CN115732346A - Center contact impact-free die bonding method - Google Patents

Abstract

The invention provides a center-contact impact-force-free die bonding method, which comprises the following steps: picking up the crystal grains by the crystal fixing device, wherein the surfaces of the crystal grains have no tin balls and no copper columns; the die bonder moves the die to one side of the die placement area, and the surface of the substrate has no solder balls and no copper columns; the die bonder blows the center of the crystal grain through positive pressure to enable the center of the crystal grain to deform so as to contact the center of the crystal grain placing area; the center of the crystal grain forms a fitting wave after contacting the center of the crystal grain placing area, and the fitting wave expands from the center of the crystal grain to the periphery of the crystal grain so that the crystal grain gradually separates from the crystal grain fixing device and is fixed on the crystal grain placing area; and the die is completely fixed on the die placement area. Therefore, the contact between the center of the crystal grain and the substrate is controlled by the positive pressure without impact force, the force is extremely small, and the crystal grain cannot be damaged.

Description

Center contact impact-free die bonding method

Technical Field

The invention relates to a die bonding method, in particular to a non-impact die bonding method for fixing a die in the center contact of a substrate.

Background

Integrated circuits are fabricated in bulk on a semiconductor wafer through multiple processes, and the wafer is further divided into multiple dies. In other words, the die is a small integrated circuit body made of semiconductor material without being packaged. The plurality of divided crystal grains are orderly attached to a bearing device, then a bearing frame is responsible for conveying the bearing device, and the plurality of crystal grains are sequentially transferred to a plurality of crystal grain placing areas of the substrate, so that subsequent processing procedures can be favorably carried out.

Wafer to wafer (wafer) direct bonding techniques have been used for years and are a front end of the line to facilitate control of cleanliness and crystallinity. Furthermore, the size of the wafer is typically 6-12 inches, and the larger size makes it relatively easy to control the generation of the sticking wave. The problem with direct wafer-to-wafer bonding is: application on a system on a chip is less easy. The reason is that: the single chip system is usually formed by combining chips of different manufacturers, and the cost is very high for manufacturing different logic circuits with the same photomask.

The die-to-wafer bonding technology is developed for integrating small chips (chiplets) of different manufacturers, can save a large amount of development cost, can be directly applied to the existing small chip solutions (chiplet solutions) of other manufacturers in the single chip system manufacturing process, and does not need to additionally develop a special logic circuit. Therefore, die to wafer (die to wafer) bonding technology is a current trend.

As conventional solder bonding techniques have approached the limit, copper contact direct bonding techniques (i.e., hybrid bonding techniques) have become the preferred solution in terms of die-to-wafer bonding techniques in order to reduce die size and contact size.

However, since the size of the die is small and the control of the bonding wave is difficult, a hybrid bonding technique suitable for the die-to-wafer bonding has not been successfully developed. Three die-to-wafer bonding techniques that are currently in common use are described below.

The first die-to-wafer bonding technique is: the crystal grain is firstly sucked from the bearing device by the crystal grain fixing device, then the crystal grain is moved to the substrate, so that the crystal grain is directly contacted with the substrate, and finally the crystal grain fixing device is separated from the crystal grain, so that the crystal grain is fixed on the substrate. The problems with this technique are: the situation that the crystal grains and the substrate jointly enclose the bubbles to generate cavities (void) is easy to occur, so that the crystal grains and the substrate are not completely and tightly attached, the subsequent processing procedure of the crystal grains is easily influenced by the bubbles, and the product yield of the subsequent processing is reduced.

The second die-to-wafer bonding technique is: the die bonder transfers the die to the substrate by way of air polishing. The problems with this technique are: firstly, the crystal grains have certain mass, and under the influence of gravity, the crystal grains fall to a crystal grain placing area at an accelerated speed to generate larger impact force, so that the crystal grains are damaged due to larger force when contacting the substrate; secondly, it is difficult to precisely place the die on the die placement area.

