Method for observing die bonding process using light and shadow

Abstract

The present invention provides a method for observing the die bonding process using light and shadow, comprising the following steps: The suction nozzle picks up the die and is located above the substrate; The light of the lateral light source irradiates towards the die, causing the light and shadow of the die to be projected onto the substrate; The first image capture device captures the light and shadow image and transmits the light and shadow image information to the control device; The control device controls the suction nozzle to move towards the substrate; After the die moves to the die placement area, the light and shadow disappear or there is only a small area remaining, and the first image capture device does not capture the light and shadow image or only captures a small area image. The control device controls the suction nozzle to stop moving, so that the die is completely fixed on the die placement area. Thus, the present invention can monitor the relative position of the die and the substrate by observing the light and shadow, and control the moving distance of the suction nozzle to ensure that the suction nozzle directly and accurately fixes the die on the substrate.

Description

Technical Field

[0001] The present invention relates to a die bonding method, and particularly to a method for observing the die bonding process by using light and shadow. Background Art

[0002] Integrated circuits are fabricated on a semiconductor wafer in a large batch through multiple processes, and the wafer is further divided into multiple die. In other words, a die is a small piece of integrated circuit body made of semiconductor material without encapsulation. The divided multiple die are neatly attached to a carrier film, and then a carrier frame is responsible for transporting the carrier film. Then, a suction nozzle sucks the multiple die on the carrier film, and finally the suction nozzle fixes the multiple die to multiple die placement areas on a substrate, which is beneficial for subsequent processing procedures.

[0003] As Figure 1 shown, before the die bonding process, first, a distance measuring device (not shown in the figure) measures a distance D1 between the suction nozzle 1 and the substrate 3. The moving distance of the suction nozzle 1 is the distance D1 minus the thickness T of the die 2. Then, as Figure 2A shown, during the die bonding process, a distance measuring device measures a distance D2 between the die 2 on the suction nozzle 1 and the substrate 3. In an ideal state, the drive shaft (not shown in the figure) controlling the movement of the suction nozzle 1 maintains a normal state, and the distance D1 minus the thickness T of the die 2 is equal to the distance D2. At this time, the moving distance of the suction nozzle 1 is exactly equal to the distance D2. Therefore, as Figure 2B shown, the suction nozzle 1 can directly and precisely fix the die 2 on the die placement area 301.

[0004] However, the drive shaft controlling the movement of the suction nozzle 1 will cause the relative distance between the suction nozzle 1 and the substrate 3 to change continuously due to thermal expansion and contraction.

[0005] As Figure 3A shown, if the relative distance between the suction nozzle 1 and the substrate 3 becomes larger, then the distance D2 becomes larger, and the distance D1 minus the thickness T of the die 2 is less than the distance D2. At this time, the moving distance of the suction nozzle 1 is less than the distance D2. As Figure 3B shown, the suction nozzle 1 can only move the die 2 above the die placement area 301 and cannot directly fix the die 2 on the die placement area 301. As Figure 3C shown, the suction nozzle 1 must stop sucking the die 2, and then the die 2 can fall onto the die placement area 301 in an empty throw manner. However, in the empty throw manner, it is difficult to accurately place the die 2 on the die placement area 301.

[0006] As Figure 4A shown, if the relative distance between the suction nozzle 1 and the substrate 3 becomes smaller, then the distance D2 becomes smaller, and the distance D1 minus the thickness T of the die 2 is greater than the distance D2. At this time, the moving distance of the suction nozzle 1 is greater than the distance D2. AsFigure 4B As shown, although the suction nozzle 1 can directly and precisely fix the crystal grain 2 on the crystal grain placement area 301, the suction nozzle 1 will further move towards the substrate 3 and crush the crystal grain 2. Summary of the Invention

[0007] The main object of the present invention is to provide a method for observing the die bonding process using light and shadow, which can monitor the relative positions of the crystal grain and the substrate in real time by observing the changes in light and shadow, and control the moving distance of the suction nozzle to ensure that the suction nozzle can directly and precisely fix the crystal grain on the substrate, preventing the crystal grain from being thrown empty or crushed by the suction nozzle.

