A wafer coating method based on a microchannel structure

Abstract

The present invention provides a wafer coating method based on a microchannel structure. The method includes: providing a silicon wafer with a microchannel structure; closely attaching the silicon wafer with the microchannel structure to the wafer to be coated; dropping a liquid coating material on the silicon wafer with the microchannel structure, and the liquid coating material fills the microchannel cavity units on the silicon wafer with the microchannel structure; when the microchannel cavity units are filled, removing the silicon wafer with the microchannel structure to form a uniform coating layer; the microchannel cavity units are regular polygons with no less than 6 sides, the cavity wall thickness is not greater than 50 μm, the window opening gap is between 100 μm and 200 μm, and the inner angle of the cavity wall is greater than 90°. The present invention guides the flow of liquid materials through the microchannel structure, and uses capillary action and surface tension to achieve uniform distribution, solves the technical problems of uneven material distribution and inconsistent thickness in the existing wafer coating technology, and improves the performance and reliability of the wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and particularly to a wafer coating method based on a microchannel structure. Background Art

[0002] With the rapid development of integrated circuit technology, the continuous improvement of chip performance has put forward higher requirements for semiconductor manufacturing processes. In the semiconductor manufacturing process, wafer coating is a key process step, and its quality directly affects the performance and reliability of chips.

[0003] Existing wafer coating technologies mainly include methods such as drop coating and spin coating.

[0004] Drop coating technology is to directly drop the coating material on the wafer surface. This method is simple to operate, but the material distribution is often uneven, and it is easy to form thickness differences in some areas of the wafer, resulting in unstable product performance. The method of drop coating glue is easy to stack heights at the glue overlapping positions, affecting the overall uniformity.

[0005] Spin coating technology rotates the wafer at high speed to spin coat the glue. First, the glue is dropped in the center of the wafer, and then the glue is spread over the entire wafer by rotating the wafer. However, due to the action of centrifugal force, the coating material is easy to accumulate at the wafer edge or be thin in the central area, resulting in the problem of inconsistent thickness.

[0006] In addition, it is difficult for existing coating methods to achieve good interfacial bonding between the material and the wafer. Especially when the viscosity of the coating material is high or the wafer surface has a complex topological structure, the interfacial bonding force between the coating material and the wafer is insufficient, which is easy to cause defects such as bubbles and delamination, thereby affecting the integrity and reliability of the packaging structure.

[0007] These deficiencies lead to problems such as uneven distribution of packaging materials, inconsistent thickness of the packaging layer, and insufficient interfacial bonding force between the material and the wafer during the wafer packaging process, ultimately reducing the performance and reliability of the wafer. Summary of the Invention

[0008] The purpose of the present invention is to provide a wafer coating method based on a microchannel structure to solve the problems of uneven distribution of packaging materials and inconsistent thickness of the packaging layer.

[0009] To achieve the above technical purpose, the present invention provides a wafer coating method based on a microchannel structure, including:

[0010] Providing a silicon wafer with a microchannel structure, the microchannel structure silicon wafer including a plurality of microchannel cavity units distributed on the silicon wafer surface;

[0011] Closely fitting the microchannel structure silicon wafer with the wafer to be coated;

[0012] Drop a liquid coating material on the microchannel structure silicon wafer, and the liquid coating material fills the microchannel cavity unit;

[0013] And after the microchannel cavity unit is filled, remove the microchannel structure silicon wafer to form a coating layer.

[0014] Optionally, the total volume of the liquid coating material matches the total volume of the microchannel cavity unit.

[0015] Optionally, the microchannel cavity unit has a cavity wall, and the height of the cavity wall corresponds to the required thickness of the coating material.

[0016] Optionally, the wall thickness of the microchannel cavity unit is not greater than 50 μm.

[0017] Optionally, the inner angle of the cavity wall of the microchannel cavity unit is greater than 90°.

[0018] Optionally, the shape of the microchannel cavity unit is a regular polygon with no less than 6 sides.