The third die-to-wafer bonding technique is: the die bonder is internally provided with three elastic pieces which are positioned on the opposite sides of the fixed surface, and the K value of the two elastic pieces at the periphery is smaller than that of the elastic piece positioned at the center, namely the spring coefficient. When the die bonder moves towards the direction of the substrate, the inertia deforms the elastic parts with different internal and external K values, so that the center of the crystal grain contacts the substrate first and then generates a bonding wave, and the crystal grain is transferred to the crystal grain placing area accurately. The problems with this technique are: firstly, when the die bonder moves towards the direction of the substrate, the three elastic pieces can provide larger mass inertia of the crystal grains, so that the impact force of the crystal grains contacting the substrate is larger and the crystal grains are damaged; secondly, because the die bonder has a small volume, the elastic element is very tiny, difficult to assemble and high in manufacturing cost.

In addition, when the die is bonded to the substrate, the bonding speed of the die is too fast, which causes the die to be easily damaged, distorted or bent.

Disclosure of Invention

The main objective of the present invention is to provide a center-contact impact-free die bonding method, which can control the die to contact the die-placing region as the center through the impact-free positive pressure, and has the advantages of small force path, no damage to the die, no need of installing an elastic member, and low manufacturing cost.

Another objective of the present invention is to provide a center-contact impact-free die attach method, which can completely fix a die on a die-placing area by a bonding wave, so that the die can be precisely placed on the die-placing area, and the die can be tightly bonded to a substrate, thereby completely eliminating the bubble-enclosed situation between the die and the substrate, and avoiding any void (void) between the die and the substrate, thereby improving the yield of the product manufactured by the subsequent processing of the die.

Another objective of the present invention is to provide a center-contact impact-free die bonding method, which can control a die to be attached to a die-placing region at a proper attachment speed by gradually weakening a positive pressure and further switching to a central negative pressure, so as to prevent the die from being damaged, tilted, or bent.

In order to achieve the above object, the present invention provides a center-contact impact-free die bonding method, comprising the following steps: a, a die bonder picks up a die, wherein the surface of the die has no tin ball and no copper column; b, the die bonder moves the die to one side of a die placement area of a substrate, and the surface of the substrate is free of solder balls and copper columns; c, blowing the center of the crystal grain by the crystal grain fixing device through positive pressure to make the center of the crystal grain deform in a flexing manner so as to contact the center of the crystal grain placing area; d, forming a fitting wave after the center of the crystal grain contacts the center of the crystal grain placing area, wherein the fitting wave gradually expands from the center of the crystal grain to the periphery of the crystal grain so that the crystal grain gradually separates from the crystal fixing device and is fixed on the crystal grain placing area; and e, completely fixing the crystal grain on the crystal grain placing area.

In some embodiments, in step a, the die bonder adsorbs the periphery of the die by a peripheral negative pressure to fix the die and pick up the die.

In some embodiments, in step b and step c, the die bonder continuously sucks the periphery of the die through the peripheral negative pressure to fix the die.

In some embodiments, in step d, the ambient negative pressure is gradually reduced.

In some embodiments, in step e, the peripheral negative pressure is completely stopped.

In some embodiments, the die bonder has a plurality of air holes, the air holes are connected to a vacuum device, the vacuum device evacuates the air holes to generate vacuum and provide a peripheral negative pressure, and the peripheral negative pressure adsorbs the periphery of the die through the air holes.

In some embodiments, in step d, the positive pressure is completely stopped or maintained at a steady pressure.

In some embodiments, the die bonder has a shaft hole connected to a gas supply device, and the gas supply device blows air into the shaft hole to generate a gas flow and provide positive pressure.

In order to achieve the above object, the present invention provides a center-contact impact-free die bonding method, comprising the following steps: a die bonder picks up a die, the surface of which has no tin ball and no copper column; b, the die bonder moves the die to one side of a die placement area of a substrate, and the surface of the substrate is free of solder balls and copper columns; c, blowing the center of the crystal grain by the crystal grain fixing device through positive pressure to enable the center of the crystal grain to be in flexural deformation so as to contact the center of the crystal grain placing area; d, forming a fitting wave after the center of the crystal grain contacts the center of the crystal grain placing area, wherein the fitting wave gradually expands from the center of the crystal grain to the periphery of the crystal grain, then the positive pressure gradually decreases and is further switched into a central negative pressure, so that the crystal grain gradually separates from the crystal fixing device and is fixed on the crystal grain placing area; and e, completely fixing the crystal grain on the crystal grain placing area.

