Wafer edge hydrophobic surface treatment method

Abstract

The invention discloses a wafer edge hydrophobic surface treatment method, which comprises the following steps of: performing hydrophobic treatment on an annular region on the peripheral edge of a bonding interface to form a hydrophobic ring to prevent cleaning fluid from permeating, and keeping the hydrophilicity of a bonding central region to ensure the adhesion strength; according to the method, the surface of the wafer is cleaned after the wafer is bonded, the hydrophobic layer on the edge blocks liquid permeation, so that the cleaning liquid cannot permeate into the bonding interface to cause layering, the permeation phenomenon of the cleaning liquid on the edge of the chip is obviously reduced, and the mechanical stability, the electrical performance and the durability of the processed chip are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device design and manufacturing, and in particular to a method for treating the hydrophobic surface of wafer edges in IC manufacturing. Background Technology

[0002] In IC manufacturing, post-bonding surface cleaning is a necessary step. Cleaning solutions (such as deionized water, IPA, SC1 solution) seep into the bonding interface from the edge due to capillary action, weakening the adhesion between the bonding interfaces. In other words, cleaning solution penetration leads to bonding failure and delamination.

[0003] While some existing processes can be improved by adjusting the cleaning process, such as pressure and time, or by improving the cleaning equipment, they still have significant shortcomings in preventing the cleaning fluid from penetrating the interface from the edge, making it difficult to effectively solve this problem. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for treating the hydrophobic surface of a wafer edge.

[0005] To address the aforementioned issues, this invention provides a method for hydrophobic surface treatment at the edge of a wafer. This method involves performing hydrophobic treatment on the annular region at the outer edge of the bonding interface to form a hydrophobic ring that prevents cleaning fluid from penetrating, while simultaneously maintaining the hydrophilicity of the bonding center region to ensure adhesion strength.

[0006] Furthermore, the annular region is located at the edge of the wafer, and the width of the annular region is 0.5 to 2 mm.

[0007] Furthermore, the hydrophobic treatment includes coating the annular region with a hydrophobic material, wherein the coating thickness of the hydrophobic material is 50–200 nm.

[0008] Furthermore, the hydrophobic material comprises a fluorinated polymer or a silane compound.

[0009] Furthermore, the cleaning solution comprises deionized water, IPA, and SC1 solution.

[0010] Furthermore, after coating with a hydrophobic material, the process also includes drying and curing steps.

[0011] Furthermore, the curing process includes thermal curing, light curing, or room temperature curing.

[0012] Furthermore, before performing the hydrophobic treatment, a pre-cleaning step is included, in which the 0.5-2mm annular area at the edge of the chip is cleaned after the wafer-to-wafer or bare die-to-wafer bonding is completed.

[0013] The processing method of this invention cleans the wafer surface after wafer bonding. Because there is a hydrophobic layer at the edge to block liquid penetration, the cleaning solution will not seep into the bonding interface and cause delamination. The penetration of the cleaning solution at the chip edge is significantly reduced. The processed chip shows significant improvement in mechanical stability, electrical performance and durability. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the wafer edge hydrophobic surface treatment method of the present invention. Hydrophobic treatment is performed on the annular region at the edge of the wafer to form a hydrophobic ring, making it difficult for the cleaning solution to cross the hydrophobic ring and enter the central bonding region. Detailed Implementation

[0015] The following detailed description, in conjunction with the accompanying drawings, provides specific embodiments of the present invention and clearly and completely describes the technical solutions of the present invention. However, the present invention is not limited to the following embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise ratios, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be understood that the present invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals denote the same elements throughout. It should be understood that when an element or layer is referred to as “on,” “adjacent to,” “connected to,” or “coupled to” other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as “directly on,” “directly adjacent to,” “directly connected to,” or “directly coupled to” other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0017] This invention provides a process method for preventing cleaning solution from penetrating into the bonding interface after wafer-to-wafer or die-to-wafer bonding by selectively hydrophobicating the edges. As revealed in the background section, the main cause of bonding interface failure is that the cleaning fluid enters the bonding interface due to capillary action, leading to a weakening of the adhesion energy. Therefore, this invention employs a technical method to selectively hydrophobically treat the outer region of the bonding area, forming a "hydrophobic ring" to prevent the cleaning fluid from penetrating, while maintaining the hydrophilicity of the bonding center region to ensure adhesion strength.

[0018] The hydrophobic ring is located on the periphery of the bonding region, forming a ring-shaped hydrophobic area that blocks the cleaning agent.

[0019] In one specific embodiment, for example, two 12-inch wafers are bonded together. The wafers are processed as follows: First, the wafer undergoes cleaning and pretreatment. After wafer-to-wafer or die-to-wafer bonding, the annular region with a width of 0.5–2 mm at the chip edge is cleaned. Ultrapure water or similar methods are used to thoroughly clean this annular region, which will be used to fabricate a hydrophobic ring.

