KR20030043478A - Wafer bonding machine with plasma treatment and control method thereof - Google Patents

Abstract

PURPOSE: A wafer bonding machine with plasma treatment and control method thereof are provided to be capable of preventing environmental pollution and improving the characteristic of attachment by attaching between substrates using plasma instead of an adhesive in vacuum state. CONSTITUTION: Vacuum state is conserved in a substrate attaching chamber(1) by using vacuum exhaust pump(15). Hydrogen gas is supplied from a gas cylinder(19) through a gas flow rate controller(18) to the substrate attaching chamber(1). Plasma is generated between an upper substrate(24) and a lower substrate(23) by using RF(Radio Frequency) voltage regulator(21). At this time, the surfaces of the upper and lower substrate(24,23) are activated by the plasma. Then, the attachment between the upper and lower substrate(24,23) is carried out from the center portion to the edge portion by using pressure.

Description

Substrate bonding apparatus with plasma pretreatment and its control method {Wafer bonding machine with plasma treatment and control method

The present invention relates to a substrate bonding apparatus capable of bonding a silicon substrate and a silicon substrate or a silicon substrate and a glass substrate, and a method of controlling the same. More specifically, the present invention relates to a substrate bonding apparatus in which a small amount of gas plasma is activated in a vacuum state. A substrate bonding apparatus having a plasma pretreatment for improving bonding strength and a control method thereof.

The process technology for joining two substrates includes the joining of semiconductor devices such as the fabrication of micro-electro-mechanical system (MEMS) structures, including microsensors and actuators, and the fabrication of silicon-on-insulator (SOI) substrates for high-speed and high-voltage semiconductor devices. This is a technology corresponding to the field of implementation. Silicon Direct Bonding (SDB), which performs bonding by surface activation and heat treatment, is most widely used in the substrate bonding process and has the following characteristics. First, since the joining process is performed in the solid state, generation of pollutants and deformation of the structure can be prevented. Secondly, it can be bonded in a vacuum atmosphere and can be used for vacuum mounting of devices. Third, since the bonding between the two substrates is made through atomic bonds, strong and stable bonding is possible. Fourth, since it is compatible with the existing semiconductor process, it is easy to apply to manufacturing semiconductor devices.

In general, since the surface activation process uses chemicals in silicon direct bonding, it causes environmental pollution due to the disposal of chemicals after the surface activation process, and the apparatus for performing the substrate bonding process separately from the apparatus for performing the surface activation process In addition, the surface of the substrate is contaminated by air pollutants or dust particles in the process of transferring and installing the substrate activated by chemicals to the substrate bonding apparatus, thereby causing a problem of degrading the substrate bonding characteristics. In addition, in the bonding of two substrates, when the bonding starts at the center of the two substrates and spreads to the outer shell, air existing between the two substrates to be bonded is pushed outward to prevent generation of non-bonded regions by air particles at the bonding interface. can do. However, in the conventional substrate bonding apparatus, the bonding is performed in a state where the two surfaces are parallel, so that the bonding can start from the outer side and spread out to the center instead of starting at the center of the two substrates, thereby falling out of the two substrates. There is a tendency for non-bonded regions to occur due to air particles remaining between the two substrates without going.

The present invention has been invented to solve the above problems, the surface activation process of the two substrates through the substrate bonding apparatus having a plasma processing mechanism to be carried out by a small amount of gas at the same time to reduce the environmental pollution caused by the use of chemicals It is possible to improve the bonding characteristics by preventing the contamination of the surface of the substrate by using a bonding mechanism that can be prevented and the bonding can be performed without the two substrates exposed to the atmosphere after the surface activation process. It is an object of the present invention to provide a substrate bonding apparatus having a plasma pretreatment and a method of controlling the same, which are capable of spreading to the outer shell to prevent the generation of non-bonded regions by completely removing air particles between the two substrates. .