In some embodiments, in step a, the die bonder sucks the periphery of the die by a peripheral negative pressure to fix the die and pick up the die.

In some embodiments, in step b and step c, the die bonder continuously adsorbs the periphery of the die through the peripheral negative pressure to fix the die.

In some embodiments, in step d, the peripheral negative pressure is gradually reduced.

In some embodiments, in step e, the peripheral negative pressure is completely stopped.

In some embodiments, the die bonder has a plurality of air holes, the air holes are connected to a vacuum device, the vacuum device evacuates the air holes to generate vacuum and provide a peripheral negative pressure, and the peripheral negative pressure adsorbs the periphery of the die through the air holes.

In some embodiments, the die bonder has a shaft hole, the shaft hole is connected to a gas supply device and a vacuum device, the gas supply device blows air into the shaft hole to generate gas flow and provide positive pressure, and the vacuum device evacuates air into the shaft hole to generate vacuum and provide central negative pressure.

The invention has the advantages that the invention can control the crystal grain to contact with the crystal grain placing area as the center through the positive pressure without impact force, the force of the crystal grain contacting the substrate is only limited to the quality of the crystal grain, the force is extremely small, the crystal grain can not be damaged, an elastic piece is not required to be arranged, and the manufacturing cost is lower.

In addition, the invention can completely fix the crystal grains on the crystal grain placing area through the attaching wave, so that the crystal grains can be accurately placed on the crystal grain placing area, the crystal grains can be tightly attached on the substrate, the condition that the crystal grains and the substrate enclose air bubbles is completely eliminated, no void (void) exists between the crystal grains and the substrate, and the product yield of the subsequent processing of the crystal grains is improved.

In addition, the invention can control the crystal grains to be attached to the crystal grain placing area at a proper attaching speed by gradually weakening the positive pressure and further switching the positive pressure into the central negative pressure, thereby avoiding the crystal grains from being damaged, inclined or bent.

Drawings

FIG. 1 is a flow chart of the center contact impact-free die bonding method of the present invention.

Fig. 2 is a schematic diagram of a first pickup manner in step S1 according to the preferred embodiment of the invention.

Fig. 3 is a schematic diagram of the second pick-up mode in step S1 according to the preferred embodiment of the invention.

Fig. 4A and 4B are schematic diagrams of a third picking mode in step S1 according to a preferred embodiment of the present invention.

Fig. 5 is a schematic diagram of a fourth pick-up mode in step S1 according to the preferred embodiment of the invention.

Fig. 6 is a schematic diagram of a fifth pick-up mode in step S1 according to the preferred embodiment of the invention.

Fig. 7 is a schematic diagram of a sixth pick-up mode in step S1 according to a preferred embodiment of the invention.

FIG. 8 is a diagram illustrating step S2 according to the preferred embodiment of the present invention.

FIG. 9 is a diagram illustrating step S3 according to the preferred embodiment of the present invention.

FIG. 10 is a diagram illustrating step S4 according to the preferred embodiment of the present invention.

FIG. 11 is a diagram illustrating step S5 according to the preferred embodiment of the present invention.

Fig. 12 is a schematic diagram of step S4 of another embodiment of the present invention.

Fig. 13 is a schematic diagram of step S4 according to still another embodiment of the present invention.

Fig. 14 is a schematic diagram of step S5 of still another embodiment of the present invention.

FIG. 15 is a schematic view of a die bonding apparatus, a gas supply apparatus and a vacuum apparatus according to the present invention.