[0020] Next, a hydrophobic material coating is applied. A hydrophobic material is sprayed onto the cleaned annular area. This material repels the cleaning agent, similar to water droplets on a lotus leaf, preventing external cleaning liquid from crossing the hydrophobic ring and entering the central bonding region. The hydrophobic material coating is applied to the hydrophobic ring area, with an annular width L of 0.5–2 mm, resulting in a hydrophobic material thickness in the range of 50–200 nm. Figure 1 As shown.

[0021] The hydrophobic material can be any material that repels the cleaning solution, such as conventional fluorinated polymers and silane compounds. In this embodiment, a fluorinated polymer is selected, and a ring-shaped hydrophobic film with a thickness of 200 nm and a width of 1 mm is coated on the edge of the chip using a spin-coating method.

[0022] Next, a curing process is performed to cure the chip or wafer coated with the hydrophobic material, allowing the hydrophobic material to adhere stably in the hydrophobic areas. Curing methods include thermal curing, photocuring, or room temperature curing.

[0023] Finally, a post-bonding cleaning step is performed. The cleaning solution includes deionized water, IPA, SC1 solution, etc. For example, the wafer is cleaned with SC1 solution for 10 minutes. After bonding, the wafer surface is cleaned. Because there are hydrophobic rings at the edges that prevent the cleaning solution from penetrating, the cleaning solution will not cross the hydrophobic ring area and enter the bonding interface, thus preventing interface adhesion failure and delamination.

[0024] After the above steps, the results show that after cleaning the wafer surface after bonding, the cleaning solution will not penetrate into the bonding interface and cause delamination because the hydrophobic layer at the edge blocks liquid penetration. The penetration of cleaning solution at the chip edge is significantly reduced, and the treated chip shows significant improvement in mechanical stability, electrical performance and durability.

[0025] The technical effects of this invention are mainly in the following aspects: 1. Prevent cleaning fluid from penetrating: By applying hydrophobic surface treatment to the chip edges, the contact area and penetration ability of the cleaning fluid at the edges are significantly reduced, effectively preventing the cleaning fluid from penetrating into the interface from the edges, thereby avoiding the risk of the upper wafer or die detaching from the substrate and improving the mechanical stability of the chip.

[0026] 2. Improved Adhesion Strength: The coating and curing process of hydrophobic materials enhances surface energy matching and chemical bonding at the chip edges, improving the adhesion strength between the upper wafer or die and the substrate. This helps resist the effects of external mechanical stress and chemical action on the bonding interface, extending the chip's lifespan.

[0027] 3. Improved cleaning effect: Since the cleaning solution is less likely to accumulate and penetrate at the edges, it reduces the potential damage to the internal structure of the chip during the cleaning process, while improving cleaning efficiency and quality and reducing the impact of cleaning residue on chip performance.

[0028] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating the hydrophobic surface of a wafer edge, characterized in that: A hydrophobic treatment is applied to the annular region at the outer edge of the bonding interface to form a hydrophobic ring that prevents cleaning fluid from penetrating, while maintaining the hydrophilicity of the bonding center region to ensure adhesion strength.

2. The wafer edge hydrophobic surface treatment method as described in claim 1, characterized in that: The annular region is located at the edge of the wafer, and the width of the annular region is 0.5 to 2 mm.

3. The wafer edge hydrophobic surface treatment method as described in claim 1, characterized in that: The hydrophobic treatment includes coating the annular region with a hydrophobic material, the coating thickness of which is 50–200 nm.

4. The wafer edge hydrophobic surface treatment method as described in claim 3, characterized in that: The hydrophobic material comprises fluorinated polymers or silane compounds.

5. The method for treating hydrophobic surfaces at wafer edges as described in claim 1, characterized in that: The cleaning solution contains deionized water, IPA, and SC1 solution.

6. The wafer edge hydrophobic surface treatment method as described in claim 3, characterized in that: After coating with a hydrophobic material, the process also includes drying and curing steps.

7. The wafer edge hydrophobic surface treatment method as described in claim 6, characterized in that: The curing process includes thermal curing, light curing, or room temperature curing.

8. The method for treating hydrophobic surfaces at wafer edges as described in claim 1, characterized in that: Before performing the hydrophobic treatment, a pre-cleaning step is also included, in which a 0.5-2 mm annular area at the edge of the chip is cleaned after wafer-to-wafer or bare die-to-wafer bonding is completed.

9. The method for treating hydrophobic surfaces at wafer edges as described in claim 1, characterized in that: When performing the hydrophobic treatment, it is necessary to maintain the hydrophilicity of the bonding center region to ensure adhesion strength.

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