1 is a side view of a substrate bonding apparatus according to the present invention;

2 is a side view of a substrate bonding apparatus in which two substrates to be bonded are mounted;

3 is a side view of a substrate bonding apparatus in which plasma is generated and two substrate surfaces to be bonded are activated;

4 is a side view of the substrate bonding apparatus in which the upper substrate support is lowered for bonding and the two substrates are separated by a predetermined interval by the upper substrate fixing mechanism.

5 is a side view showing a substrate bonding apparatus in which a pressure is applied to a central portion of a lower substrate by a lower substrate pressure applying mechanism and the lower substrate is bent in an elliptical shape and is bonded at the upper substrate and the central portion;

6 is a side view of the substrate bonding apparatus showing a state in which the two substrates are bonded from the center to the edge while the upper substrate fixing mechanism is separated out of the two substrates.

7 is a side view showing a substrate bonding apparatus in which the upper substrate support and the lower pressure applying mechanism are moved to their original positions after the bonding of the two substrates is completed;

Explanation of symbols on the main parts of the drawings

1.Board bonding chamber 2 ... Upper vertical motion cylinder

3.Upper cylinder pressure rod 4 ... Corrugated pipe

5 ... Upper substrate support 6 ... Left and right horizontal motion cylinder

7.Right & Left Cylinder Pressure Bar 8 ... Top Board Fixture

9 Lower board support 10 Lower board pressure applicator

11. Lower pressure cylinder with lower cylinder 12. Lower cylinder with vertical motion

13..Vacuum exhaust pipe 14..Vacuum exhaust valve

15. Vacuum exhaust pump 16. Gas injection pipe

17.Gas injection valve 18.Gas flow regulator

19. Gas cylinder 20. High frequency power supply wire

21. High frequency power regulator 22. High frequency power generator

23. Lower board 24. Upper board

25.Plasma

In order to achieve the above object, the present invention provides a structure in which the surfaces to be bonded to the two substrates are installed to face each other, while the plasma generating mechanism for activating the surfaces of the two substrates and the two surface activated substrates are provided. It consists of a bonding mechanism that moves the upper substrate to the lower substrate so as to be bonded to be located at a close distance, and a means for applying the pressure to the center of the lower substrate so that the joining of the two substrates can be started in the center portion.

In the control method of the substrate bonding apparatus with the plasma pretreatment according to the present invention, the spacer of the upper substrate fixing mechanism is pulled into the upper substrate to support the upper substrate by pulling the left and right horizontal operation cylinders inward. Seating the lower substrate on the support, operating the vacuum exhaust pump and open the vacuum exhaust valve to discharge the air particles present in the substrate bonding chamber to the outside through the vacuum exhaust pipe to make the inside of the substrate bonding chamber into a vacuum atmosphere Step, when the degree of vacuum inside the substrate bonding chamber reaches a predetermined level capable of generating plasma, the gas injection valve is opened to supply gas from the gas filled gas cylinder, and a certain amount of gas is supplied through the gas injection tube by the gas flow regulator. Supplied to the bonding chamber to maintain a constant vacuum inside the substrate bonding chamber Filling the gas, generating a plasma between the upper substrate and the lower substrate by applying a high frequency power source of 13.56 MHz to both the lower substrate support and the upper substrate support, and moving the upper substrate to the lower substrate after the plasma treatment. Positioning at a constant proximity by the spacer of the substrate holding mechanism, the lower vertical vertical cylinder is operated to move the lower substrate pressure applying mechanism upward through the lower upper and lower cylinder pressure applying rod to apply pressure to the center of the lower substrate The substrate is bent so that the bonding is performed from the center of the upper substrate and the lower substrate, and the upper substrate fixing mechanism exits outward from the two substrates while the upper substrate and the lower substrate are bonded at the center, and then along the inclined surface of the spacer. As the gap between the two substrates gradually decreases The sum is expanded from the center to the outer shell; after the bonding between the two substrates is completed, the upper substrate support is moved upward so that the two bonded substrates can be taken out of the substrate bonding chamber; and the operation of the vacuum exhaust pump is stopped. After the interior of the chamber is brought to atmospheric pressure to remove the two bonded substrates, the upper substrate and the lower substrate to be bonded again consists of a step of repeatedly performing the bonding process.

