on the carriers P1 and P2. The length of a die D is 0.1 mm, and the distance between the die D is 0.025 mm, that is, the length of each die D of the wafer W after the dicing and the distance between it and the next die D. The total length of the spacing is 0.125mm, and the eight times of 0.125mm is 1mm, and 1mm is the length of each die D on the carrier P1 and P2 and the length of the distance between the next die D and the sum of the lengths , the two are in a multiple relationship. Set according to the distance and quantity of the chips D to be placed on the carriers P1 and P2, and the part of the magnetic suction head H of the chip removal chuck T is set to an array order of 5×5 ( That is, there are 5 dies D in the length and width respectively. When removing the dies D, the distribution of the dies D sucked by the part of the magnetic suction head H just corresponds to each die placement block P11 The array order of the dies D to be placed on P16 and P21 to P26 is 5×5; in another embodiment, the plurality of magnetic suction heads H can be arranged in a straight line, and the part of the magnetic suction heads H is set to be arranged in a straight line 1×5, when removing the die D, the die D picked up by the part of the magnetic suction head H just corresponds to the place where the die D needs to be placed on each die placement block P11 to P16 and P21 to P26. One of the rows and columns of the 5×5 array is sorted, and after removing the die D for five times in sequence, the array is sorted into 5×5. Therefore, different from the conventional pick-and-place technology when removing the die, the Only a single die transfer can be completed at a time, and each time a die is placed, the spacing between the die on the carrier board needs to be re-aligned. The die removal chuck T of the present invention can simultaneously remove multiple die D. , and the distance between the die D is a fixed distance, which effectively improves the removal efficiency and accuracy.

The plurality of magnetic suction heads H are formed by photo-etching, and the photo-etching method can be a photo-etching method in a semiconductor manufacturing process. After the plate structure of the suction cup T is removed, exposure and development are performed to perform etching; or the powder of the magnetic material is first coated on the plate structure, and then a photoresist is applied, and then exposure and development are performed to perform etching. The small size of the magnetic tip H can be fabricated by the photo-etching method. The size (area) of each magnetic tip H can be exemplified as 50 µm x 50 µm, 40 µm x 40 µ, 30 µm x 30 µm, and then open the size. It is not limited, and can be adjusted according to user needs. The area size of each of the magnetic suction heads H is 40% to 85% of the area size of the chip D to be removed; when the area size of the magnetic suction head H is smaller than the area of the chip D and is within the aforementioned suitable size range , the magnetic suction head H can be precisely aligned to the desired die D, and will not cause motor alignment errors (error) to move the wrong die D, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85%, etc., which are not limited in the present invention. The magnetic substance of the plurality of magnetic suction heads H may be permanent magnets or electromagnets. When the magnetic substances of the plurality of magnetic suction heads H are permanent magnets, the direction of the magnetic attraction force is fixed, and the switching time of the direction of the magnetic attraction force can be omitted. When the magnetic material of the plurality of magnetic suction heads H is an electromagnet, the magnitude and direction of the magnetic attraction force of each magnetic suction head H and the position of the part of the magnetic suction heads H can be adjusted as needed, eg. As shown in Figure 1, this part of the magnetic suction head H is the magnetic suction head H shown in black, which has a magnetic attractive force, and is located at positions (1,5), (1,10), (1,15) respectively as shown by the coordinate axis. , (1,20), (1,25), (5,5), (5,10), (5,15), (5,20), (5,25), (10,5), ( 10,10), (10,15), (10,20), (10,25), (15,5), (15,10), (15,15), (15,20), (15, 25), (20,5), (20,10), (20,15), (20,20), (20,25), (1,5), (25,10), (25,15) , (25,20), (25,25), and the positions (2,5), (2,10), (2,15), (2,20), (2,25), (6 ,5), (6,10), (6,15), (6,20), (6,25), (11,5), (11,10), (11,15), (11,20 ), (11,25), (16,5), (16,10), (16,15), (16,20), (16,25), (21,5), (21,10), (21,15), (21,20), (21,25), (26,5), (26,10), (26,15), (26,20), (26,25) in white The non-magnetic suction head H' makes it magnetically attractive to act as the magnetic suction head H.