[0019] Optionally, the number of sides of the regular polygon is an even number.

[0020] Optionally, the window opening gap of the microchannel cavity unit is between 100 μm and 200 μm.

[0021] Optionally, the microchannel cavity unit is formed by a silicon etching process.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] By designing a specific microchannel structure, the present invention utilizes physical effects such as capillary action and surface tension to achieve uniform distribution of the liquid coating material on the wafer surface. The microchannel structure serves as a guiding and controlling unit for the liquid coating material, precisely controlling the flow and distribution of the coating material, thereby solving the problems of uneven material distribution and inconsistent thickness in traditional coating methods. At the same time, due to the close fit between the microchannel structure and the wafer to be coated and the assisted filling by capillary action, the interfacial bonding between the coating material and the wafer surface is strengthened, improving the overall performance and reliability of the packaging structure.

[0024] In addition, the microchannel cavity unit adopted in the present invention has special structures such as a regular polygon structure with no less than 6 sides, controlling the window opening gap between 100 μm and 200 μm, and designing the inner angle of the cavity wall to be greater than 90°. This further optimizes the filling process of the liquid coating material, reduces the impact force of the liquid on the inner wall, improves the filling uniformity and integrity, and finally achieves a higher-quality wafer coating effect, providing important process support for high-performance chip packaging. Brief Description of the Drawings

[0025] Figure 1 It is a flowchart of the steps of a wafer coating method based on a microchannel structure in an embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the steps for the microchannel structure silicon wafer and the wafer to be coated to be closely attached in an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the steps for the microchannel structure silicon wafer and the wafer to be coated to be closely attached in an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of the structure of the microchannel structure silicon wafer in an embodiment of the present invention;

[0029] Figure 5 It is Figure 4 a partial enlarged view of the local microchannel structure in;

[0030] Figure 6 It is a schematic diagram of the structure of the microchannel cavity unit in an embodiment of the present invention.

[0031] In the figure, 1 is the microchannel structure silicon wafer; 11 is the local microchannel structure; 111 is the cavity wall; 112 is the window opening gap; 2 is the wafer to be coated. Detailed Embodiment

[0032] The following will describe in more detail a wafer coating method based on a microchannel structure of the present invention with reference to the accompanying drawings, in which the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0033] In the following paragraphs, the present invention will be described more specifically by way of example with reference to the accompanying drawings. The advantages and features of the present invention will be clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0034] In this embodiment, a wafer coating method based on a microchannel structure is provided. Please refer to Figure 1 - Figure 3 , and it includes the following steps:

[0035] S1: Provide a microchannel structure silicon wafer 1, and the microchannel structure silicon wafer 1 includes a plurality of microchannel cavity units distributed on the surface of the silicon wafer.

[0036] Among them, the total volume of the liquid coating material matches the total volume of the microchannel cavity unit.

[0037] In a specific example, a silicon wafer with the same size as the wafer to be coated is selected, and thinning and etching are respectively performed according to the microchannel structure designed by the present invention. Taking a 12-inch wafer (diameter 300 mm) as an example, the microchannel structure wafer 1 is designed with a channel structure evenly distributed within the entire wafer area, aiming to ensure that the liquid material can be uniformly filled in the entire bottom silicon wafer under the guidance of the microchannel structure and the action of capillary force and liquid surface tension.

[0038] Please refer to Figure 4 - Figure 5 , the microchannel structure wafer 1 has a local microchannel structure 11, and the local microchannel structure 11 includes a plurality of microchannel cavity units. The microchannel cavity units are used to guide the liquid coating material to be evenly distributed by capillary action after being attached to the wafer 2 to be coated. Figure 4 The arrow in indicates the flow direction of the liquid coating material in the microchannel cavity unit schematically.

[0039] The microchannel cavity unit has a cavity wall 111, and the height of the cavity wall 111 corresponds to the thickness of the material to be coated. In practical applications, the microchannel structure wafer 1 has the same size as the wafer 2 to be coated to ensure that the coating range can completely cover the wafer surface. For wafers of different specifications, microchannel structure wafers 1 of different sizes can be prepared accordingly.