Description of the reference numerals:

10-a die bonding device; 11-shaft hole; 12-air holes; 20-crystal grains; 21-perimeter; 22-center; 30-a carrier film; 30A-a carrying tray; 30B-a vacuum tray; 31-a first surface; 32-a second surface; 33-a groove; 40-pushing the piece; 40A-suction nozzle; 41-door panel; 50-a picking device; 60-a substrate; 61-a die placement area; 611-center; 70-a gas supply; 71-positive pressure; 80-a vacuum device; 81-peripheral negative pressure; 82, 83-negative pressure; 84-central negative pressure; 91-laminating wave; S1-S5; S11-S14-.

Detailed Description

The embodiments of the present invention will be described in more detail with reference to the drawings and the reference numerals, so that those skilled in the art can implement the embodiments after reading the description.

The invention provides a center-contact impact-force-free die bonding method, which aims at the problem that the die bonding method in the prior art is easy to damage due to larger impact force when the die contacts a substrate.

Referring to fig. 1 to 11, fig. 1 is a flowchart illustrating a center-contact impact-free die bonding method according to the present invention, and fig. 2 to 11 are schematic diagrams illustrating steps S1 to S5, respectively, according to a preferred embodiment of the present invention. The invention provides a center-contact impact-free die bonding method, which comprises the following steps:

step S1, as shown in fig. 1 to fig. 7, a die bonder 10 picks up a die 20, and the surface of the die 20 has no solder balls (solder) and no copper pillars (bump). Seven pickup modes of step S1 will be listed below.

The first picking mode is as follows: as shown in fig. 2, in step S11, a carrier film 30 has a plurality of dies 20 on a first surface 31 thereof; step S12, the die bonder 10 adsorbs the periphery 21 of the die 20 by a peripheral negative pressure 81 to bond the die 20; in step S13, the die bonder 10 moves upward to separate the die 20 from the carrier film 30, thereby achieving the effect of picking up the die 20.

A second pickup mode: as shown in fig. 3, in step S11, a plurality of dies 20 are disposed in a plurality of grooves 33 of a carrier tray 30A; step S12, the die bonder 10 adsorbs the periphery 21 of the die 20 by a peripheral negative pressure 81 to bond the die 20; in step S13, the die bonder 10 moves upward to separate the die 20 from the recess 33 of the tray 30A, thereby achieving the effect of picking up the die 20.

A third pickup mode: as shown in fig. 4A, in step S11, a first surface 31 of a carrier film 30 has a plurality of dies 20 thereon, and a second surface 32 of the carrier film 30 is disposed on a vacuum tray 30B; as shown in fig. 4B, in step S12, the vacuum tray 30B absorbs a local area of the carrier film 30 by a negative pressure 82, so as to reduce the contact area between the die 20 and the carrier film 30, and thus the die 20 is partially peeled off from the carrier film 30; step S13, the die bonder 10 adsorbs the periphery 21 of the die 20 by a peripheral negative pressure 81 to bond the die 20; in step S14, the die bonder 10 moves upward to separate the die 20 from the carrier film 30, thereby achieving the effect of picking up the die 20.

The picking mode is four: as shown in fig. 5, in step S11, a carrier film 30 has a plurality of dies 20 on a first surface 31 thereof; step S12, a pushing member 40 aligns with one of the dies 20, contacts a second surface 32 of the carrier film 30, and pushes the die 20 to an end of the die attach apparatus 10 through the carrier film 30, so as to reduce a contact area between the die 20 and the carrier film 30, such that the die 20 is partially peeled off from the carrier film 30, and the die attach apparatus 10 adsorbs a periphery 21 of the die 20 through a peripheral negative pressure 81, so as to attach the die 20; in step S13, the die bonder 10 moves upward to separate the die 20 from the carrier film 30, thereby achieving the effect of picking up the die 20.