[0008] To achieve the foregoing object, the present invention provides a method for observing the die bonding process using light and shadow, including the following steps: Step a: A suction nozzle sucks a crystal grain and is located above a crystal grain placement area of a substrate, and the crystal grain is parallel to the substrate; Step b: A light ray of a lateral light source irradiates towards the crystal grain from one side above the crystal grain at an irradiation angle inclined relative to the crystal grain, so that a light and shadow of the crystal grain is projected on the substrate; Step c: A first image capture device captures an image of the light and shadow to obtain light and shadow image information, and transmits the light and shadow image information to a control device; Step d: The control device controls the suction nozzle to move towards the substrate, the light and shadow gradually moves towards the crystal grain placement area, the first image capture device continuously captures an image of the light and shadow and continuously transmits the light and shadow image information to the control device; and Step e: After the crystal grain moves to the crystal grain placement area, the light and shadow completely disappears or only a small area remains, the first image capture device does not capture an image of the light and shadow or only captures a small area image of the light and shadow to obtain small area image information, the control device does not receive the light and shadow image information or receives the small area image information and controls the suction nozzle to stop moving, so that the crystal grain is completely fixed on the crystal grain placement area.

[0009] In some embodiments, in step a, the bottom edge of one side of the crystal grain is a right angle; and, in step e, after the crystal grain moves to the crystal grain placement area, the bottom edge of one side of the crystal grain completely adheres to the crystal grain placement area, so that the light and shadow completely disappears, the first image capture device does not capture an image of the light and shadow, the control device does not receive the light and shadow image information and controls the suction nozzle to stop moving, so that the crystal grain is completely fixed on the crystal grain placement area.

[0010] Preferably, in step c, the control device calculates a width of the light and shadow according to the light and shadow image information; and, in step d, when the control device determines that the width of the light and shadow is equal to a predetermined height of the crystal grain relative to the substrate, the control device controls the suction nozzle to stop moving and sets the predetermined height as a moving distance, and the control device controls the suction nozzle to continue to move towards the substrate according to the moving distance.

[0011] In some embodiments, in step a, the bottom edge of one side of the crystal grain is beveled; and, in step e, after the crystal grain moves to the crystal grain placement area, the bottom edge of one side of the crystal grain does not adhere to the crystal grain placement area, so that there is a small range of light and shadow remaining, and the first image capture device only captures a small range of images of the light and shadow to obtain small range image information. The control device receives the small range image information and controls the suction nozzle to stop moving, so that the crystal grain is completely fixed on the crystal grain placement area.

[0012] Preferably, in step a, a second image capture device captures an image of the bevel to obtain bevel image information, and transmits the bevel image information to the control device. The control device calculates a width of the bevel according to the bevel image information; in step c, the control device calculates a width of the light and shadow according to the light and shadow image information; and, in step d, when the control device determines that the width of the light and shadow is equal to the sum of the width of the bevel and a predetermined height of the crystal grain relative to the substrate, the control device controls the suction nozzle to stop moving and sets the predetermined height as a moving distance, and the control device controls the suction nozzle to continue to move in the direction of the substrate according to the moving distance.

[0013] Preferably, the predetermined height is 2μm.

[0014] In some embodiments, in step c, the first image capture device and the lateral light source are on the same side and shoot from above one side of the crystal grain in a shooting angle inclined relative to the substrate in the direction of the crystal grain placement area, and the irradiation angle is greater than the shooting angle.

[0015] In some embodiments, in step a, when the crystal grain is inclined relative to the substrate, a distance measuring device senses two distances between the two sides of the crystal grain and the substrate and transmits the two distances to the control device. The control device calculates a difference between the two distances, the control device calculates an angle of the crystal grain relative to the substrate according to the difference, and the control device controls the suction nozzle to rotate according to the angle until the control device determines that the angle is 0°, at this time the crystal grain is parallel to the substrate.

[0016] The effect of the present invention is that the present invention can observe the change of the light and shadow, monitor the relative position of the crystal grain and the substrate in real time, and control the moving distance of the suction nozzle to ensure that the suction nozzle can directly and accurately fix the crystal grain on the substrate, preventing the crystal grain from being thrown empty or crushed by the suction nozzle. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the prior art measuring the distance between the suction nozzle and the substrate through a distance measuring device.

[0018] Figure 2A and Figure 2B is a schematic diagram of the prior art transferring crystal grains in an ideal state.

[0019] Figures 3A to 3C It is a schematic diagram of transferring a crystal grain when the relative distance between the suction nozzle and the substrate increases in the conventional technology.

[0020] Figure 4A and Figure 4B It is a schematic diagram of transferring a crystal grain when the relative distance between the suction nozzle and the substrate decreases in the conventional technology.

[0021] Figure 5 It is a flowchart of the method for observing the die bonding process using light and shadow in the present invention.

[0022] Figure 6 It is a schematic diagram of steps S1 to S3 in the first embodiment of the present invention.

[0023] Figure 7 and Figure 8 It is a schematic diagram of step S4 in the first embodiment of the present invention.

[0024] Figure 9 It is a schematic diagram of step S5 in the first embodiment of the present invention.

