A simple harmonic motion wafer cleaning and drying method

Abstract

The invention discloses a simple harmonic motion type wafer cleaning and drying method, comprising the following steps: step 1, placing a wafer in a wafer cleaning tank; step 2, blowing nitrogen into the wafer cleaning tank, after the nitrogen blowing is completed, transporting ultrapure water into the wafer cleaning tank to wet the wafer; step 3, discharging the ultrapure water, blowing isopropyl alcohol into the wafer cleaning tank, transporting ultrapure water into the wafer cleaning tank to wet the wafer; step 4, blowing isopropyl alcohol into the wafer cleaning tank again, and the wafer performs simple harmonic motion under the drive of an oscillating mechanism; step 5, blowing a heated isopropyl alcohol and nitrogen mixture into the wafer cleaning tank, and the ultrapure water is discharged; step 6, while the wafer performs simple harmonic motion, continuously blowing isopropyl alcohol and nitrogen mixture into the wafer cleaning tank until the wafer surface is dry. The present invention allows water molecules to be quickly taken away from the tank body under the control of the circulating airflow field force that has been completed by the continuous intermittent oscillation of the isopropyl alcohol molecules, thereby achieving a drying effect.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials, and in particular relates to a simple harmonic motion type wafer cleaning and drying method. Background Art

[0002] Wafer drying is an essential step in meeting the demands of semiconductor wafer cleaning technology. Wafer drying is the final step in the wet cleaning process, ensuring the effective removal of residual moisture from the wafer surface while also maintaining control over the wafer surface cleanliness.

[0003] Existing drying processes limit the types of wafer products available. Wafer products are categorized as unprocessed wafers, flat wafers after surface treatment, and partially patterned wafers. The third type of wafer product is a patterned wafer with a relatively flat aspect ratio and minimal undulations. For patterns with high aspect ratios, the capillary effect created by the pattern's surface tension causes moisture to be adsorbed into the high-aspect-ratio pores or columns, forcing water molecules to flow back into the large depletion zones beneath the pattern. While the wafer surface dries during the drying process, the majority of the moisture is deposited within the depletion zones, resulting in ineffective drying. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a simple harmonic motion wafer cleaning and drying method. The present invention utilizes the gas phase replacement process of the organic solvent isopropyl alcohol and nitrogen to enable the isopropyl alcohol to remove the residual moisture on the wafer surface. The release and diffusion of the gas effectively improves the drying efficiency of the wafer.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a simple harmonic motion wafer cleaning and drying method, comprising the following steps:

[0007] Step 1: Place the wafer in a wafer cleaning tank, and close the wafer cleaning tank to form a sealed structure;

[0008] Step 2: Blow nitrogen into the wafer cleaning tank. After the nitrogen blowing is completed, ultrapure water is transported into the wafer cleaning tank to wet the wafer;

[0009] Step 3: Drain the ultrapure water, blow isopropyl alcohol into the wafer cleaning tank, and then supply ultrapure water to the wafer cleaning tank again to wet the wafer;

[0010] Step 4: Drain the ultrapure water, blow isopropyl alcohol into the wafer cleaning tank again, and deliver ultrapure water into the wafer cleaning tank again to wet the wafer. The wafer performs simple harmonic motion driven by the swing mechanism.

[0011] Step 5: Blow the heated isopropyl alcohol and nitrogen mixture into the wafer cleaning tank and discharge the ultrapure water;

[0012] Step 6: Continue blowing a mixture of isopropyl alcohol and nitrogen into the wafer cleaning tank while the wafer is in simple harmonic motion until the wafer surface is dry, and then position the wafer.

[0013] As an optimal technical solution, in step four, the swing mechanism includes a driving motor, a sliding rail, a sliding block, an axially connected rail and a swing arm, the sliding rail is arranged parallel to the axially connected rail, the sliding rail is located above the axially connected rail, the sliding block is slidably installed on the sliding rail, the driving motor is used to control the sliding block to perform reciprocating motion on the sliding rail, and the swing arm is provided with at least two swing arms, the swing arm includes a first support arm and a second support arm arranged in parallel, a sliding groove is provided on the upper part of the first support arm along the length direction, a sliding wheel is correspondingly installed on the sliding block, the sliding wheel is installed in the sliding groove, the lower end of the first support arm is axially mounted on the connection point on the axially connected rail, and the lower end of the second support arm is provided with a wafer carrying area.

[0014] As a preferred technical solution, the swing angle of the swing arm is 15-30 degrees.

[0015] As a preferred technical solution, the length of the second arm is greater than that of the first arm; and the wafer box carrying area is arranged on a side of the second arm away from the first arm.

[0016] As a preferred technical solution, in step five, isopropyl alcohol and nitrogen are mixed in a mixing container, isopropyl alcohol is stored in the mixing container, a nitrogen connection port is provided on one side of the mixing container, the nitrogen connection port is connected to a nitrogen delivery pipe, and the nitrogen delivery pipe is connected to a heating device.

