TWI870271B - Method of heating and fixing die to prevent bubbles - Google Patents

Abstract

A method of heating and fixing die to prevent bubbles includes the following steps: distributing liquid on a substrate; fixing a die on the substrate in the liquid; heating the die so that the liquid evaporate into water vapor; heating and pressurizing the die; and stopping heating and pressurizing the die so that the die is gradually cooled and fixed on the substrate . Such that, the liquid will adhere to the surface of the substrate and provide a bubble-free environment, the die can be fixed on the substrate in the bubble-free environment provided by the liquid, and heated to remove water vapor to avoid the die and the substrate enveloping air or water vapor together to create bubbles and form cavities during fixing process.

Description

Heating die bonding method to prevent bubble generation

The present invention relates to a crystal bonding method, in particular to a heating crystal bonding method for preventing the generation of bubbles.

Integrated circuits are manufactured on semiconductor wafers in large quantities through multiple processes, and the wafers are further divided into multiple dies. In other words, a die is a small piece of integrated circuit body made of semiconductor materials that has not been packaged. The divided multiple dies are neatly attached to a carrier, and then a carrier frame is responsible for transporting the carrier, and then the dies are transferred to the substrate in sequence to facilitate subsequent processing procedures.

Specifically, during the process of transferring the die to the substrate, a local area of the die contacts the substrate to form a bonding wave. The bonding wave spreads from the local area of the die to other areas of the die, so that the die is gradually fixed on the substrate.

However, air or water vapor may be trapped between the die and the substrate, resulting in bubbles and voids. If there are voids between the die and the substrate, the die and the substrate are not tightly attached, which will cause the subsequent processing procedures such as picking or identifying the die to be easily affected by the bubbles, reducing the yield of the products made by subsequent processing.

The main purpose of the present invention is to provide a heat bonding method for preventing the generation of bubbles, which can prevent the crystal grain and the substrate from enclosing air or water vapor to generate bubbles and form cavities.

In order to achieve the aforementioned purpose, the present invention provides a heat-bonding method for preventing the generation of bubbles, comprising the following steps: distributing a liquid on a substrate; fixing a crystal grain on the substrate in the liquid; heating the crystal grain so that the liquid evaporates into water vapor; heating and pressurizing the crystal grain; and stopping heating and pressurizing the crystal grain so that the crystal grain gradually cools down and is fixed on the substrate.

In some embodiments, the step of distributing the liquid on the substrate further includes: a crystal bonding device sucking the crystal grain; wherein, the step of placing the crystal grain on the substrate in the liquid further includes: the crystal bonding device moving downward so that the crystal grain gradually approaches the substrate and enters the liquid.

In some embodiments, the step of heating the crystal grain further includes: the crystal bonding device heats the crystal grain; wherein, the step of heating and pressurizing the crystal grain further includes: the crystal bonding device heats and pressurizes the crystal grain; wherein, the step of stopping heating and pressurizing the crystal grain further includes: the crystal bonding device stops heating and pressurizing the crystal grain.

In some embodiments, the step of heating the die further includes: a light source heats the die; wherein, the step of heating and pressurizing the die further includes: the light source heats the die, and the die bonding device pressurizes the die; wherein, the step of stopping heating and pressurizing the die further includes: the light source stops heating the die, and the die bonding device stops pressurizing the die.

In some embodiments, the step of heating the grain further includes: the substrate heats the grain; wherein the step of heating and pressurizing the grain further includes: the substrate heats and pressurizes the grain; wherein the step of stopping heating and pressurizing the grain further includes: the substrate stops heating and pressurizing the grain.

In some embodiments, the step of heating the die further includes: a light source heats the die; wherein, the step of heating and pressurizing the die further includes: the light source heats the die while the substrate presses the die; wherein, the step of stopping heating and pressurizing the die further includes: the light source stops heating the die while the substrate stops pressurizing the die.

In some embodiments, the step of distributing the liquid on the substrate further includes: the substrate includes another die and a wafer, and the other die is fixed in a die placement area of the wafer; wherein, the step of fixing the die on the substrate in the liquid further includes: the die is fixed on the other die in the liquid.

In some embodiments, the step of distributing the liquid on the substrate further includes: the substrate is a wafer; wherein the step of fixing the die on the substrate in the liquid further includes: the die is fixed in the liquid on a die placement area of the wafer.