[0040] The thickness of the cavity wall 111 of the microchannel cavity unit is not greater than 50 μm. In a specific example, the thickness of the cavity wall 111 can be appropriately adjusted according to the specific etching process capabilities, but a smaller thickness should be maintained to maximize the effective coating area.

[0041] Please refer to Figure 6 , the microchannel cavity units on the microchannel structure wafer 1 are distributed in a regular hexagon, forming a structure similar to a honeycomb.

[0042] In a specific example, the shape of the microchannel cavity unit can be a regular polygon with no less than 6 sides, such as a regular hexagon, a regular octagon, or a regular dodecagon.

[0043] Selecting a regular polygon with no less than 6 sides is to ensure that the interior angle of the unit cavity wall 111 is greater than 90°, so as to reduce the impact force of the liquid on the inner wall when the liquid material fills the cavity unit, which is beneficial to more complete filling inside the cavity unit.

[0044] In a preferred embodiment, the number of sides of the regular polygon is an even number, such as 6, 8, 10, 12, etc. This design is to facilitate the splicing and arrangement of the microchannel cavity units on the silicon wafer surface, ensuring that the microchannel structure can completely cover the entire silicon wafer surface without gaps.

[0045] The window opening gap 112 of the microchannel cavity unit is between 100 μm and 200 μm. If the window opening gap 112 is too small, it will affect the effect of capillary action and cause incomplete filling; if the window opening gap 112 is too large, it may cause uneven flow of the liquid material. Selecting an appropriate window opening gap 112 is crucial for achieving uniform coating.

[0046] The microchannel cavity unit is formed by a silicon wafer etching process.

[0047] Specifically, deep reactive ion etching (DRIE), wet etching or other suitable microfabrication processes can be used to process the silicon wafer to form the designed microchannel structure.

[0048] In a specific example, the pattern of the microchannel cavity unit can be first formed on the silicon wafer surface through lithography technology, and then the pattern can be transferred to the silicon wafer through an etching process to form the required three-dimensional microchannel structure.

[0049] The microchannel structure silicon wafer 1 provided in this embodiment for wafer coating can effectively guide the uniform distribution of the liquid material; by adjusting the cavity wall height, coating applications with different thickness requirements can be satisfied; it is manufactured by mature semiconductor processes such as silicon wafer etching, with high precision and consistency. Under the conditions of proper cleaning and maintenance, the microchannel structure silicon wafer 1 can be reused multiple times, reducing the coating cost; this microchannel structure silicon wafer 1 can be used in cooperation with existing wafer processing equipment.

[0050] S2: Closely attach the microchannel structure silicon wafer 1 to the wafer 2 to be coated.

[0051] When applying the liquid material for coating, first closely mount the microchannel structure silicon wafer 1 to the wafer to be coated. During the attachment process, it is necessary to ensure that there are no air bubbles and impurities between the two to avoid affecting the uniformity of subsequent coating. The attachment can be carried out by physical pressing or using an appropriate temporary adhesive for fixation. The specific operation methods belong to the common means of those skilled in the art and will not be elaborated here.

[0052] S3: Drop the liquid coating material on the microchannel structure silicon wafer 1, and the liquid coating material fills the microchannel cavity unit.

[0053] After appropriately dropping the liquid material on each area of the wafer by drop coating, let it stand. Under the action of capillary force, the liquid material will gradually fill the entire cavity of the microchannel structure. To ensure uniform filling, several injection points can be pre-designed on the silicon wafer so that the liquid material can be quickly distributed over the entire surface of the silicon wafer.

[0054] In a specific example, the total volume of the liquid coating material matches the total volume of the microchannel cavity unit. This matching relationship can be established by calculating the total volume of the microchannel cavity and then accurately controlling the volume of the dropped liquid material. In this way, it can be ensured that during the coating process, neither incomplete filling due to insufficient material nor uneven thickness due to excessive material will occur.