[0017] As a preferred technical solution, three nitrogen connection ports are provided.

[0018] As a preferred technical solution, the shell of the wafer cleaning tank is made of metal material.

[0019] As a preferred technical solution, a drain port is provided at the bottom of the wafer cleaning tank, and a top cover is provided at the top of the wafer cleaning tank, and the top cover is connected to the shaft of the wafer cleaning tank.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] (1) When the water molecules in the structured pattern on the wafer surface of the present invention are dried, before the water molecules are gradually taken away from the wafer surface, periodic high-temperature nitrogen jets are used, so that the water molecules are quickly taken away from the tank under the control of the circulating air flow field force of the isopropyl alcohol molecules that are continuously and intermittently oscillated, thereby achieving a drying effect.

[0022] (2) The present invention forms an arc-shaped motion path through a swinging mechanism, so that the wafer forms special vibration and swing during the swinging process. The effective swing motion makes the setting of the cleaning equipment more flexible, and improves the universality and feasibility of the general wet process construction.

[0023] (3) The present invention realizes micro-swing of the wafer through an oscillating motion mechanism, so that the water molecules in the specially patterned high aspect ratio structure can continuously destroy the surface tension between the water molecules and the high aspect ratio pore structure through the interaction of heated nitrogen and isopropyl alcohol during the drying process, and conversely, the water molecules in the depletion zone due to capillary phenomenon are continuously precipitated to undergo a drying reaction of water molecule replacement.

[0024] (4) The present invention causes the patterned microstructure on the wafer to have a slight tilt angle, and the droplet structure moves at the corner of the structure. By utilizing the instantaneous imbalance of the tension between the droplet and the corner of the microstructure, it is easier to readjust the tension between the water molecules, isopropyl alcohol and the wafer surface during nitrogen evaporation or isopropyl alcohol replacement. In the process of water molecules being successively extracted from the wafer pore structure, the structural integrity of the water molecule droplets is analytically destroyed and disintegrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 It is a structural schematic diagram of the wafer cleaning tank of the present invention.

[0027] Figure 2 This is one of the structural diagrams of the swing mechanism of the present invention.

[0028] Figure 3 This is the second structural diagram of the swing mechanism of the present invention.

[0029] Figure 4 It is a motion diagram of the swing mechanism of the present invention.

[0030] Figure 5 A schematic structural diagram of a mixing container according to the present invention.

[0031] Among them, the specific descriptions of the accompanying drawings are as follows: wafer cleaning tank 1, top cover 2, drive motor 3, sliding rail 4, sliding block 5, shaft-connected rail 6, swing arm 7, sliding groove 8, wafer carrying area 9, first support arm 10, second support arm 11, mixing container 12, nitrogen connection port 13, nitrogen delivery pipeline 14, heating device 15. DETAILED DESCRIPTION

[0032] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0033] Example 1

[0034] like Figures 1-4 As shown, this embodiment provides a self-oscillating wafer cleaning and drying device, comprising a wafer cleaning tank 1 and an oscillating mechanism disposed within the wafer cleaning tank 1. The oscillating mechanism is provided with two wafer cassette supporting areas 9 for placing wafer cassettes. The outer shell of the wafer cleaning tank 1 is made of metal material.

[0035] In this embodiment, the swing mechanism includes a drive motor 3, a sliding rail 4, a sliding block 5, an axially connected rail 6 and a swing arm 7. The sliding rail 4 is arranged parallel to the axially connected rail 6, and the sliding rail 4 is located above the axially connected rail 6. The sliding block 5 is slidably installed on the sliding rail 4, and the drive motor 3 is used to control the sliding block 5 to perform reciprocating motion on the sliding rail 4.

[0036] There are two swing arms 7, which include a first arm 10 and a second arm 11 arranged in parallel. A sliding groove 8 is provided on the upper part of the first arm 10 along the length direction. A sliding wheel is correspondingly installed on the sliding block 5, and the sliding wheel is installed in the sliding groove 8. The lower end of the first arm 10 is axially installed with the connection point on the axial track 6, and the wafer box carrying area is set at the lower end of the second arm 11.

[0037] The movement process of this embodiment is: the sliding block 5 is driven by the driving motor 3 to move along the sliding track 4, and the movement of the sliding block 5 drives the sliding wheel to slide along the sliding groove 8, so that the swing arm 7 swings along the axis connection point on the axis connection track 6, realizing the simple harmonic motion of the wafer.