The effect of the present invention is that the liquid will adhere to the surface of the substrate and provide a bubble-free environment. The crystal grains can be fixed on the substrate in the bubble-free environment provided by the liquid, and the water vapor is removed by heating, so as to avoid the crystal grains and the substrate jointly enclosing air or water vapor to generate bubbles and form cavities during the crystal bonding process.

The following is a more detailed description of the implementation of the present invention with reference to the drawings and component symbols, so that those skilled in the art can implement the present invention accordingly after reading this specification.

FIG. 1 is a flow chart of the method of the present invention. FIG. 2 is a schematic diagram of step S10 of the first embodiment of the method of the present invention. FIG. 3 is a schematic diagram of step S20 of the first embodiment of the method of the present invention. FIG. 4 and FIG. 5 are schematic diagrams of step S30 of the first embodiment of the method of the present invention. FIG. 6 is a schematic diagram of step S40 of the first embodiment of the method of the present invention. FIG. 7 is a schematic diagram of step S50 of the first embodiment of the method of the present invention. The present invention provides a heating die bonding method for preventing the generation of bubbles, comprising the following steps:

In step S10 , as shown in FIG. 1 and FIG. 2 , a liquid 10 is distributed on a substrate 20 .

In step S20 , as shown in FIG. 1 and FIG. 3 , a die 30 is fixed on the substrate 20 in the liquid 10 .

In step S30, as shown in FIG. 1 , FIG. 4 and FIG. 5 , the crystal grain 30 is heated so that the liquid 10 evaporates into water vapor 11 .

In step S40, as shown in FIG. 1 and FIG. 6, the die 30 is heated and pressurized.

In step S50, as shown in FIG. 1 and FIG. 7, the heating and pressurizing of the die 30 is stopped, so that the die 30 is gradually cooled and fixed on the substrate 20.

As shown in FIG. 2 , in the first embodiment, step S10 further includes: the substrate 20 includes another die 21 and a wafer 22, the other die 21 is fixed in a die placement area 221 of the wafer 22; a die bonding device 40 absorbs the die 30; the liquid 10 continuously flows out from a nozzle 50 and flows downward continuously by gravity, so that the liquid 10 gradually diffuses after contacting the substrate 20; the liquid 10 is distributed on the substrate 20; and the nozzle 50 continuously replenishes the liquid 10 to the substrate 20.

As shown in FIG. 3 , in the first embodiment, step S20 further includes: the die bonding device 40 moves downward so that the die 30 gradually approaches another die 21 and enters the liquid 10; the die bonding device 40 can generate an airflow through a positive pressure 41 to blow a local block of the die 30, so that the local block of the die 30 is separated from the die bonding device 40 in the liquid 10 and is bent and deformed to contact another die 21, and a bonding wave is formed after the local block of the die 30 contacts the other die 21; and the bonding wave diffuses from the local block of the die 30 toward other blocks of the die 30, so that the die 30 is gradually fixed on the other die 21 in the liquid 10. Importantly, during the bonding wave diffusion process, the die 30 will gradually squeeze the liquid 10 out of the gap between the die 30 and another die 21, thereby ensuring that the die 30 and another die 21 are tightly bonded.

As shown in FIG4 and FIG5, in the first embodiment, step S30 further includes: the crystal bonding device 40 heats the crystal grain 30. As shown in FIG6, in the first embodiment, step S40 further includes: the crystal bonding device 40 heats and pressurizes the crystal grain 30. As shown in FIG7, in the first embodiment, step S50 further includes: the crystal bonding device 40 stops heating and pressurizing the crystal grain 30.

Some embodiments differ from the first embodiment in that: first, step S10 further includes: the substrate 20 is a wafer 22; second, step S20 further includes: the grain is fixed on the grain placement area 221 of the wafer 22 in the liquid 10.

Figures 8 and 9 are schematic diagrams of step S30 of the second embodiment of the method of the present invention. Figure 10 is a schematic diagram of step S40 of the second embodiment of the method of the present invention. Figure 11 is a schematic diagram of step S50 of the second embodiment of the method of the present invention. The difference between the second embodiment and the first embodiment is: first, as shown in Figures 8 and 9, step S30 further includes: the wafer 22 heats the other grain 21, and the other grain 21 heats the grain 30; second, as shown in Figure 10, step S40 further includes: the wafer 22 heats and pressurizes the other grain 21, and the other grain 21 heats and pressurizes the grain 30; third, as shown in Figure 11, step S50 further includes: the wafer 22 stops heating and pressurizing the other grain 21, and the other grain 21 stops heating and pressurizing the grain 30.