[0025] Figure 10 It is a schematic diagram of step S1 in the second embodiment of the present invention.

[0026] Figure 11 It is a schematic diagram of steps S2 and S3 in the second embodiment of the present invention.

[0027] Figure 12 It is a schematic diagram of step S4 in the second embodiment of the present invention.

[0028] Figure 13 It is a schematic diagram of step S5 in the second embodiment of the present invention.

[0029] Explanation of reference numerals:

[0030] 1 - suction nozzle; 2 - crystal grain; 3 - substrate; 301 - crystal grain placement area; 10 - suction nozzle; 20 - crystal grain; 21, 21A - bottom edge; 22 - light and shadow; 30 - substrate; 31 - crystal grain placement area; 41 - light ray; 50 - first image capture device; 51 - light and shadow image information; 52 - small range image information; 60 - control device; 70 - second image capture device; 71 - oblique angle image information; D1, D2 - spacing; S1 to S5 - steps; T - thickness; θ1 - irradiation angle; θ2 - shooting angle. Detailed Description of the Invention

[0031] The following further describes the embodiments of the present invention in detail with reference to the drawings and component symbols, enabling those skilled in the art to implement it after studying this specification.

[0032] Please refer to Figures 5 to 9 ,Figure 5 is a flowchart of the method for observing the die bonding process using light and shadow according to the present invention, Figure 6 is a schematic diagram of steps S1 to S3 of the first embodiment of the present invention, Figure 7 and Figure 8 is a schematic diagram of step S4 of the first embodiment of the present invention, Figure 9 is a schematic diagram of step S5 of the first embodiment of the present invention.

[0033] The present invention provides a method for observing the die bonding process using light and shadow, comprising the following steps:

[0034] Step S1: As shown in Figure 5 and Figure 6 , a suction nozzle 10 sucks a die 20 and is located above a die placement area 31 of a substrate 30. The die 20 is parallel to the substrate 30, and a bottom edge 21 on one side of the die 20 is a right angle.

[0035] Step S2: As shown in Figure 5 and Figure 6 , a light ray 41 of a lateral light source (not shown in the figure) irradiates the die 20 from one side of the die 20 at an irradiation angle θ1 inclined relative to the die 20, so that a light and shadow 22 of the die 20 is projected onto the substrate 30.

[0036] Step S3: As shown in Figure 5 and Figure 6 , a first image capture device 50 captures an image of the light and shadow 22 to obtain a light and shadow image information 51, and transmits the light and shadow image information 51 to a control device 60. The control device 60 calculates a width of the light and shadow 22 according to the light and shadow image information 51.

[0037] Step S4: As shown in Figure 5 and Figure 7 , the control device 60 controls the suction nozzle 10 to move towards the substrate 30, and the light and shadow 22 gradually moves towards the die placement area 31. The first image capture device 50 continuously captures an image of the light and shadow 22 and continuously transmits the light and shadow image information 51 to the control device 60. As shown in Figure 5 and Figure 8 , when the control device 60 determines that the width of the light and shadow 22 is equal to a predetermined height of the die 20 relative to the substrate 30, the control device 60 controls the suction nozzle 10 to stop moving and sets the predetermined height as a moving distance. The control device 60 controls the suction nozzle 10 to continue moving towards the substrate 30 according to the moving distance. The predetermined height is preferably 2 μm.

[0038] Step S5: As shown in Figure 5 and Figure 9As shown, after the crystal grain 20 moves to the crystal grain placement area 31, the bottom edge 21 on one side of the crystal grain 20 completely adheres to the crystal grain placement area 31, causing the light and shadow 22 to completely disappear. The first image capture device 50 fails to capture the image of the light and shadow 22, and the control device 60 does not receive the light and shadow image information 51 and controls the suction nozzle 10 to stop moving, so that the crystal grain 20 is completely fixed on the crystal grain placement area 31.

