Novel semiconductor test probe manufacturing process

Abstract

The invention relates to the technical field of semiconductor micro-nano manufacturing, and discloses a novel semiconductor test probe manufacturing process which comprises the following steps: preparing an ionic liquid electrolyte containing a high-pressure priority adsorbent and a low-pressure priority adsorbent; a first voltage pulse is applied between the microelectrode and the conductive base, the amplitude of the first voltage pulse enables the high-voltage preferential adsorbent to preferentially adsorb on the surface of the microelectrode, and a flexible probe root and a flexible probe body are formed through deposition; then, a second voltage pulse is applied, and the amplitude of the second voltage pulse is lower than that of the first voltage pulse, so that the low-voltage preferential adsorbent preferentially adsorbs and deposits to form a superhard probe tip. The probe with the functional gradient structure is integrally manufactured by programmed voltage regulation and control in single continuous deposition, high hardness of the needle tip and high flexibility of the needle body are simultaneously realized on a single structure, the manufacturing process is remarkably simplified, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor micro-nano manufacturing technology, specifically to a novel semiconductor test probe manufacturing process. Background Technology

[0002] Probe cards are essential components for electrical performance testing (i.e., wafer testing) of semiconductor wafers before they leave the factory. Test probes, as the core component of the probe card, have tips that directly contact the pads on the wafer to establish temporary electrical pathways. With the continuous miniaturization of semiconductor process nodes and the increasing integration of chips, more stringent requirements are being placed on the performance and manufacturing technology of test probes.

[0003] An ideal test probe must simultaneously meet two contradictory mechanical performance requirements: First, the probe tip must possess extremely high hardness and wear resistance to ensure that the tip is not easily worn or deformed during tens of thousands of repeated contact tests, thereby ensuring the long-term stability of contact resistance and the reliability of test results; Second, the probe body and root must possess good flexibility or elasticity so as to effectively buffer contact force during the overdrive stroke of the test, avoid damage to expensive wafer pads, and adapt to the slight unevenness of the pad height.

[0004] Existing technologies face significant challenges in meeting these dual performance requirements. Probes manufactured using conventional processes from a single homogeneous material (such as tungsten, rhenium, or their alloys) exhibit uniform material properties throughout their structure. This design is essentially a performance compromise: if a high-hardness material is chosen to ensure tip wear resistance, the entire probe will exhibit high stiffness and brittleness, making it prone to breakage or wafer damage during overdrive; conversely, if a more flexible material is chosen, insufficient tip hardness and wear resistance lead to rapid wear during testing, shortening its lifespan and affecting testing accuracy.

[0005] To overcome the limitations of single materials, the industry has developed manufacturing methods employing complex microelectromechanical systems (MEMS) processes or multi-component assembly. These methods, for example, involve constructing the spring structure of probes through multiple steps such as photolithography, electroplating, and etching, or welding pre-prepared hard tips onto flexible probe bodies. However, these processes are typically very complex, involving multiple photolithography masking, alignment, etching, and material deposition steps, resulting in long manufacturing cycles, high costs, and strong equipment dependence. Furthermore, material interfaces or weld points introduced by step-by-step manufacturing or component assembly often become stress concentration points, easily becoming weak points for structural failure under cyclic loading. Simultaneously, the minimum probe spacing achievable by optical lithography-based manufacturing methods is limited by the optical diffraction limit, making it difficult to meet the testing requirements of future higher-density chips.

[0006] Therefore, there is a lack of existing technologies that can simultaneously achieve high tip hardness and needle body flexibility within a single structure of a probe, while simplifying the manufacturing process, reducing costs, and breaking through the size limitations of traditional micro-manufacturing. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a novel semiconductor test probe manufacturing process. It aims to resolve the inherent performance contradiction in existing technologies, where homogeneous probe materials cannot simultaneously meet the requirements of high hardness and high wear resistance at the probe tip and the flexibility required by the probe body. It also addresses the problems of cumbersome manufacturing processes, high costs, and difficulty in manufacturing probes with smaller pitches.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] The first aspect of this invention provides a manufacturing process for a semiconductor test probe, comprising the following steps:

[0010] S1. Electrolyte Preparation Steps: A voltage-responsive functional gradient ionic liquid electrolyte is prepared under an inert atmosphere. The composition and concentration of the electrolyte are as follows:

[0011] Ionic liquid solvent: 1-Butyl-3-methylimidazolium tetrafluoroborate;

[0012] Metal precursors: anhydrous tungsten hexachloride at a concentration of 0.05–0.20 mol / L and anhydrous rhenium trichloride at a concentration of 0.01–0.05 mol / L;

[0013] Low-pressure preferred adsorbent: N-(2-hydroxyethyl)thiourea at a concentration of 100–500 ppm;

[0014] High-pressure preferred adsorbent: poly(diallyldimethylammonium chloride) at a concentration of 50–300 ppm.

[0015] S2. Programmed in-situ synthesis step: A substrate with a conductive base is used as the anode, and a microelectrode is used as the cathode. The conductive base and microelectrode are immersed in the voltage-responsive functional gradient ionic liquid electrolyte prepared in step S1. By applying a preset voltage pulse between the microelectrode and the conductive base, a tungsten-rhenium alloy is deposited layer by layer on the conductive base to form a probe. The mechanism of this step is that by controlling the electric field strength, i.e., the voltage amplitude, the adsorption competition relationship between the two additives on the cathode surface is changed, thereby controlling the microstructure and macroscopic properties of the deposited layer. This step specifically includes:

[0016] S2.1 Synthesis of Flexible Root and Needle Body: A first voltage pulse with an amplitude of -3.2V to -4.0V is applied. Within this voltage range, the charged high-voltage preferential adsorbent preferentially migrates and adsorbs onto the cathode surface due to the electrophoretic effect. Its steric hindrance effect leads to the formation of a microstructure with relatively coarse grains and low internal stress in the deposited layer, thereby obtaining a probe flexible root and needle body with high flexibility.

[0017] S2.2 Synthesis of the ultrahard tip: A second voltage pulse with an amplitude of -2.0V to -2.8V is applied. Within this voltage range, the electrophoretic driving force of the high-pressure preferential adsorbent is weakened, and the smaller, neutral low-pressure preferential adsorbent dominates the adsorption competition in a diffusion-controlled manner. Its adsorption behavior inhibits grain growth and promotes the formation of new crystal nuclei, resulting in the formation of a fine-grained or even nanocrystalline structure in the deposited layer, thereby obtaining an ultrahard probe tip with high hardness at the flexible root and the tip of the needle body.

[0018] S3. Post-processing steps: Clean and dry the substrate with the probe deposited.

[0019] A second aspect of the present invention provides a voltage-responsive functionally graded ionic liquid electrolyte for the fabrication of semiconductor test probes, characterized in that its components and concentrations are as follows:

[0020] Ionic liquid solvent: 1-Butyl-3-methylimidazolium tetrafluoroborate;

[0021] Metal precursors: anhydrous tungsten hexachloride at a concentration of 0.05–0.20 mol / L and anhydrous rhenium trichloride at a concentration of 0.01–0.05 mol / L;

[0022] Low-pressure preferred adsorbent: N-(2-hydroxyethyl)thiourea at a concentration of 100–500 ppm;

[0023] High-pressure preferred adsorbent: poly(diallyldimethylammonium chloride) at a concentration of 50–300 ppm.

[0024] In one specific embodiment, the preparation method of the low-pressure preferential adsorbent is as follows: thiourea and 2-chloroethanol are refluxed in anhydrous ethanol solvent, the solvent is removed by rotary evaporation after the reaction is completed, and then N-(2-hydroxyethyl)thiourea is obtained by recrystallization and vacuum drying.

[0025] In another specific embodiment, the high-pressure preferential adsorbent is prepared by: using diallyl dimethyl ammonium chloride as a monomer and ammonium persulfate as an initiator, a free radical polymerization reaction is carried out in deionized water, and after the reaction is completed, the poly(diallyl dimethyl ammonium chloride) is obtained by dialysis purification and freeze drying.