As shown in FIG. 3 , each die D of the diced wafer W has a magnetic layer, each of which has an independent magnetic attraction force, and the die D adjacent to each other have magnetic attraction forces in different directions, and the diagonal lines The magnetic attraction direction of the crystal grains D is the N pole, and the magnetic attraction direction of the non-twill crystal grains D is the S pole. In this way, when the part of the magnetic suction head H approaches the die D, the to-be-transferred die D can be sucked by the magnetic attraction direction, and the adjacent peripheries will be repelled because the magnetic attraction direction is the same. Die D, in order to achieve accurate displacement of the die D to be transferred. Specifically, when the magnetic attraction direction of the part of the magnetic suction head H is the N pole, and the magnetic attraction direction of the die D to be transferred is the S pole, the part of the magnetic suction head H is close to the diced wafer W At the same time, the part of the magnetic suction head H can absorb the chip D to be removed (the N pole and the S pole attract each other), and repel the surrounding chips D adjacent to the chip D to be removed (the N pole and the S pole are attracted to each other) The N poles repel each other), so that the die removing chuck T can correctly remove the desired die D, and prevent other die D from being erroneously removed.

In a preferred embodiment, an alignment mark F is provided on the substrate S, and the alignment mark F can correspond to the alignment member F' on the wafer W, which facilitates the alignment of the two.

In a preferred embodiment, the substrate S is a transparent substrate, and the die removal chuck T further includes a camera unit C, which is disposed above the substrate S and can be used for the die removal chuck T and the die removal chuck T. For the alignment of circle W, automatic alignment correction is performed.

Please refer to FIGS. 4 to 6, 7 to 9, which are the side views (1) to (3) and the top views (1) to (3) of the method for removing the die according to the present invention; in FIGS. 7 to 9, the die removing The suction cups T1 and T2 are represented by dashed squares, respectively.

The method for removing the die of the present invention, the steps of which include: (a) providing a wafer W composed of a plurality of die D after dicing, and each of the plurality of die D has a magnetic attraction; ( b) using two die-removing chucks T1 and T2 of the present invention, and using the plurality of magnetic suction heads H to remove a portion of the plurality of dies D to the carrier plates P1 and P2 with magnetic attraction, and the The magnetic attraction force of the carriers P1 and P2 > the magnetic attraction force of the plurality of magnetic suction heads H > the magnetic attraction force of each of the plurality of crystal grains D, so that the plurality of crystal grains D in this part can be controlled by the plurality of magnetic suction heads H transfer onto the carriers P1 and P2; and (c) repeat the step (b) until the transfer of the dies D required by the carriers P1 and P2 is completed.

In the steps (b) and (c), the die removal chucks T1 and T2 are repeatedly moved to the wafer W in sequence to complete the removal of the die D. As shown in FIGS. 4 and 7 , the die removal chuck T1 moves to the wafer W to remove the die D to be moved, and at the same time, the die removal chuck T2 is positioned above the carrier P2; then 5 and 8 , the die removal chuck T1 places the die D to be moved to the die placement block P11 of the carrier P1, and at the same time, the die removal chuck T2 moves to the die placement block P11 of the carrier P1. The wafer W is used to remove the die D to be moved; then, as shown in FIGS. 6 and 9 , the die removal chuck T2 places the die D to be moved to the die placement block P21 of the carrier P2 , at the same time, the die removal chuck T1 will move to the wafer W to remove the die D to be moved; finally, this process will be repeated to the six die placement blocks P11 to P2 of the carriers P1 and P2 P16 and P21 to P26 are all covered with die D.

