MEMS probe manufacturing method based on atomic layer deposition technology

Abstract

The present invention discloses a method for manufacturing a MEMS probe based on atomic layer deposition technology, wherein porous anodized aluminum is used as a substrate, nano-channels are etched into a probe mold, and atomic layer deposition is performed in the probe mold to form a stacked multi-layer metal layer; after the top metal layer is subjected to CMP treatment, the MEMS probe can be obtained by demolding. The present invention uses atomic layer deposition technology to prepare the ultra-thin metal layer of the MEMS probe. The atomic layer deposition technology can realize the sequential deposition of single atomic layers, thereby accurately controlling the thickness and composition of the film, which is crucial for manufacturing high-performance MEMS probes.

Description

Technical Field

[0001] The invention relates to the technical field of MEMS probes, and in particular to a method for manufacturing a MEMS probe based on atomic layer deposition technology. Background Art

[0002] MEMS probes are miniature probes made with micro-electromechanical system technology. These probes have a complex mechanical structure with multiple layers of different metals stacked to achieve excellent current resistance. Increasing the number of internal stacking layers can significantly improve performance.

[0003] The traditional MEMS probe manufacturing process involves steps such as photolithography, electroplating, and chemical mechanical polishing (CMP), which is similar to the manufacturing process of semiconductor chips. During manufacturing, the substrate needs to be immersed in an electroplating solution containing a specific alloy, and a metal layer is deposited on the pattern through an electroplating process. The deposited metal layer has an uneven surface and needs to be smoothed through CMP technology. Then the next metal layer is deposited, and so on. Repeat the electroplating and CMP processes many times to finally manufacture a MEMS probe with a multi-layer stacked structure.

[0004] However, the manufacturing process of traditional MEMS probe cards has shown some obvious shortcomings when facing the high requirements of modern semiconductor testing. First, this process is quite cumbersome and requires repeated steps such as metal sputtering, photolithography, electroplating, and chemical mechanical grinding and polishing. The complexity of these steps not only increases the manufacturing time, but also increases the production cost. Secondly, due to the insufficient bonding force between layers, this limits the structural stability and durability of the probe card and cannot meet the needs of high-precision testing.

[0005] In addition, traditional processes also have difficulties in preparing ultra-thin metal layers, because the flatness of electroplating is not high, and it is necessary to rely on the CMP process to thin the probe surface to achieve the required flatness. This process not only increases the complexity of the process, but also limits the minimum thickness of the metal layer. These problems together lead to the limitations of traditional MEMS probe cards in modern high-precision, high-density semiconductor testing applications, and new technologies and processes are urgently needed to overcome these challenges. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a MEMS probe manufacturing method based on atomic layer deposition technology, which can accurately control the thickness of the metal layer and flexibly adjust the number of layers, thereby significantly improving the manufacturing accuracy of the probe.

[0007] To this end, the technical solution of the present invention is: a method for manufacturing a MEMS probe based on atomic layer deposition technology, using porous anodized aluminum as a substrate, etching its nanopores into a probe mold, performing atomic layer deposition in the probe mold to form stacked multi-layer metal layers; after CMP treatment of the top metal layer, demolding can obtain the MEMS probe.

[0008] On the basis of the above scheme and as a preferred scheme of the above scheme: in the probe mold, it also includes a plated metal layer formed by electroplating, a deposited metal layer formed by atomic layer deposition, and the electroplated metal layer and the deposited metal layer are combined to form a multi-layer metal layer.

[0009] On the basis of the above scheme and as a preferred scheme of the above scheme: the processing steps of the probe mold are as follows:

[0010] a1. Perform photolithography on porous anodized aluminum, apply photoresist and perform pattern development to form a probe pattern;

[0011] a2. Etch corresponding grooves in the nanochannel of the substrate to form a probe mold.

[0012] On the basis of the above scheme and as a preferred scheme of the above scheme: the probe mold etched with the nano-channel of the substrate has an aspect ratio of x:30, where the value of x is 0-1 and is not 0.

[0013] On the basis of the above solution and as a preferred solution of the above solution: the material of the electroplated metal layer and the deposited metal layer is gold or nickel target alloy.