The difference between some embodiments and the second embodiment is: first, step S10 further includes: the substrate 20 is a wafer 22; second, step S20 further includes: the grain 30 is fixed on the grain placement area 221 of the wafer 22 in the liquid 10; third, step S30 further includes: the wafer 22 heats the grain 30; fourth, step S40 further includes: the wafer 22 heats and pressurizes the grain 30; fifth, step S50 further includes: the wafer 22 stops heating and pressurizing the grain 30.

Fig. 12 and Fig. 13 are schematic diagrams of step S30 of the third embodiment of the method of the present invention. Fig. 14 is a schematic diagram of step S40 of the third embodiment of the method of the present invention. Fig. 15 is a schematic diagram of step S50 of the third embodiment of the method of the present invention. The difference between the third embodiment and the first embodiment is that: first, as shown in Fig. 12 and Fig. 13, step S30 further includes: a light source 60 heats the grain 30; second, as shown in Fig. 14, step S40 further includes: the light source 60 heats the grain 30, and the crystal bonding device 40 pressurizes the grain 30; third, as shown in Fig. 15, step S50 further includes: the light source 60 stops heating the grain 30, and the crystal bonding device 40 stops pressurizing the grain 30. The light source 60 may be an infrared heater or a laser heater.

The difference between some embodiments and the third embodiment is that: first, step S40 further includes: the light source 60 heats the die 30, and at the same time the wafer 22 presses the other die 21 and the other die 21 presses the die 30; second, step S50 further includes: the light source 60 stops heating the die 30, and at the same time the wafer 22 stops pressurizing the other die 21 and the other die 21 stops pressurizing the die 30.

The differences between some embodiments and the third embodiment are: first, step S10 further includes: the substrate 20 is a wafer 22; second, step S20 further includes: the grain 30 is fixed on the grain placement area 221 of the wafer 22 in the liquid 10; third, step S40 further includes: the light source 60 heats the grain 30, and the wafer 22 pressurizes the grain 30; fourth, step S50 further includes: the light source 60 stops heating the grain 30, and the wafer 22 stops pressurizing the grain 30.

In summary, the liquid 10 adheres to the surface of the substrate 20 and provides a bubble-free environment. The die 30 can be fixed on the substrate 20 in the bubble-free environment provided by the liquid 10, and the moisture is removed by heating to avoid the die 30 and the substrate 20 enclosing air or moisture together to generate bubbles and form cavities during the die bonding process, thereby ensuring that the die 30 and the substrate 20 are closely attached. The subsequent processing procedures of the die 30, such as picking or identifying, will not be affected by bubbles, thereby improving the yield rate of the products made by the subsequent processing.

Furthermore, the liquid 10 can be used as a bonding medium to increase the fixing effect of the crystal grain 30 and the substrate 20. Among all the liquids 10, water is preferably used as a bonding medium because water can be used as one of the bonding chemical reactants in the solid crystal method. More specifically, water molecules will generate hydroxyl OH-Si-OH on the surface of the activated substrate 20, and further undergo a chain reaction to synthesize a stable _SiO2 structure, whose chemical formula is: Si-OH HO-Si Si-O-Si H ₂ O. Among them, ultrapure water is more preferred as the bonding medium because it is very pure and clean and contains no impurities. Ultrapure water can not only provide a bubble-free environment and serve as a bonding medium, but also ensure that there are no impurities, avoiding the formation of voids between the crystal grain 30 and the substrate 20 during the crystal bonding process, thereby ensuring that the crystal grain 30 and the substrate 20 are closely bonded. Subsequent processing procedures such as picking or identifying the crystal grain 30 will not be affected by impurities, thereby improving the yield rate of the products made by subsequent processing.

The above is only used to explain the preferred embodiments of the present invention, and is not intended to limit the present invention in any form. Therefore, any modifications or changes made to the present invention under the same spirit of the invention should still be included in the scope of protection of the present invention.