The magnetic attractive forces of the carriers P1 and P2 > the magnetic attractive forces of the plurality of magnetic suction heads H > the order of the magnetic attractive forces of the plurality of crystal grains D, which can effectively improve the stability of removing the crystal grains D, so that the crystal grains D can be removed. Particle D does not fall off during pipetting. Specifically, when the plurality of dies D have not been transferred, since the magnetic attraction of the plurality of dies D is weak, the dies D will not repel and attract each other. Stays stably and doesn't move. When the plurality of magnetic suction heads H are close to the plurality of crystal grains D, since the magnetic attractive force of the plurality of magnetic suction heads H is larger than the magnetic attractive force of the plurality of crystal grains D, the plurality of magnetic suction heads H The head H can start the transfer after removing the desired die D. Subsequently, when the plurality of magnetic suction heads H move close to the carrier plates P1 and P2, since the carrier plates P1 and P2 have a larger magnetic attraction force relative to the plurality of magnetic suction heads H, the plurality of crystal grains D will be attracted to the carriers P1 and P2 by magnetic attraction and fixed.

The magnetic attraction force of the carrier boards P1 and P2 is provided by a carrier platform, and the carrier boards P1 and P2 are placed on the carrier platform for chip D extraction; the magnetic attraction force of the carrier platform is a permanent magnet, and its magnetic The size of the attractive force is 5-10 times that of the magnetic suction head H, which can firmly attract the chips transferred to the carriers P1 and P2.

The method for removing the die of the present invention is to directly remove the plurality of die D after the wafer W is cut. For example, after the wafer W is cut, the cutting line between the plurality of die D is 0.025 mm, that is, the distance between the plurality of grains D is 0.025 mm, and the grains can be removed directly after cutting. In the prior art, a stretch film is generally used to stretch the wafer after dicing, and the distance between the die is enlarged before transferring. Therefore, in the prior art, there will be no problems of uneven spacing between the crystal grains after being stretched, resulting in difficult alignment and misalignment when removing the crystal grains.

The die removal method of the present invention can be used to prepare an RGB display panel, as shown in FIG. 10 ; as shown in FIG. 10( a ), when the carriers P1 and P2 are moved to both sides of the red wafer RW, the red die Die removal chucks RT1 and RT2 will respectively remove a plurality of red dies RD to the carriers P1 and P2; then, as shown in FIG. 10(b), the carriers P1 and P2 move to the green wafer GW On both sides, the green die removal suction cups GT1 and GT2 will respectively remove a plurality of green die GD to the carrier P1 and P2, and the plurality of green die GD will be arranged in the same arrangement on the plurality of red die. The same side of RD; then, as shown in Figure 10(c), the carriers P1 and P2 are moved to the two sides of the blue wafer BW, and the blue die removal suction cups BT1 and BT2 will respectively remove a plurality of blue wafers. The color dies BD are transferred to the carriers P1 and P2, and the plurality of blue dies BD will be arranged on the same side of the plurality of green dies GD; this process will be repeated to the carriers P1 and P2. All die placement blocks of P2 are covered with the red die RD, the green die GD and the blue die BD. The dies and carriers P1 and P2 of the red wafer RW, the blue wafer BW, and the green wafer GW shown in FIG. 10 are simplified example diagrams, and the number of the plurality of dies (RD, GD, BD) is shown in FIG. And the size of the carrier boards P1 and P2 can be adjusted as needed.

To sum up, the chip removal chuck of the present invention has a plurality of magnetic suction heads, and some of the suction heads with magnetic attraction are arranged in an array or linear order with equal spacing, which can transfer a plurality of chips to the carrier. Plate and complete the arrangement, improve the efficiency and accuracy of removing the die. In addition, the plurality of magnetic tips are completed by photo-etching, and the size is small, which is 40% to 85% of the size of the grains to be removed, so it can effectively align and reduce the alignment error during movement. To remove the MicroLED die. In addition, Mingzhi's die-transfer method can use a plurality of die-transfer chucks to simultaneously transfer dies to a plurality of carriers, thereby improving the process efficiency. In addition, by the magnetic attraction of the carrier > the magnetic attraction of the plurality of magnetic heads > the magnetic attraction of the magnetic attraction of the plurality of crystal grains, the stability of removing the crystal grains can be effectively improved, so that the The grains do not fall off during the removal process.

The die transfer suction cup and the die transfer method of the present invention can be applied to the mass transfer of die, especially Micro-LED, which has industrial applicability.