[0039] Please refer to Figures 10 to 13 , Figure 10 which is a schematic diagram of step S1 of the second embodiment of the present invention, Figure 11 which is a schematic diagram of steps S2 and S3 of the second embodiment of the present invention, Figure 12 which is a schematic diagram of step S4 of the second embodiment of the present invention, Figure 13 which is a schematic diagram of step S5 of the second embodiment of the present invention. As Figure 10 shown, the difference between step S1 of the second embodiment and step S1 of the first embodiment is that: the bottom edge 21A on one side of the crystal grain 20 is an oblique angle, and a second image capture device 70 captures the image of the oblique angle to obtain an oblique angle image information 71, and transmits the oblique angle image information 71 to the control device 60. The control device 60 calculates the width of the oblique angle according to the oblique angle image information 71. As Figure 11 shown, step S2 of the second embodiment is exactly the same as step S2 of the first embodiment, and step S3 of the second embodiment is exactly the same as step S3 of the first embodiment. As Figure 12 shown, the difference between step S4 of the second embodiment and step S4 of the first embodiment is that: when the control device 60 determines that the width of the light and shadow 22 is equal to the sum of the width of the oblique angle and a predetermined height of the crystal grain 20 relative to the substrate 30, the control device 60 controls the suction nozzle 10 to stop moving and sets the predetermined height as a moving distance, and the control device 60 controls the suction nozzle 10 to continue to move in the direction of the substrate 30 according to the moving distance. As Figure 13 shown, the difference between step S5 of the second embodiment and step S5 of the first embodiment is that: after the crystal grain 20 moves to the crystal grain placement area 31, the bottom edge 21A on one side of the crystal grain 20 does not adhere to the crystal grain placement area 31, causing a small range of the light and shadow 22 to remain. The first image capture device 50 only captures the small range image of the light and shadow 22 to obtain a small range image information 52, and the control device 60 receives the small range image information 52 and controls the suction nozzle 10 to stop moving, so that the crystal grain 20 is completely fixed on the crystal grain placement area 31.

[0040] In summary, regardless of whether the drive shaft (not shown in the figure) that controls the movement of the suction nozzle 10 remains in a normal state or the relative distance between the suction nozzle 10 and the substrate 30 keeps changing due to thermal expansion and contraction, the present invention can illuminate the die 20 with the light 41 of the lateral light source to project its light and shadow 22 onto the substrate 30, and use the first image capture device 50 to observe the change of the light and shadow 22, monitor the relative position of the die 20 and the substrate 30 in real time, and then cooperate with the control device 60 to control the moving distance of the suction nozzle 10 to ensure that the suction nozzle 10 can directly and accurately fix the die 20 on the die placement area 31, preventing the die 20 from being thrown empty or crushed by the suction nozzle 10.

[0041] Furthermore, in the first embodiment, since the bottom edge 21 of the die 20 may be very sharp and form a right angle during cutting, the relative distance between the die 20 and the substrate 30 is substantially equal to the width of the light and shadow 22. In order to more precisely control the moving distance of the suction nozzle 10, the first embodiment can first set a certain relative distance between the die 20 and the substrate 30 as the predetermined height, and then by judging whether the width of the light and shadow 22 is equal to the relative distance between the die 20 and the substrate 30, monitor the relative position of the die 20 and the substrate 30 in real time, and set this predetermined height as the moving distance of the suction nozzle 10 to ensure that the suction nozzle 10 can directly and accurately fix the die 20 on the substrate 30, preventing the die 20 from being thrown empty or crushed by the suction nozzle 10.

[0042] In addition, in the second embodiment, since the bottom edge 21A of the die 20 is not sharp enough and forms an oblique angle (i.e., a cracked edge) during cutting, the sum of the relative distance between the die 20 and the substrate 30 and the width of the oblique angle is substantially equal to the width of the light and shadow 22. In order to more precisely control the moving distance of the suction nozzle 10, the second embodiment can first set a certain relative distance between the die 20 and the substrate 30 as the predetermined height, and then by judging whether the width of the light and shadow 22 is equal to the sum of the relative distance between the die 20 and the substrate 30 and the width of the oblique angle, monitor the relative position of the die 20 and the substrate 30 in real time, and set this predetermined height as the moving distance of the suction nozzle 10 to ensure that the suction nozzle 10 can directly and accurately fix the die 20 on the substrate 30, preventing the die 20 from being thrown empty or crushed by the suction nozzle 10.

[0043] In step S1 of the first embodiment and the second embodiment, when the die 20 is inclined with respect to the substrate 30, a distance measuring device (not shown in the figure) senses the two distances between the two sides of the die 20 and the substrate 30 and transmits the two distances to the control device 60. The control device 60 calculates a difference between the two distances, and the control device 60 calculates the angle of the die 20 with respect to the substrate 30 according to the difference. The control device 60 controls the rotation of the nozzle 10 according to the angle until the control device 60 determines that the angle is 0°. At this time, the die 20 is parallel to the substrate 30. General distance measuring devices (for example, infrared distance measuring devices) can adjust the parallelism between the die 20 and the substrate 30 to ±0.1 μm, and high-precision laser distance measuring devices can adjust the parallelism between the die 20 and the substrate 30 to ±5 nm.

