CN-116313882-B - Liquid tension control method capable of improving wafer drying efficiency

CN116313882BCN 116313882 BCN116313882 BCN 116313882BCN-116313882-B

Abstract

The invention relates to a liquid tension control method capable of improving the drying efficiency of a wafer, which comprises the steps of firstly, placing a wafer box into a drying groove body through a connection swinging mechanism, loading the wafer into the wafer box, combining the drying groove body with an upper cover dome to keep the sealing degree, evacuating trace gas, secondly, injecting normal-temperature nitrogen from the upper cover dome, injecting ultrapure water into the drying groove body to wet the surface of the wafer, thirdly, immersing the surface of the wafer, and thirdly, performing the following operation of S1, injecting a mixture of isopropanol and heating nitrogen into the drying groove body through a special integrated module, simultaneously discharging the ultrapure water from the bottom of the drying groove body at a controlled speed, S2, operating the swinging mechanism to carry the wafer to form planetary swinging in the process of discharging the ultrapure water, so that water molecules on the wafer are separated quickly, and fourthly, repeatedly completing the drying of the wafer. The invention leads the residual moisture on the surface of the wafer to be carried away in an acceleration way by a planetary arc swinging drying technology, and realizes the rapid drying of the wafer by effectively controlling the liquid tension.

Inventors

JIANG YUAN
LIAO SHIBAO
DENG XINFU
LI PANPAN
LU ZHENGKAI

Assignees

上海至纯洁净系统科技股份有限公司
至微半导体(上海)有限公司

Dates

Publication Date: 20260505
Application Date: 20220908

Claims (6)