The present invention, the surface activation process of the two substrates by the above configuration can be performed at the same time by a small amount of gas to prevent environmental pollution due to the use of chemicals, and immediately after the surface activation process without exposing both substrates to the atmosphere Bonding mechanisms can be used to prevent contamination of the substrate surface and to shorten the process time.The bonding of the two substrates starts from the center and spreads outwards to completely remove the air particles between the two substrates. It is characterized by the fact that generation | occurrence | production of a junction area | region can be prevented.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the preferred embodiment of the present invention.

1 is a schematic view of a bonding apparatus having a plasma processing mechanism and a substrate bonding mechanism according to the present invention, wherein the substrate to be bonded includes a glass substrate and a glass substrate or a glass substrate and a silicon substrate (hereinafter referred to as substrate). A device for joining, which has a substrate joining chamber (1) to enable plasma and bonding processes to be performed in a vacuum atmosphere, and also has an upper substrate (24) on top of the substrate joining chamber (1). ) Is a mechanism for installing the upper substrate support (5) capable of supporting the upper substrate 24, the upper substrate 24 is fixed to the upper substrate support (5) while the center of the bonding with the lower substrate (23) The upper substrate fixing mechanism 8 and the upper substrate fixing mechanism 8 having the spacers 8a serving as guides so as to be joined from the portion are fixed inward to fix the upper substrate 24. Horizontally actuated horizontal cylinder 6 and horizontally actuated cylinder 7 and upper and lower vertical cylinders for moving the upper substrate 24 to the lower substrate 23 and placing them at a close distance after the plasma 25 treatment. (2) and the upper and lower cylinder pressure applying rods (3). The spacer 8a, which is a substrate fixing portion of the upper substrate fixing mechanism 8, has a lower upward surface with a constant upward inclined surface from the outer side to the central direction, so that the upper substrate 24 and the lower substrate 23 have a lower substrate pressure applying mechanism 10. After joining takes place at the center by the upper substrate fixing mechanism 8, the upper substrate fixing mechanism 8 exits in the outward direction of the two substrates 23 and 24 along the inclined surface of the substrate fixing portion, so that the gap between the two substrates 23 and 24 Gradually shrinking, the junction extends from the center to the outer shell. The mechanism for installing the lower substrate 23 includes a lower substrate support 9 capable of supporting the lower substrate 23, and an upper substrate 24 and a lower substrate 23 for fixing the upper substrate fixing mechanism 8. The lower substrate pressure applying mechanism that applies pressure to the central portion of the lower substrate 23 when it is located at a close distance by the portion so that the lower substrate 23 is bent so that the bonding is performed at the central portions of the two substrates 23 and 24. And a lower vertical cylinder 12 and a lower upper and lower cylinder pressure applying rod 11 for moving the lower substrate pressure applying mechanism 10.

In addition, the vacuum installation mechanism for bringing the inside of the substrate bonding chamber 1 into a vacuum atmosphere state includes a vacuum exhaust valve 15 for maintaining the degree of vacuum of the vacuum exhaust pump 15 for vacuum evacuation and the substrate bonding chamber 1 at a desired level. 14) and a vacuum exhaust pipe 13 for connecting the vacuum exhaust pump 15 to the substrate joining chamber 1.

In addition, the plasma generating mechanism for surface activation of the substrates 23 and 24 includes a gas injection mechanism and a high frequency power supply mechanism. The gas injection mechanism includes a gas cylinder 19 for supplying gas, a gas flow controller 18 for adjusting the flow rate of gas, a gas injection valve 17 for injecting and blocking gas, and a substrate bonding chamber ( It is composed of a gas injection pipe 16 to be injected into 1), the operation of the gas injection valve 17 is open can be operated automatically or manually to operate the valve on, off function, the adjustment of the gas injection amount If necessary, a predetermined amount can be injected through a device called a mass flow controller (MFC). The high frequency power supply mechanism includes a high frequency power generating mechanism 22 for supplying high frequency power, a high frequency power regulator 21 for high frequency power supply without loss, and a high frequency power supplying the high frequency power to the lower substrate support 9. It consists of the electric wire 20 for power supply.