A fifth picking mode: as shown in fig. 6, in step S11, a carrier film 30 has a plurality of dies 20 on a first surface 31 thereof; step S12, aligning one of the dies 20 with a suction nozzle 40A and contacting a second surface 32 of the carrier film 30, opening a door 41 of the suction nozzle 40A, sucking a local area of the carrier film 30 by the suction nozzle 40A through a negative pressure 83, reducing a contact area between the die 20 and the carrier film 30, so that the die 20 is partially peeled off from the carrier film 30, and simultaneously sucking the periphery 21 of the die 20 by the die bonder 10 through a peripheral negative pressure 81 to bond the die 20; in step S13, the die bonder 20 moves upward to separate the die 20 from the carrier film 30, thereby achieving the effect of picking up the die 20.

A sixth picking mode: as shown in fig. 7, in step S11, a plurality of dies 20 are disposed on a first surface 31 of a carrier film 30, and a picking device 50 picks one of the dies 20; step S12, the picking device 50 moves the die 20 to one end of the die bonder 10, and the die bonder 10 absorbs the periphery 21 of the die 20 through a peripheral negative pressure 81; in step S13, the die bonder 20 moves upward to separate the die 20 from the picking device 50, thereby achieving the effect of picking up the die 20.

In step S2, as shown in fig. 1 and 8, the die bonder 10 moves the die 20 to a side of a die-placing area 61 of a substrate 60, and the surface of the substrate 60 has no solder balls (solder balls) and no copper pillars (bump).

Preferably, in step S2, the die bonder 10 continuously sucks the periphery 21 of the die 20 through the peripheral negative pressure 81 to fix the die 20 and prevent the die 20 from being detached from the die bonder 10.

In other embodiments, the die bonder 10 may also use other fixing means to fix the die 20 to achieve the same effect.

In step S3, as shown in fig. 1 and fig. 9, the die bonder 10 blows the center 22 of the die 20 by a positive pressure 71, so that the center 22 of the die 20 is deformed to contact the center 611 of the die-placing area 61.

Preferably, in step S3, the die bonder 10 continuously sucks the periphery 21 of the die 20 by the peripheral negative pressure 81 to fix the die 20, so as to not only prevent the die 20 from being detached from the die bonder 10, but also ensure that the entire die 20 has only its center 22 that is deflected and most protruded, so that the center 22 of the die 20 can contact the center 611 of the die placement area 61 in a point contact manner.

In step S4, as shown in fig. 1 and 10, after the center 22 of the die 20 contacts the center 611 of the die-placing region 61, a bonding wave 91 (bond wave) is formed, and the bonding wave 91 gradually spreads from the center 22 of the die 20 to the periphery 21 of the die 20, so that the die 20 gradually detaches from the die attach apparatus 10 and is fixed on the die-placing region 61. Specifically, since the center 22 of the die 20 contacts the center 611 of the die-placing region 61 in a point contact manner, the center 22 of the die 20 and its neighboring region generate a bonding force, which further forms the fitting wave 91 and gradually expands toward the periphery 21 of the die 20.

Preferably, in step S4, the peripheral negative pressure 81 is gradually reduced, so as to reduce the interference of the peripheral negative pressure 81 on the spreading of the bonding wave 91, and ensure that the bonding wave 91 gradually spreads from the center 22 of the die 20 to the periphery 21 of the die 20.

Preferably, in step S4, the positive pressure 71 can be completely stopped, so as to achieve the effect of saving energy.

In step S5, as shown in fig. 1 and fig. 11, the die 20 is completely fixed on the die-placing area 61. Specifically, the peripheral negative pressure 81 is completely stopped, the die bonder 10 no longer fixes the die 20, and the die 20 is completely fixed on the die receiving area 61.

Fig. 12 is a schematic diagram of step S4 of another embodiment of the present invention. As shown in fig. 12, in step S4 of another embodiment, the positive pressure 71 maintains a steady pressure, and maintains the blowing of the center 22 of the die 20, so as to ensure that the center 22 of the die 20 remains fixed at the center 611 of the die-placing area 61, and the positive pressure 71 is not completely stopped until the die 20 is fixed at the die-placing area 61.

Fig. 13 and 14 are schematic diagrams of step S4 and step S5, respectively, according to still another embodiment of the present invention. In step S4 of yet another embodiment, as shown in fig. 13, the positive pressure 71 is gradually decreased and further switched to a central negative pressure 84. As shown in fig. 14, in step S5 of still another embodiment, the central negative pressure 84 is continuously maintained.