[0014] On the basis of the above scheme and as a preferred scheme of the above scheme: when demolding, immerse the entire substrate in HF / H2O2 solution for etching to remove the porous anodized aluminum substrate.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention uses atomic layer deposition technology to prepare the ultra-thin metal layer of the MEMS probe. This technology is known for its high degree of precision control and excellent uniformity, and is particularly suitable for manufacturing high-density coatings. Atomic layer deposition technology can achieve single atomic layer deposition one by one, thereby accurately controlling the thickness and composition of the film, which is crucial for manufacturing high-performance MEMS probes.

[0017] The present invention can combine atomic layer deposition technology with electroplating technology, while obtaining the high deposition rate advantage of electroplating and the precise control advantage of atomic layer deposition, further optimizing the regulation of film thickness and composition, and improving the flexibility and efficiency of the manufacturing process.

[0018] The present invention converts the nanopores of porous anodized aluminum into a probe mold, which can significantly improve the aspect ratio and mechanical strength of the MEMS probe. This high aspect ratio design enables the MEMS probe to maintain structural stability when subjected to greater pressure, reducing the risk of deformation or fracture that may occur during testing, thereby ensuring the accuracy and reliability of the test.

[0019] The present invention avoids the need for CMP treatment between each layer, and only performs CMP treatment on the top metal layer, which greatly simplifies the difficulty of manufacturing the MEMS probe, reduces the production cost, and speeds up the production speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following is further detailed description with reference to the accompanying drawings and implementation modes:

[0021] Figure 1 Schematic diagram of the probe manufacturing process of Example 1, wherein: ① photolithography, ② etching, ③ atomic layer deposition, ④ CMP, ⑤ substrate removal;

[0022] Figure 2 It is a schematic diagram of the substrate manufacturing process of Example 1, wherein: a. anodization, b. separation;

[0023] Figure 3 This is a schematic diagram of the probe manufacturing process of Example 2, wherein: ① photolithography, ② etching, ⑥ atomic layer deposition or electroplating, ④ CMP, ⑤ removing the substrate.

[0024] Marked in the figure are: substrate 1, nanochannel 11, electroplating mold 12, photoresist 2, MEMS probe 3, and aluminum substrate 4. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present invention.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, "several" and "a number" mean two or more, unless otherwise clearly and specifically defined.

[0027] like Figure 1 As shown: In Example 1, the method for preparing a MEMS probe includes the following steps:

[0028] S1. Porous anodized aluminum is selected as the substrate 1 material. This material has excellent mechanical properties and chemical stability, providing a good foundation for subsequent processes. The preparation process of the substrate is as follows (eg Figure 2 shown):

[0029] S1.1. Prepare a high-purity aluminum substrate 4 and ensure that its surface is clean and free of impurities.

[0030] S1.2. Use the anodizing process to form a uniform porous anodized aluminum layer on the surface of the aluminum substrate. The pore size and depth of this layer will directly affect the performance of the subsequent probe.

[0031] S1.3. Separate the generated porous anodized aluminum layer from the aluminum substrate to obtain a porous anodized aluminum substrate 1; separate the porous anodized aluminum layer from the aluminum substrate through a sophisticated chemical treatment method to obtain an independent porous anodized aluminum substrate. This step requires strict control of the concentration of the chemical agent and the treatment time to ensure the integrity and uniformity of the substrate.

[0032] S2. Perform photolithography on the substrate 1, apply photoresist 2 and perform pattern development to form a desired probe pattern.

[0033] S3. Etching is performed in the nanopore 11 of the substrate 1 by wet etching or dry etching to form a high aspect ratio electroplating mold 12. Taking wet etching as an example, the etching liquid is evenly distributed on the vertical straight wall to ensure the accuracy and consistency of the mold. A nanopore with a specific aspect ratio is formed, which will be used as an electroplating mold, and its aspect ratio can be controlled within the range of 0 to 1:30 to meet the requirements of probe aspect ratio in different application scenarios.

[0034] S4. Atomic layer deposition technology is used to stack multiple layers of metal in the etched grooves. This technology combines the high deposition rate of electroplating with the precise control of atomic layer deposition to achieve precise control of film thickness and composition.

[0035] In the etched grooves, a single atomic layer deposition technology can be used to prepare high-precision, ultra-thin metal layers. This technology, with its characteristics of successive deposition of single atomic layers, can achieve precise control of film thickness and composition. It is particularly suitable for the preparation of high-density coatings and uniform coverage on complex-shaped components.