FIG. 2 shows a substrate bonding apparatus in which the upper substrate 24 and the lower substrate 23 to be bonded to the substrate bonding chamber 1 are provided on the upper substrate support 5 and the lower substrate support 9, respectively. In order to fix the upper substrate 24 to the upper substrate support 5, the left and right horizontal operation cylinder 6 is pulled inward, and the upper substrate fixing mechanism 7 The substrate fixing portion of 8) enters the upper substrate 24 to support the upper substrate 24. The lower substrate 23 is completed by the operation located on the lower substrate support (9).

3 shows a state of a substrate bonding apparatus that generates a plasma 25 and activates surfaces of the upper substrate 24 and the lower substrate 23. In order to generate the plasma 25, the inside of the substrate bonding chamber 1 is brought into a vacuum atmosphere. To this end, first, the vacuum exhaust pump 15 is operated, and then the vacuum exhaust valve 14 is opened so that air particles existing in the substrate bonding chamber 1 are transferred to the outside of the substrate bonding chamber 1 through the vacuum exhaust pipe 13. Pull it out. When the degree of vacuum in the substrate bonding chamber 1 reaches a predetermined level, hydrogen gas is injected into the substrate bonding chamber 1 to generate the plasma 25. Here, the predetermined level is a process variable that the user changes depending on the type of gas, the degree of surface treatment through plasma, and the type of substrate treated with the surface, and indicates the degree of vacuum at the time of plasma generation. It is enough.

First, when the hydrogen gas injection valve 17 is opened, the gas is supplied from the gas cylinder 19 filled with gas, and a predetermined amount of gas is supplied through the gas injection tube 16 through the gas flow regulator 18. Supplied to. Accordingly, the gas is filled in the substrate bonding chamber 1 to maintain a constant vacuum degree. At this time, when the high frequency power is supplied, the plasma 25 is generated between the upper substrate 24 and the lower substrate 23. The high frequency power is generated and supplied through the high frequency power generating mechanism 22 and supplied to the lower substrate support 9 through the high frequency power supply wire 20 without loss of the high frequency power by the high frequency power regulator 21. A high frequency power source of 13.56 MHz is applied to both ends of the lower substrate support 9 and the upper substrate support 5 to generate the plasma 25, and the upper substrate 24 and the lower substrate 23 by the plasma 25. The surface is activated, but the frequency of the high frequency power source used here may be a frequency of a different band, but in the semiconductor equipment worldwide, it is a frequency used uniformly at 13.56 MHz to prevent mixing with the frequency used elsewhere.

4 shows that the upper substrate 24 is moved to the lower substrate 23 after the plasma 25 treatment, and the upper substrate 24 is lowered by the spacer 8a of the upper substrate fixing mechanism 8. The substrate bonding device is shown to be positioned at a constant proximity to the. In more detail, the upper vertical vertical cylinder 2 moves the upper substrate support 5 downward through the upper upper and lower cylinder pressure-applying rods 3, and the substrate fixing portion of the upper substrate fixing mechanism 8 The in-spacer 8a stops at the position where it contacts the lower substrate 23. At this time, the upper substrate support 5 was gradually moved downward by the elasticity of the corrugated pipe 4 by using the corrugated pipe 4, and the upper part of the corrugated pipe 4 was welded to the substrate joining chamber 1 and the lower part was upper part. By welding to the substrate support 5, the vacuum in the substrate bonding chamber 1 is maintained even when the upper substrate support 5 is operated by the vertical upper and lower cylinder pressure applying rods 3. Here, the corrugated pipe 4 is, for example, bellows, and is a pipe-shaped pipe made of a metal material, which is different from a general pipe, in which a corrugation is formed in a direction perpendicular to the longitudinal direction of the tube, thereby expanding and narrowing the corrugated pipe. Due to the inherent elasticity of the metal, the corrugated tube is made to be elastic.