FIG. 15 is a schematic view of the die bonding apparatus 10, the gas supplying apparatus 70 and the vacuum apparatus 80 according to the present invention. As shown in fig. 15, the die bonder 10 has a shaft hole 11 and a plurality of air holes 12, the shaft hole 11 is connected to a gas supply device 70 and a vacuum device 80, and the air holes 12 are connected to a vacuum device 80. As shown in fig. 9, in step S3 of the preferred embodiment, the gas supply device 70 blows gas into the shaft hole 11 to generate a gas flow and provide a positive pressure 71. As shown in fig. 12, in step S4 of another embodiment, the gas supply device 70 continuously supplies a stable pressure to blow the shaft hole 11. As shown in fig. 2 to 10 and 12 to 14, in step S13 and steps S2 to S4 of the above three embodiments, the vacuum apparatus 80 evacuates the plurality of air holes 12 to generate vacuum and provides a peripheral negative pressure 81, and the peripheral negative pressure 81 adsorbs the periphery 21 of the die 20 through the plurality of air holes 12. As shown in fig. 13, in step S4 of still another embodiment, the pressure of the air blown into the shaft hole 11 by the air supply device 70 is gradually decreased, so that the positive pressure 71 is gradually decreased, and after the air blowing into the shaft hole 11 by the air supply device 70 is stopped, the pressure of the air sucked into the shaft hole 11 by the vacuum device 80 is gradually increased to further generate the vacuum and switch to the central negative pressure 84. As shown in fig. 14, in step S5 of still another embodiment, the vacuum device 80 continuously pumps air into the axial hole 11 to maintain the vacuum and provide a stable central negative pressure 84.

In summary, the present invention can control the die 20 to contact the die-placing region 61 as the center through the non-impact positive pressure 71, the force of the die 20 contacting the substrate 60 is limited to the mass of the die 20, the force is extremely small, the die 20 is not damaged, and no elastic member is required to be installed, so the manufacturing cost is low.

Furthermore, the die 20 can be completely fixed on the die placement area 61 by the bonding wave 91, so that the die 20 can be accurately placed on the die placement area 61, the die 20 can be tightly bonded on the substrate 60, the situation that the die 20 and the substrate 60 enclose air bubbles is completely eliminated, no void (void) exists between the die 20 and the substrate 60, and the product yield of the subsequent processing of the die 20 is improved.

The invention can control the crystal grain 20 to be attached to the crystal grain placing area 61 at a proper attaching speed by gradually reducing the positive pressure 71 and further switching the positive pressure into the central negative pressure 84, thereby avoiding the crystal grain 20 from being damaged, inclined or bent.

It should be noted that, since the center-contact impact-free die bonding method of the present invention is developed for hybrid bonding (hybrid bonding) and the hybrid bonding method is a tin-free bonding method, the present invention selects the die 20 and the substrate 60 without solder balls and copper pillars to emphasize that the method of the present invention is limited to the hybrid bonding technique.

Note that the surfaces of die 20 and substrate 60 are important when performing a non-tinning package. The surfaces of the die and the substrate are directly butted after the chemical mechanical polishing process, so the surfaces of the die 20 and the substrate 60 must be close to mirror surface because: some variations in surface roughness may cause a failure in bonding die 20 to substrate 60. After the chemical mechanical polishing process, the polishing degree is different due to different materials, and usually the acceptable range of the polishing degree error is within ± 10nm, and two defects are easily generated when the polishing degree error exceeds 10 nm: (1) copper contact grinding head; (2) Too many copper contacts are left and the base of the substrate 60 is lapped over.