[0026] In one embodiment, in step S2.1 of the programmed in-situ synthesis step, the pulse width of the first voltage pulse is 100 μs to 500 μs, and the pulse interval time is 200 μs to 1000 μs.

[0027] In one embodiment, in step S2.2 of the programmed in-situ synthesis step, the pulse width of the second voltage pulse is 50 μs to 200 μs, and the pulse interval is 100 μs to 500 μs.

[0028] In a preferred embodiment, between the synthesis step of the flexible root and the needle body and the synthesis step of the superhard needle tip, a transition layer synthesis step is further included: by linearly or stepwise reducing the amplitude of the applied voltage pulse from the amplitude range of the first voltage pulse to the amplitude range of the second voltage pulse, a transition layer with continuously changing microstructure and mechanical properties is deposited between the flexible root and the needle body and the superhard needle tip.

[0029] In one embodiment, the microelectrode is made of tungsten or platinum-iridium alloy wire with a tip curvature radius of 50 nm to 200 nm.

[0030] In one embodiment, the conductive base is a double-layer structure disposed on a silicon dioxide insulating layer, wherein the bottom layer is a titanium attachment layer with a thickness of 10-30nm and the upper layer is a gold conductive layer with a thickness of 50-100nm.

[0031] In one embodiment, the cleaning process in the post-processing step is as follows: the substrate is ultrasonically cleaned sequentially using acetonitrile and isopropanol.

[0032] In one embodiment, in the programmed in-situ synthesis step, the Z-axis position of the microelectrode is retracted upward by 0.1 nm to 0.5 nm in each pulse cycle according to a preset growth model, so as to maintain the stability of the deposition process.

[0033] This invention provides a novel semiconductor test probe manufacturing process. It offers the following advantages:

[0034] 1. The manufacturing process of this invention selectively drives the high-pressure preferential adsorbent and the low-pressure preferential adsorbent to compete for adsorption in a single electrolyte system by using a programmably controlled voltage pulse amplitude. This method enables a gradient distribution of microstructure and macroscopic mechanical properties on a single probe structure, from the root, body to the tip, thereby solving the technical contradiction of the required flexibility at the probe root and body and the required hardness and wear resistance at the tip in a single continuous manufacturing process.

[0035] 2. This invention employs bottom-up field-induced localized electrochemical deposition as an additive manufacturing method, directly growing probes layer by layer on a conductive substrate. This method eliminates the need for multiple steps in traditional processes, such as photolithography mask preparation, pattern transfer, and chemical etching, thereby significantly simplifying the overall process flow, shortening the manufacturing cycle, and reducing reliance on expensive photolithography equipment.

[0036] 3. The manufacturing precision of the probe array, especially the minimum pitch of the probes, directly depends on the three-dimensional positioning precision of the microelectrode system in this invention, rather than the optical diffraction limit of traditional photolithography. Therefore, it can be used to manufacture probe arrays with smaller pitches. Simultaneously, the macroscopic geometry of the probes, such as taper and aspect ratio, can be set by editing the deposition program, providing high flexibility for probe structure design. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specification of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on 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.

[0038] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0039] Ionic liquid solvent:

[0040] 1-Butyl-3-methylimidazolium tetrafluoroborate: CAS No.: 174501-64-5; purity ≥99%, water content <20ppm.

[0041] Metal precursors:

[0042] Anhydrous tungsten hexachloride: CAS No.: 13283-01-7, purity 99.9%.

[0043] Anhydrous rhenium trichloride: CAS No.: 13569-63-6, purity 99.9%.

[0044] Additive synthesis raw materials:

[0045] Thiourea: CAS No.: 62-56-6, purity ≥99%.

[0046] 2-Chloroethanol: CAS No.: 107-07-3, purity ≥98%.

[0047] Diallyl dimethyl ammonium chloride: CAS No.: 7398-69-8, specification: 65wt% aqueous solution.

[0048] Ammonium persulfate: CAS No.: 7727-54-0, purity ≥98%.

[0049] Other reagents and consumables:

[0050] Anhydrous ethanol: CAS No.: 64-17-5, purity ≥99.5%.

[0051] Acetonitrile: CAS No.: 75-05-8, purity ≥99.8%.