5 shows that when pressure is applied to the central portion of the lower substrate 23 by the lower substrate pressure applying mechanism 10, the lower substrate 23 is bent so as to be joined at the center of the upper substrate 24 and the lower substrate 23 first. The substrate joining apparatus is configured such that the lower substrate pressure applying mechanism 10 is lifted upward through the lower upper and lower cylinder pressure applying rods 11 when the lower vertical operation cylinder 12 operates. The pressure is applied to the center of the figure.

FIG. 6 shows that between the two substrates 23 and 24 when the upper substrate fixing mechanism 8 exits outward from the two substrates 23 and 24 in a state where the upper substrate 24 and the lower substrate 23 are joined at the center. As the spacing gradually decreases, the bonding apparatus extends from the center to the outer shell. That is, the upper substrate fixing mechanism 8 exits in the outward direction of the two substrates 23 and 24 along the inclined surface of the spacer 8a, which is the substrate fixing portion, so that the gap between the two substrates 23 and 24 gradually increases. As the shrinkage decreases, the bonding extends from the center to the outer shell, and the bonding between the two substrates 23 and 24 is completed at the moment when the upper substrate fixing mechanism 8 completely exits the two substrates 23 and 24.

FIG. 7 shows a state where the upper substrate support 5 is moved upward after the bonding between the two substrates 23 and 24 is completed so that the two bonded substrates 23 and 24 can be taken out of the substrate bonding chamber 1. Show the substrate bonding device. The upper and lower vertical operation cylinder 2 moves the upper substrate support 5 upward through the upper upper and lower cylinder pressure applying rods 3, and stops the operation of the vacuum exhaust pump 15, thereby inside the substrate bonding chamber 1. Atmospheric pressure is taken out of the two bonded substrates (23, 24).

Thereafter, the upper substrate 24 and the lower substrate 23 to be bonded again may be installed to repeat the operations of FIGS. 2 to 6.

According to the present invention, surface activation of two substrates to be bonded by a trace amount of gas plasma can be simultaneously performed to prevent environmental pollution due to the use of chemicals, and the two substrates can be directly bonded without being exposed to the atmosphere after the surface activation process. The bonding mechanism can be used to prevent contamination of the surface of the substrate and to shorten the processing time. The bonding of the two substrates starts from the center and spreads outwards to completely remove the air particles between the two substrates. There is an effect that can prevent the occurrence.

Claims (8)