It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims (15)

1. A center-contact impact-free die bonding method is characterized by comprising the following steps:

a, a die bonder picks up a die, wherein the surface of the die has no solder ball and no copper column;

b, the die bonder moves the crystal grains to one side of a crystal grain placing area of a substrate, and the surface of the substrate is free of solder balls and copper columns;

c, blowing the center of the crystal grain by the die bonder through positive pressure to enable the center of the crystal grain to be in flexural deformation so as to contact the center of the crystal grain placement area;

d, forming a fitting wave after the center of the crystal grain contacts the center of the crystal grain placing area, wherein the fitting wave gradually expands from the center of the crystal grain to the periphery of the crystal grain so that the crystal grain gradually departs from the crystal grain fixing device and is fixed on the crystal grain placing area; and

and e, completely fixing the crystal grains on the crystal grain placement area.

2. The center-contact impact-free die bonding method according to claim 1, wherein in step a, the die bonding apparatus sucks the periphery of the die by a peripheral negative pressure to fix the die and pick up the die.

3. The center-contact impact-free die bonding method according to claim 2, wherein in the step b and the step c, the die bonding apparatus continuously sucks the periphery of the die by the peripheral negative pressure to fix the die.

4. The center-contact impact-free die bonding method according to claim 3, wherein in step d, the peripheral negative pressure is gradually reduced.

5. The center-contact impact-free die bonding method according to claim 3, wherein in step e, the peripheral negative pressure is completely stopped.

6. The center-contact impact-free die bonding method according to any one of claims 2 to 5, wherein the die bonding apparatus has a plurality of air holes, the air holes are connected to a vacuum apparatus, the vacuum apparatus evacuates the air holes to generate vacuum and provide the peripheral negative pressure, and the peripheral negative pressure adsorbs the periphery of the die through the air holes.

7. The center-contact impact-free die bonding method according to claim 1, wherein in step d, the positive pressure is completely stopped or maintained at a stable pressure.

8. The center-contact impact-free die bonding method according to claim 1, wherein the die bonding apparatus has a shaft hole, the shaft hole is connected to a gas supply apparatus, and the gas supply apparatus blows air into the shaft hole to generate gas flow and provide the positive pressure.

9. A center contact impact-free die bonding method comprises the following steps:

a die bonder picks up a die, wherein the surface of the die has no solder ball and no copper column;

b, the die bonder moves the die to one side of a die placement area of a substrate, and the surface of the substrate is free of solder balls and copper columns;

c, blowing the center of the crystal grain by the die bonder through positive pressure to enable the center of the crystal grain to be in flexural deformation so as to contact the center of the crystal grain placement area;

d, forming a fitting wave after the center of the crystal grain contacts the center of the crystal grain placing area, wherein the fitting wave gradually expands from the center of the crystal grain to the periphery of the crystal grain, then the positive pressure gradually decreases and is further switched into a central negative pressure, so that the crystal grain gradually departs from the crystal fixing device and is fixed on the crystal grain placing area; and

and e, completely fixing the crystal grains on the crystal grain placement area.

10. The center-contact impact-free die bonding method according to claim 9, wherein in the step a, the die bonding device sucks the periphery of the die by a peripheral negative pressure to fix the die and pick up the die.

11. The center-contact impact-force-free die bonding method according to claim 10, wherein in the step b and the step c, the die bonding apparatus continuously sucks the periphery of the die by the peripheral negative pressure to fix the die.

12. The center-contact impact-free die bonding method according to claim 11, wherein in step d, the peripheral negative pressure is gradually reduced.

13. The center-contact impact-free die bonding method according to claim 11, wherein in step e, the peripheral negative pressure is completely stopped.

14. The center-contact impact-free die bonding method according to any one of claims 10 to 13, wherein the die bonding apparatus has a plurality of air holes, the air holes are connected to a vacuum apparatus, the vacuum apparatus evacuates the air holes to generate vacuum and provide the peripheral negative pressure, and the peripheral negative pressure sucks the periphery of the die through the air holes.

15. The center-contact impact-free die bonding method according to claim 9, wherein the die bonding apparatus has a shaft hole, the shaft hole is connected to a gas supply apparatus and a vacuum apparatus, the gas supply apparatus blows air into the shaft hole to generate gas flow and provide the positive pressure, and the vacuum apparatus evacuates the shaft hole to generate vacuum and provide the central negative pressure.

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