[0038] In this embodiment, the length of the second arm 11 is greater than that of the first arm 10. This arrangement increases the swing amplitude of the wafer, and the swing angle range of the swing arm 7 is 15-30 degrees, which can better achieve drying. The wafer box carrying area is arranged on the side of the second arm 11 away from the first arm 10, avoiding mutual interference during movement. The bottom of the wafer cleaning tank 1 is provided with a discharge port, and the top of the wafer cleaning tank 1 is provided with a top cover 2, which is connected to the axis of the wafer cleaning tank 1. The cleaning agent in the wafer cleaning tank 1 is a mixture of nitrogen and isopropyl alcohol, and the wafer box carrying area 9 is a hollow structure. The present invention realizes a slight swing of the wafer through a swinging motion mechanism, so that the water molecules in the specially patterned high aspect ratio structure can continuously destroy the surface tension of the water molecules and the high aspect ratio pore structure through the interaction of heated nitrogen and isopropyl alcohol during the drying process, and reversely causes the water molecules of the capillary phenomenon in the depletion zone to be continuously precipitated to undergo a drying reaction of water molecule replacement.

[0039] Example 2

[0040] This embodiment provides a simple harmonic motion wafer cleaning and drying method, comprising the following steps:

[0041] Step 1: Place the wafer in the wafer cleaning tank 1 and close the wafer cleaning tank 1 to form a sealed structure;

[0042] Step 2: blowing nitrogen into the wafer cleaning tank 1. After the nitrogen blowing is completed, ultrapure water is transported into the wafer cleaning tank 1 to wet the wafer;

[0043] Step 3: drain the ultrapure water, blow isopropyl alcohol into the wafer cleaning tank 1, and then supply ultrapure water into the wafer cleaning tank 1 again to wet the wafer;

[0044] Step 4: drain the ultrapure water, blow isopropyl alcohol into the wafer cleaning tank 1 again, and deliver ultrapure water into the wafer cleaning tank 1 again to wet the wafer. The wafer performs simple harmonic motion driven by the swing mechanism;

[0045] Step 5: Blow the heated isopropyl alcohol and nitrogen mixture into the wafer cleaning tank 1, and discharge the ultrapure water;

[0046] Step 6: Continue blowing a mixture of isopropyl alcohol and nitrogen into the wafer cleaning tank 1 while the wafer is in simple harmonic motion until the wafer surface is dry, and then position the wafer.

[0047] Among them, isopropyl alcohol and nitrogen are mixed in a mixing container 12, and isopropyl alcohol is stored in the mixing container 12. A nitrogen connecting port 13 is provided on one side of the mixing container 12. There are three nitrogen connecting ports 13. The nitrogen connecting port 13 is connected to a nitrogen delivery pipe 14, and the nitrogen delivery pipe 14 is connected to a heating device 15.

[0048] Although the above embodiments have been described in detail for the present invention, it should be understood by those skilled in the art that modifications or improvements can be made based on the contents disclosed in the present invention without departing from the spirit and scope of the present invention, and that these modifications and improvements are within the spirit and scope of the present invention.

Claims

1. A simple harmonic motion wafer cleaning and drying method, characterized in that: The following steps are involved: Step 1: Place the wafer in a wafer cleaning tank, and close the wafer cleaning tank to form a sealed structure; Step 2: Blow nitrogen into the wafer cleaning tank. After the nitrogen blowing is completed, ultrapure water is transported into the wafer cleaning tank to wet the wafer; Step 3: Drain the ultrapure water, blow isopropyl alcohol into the wafer cleaning tank, and then supply ultrapure water to the wafer cleaning tank again to wet the wafer; The cam is provided with a plurality of support arms, the support arms being provided with a plurality of support arms, the support arms being provided with a plurality of support arms, the support arms being provided with a plurality of support arms and a plurality of support arms being provided with a plurality of support arms. Step 5: Blowing the heated isopropyl alcohol and nitrogen mixture into the wafer cleaning tank to discharge the ultrapure water; the isopropyl alcohol and nitrogen are mixed in a mixing container, wherein the mixing container contains isopropyl alcohol, and a nitrogen connection port is provided on one side of the mixing container, wherein the nitrogen connection port is connected to a nitrogen delivery pipe, and the nitrogen delivery pipe is connected to a heating device; Step 6: Continue blowing a mixture of isopropyl alcohol and nitrogen into the wafer cleaning tank while the wafer is in simple harmonic motion until the wafer surface is dry, and then position the wafer.

2. The simple harmonic motion wafer cleaning and drying method according to claim 1, wherein: The length of the second arm is greater than that of the first arm; and the wafer box carrying area is arranged on a side of the second arm away from the first arm.

3. The simple harmonic motion wafer cleaning and drying method according to claim 1, wherein: There are three nitrogen connection ports.

4. The simple harmonic motion wafer cleaning and drying method according to claim 1, wherein: The shell of the wafer cleaning tank is made of metal material.

5. The simple harmonic motion wafer cleaning and drying method according to claim 1, wherein: The bottom of the wafer cleaning tank is provided with a discharge port, the top of the wafer cleaning tank is provided with a top cover, and the top cover is connected to the wafer cleaning tank shaft.

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