The present invention has been described in detail above, but what has been described above is only a preferred embodiment of the present invention, and should not limit the scope of implementation of the present invention, that is, all claims made according to the scope of the patent application of the present invention are equal Changes and modifications should still fall within the scope of the patent of the present invention.

T Die removal chuck S substrate H Magnetic Tip H’ non-magnetic tip F registration mark C camera unit W wafer F’ alignment piece D die T1 Die Pickup Chuck T2 Die Pickup Chuck P1 carrier board P11 Die Placement Block P12 Die Placement Block P13 Die Placement Block P14 Die Placement Block P15 Die Placement Block P16 Die Placement Block P2 carrier board P21 Die Placement Block P22 Die Placement Block P23 Die Placement Block P24 Die Placement Block P25 Die Placement Block P26 Die Placement Block RW Red Wafer R RD red grain RT1 Red Die Pickup Suction Cup RT2 Red Die Pickup Suction Cup GW Green Wafer GD Green Die GT1 Green Die Pickup Suction Cup GT2 Green Die Pickup Suction Cup BW Blue Wafer BD blue grain BT1 Blue Die Pickup Suction Cup BT2 blue die transfer suction cup

FIG. 1 is a bottom view of the die removing chuck of the present invention.

FIG. 2 is a side view of the die removal chuck of the present invention.

FIG. 3 is a schematic diagram of a diced wafer of the present invention.

FIG. 4 is a side view (1) of the method for removing crystal grains of the present invention.

FIG. 5 is a side view (2) of the method for removing crystal grains of the present invention.

FIG. 6 is a side view (3) of the method for removing crystal grains of the present invention.

FIG. 7 is a top view (1) of the method for removing crystal grains of the present invention.

FIG. 8 is a top view (2) of the method for removing crystal grains of the present invention.

FIG. 9 is a top view (3) of the method for removing crystal grains of the present invention.

FIG. 10 is a schematic diagram of the method for chip removal of the present invention for preparing an RGB display panel.

T Die removal chuck S substrate H Magnetic Tip F registration mark

Claims (11)

A grain removal suction cup, comprising: a substrate; A plurality of magnetic suction heads are arranged on one side of the substrate; wherein, the area size of each of the magnetic suction heads is 40% to 85% of the area size of the chip to be removed. The die removal chuck according to claim 1, wherein the plurality of magnetic suction heads are arranged in a line or in an array. The die-removing chuck according to claim 1, wherein when removing the die, some of the plurality of magnetic suction heads are magnetically attractive, and the part of the magnetic suction heads have a comparable magnetic force to each other. distance. The die removal chuck as claimed in claim 1, wherein the substrate is provided with an alignment mark. The die removal chuck according to claim 1, wherein the substrate is a transparent substrate. The die removing suction cup as claimed in claim 4 further includes a camera unit, which is arranged above the substrate and can be used for alignment of the suction cup and the wafer. The die removal chuck according to any one of claims 1 to 5, wherein the plurality of magnetic suction heads are formed by photo-etching. A method for removing grains, the steps comprising: (a) providing at least one wafer that is cut to form a plurality of dies, and each of the plurality of dies has magnetic attraction; (b) using at least one of the die removal chucks as described in any one of claims 1 to 7, and using the plurality of magnetic suction heads to remove a portion of the plurality of dies to at least one carrier with magnetic attraction board, and the magnetic attraction force of the carrier plate > the magnetic attraction force of the plurality of magnetic suction heads > the magnetic attraction force of each of the plurality of crystal grains, so that the plurality of crystal grains in this part can be transferred by the plurality of magnetic suction heads to the the carrier; and (c) Repeat step (b) until the desired die transfer for the carrier is completed. The method of claim 8, wherein the number of wafers in step (a) is at least three, and the colors of the three wafers are different. The method of claim 8, wherein in the step (b), two die removal chucks are used for each of the wafers, and the two die removal chucks transfer a plurality of dies to The wafers correspond to the carriers on both sides. The method of claim 8, wherein the wafer has at least one pair of alignment marks.

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