[0044] It is worth mentioning that, as Figure 6 and Figure 11 shown, in step S3 of the first embodiment and the second embodiment, the first image capturing device 50 and the side light source are on the same side and shoot from above one side of the die 20 in a shooting angle θ2 inclined with respect to the substrate 30 in the direction of the die placement area 31, and the irradiation angle θ1 is greater than the shooting angle θ2. Therefore, the light 41 of the side light source will not be blocked by the first image capturing device 50. During the process of the nozzle 10 moving towards the substrate 30, the light and shadow of the die 20 can always be projected on the substrate 30, and the first image capturing device 50 can continuously capture the image of the light and shadow 22.

[0045] The above are only preferred embodiments for explaining the present invention, and are not intended to limit the present invention in any form. Therefore, any modification or change made to the present invention under the same inventive spirit should still be included in the scope intended to be protected by the present invention.

Claims

1. A method for observing the die bonding process using light and shadow, characterized in that, Including the following steps: Step a: A suction nozzle sucks a die and is located above a die placement area of a substrate, and the die is parallel to the substrate; Step b: A light ray of a lateral light source irradiates from above one side of the die in a direction inclined relative to the die towards the die, so that a light shadow of the die is projected onto the substrate; Step c: A first image capturing device captures an image of the light shadow to obtain light shadow image information and transmits the light shadow image information to a control device; Step d: The control device controls the suction nozzle to move towards the substrate, the light shadow gradually moves towards the die placement area, the first image capturing device continuously captures the image of the light shadow and continuously transmits the light shadow image information to the control device; and Step e: After the die moves to the die placement area, the light shadow completely disappears or a small area remains, the first image capturing device does not capture the image of the light shadow or only captures a small area image of the light shadow to obtain small area image information, the control device does not receive the light shadow image information or receives the small area image information and controls the suction nozzle to stop moving, so that the die is completely fixed on the die placement area.

2. The method for observing the die bonding process using light and shadow according to claim 1, characterized in that In step a, the bottom edge of one side of the die is a right angle; and in step e, after the die moves to the die placement area, the bottom edge of one side of the die completely fits on the die placement area, so that the light shadow completely disappears, the first image capturing device does not capture the image of the light shadow, the control device does not receive the light shadow image information and controls the suction nozzle to stop moving, so that the die is completely fixed on the die placement area.

3. The method for observing the die bonding process using light and shadow according to claim 2, wherein, In step c, the control device calculates a width of the light shadow according to the light shadow image information; and in step d, when the control device determines that the width of the light shadow is equal to a predetermined height of the die relative to the substrate, the control device controls the suction nozzle to stop moving and sets the predetermined height as a moving distance, and the control device controls the suction nozzle to continue to move towards the substrate according to the moving distance.

4. The method for observing the die bonding process using light and shadow according to claim 1, characterized in that, In step a, the bottom edge of one side of the die is an oblique angle; and in step e, after the die moves to the die placement area, the bottom edge of one side of the die does not fit on the die placement area, so that a small area of the light shadow remains, the first image capturing device only captures a small area image of the light shadow to obtain the small area image information, the control device receives the small area image information and controls the suction nozzle to stop moving, so that the die is completely fixed on the die placement area.

5. The method for observing the die bonding process using light and shadow according to claim 4, wherein In step a, a second image capturing device captures an image of the bevel angle to obtain bevel angle image information, and transmits the bevel angle image information to the control device. The control device calculates a width of the bevel angle based on the bevel angle image information. In step c, the control device calculates a width of the light and shadow based on the light and shadow image information. And in step d, when the control device determines that the width of the light and shadow is equal to the sum of the width of the bevel angle and a predetermined height of the crystal grain relative to the substrate, the control device controls the suction nozzle to stop moving and sets the predetermined height as a moving distance. The control device controls the suction nozzle to continue moving towards the substrate according to the moving distance.

6. The method for observing the die bonding process using light and shadow according to claim 3 or 5, characterized in that, The predetermined height is 2 μm.

7. The method for observing the die bonding process using light and shadow according to claim 1, wherein In step c, the first image capturing device and the lateral light source are on the same side and shoot from above one side of the crystal grain towards the crystal grain placement area at a shooting angle inclined relative to the substrate, and the irradiation angle is greater than the shooting angle.

8. The method for observing the die bonding process using light and shadow according to claim 1, characterized in that In step a, when the crystal grain is inclined relative to the substrate, a distance measuring device senses two distances between the two sides of the crystal grain and the substrate and transmits the two distances to the control device. The control device calculates a difference between the two distances. The control device calculates an angle of the crystal grain relative to the substrate according to the difference. The control device controls the suction nozzle to rotate according to the angle until the control device determines that the angle is 0°, at which time the crystal grain is parallel to the substrate.

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