[0052] Isopropanol: CAS No.: 67-63-0, purity ≥99.5%.

[0053] High-purity argon: CAS No.: 7440-37-1, purity 99.999%.

[0054] Preparation of key additives:

[0055] Preparation Example 1: Preparation of N-(2-hydroxyethyl)thiourea, a low-pressure preferential adsorbent

[0056] In a 500 mL three-necked flask equipped with a reflux condenser and a magnetic stirrer, 7.61 g (0.1 mol) of thiourea, 8.05 g (0.1 mol) of 2-chloroethanol, and 200 mL of anhydrous ethanol were added. The mixture was heated to reflux temperature (approximately 78 °C) with stirring and maintained for 8 hours. After the reaction was complete, the reaction solution was cooled to room temperature. The solvent ethanol was removed by vacuum evaporation using a rotary evaporator under a water bath at 60 °C to obtain a white solid crude product. The obtained crude product was recrystallized from 100 mL of ethanol, the crystals were collected by filtration, and dried in a vacuum drying oven at 40 °C for 12 hours to finally obtain 10.2 g of white needle-like crystals, namely N-(2-hydroxyethyl)thiourea.

[0057] Preparation Example 2: Preparation of Poly(diallyldimethylammonium chloride), a High-Pressure Preferred Adsorbent

[0058] In a 1000 mL jacketed reactor equipped with a mechanical stirrer, thermometer, and nitrogen gas inlet, 154 g of a 65 wt% aqueous solution of diallyl dimethyl ammonium chloride (DADMAC) (containing 100 g of DADMAC monomer, approximately 0.62 mol) and 300 mL of deionized water were added. High-purity nitrogen was purged into the reactor for 30 minutes with stirring to remove dissolved oxygen. The jacket temperature of the reactor was then set to 65 °C. In another beaker, 1.0 g of ammonium persulfate (APS) was dissolved in 10 mL of deionized water to prepare an initiator solution. This initiator solution was added to the reactor in one go, and the reaction was carried out at 65 °C for 8 hours under nitrogen protection and continuous stirring. After the reaction, the resulting viscous polymer solution was cooled to room temperature and transferred to a dialysis bag with a molecular weight cutoff of 1000 Da. Dialysis was performed in a large volume of deionized water for 72 hours, with the deionized water replaced every 8 hours. After dialysis, the purified polymer solution was freeze-dried to obtain a white flocculent solid, namely poly(diallyl dimethyl ammonium chloride) (PDADMAC).

[0059] Example 1:

[0060] S1. Electrolyte Preparation Procedure: The procedure was performed in an inert atmosphere glove box filled with high-purity argon. 19.8 g (corresponding to a final concentration of 0.10 mol / L) of anhydrous tungsten hexachloride and 2.7 g (corresponding to a final concentration of 0.02 mol / L) of anhydrous rhenium trichloride were added sequentially to 1 L of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid solvent. After the metal precursor was completely dissolved under magnetic stirring, N-(2-hydroxyethyl)thiourea prepared in Preparation Example 1 was added to bring the final concentration to 300 ppm; finally, poly(diallyldimethylammonium chloride) prepared in Preparation Example 2 was added to bring the final concentration to 150 ppm. The mixture was stirred continuously for 24 hours to obtain a homogeneous and clear voltage-responsive functional gradient ionic liquid electrolyte.

[0061] S2, Programmed In-Situ Synthesis Step: A substrate with a conductive base is used as the anode, and a microelectrode is used as the cathode, immersed in the electrolyte prepared in step S1. The conductive base is a double-layer structure disposed on a silicon dioxide insulating layer, with a 15nm thick titanium adhesion layer at the bottom and an 80nm thick gold conductive layer on top. The microelectrode is made of platinum-iridium alloy wire with a tip curvature radius of 100nm. Probe deposition is performed by applying a voltage pulse controlled by a precision waveform generator between the microelectrode and the conductive base. Throughout the deposition process, the Z-axis position of the microelectrode retracts upward by 0.3nm in each pulse cycle according to a preset growth model. This step specifically includes:

[0062] S2.1 Synthesis of Flexible Root and Needle Body: Apply a first voltage pulse with an amplitude of -3.6V, a pulse width of 400μs, and a pulse interval of 800μs. Continue this process until a probe flexible root and needle body with a height of 80μm are deposited.