[0036] Metal is filled in the nanochannels, preferably gold and nickel target alloys, to form a probe structure with strong conductivity and good wear resistance. During the processing, the time, current density and solution temperature must be precisely controlled to ensure the uniformity and density of the metal layer.

[0037] S5. The top metal layer is CMP treated to ensure a smooth surface, while no CMP treatment is required between layers, simplifying the process.

[0038] S6, removing the substrate, and immersing the finished product of step S5 in a HF / H2O2 solution composed of hydrofluoric acid and hydrogen peroxide for etching. The solution can effectively remove the porous anodized aluminum substrate without damaging the electroplated metal layer, and finally obtain an independent MEMS probe 3.

[0039] This embodiment can achieve a high aspect ratio of 1:30, the thickness of a single-layer mold can reach 150 microns, and a narrow spacing of less than 5 microns can be achieved. The atomic layer deposition technology can achieve deeper processing, accurately control the thickness of the metal layer, and flexibly adjust the number of layers, thereby significantly improving the manufacturing accuracy of the probe and making it possible to design more diverse probe beam arms.

[0040] like Figure 3 As shown, Example 2 is similar to Example 1, except that: in step S4, the preparation of the metal layer uses not only the atomic layer deposition technology but also the electroplating technology, and the atomic layer deposition technology is combined with the electroplating technology to produce a stacked multi-layer metal layer in the etched groove, and the two technologies can be randomly combined to give full play to the advantages of both. The random combination includes: alternating arrangement of electroplated metal layers and deposited metal layers, alternating arrangement of n-layer electroplated metal layers and m-layer deposited metal layers, and so on.

[0041] Electroplating technology is known for its high deposition rate, while atomic layer deposition technology provides precise thickness and composition control. The combination of the two can meet the needs for ultra-thin metal layers and high control accuracy, while maintaining the high production efficiency of electroplating and the high precision characteristics of atomic layer deposition.

[0042] In this embodiment, the current carrying capacity (CCC) of the MEMS probe is greatly improved by optimizing the depth ratio and structural strength of the probe. In addition, by combining atomic layer deposition technology and electroplating technology, a diversified design of the metal layer, a close bond between the layers, and the formation of a dense and uniform metal layer in the nanochannel are achieved, which not only reduces the resistance and heat generation when the current passes through, but also significantly improves the current carrying capacity of the probe. This optimized current carrying capacity means that the MEMS probe can operate under high current conditions without losing stability and reliability, which is crucial for wafer testing of high-performance logic chips and storage chips. Whether in the testing of devices such as CPU, GPU, AI, SoC, Flash, DRAM, CIS, or in high-end application fields such as high-end automotive display solutions and flexible OLED thin film packaging processes, the MEMS probe of this embodiment can provide excellent performance and reliability.

[0043] The MEMS probe manufactured in this embodiment exhibits higher mechanical strength and rigidity, so that the probe can maintain structural stability when a large needle pressure is applied, reducing the risk of deformation or breakage caused by excessive pressure. Such optimization not only ensures precise contact during the test process, but also improves the durability and service life of the probe.

[0044] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for manufacturing a MEMS probe based on atomic layer deposition technology, characterized in that: Using porous anodized aluminum as a substrate, etching its nano-channels into a probe mold, wherein the aspect ratio is x:30, and the value of x is 0-1 and is not 0; performing atomic layer deposition in the probe mold to form a stacked multi-layer metal layer, further comprising forming an electroplated metal layer by electroplating, forming a deposited metal layer by atomic layer deposition, and combining the electroplated metal layer and the deposited metal layer to form a multi-layer metal layer; After CMP treatment of the top metal layer, the MEMS probe can be obtained by demolding.

2. The method for manufacturing a MEMS probe based on atomic layer deposition technology according to claim 1, characterized in that: The processing steps of the probe mold are as follows: a1. Perform photolithography on porous anodized aluminum, apply photoresist and perform pattern development to form a probe pattern; a2. Etch corresponding grooves in the nanochannel of the substrate to form a probe mold.

3. The method for manufacturing a MEMS probe based on atomic layer deposition technology according to claim 1, characterized in that: The material of the electroplated metal layer and the deposited metal layer is gold or nickel target alloy.

4. The method for manufacturing a MEMS probe based on atomic layer deposition technology according to claim 1, characterized in that: During demolding, the entire substrate is immersed in HF / H2O2 solution for etching to remove the porous anodized aluminum substrate.

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