A substrate bonding chamber in which a space for bonding the upper substrate and the lower substrate in a vacuum atmosphere is formed; The upper substrate fixing mechanism for fixing the upper substrate in the substrate bonding chamber is fixed to the left and right horizontal actuating cylinder by the left and right acting cylinder pressure applying rod, and the left and right horizontal actuating cylinder is supported by the upper upper and lower cylinder pressure applying rod together with the upper substrate support. Upper substrate supporting means fixed to upper and lower vertical operation cylinders outside the substrate bonding chamber; A lower substrate support installed at an inner lower portion of the substrate bonding chamber to seat a lower substrate; A lower substrate supporting means comprising a pressure applying rod for applying a pressure upwardly to a central portion of the lower substrate and a lower vertical vertical operation cylinder for vertically moving the pressure applying rod; Chamber internal pressure adjusting means provided with a vacuum exhaust valve and a vacuum exhaust pump in a vacuum exhaust pipe to maintain the substrate bonding chamber in a vacuum state or an atmospheric pressure state; Gas supply means comprising a gas injection valve, a gas flow controller, and a gas cylinder installed in a gas injection pipe to supply gas into the substrate bonding chamber to activate surfaces of the substrates to be bonded; And a high frequency power supply means comprising a high frequency power regulator for supplying power for generating plasma in the substrate bonding chamber and a high frequency power generating mechanism. According to claim 1, wherein the upper substrate support means for the upper substrate and the lower substrate to be bonded to each other through the operation in which the left and right horizontal operation cylinder is pulled inwardly in order to secure the upper substrate to the upper substrate support A substrate bonding apparatus having a plasma pretreatment, characterized in that the substrate holding portion of the upper substrate holding mechanism is introduced into the upper substrate so that the upper substrate is supported. The method of claim 1, wherein the chamber internal pressure adjusting means operates the vacuum exhaust pump to generate plasma, and then opens the vacuum exhaust valve to draw air particles existing inside the substrate bonding chamber to the outside of the substrate bonding chamber through the vacuum exhaust pipe. A substrate bonding apparatus with a plasma pretreatment, wherein the substrate bonding chamber is made to have a vacuum atmosphere inside the substrate bonding chamber. The gas supply means of claim 1, wherein the gas supply means opens the gas injection valve when the degree of vacuum in the substrate bonding chamber reaches a level capable of generating plasma, and the gas is supplied from the gas filled gas cylinder and a predetermined amount of gas is supplied by the gas flow regulator. The substrate bonding apparatus having a plasma pretreatment, characterized in that the gas is supplied to the substrate bonding chamber through the gas injection tube so that the inside of the substrate bonding chamber maintains a constant vacuum degree and the gas is filled. [2] The plasma pretreatment of claim 1, wherein the high frequency power supply means is configured to generate a plasma between the upper substrate and the lower substrate by applying a high frequency power of 13.56 MHz to both the lower substrate support and the upper substrate support. One substrate bonding device. According to claim 1, wherein an outer side of the upper upper and lower cylinder pressure applying rod of the upper substrate supporting means is provided with an elastic corrugated tube surrounding the pressure applying rod, both ends of the elastic corrugated tube to the ceiling and the upper substrate support of the substrate bonding chamber Substrate bonding apparatus having a plasma pre-treatment, characterized in that each is fixed to maintain the internal vacuum state. The method of claim 1, wherein the upper substrate fixing mechanism is to secure the upper substrate to the upper substrate support while separating the upper substrate and the lower substrate at a close distance at the beginning of the bonding with the lower substrate and gradually bonding the two substrates during the bonding process. Substrate bonding apparatus having a plasma pre-treatment, characterized in that the spacer is provided with an upward inclined surface toward the center to be made. Pulling the cylinder horizontally inward and downward to allow the spacer of the upper substrate fixing device to enter the upper substrate to support the upper substrate and to seat the lower substrate on the lower substrate support. Opening the exhaust valve and discharging the air particles existing inside the substrate bonding chamber to the outside through the vacuum exhaust pipe to make the inside of the substrate bonding chamber into a vacuum atmosphere, when the vacuum degree inside the substrate bonding chamber reaches a certain level, the gas injection valve The gas is supplied from the gas filled cylinder and the gas flow regulator supplies a certain amount of gas to the substrate bonding chamber through the gas injection tube so that the inside of the substrate bonding chamber maintains a constant vacuum degree and the gas is filled. A high frequency power source with 13.56MHz frequency is supported at both ends of the support and upper substrate support. Generating a plasma between the upper substrate and the lower substrate, moving the upper substrate to the lower substrate after the plasma treatment, and placing the upper substrate at a constant distance by the spacer of the upper substrate fixing mechanism; The lower substrate pressure applying mechanism is moved upward through the lower upper and lower cylinder pressure applying rods to apply pressure to the center of the lower substrate so that the lower substrate bends and joins from the center of the upper substrate and the lower substrate, the upper substrate and the lower substrate. As the upper substrate fixing device is pulled out of the two substrates in the bonded state at the center, the gap between the two substrates gradually decreases along the inclined surface of the spacer, and the bonding is expanded from the center to the outer corner. After this is completed, move the upper substrate support up To take the two bonded substrates out of the substrate bonding chamber, stopping the operation of the vacuum exhaust pump to make the interior of the substrate bonding chamber at atmospheric pressure to remove the two bonded substrates, and then to remove the upper and lower substrates to be bonded again. Method of controlling a substrate bonding apparatus having a plasma pre-treatment comprising the step of allowing to perform the bonding process repeatedly by installing a.