1. A liquid tension control method capable of improving the drying performance of a wafer is characterized by comprising the following steps: the method comprises the steps of firstly, loading a plurality of wafers in a wafer box, placing the wafer box on a swinging mechanism, and placing the swinging mechanism carrying the wafers into a drying groove body; Injecting ultrapure water into the drying tank body, and simultaneously injecting normal-temperature nitrogen into the drying tank body through the upper cover dome, so that the liquid level of the ultrapure water injected into the drying tank body exceeds the uppermost end of the wafer, wetting the surface of the wafer, and continuously injecting the normal-temperature nitrogen into the drying tank body during the wetting; Thirdly, stopping injecting normal-temperature nitrogen after the ultrapure water is infiltrated into the surface of the wafer, and performing the following operations: s1, injecting a mixture of isopropanol and heating nitrogen into a drying groove body from an upper cover dome by utilizing an integrated module, and discharging ultrapure water in the drying groove body from the bottom at a controlled speed; S2, along with continuous decline of the ultrapure water liquid level, operating the swinging mechanism to carry the wafer to form planetary swinging in the ultrapure water discharging process, enabling each wafer to generate arc-shaped periodical small-angle movement, enabling the wafer to generate stretching phenomenon at the contact position of the ultrapure water liquid level and the surface of the wafer in the swinging process, enabling the surface tension T1 of the ultrapure water liquid phase to be stretched and increased, enabling the surface tension T2 formed by the isopropyl alcohol gas phase and the ultrapure water liquid phase to be stretched and thinned by tension and swinging, enabling the water film of the ultrapure water to be stretched and thinned, enabling water molecules in the thinned water film to move laterally faster, and controlling the liquid tension to enable water molecules on the wafer to be separated quickly; fourthly, operating the swinging mechanism to drive the wafer box to swing continuously until the ultrapure water is discharged to a position where the liquid level is lower than the bottom of the wafer box, finishing the drying in the first stage, checking whether repeated cleaning and drying are needed, if so, repeating the second to third steps, and drying in the second and subsequent stages until the wafer is dried; In the third step, the integrated module structurally comprises an isopropyl alcohol input pipeline, a circulating ultrapure water output pipeline, a heating nitrogen input pipeline, a mixing tank body and a mixed gas-liquid coexisting liquid output pipeline, wherein the mixing tank body structurally comprises a shell and a mixing tank, the shell is of a box-shaped structure with a tank door plate, and at least one mixing tank is arranged in the shell; An isopropyl alcohol input port is arranged at the position, close to the bottom, of the front side wall of the shell, the isopropyl alcohol input port is connected with the isopropyl alcohol input pipeline, an ultrapure water input port and an ultrapure water output port are arranged on one side wall of the shell and are respectively and correspondingly connected with the circulating ultrapure water input pipeline and the circulating ultrapure water output pipeline, a heating nitrogen input port is arranged on the rear side wall of the shell and is connected with the heating nitrogen input pipeline, a mixed gas-liquid coexisting body output port is also arranged on the rear side wall of the shell and is connected with one end of a mixed gas-liquid coexisting liquid output pipeline, and the other end of the mixed gas-liquid coexisting liquid output pipeline is communicated with the upper cover dome so as to convey a mixture of isopropyl alcohol and heating nitrogen into the drying tank body; The utility model provides a mixing tank appearance be the cylinder, the inside three-layer construction that includes vortex mixing channel, buffering reflux tank and hot water bath region of mixing tank, wherein vortex mixing channel is the back taper cavity that mixing tank center set up, the bottom central point of mixing tank puts and is equipped with jar body entry, the top central point of mixing tank puts and is equipped with jar body export, jar body entry UNICOM isopropanol input port in order to receive the isopropanol input to vortex mixing channel, the buffering reflux tank in the upper position UNICOM heating nitrogen input port in order to receive heating nitrogen, the hot water bath region UNICOM in the mixing tank ultrapure water input port and ultrapure water output port in order to receive circulating ultrapure water, jar body export UNICOM mixed back gas-liquid coexistence body output port.
2. The method according to claim 1, wherein in the third step, the wafer cassette is driven by the swing mechanism to perform a regular swing motion in the drying tank, so that wafers arranged in the wafer cassette exhibit a regular swing, and the wafers are symmetrically reciprocated in an inclined angle with the center of the wafer as an axis during the swing.
3. The method for controlling liquid tension capable of improving drying efficiency of a wafer according to claim 2, wherein the swinging mechanism comprises a driving motor, a sliding rail, a sliding block, a shaft connection rail and an L-shaped swinging arm, the sliding rail is arranged in parallel with the shaft connection rail, the sliding rail is positioned above the shaft connection rail, the sliding block is slidably mounted on the sliding rail, the driving motor drives the sliding block to reciprocate on the sliding rail to serve as a linear robot, the L-shaped swinging arm is at least two, the L-shaped swinging arm comprises a first support arm and a second support arm which are arranged in parallel, a sliding groove is arranged on the upper portion of the first support arm along the length direction, a sliding wheel is correspondingly mounted on the sliding block, the sliding wheel is mounted in the sliding groove, the lower end of the first support arm is mounted on a connecting point shaft on the shaft connection rail, and the lower end of the second support arm is provided with a wafer box bearing area.
4. The method of claim 3, wherein the linear robot moves back and forth to drive the L-shaped swing arm to perform a fixed axis rotation, thereby forming an arc swing mode with a fixed axis.
5. A liftable according to claim 4A method for controlling the liquid tension of wafer drying effect, the swing mechanism is characterized in that the movement positioning mode of the swing mechanism is as follows: When the L-shaped swing arm is driven to perform axial fixed rotation in a back-and-forth movement mode, the linear robot is provided with three positioning sensors for detecting corresponding swing positions when the linear robot moves back and forth in a reciprocating mode: The corresponding phase of the wafer swings, the corresponding center normal line is positioned as A1, and the corresponding phase included angle of the wafer swings is 0 degree: the position swinging towards the front end is positioned as A0, and the corresponding relative phase included angle of the wafer swinging is +theta degrees, wherein theta is 2 degrees <15 degrees; the position of the back-end swing is positioned as A2, and the corresponding relative phase included angle of the wafer swing is-theta degrees, wherein theta is 2 degrees <15 degrees.
6. The method according to claim 1, wherein in the third step, the mixture of isopropyl alcohol and heated nitrogen is made of an integrated module, and is transferred to the upper cover dome to spray downward into the drying tank, the vapor phase of isopropyl alcohol and water molecules volatilize upward, the liquid phase of water molecules moves downward under tension control, and ultrapure water is injected and discharged from the bottom of the drying tank.