[0055] S4: When the microchannel cavity unit is filled, remove the microchannel structure silicon wafer 1, and the liquid coating material fills the microchannel cavity unit.

[0056] After all the microchannel cavity unit structures are filled, remove the microchannel structure silicon wafer 1 and continue to let it stand. The material liquid will fill the gaps caused by the cavity wall 111 of the original microchannel cavity under the action of surface tension, and finally uniformly coat the liquid material on the entire surface of the wafer to be coated, forming a uniform coating layer.

[0057] During the process of removing the microchannel structure silicon wafer 1, attention should be paid to controlling the peeling speed and angle to avoid disturbing the formed liquid coating layer. In a specific example, the microchannel structure silicon wafer 1 can be removed by slowly pulling it vertically to maintain the uniformity of the coating layer to the greatest extent.

[0058] The inner angle of the cavity wall 111 of the microchannel cavity unit is greater than 90°. This design helps to reduce the impact force when the liquid coating material is filled and can reduce the adhesion of the liquid when removing the microchannel structure silicon wafer 1, which is beneficial to forming a uniform and flat coating layer.

[0059] The wafer coating method based on the microchannel structure provided in this embodiment realizes the uniform distribution and consistent thickness of the coating material on the wafer surface by designing a specific microchannel structure silicon wafer 1 and utilizing physical phenomena such as capillary force and surface tension. Compared with the traditional drop coating and spin coating methods, this method has the following obvious advantages:

[0060] The microchannel structure design ensures that the liquid material can be evenly distributed on the wafer surface, avoiding the local aggregation or missing phenomena that are prone to occur in traditional methods; the thickness consistency is guaranteed, and by precisely controlling the height of the microchannel cavity and the dosage of the liquid material, high-precision control of the coating layer thickness is achieved; the design of the microchannel structure helps the liquid material to fully contact the wafer surface, improving the interfacial bonding force between the material and the wafer; the coating process relies on natural physical phenomena, reducing the influence of human factors and improving the stability and repeatability of the process.

[0061] In summary, the wafer coating method based on the microchannel structure provided by the present invention realizes the control of the flow and uniform distribution of the material through the microchannel structure silicon wafer composed of microchannel cavity units, effectively solving the problems of uneven material distribution, inconsistent thickness, and insufficient interfacial bonding force existing in the existing wafer coating technology, providing a new solution for the wafer coating technology, and helping to improve the performance and reliability of the wafer.

[0062] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A wafer coating method based on a microchannel structure, characterized in that, Comprising: Providing a silicon wafer with a microchannel structure, the silicon wafer with the microchannel structure comprising a plurality of microchannel cavity units distributed on the surface of the silicon wafer; Closely attaching the silicon wafer with the microchannel structure to the wafer to be coated; Dropping a liquid coating material on the silicon wafer with the microchannel structure, the liquid coating material filling the microchannel cavity units; And when the microchannel cavity units are filled, removing the silicon wafer with the microchannel structure to form a coating layer.

2. The method according to claim 1, wherein The total volume of the liquid coating material matches the total volume of the microchannel cavity units.

3. The method according to claim 2, wherein The microchannel cavity units have cavity walls, and the height of the cavity walls corresponds to the required thickness of the coating material.

4. The method according to claim 3, wherein The thickness of the cavity walls of the microchannel cavity units is not greater than 50 μm.

5. The method according to claim 3, characterized in that, The inner angles of the cavity walls of the microchannel cavity units are greater than 90°.

6. The method according to claim 1, wherein The shape of the microchannel cavity units is a regular polygon with no less than 6 sides.

7. The method according to claim 6, wherein The number of sides of the regular polygon is an even number.

8. The method according to claim 1, characterized in that, The window opening gap of the microchannel cavity units is between 100 μm and 200 μm.

9. The method according to claim 1, characterized in that, The microchannel cavity units are formed by a silicon etching process.

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