10: Liquid

11: Water vapor

20: Substrate

21: Another grain

22: Wafer

221: Die placement area

30: Grain

40: Die bonding device

41: Positive pressure

50: Nozzle

60: Light source

S10~S50: Steps

FIG. 1 is a flow chart of the method of the present invention. FIG. 2 is a schematic diagram of step S10 of the first embodiment of the method of the present invention. FIG. 3 is a schematic diagram of step S20 of the first embodiment of the method of the present invention. FIG. 4 and FIG. 5 are schematic diagrams of step S30 of the first embodiment of the method of the present invention. FIG. 6 is a schematic diagram of step S40 of the first embodiment of the method of the present invention. FIG. 7 is a schematic diagram of step S50 of the first embodiment of the method of the present invention. FIG. 8 and FIG. 9 are schematic diagrams of step S30 of the second embodiment of the method of the present invention. FIG. 10 is a schematic diagram of step S40 of the second embodiment of the method of the present invention. FIG. 11 is a schematic diagram of step S50 of the second embodiment of the method of the present invention. Fig. 12 and Fig. 13 are schematic diagrams of step S30 of the third embodiment of the method of the present invention. Fig. 14 is a schematic diagram of step S40 of the third embodiment of the method of the present invention. Fig. 15 is a schematic diagram of step S50 of the third embodiment of the method of the present invention.

S10~S50: Steps

Claims (8)

A heat-bonding method for preventing the generation of bubbles comprises the following steps: Distributing a liquid on a substrate; Fixing a crystal grain on the substrate in the liquid; Heating the crystal grain so that the liquid evaporates into water vapor; Heating and pressurizing the crystal grain; and Stop heating and pressurizing the crystal grain so that the crystal grain gradually cools down and is fixed on the substrate. A heated crystal bonding method for preventing the generation of bubbles as described in claim 1, wherein the step of distributing the liquid on the substrate further includes: a crystal bonding device sucking the crystal grain; wherein the step of placing the crystal grain on the substrate in the liquid further includes: the crystal bonding device moving downward so that the crystal grain gradually approaches the substrate and enters the liquid. A heating and crystal bonding method for preventing the generation of bubbles as described in claim 2, wherein the step of heating the crystal grain further includes: the crystal bonding device heats the crystal grain; wherein the step of heating and pressurizing the crystal grain further includes: the crystal bonding device heats and pressurizes the crystal grain; wherein the step of stopping heating and pressurizing the crystal grain further includes: the crystal bonding device stops heating and pressurizing the crystal grain. A heating and die bonding method for preventing the generation of bubbles as described in claim 2, wherein the step of heating the die further includes: a light source heats the die; wherein the step of heating and pressurizing the die further includes: the light source heats the die and the die bonding device pressurizes the die; wherein the step of stopping heating and pressurizing the die further includes: the light source stops heating the die and the die bonding device stops pressurizing the die. A heating and die bonding method for preventing the generation of bubbles as described in claim 1, wherein the step of heating the crystal grain further includes: the substrate heats the crystal grain; wherein the step of heating and pressurizing the crystal grain further includes: the substrate heats and pressurizes the crystal grain; wherein the step of stopping heating and pressurizing the crystal grain further includes: the substrate stops heating and pressurizing the crystal grain. A heating and die bonding method for preventing the generation of bubbles as described in claim 1, wherein the step of heating the crystal grain further includes: a light source heats the crystal grain; wherein the step of heating and pressurizing the crystal grain further includes: the light source heats the crystal grain and the substrate pressurizes the crystal grain at the same time; wherein the step of stopping heating and pressurizing the crystal grain further includes: the light source stops heating the crystal grain and the substrate stops pressurizing the crystal grain at the same time. A heated die bonding method for preventing the generation of bubbles as described in claim 1, wherein the step of distributing the liquid on the substrate further includes: the substrate includes another die and a wafer, and the other die is fixed on a die placement area of the wafer; wherein the step of fixing the die on the substrate in the liquid further includes: the die is fixed on the other die in the liquid. A heated die bonding method for preventing the generation of bubbles as described in claim 1, wherein the step of distributing the liquid on the substrate further includes: the substrate is a wafer; wherein the step of fixing the grain on the substrate in the liquid further includes: the grain is fixed in the liquid on a grain placement area of the wafer.

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