Description

Liquid tension control method capable of improving wafer drying efficiency Technical Field The present invention relates to the field of semiconductors, and more particularly, to a liquid tension control method for improving wafer drying efficiency during wafer drying. Background In semiconductor wafer cleaning, a drying technology is indispensable, and there are different wafer drying technologies for different wafer products. The wafer drying is performed in a final ending action in a wet cleaning process, the control of effectively removing residual moisture on the surface of the wafer and the surface cleanliness is required to be ensured, the continuous optimization and the efficiency improvement of a drying method are realized, the important points of special attention for developing wafer cleaning equipment and technology are realized, the method used in the wafer drying process is various, and the effective batch drying in a designated time influences the batch and the operation of the whole working efficiency of the whole wafer cleaning process, so that an effective wafer drying method with the drying efficiency is established as a ring of special attention for the current wafer wet cleaning technology. In the prior art, utility model patent CN204257600U discloses a cleaning tank for cleaning semiconductor wafers. The method changes the surface tension of liquid by using an externally applied magnetic field in the cleaning process, monitors the surface tension value of the liquid in real time by using a surface tensiometer, and feeds back the monitored information to a magnetizing device so as to control the magnetic field intensity, so that the magnetic field intensity value is kept at a preset value, and finally, the surface tension value of water is stabilized at a required value, thereby meeting the technological requirements of wafer production. The technology needs to specially design a magnetizing device in a cleaning tank to generate a magnetic field, is complex and tedious to operate, and needs to control the magnetic field strength in real time in order to maintain the tension of the water surface, so that the difficulty of operation is increased intangibly, and even the cleaning and drying efficiency is affected. Therefore, there is a need for a simpler and faster way to control the liquid tension to improve the drying performance of the wafer. Disclosure of Invention In order to solve the above-mentioned problems in the prior art, the present invention provides a liquid tension control method for improving the drying performance of a wafer during the wafer drying process. The liquid tension control method for improving the drying efficiency of the wafer in the wafer drying process can effectively control the liquid tension, and realizes the rapid separation of water molecules on the wafer by comprehensive control to finish the rapid drying of the wafer. In order to achieve the above object, the present invention provides the following technical solutions: A liquid tension control method capable of improving the drying efficiency of a wafer is disclosed, wherein in the process of gas phase replacement of isopropanol and nitrogen, the residual moisture on the surface of the wafer is carried away by the isopropanol through a planetary arc swing drying technology during the drying of the wafer, and the method comprises the following steps: The method comprises the steps of firstly, loading a plurality of wafers in a wafer box, placing the wafer box on a swinging mechanism, and placing the swinging mechanism carrying the wafers into a drying groove body; Injecting ultrapure water into the drying tank body, and simultaneously injecting normal-temperature nitrogen into the drying tank body through the upper cover dome, so that the liquid level of the ultrapure water injected into the drying tank body exceeds the uppermost end of the wafer, wetting the surface of the wafer, and continuously injecting the normal-temperature nitrogen into the drying tank body during the wetting; Thirdly, stopping injecting normal-temperature nitrogen after the ultrapure water is infiltrated into the surface of the wafer, and performing the following operations: s1, injecting a mixture of isopropanol and heating nitrogen into a drying groove body from an upper cover dome by utilizing a special integrated module, and discharging ultrapure water in the drying groove body from the bottom at a controlled speed; S2, along with continuous decline of the ultrapure water liquid level, operating the swinging mechanism to carry the wafer to form planetary swinging in the ultrapure water discharging process, enabling each wafer to generate arc-shaped periodical small-angle movement, enabling the wafer to generate stretching phenomenon at the contact position of the ultrapure water liquid level and the surface of the wafer in the swinging process, enabling tension T1 of the ultrapure water liquid phase to be stretched and incr