[0063] S2.2 Synthesis of the transition layer: The applied voltage pulse amplitude was linearly and continuously reduced from -3.6V to -2.4V over 10 minutes, while the pulse timing parameters remained constant. During this period, the probe continued to grow by 10μm, forming a transition layer.

[0064] S2.3 Synthesis of the superhard tip: Apply a second voltage pulse with an amplitude of -2.4V, and adjust the pulse width to 150μs and the pulse interval to 300μs. Continue this process until the probe regenerates to 10μm, forming a probe structure with a total height of 100μm, of which the top 10μm is the superhard tip.

[0065] S3. Post-processing steps: Remove the substrate with the deposited probe from the electrolyte and perform ultrasonic cleaning sequentially using acetonitrile and isopropanol, with each cleaning session lasting 10 minutes. After cleaning, dry the substrate using a high-purity argon gas stream to obtain the finished semiconductor test probe.

[0066] Example 2:

[0067] S1. Electrolyte preparation steps: The electrolyte was prepared according to the method in Example 1, and the final concentrations of each component were: anhydrous tungsten hexachloride 0.15 mol / L, anhydrous rhenium trichloride 0.04 mol / L, N-(2-hydroxyethyl)thiourea 450 ppm, and poly(diallyldimethylammonium chloride) 250 ppm.

[0068] S2. Programmed in-situ synthesis steps:

[0069] S2.1 Synthesis of flexible root and needle body: A first voltage pulse with an amplitude of -3.8V is applied, the pulse width is 500μs, and the pulse interval is 1000μs, to deposit a probe flexible root and needle body with a height of 80μm.

[0070] S2.2 Synthesis of the transition layer: The applied voltage pulse amplitude starts from -3.8V and decreases stepwise by 0.2V each time, until it reaches -2.2V. Each voltage step maintains a deposition growth height of 2μm.

[0071] S2.3 Synthesis of ultrahard tips: Apply a second voltage pulse with an amplitude of -2.2V, a pulse width of 100μs, and a pulse interval of 200μs to deposit the tip portion of the probe.

[0072] The remaining steps, including the preparation of the substrate and microelectrodes, Z-axis retraction control (0.3nm retraction per pulse cycle), and post-processing steps, are the same as those described in Example 1.

[0073] Comparative Example 1:

[0074] The difference from Example 1 is that N-(2-hydroxyethyl)thiourea and poly(diallyldimethylammonium chloride) are not added in the S1 electrolyte preparation step. All other steps and process parameters are exactly the same as in Example 1.

[0075] Comparative Example 2:

[0076] The difference from Example 1 is that, in the S1 electrolyte preparation step, only N-(2-hydroxyethyl)thiourea at a concentration of 300 ppm is added as an additive, instead of poly(diallyldimethylammonium chloride). All other steps and process parameters are exactly the same as in Example 1.

[0077] Comparative Example 3:

[0078] Compared to Example 1, the difference lies in that, in the S2 programmed in-situ synthesis step, a constant voltage pulse with an amplitude of -3.0V is applied throughout the entire probe deposition process, without distinguishing the synthesis voltage for the flexible root and the ultrahard tip, and without synthesizing the transition layer. All other steps (including electrolyte formulation) and process parameters are exactly the same as in Example 1.

[0079] Test Example 1: Probe Tip Hardness Test

[0080] Test objective:

[0081] This test case aims to quantitatively evaluate the nanohardness of probes prepared by different processes in the tip region.

[0082] Test subject:

[0083] Probe prepared in Example 1

[0084] Probe prepared in Comparative Example 1

[0085] Probe prepared in Comparative Example 2

[0086] Probe prepared in Comparative Example 3

[0087] Test equipment and methods:

[0088] The tests were conducted using a nanoindenter equipped with a Berkovich indenter. The test procedures are as follows:

[0089] Sample preparation: The substrate with the probe array deposited on it is fixed on the sample stage of the nanoindenter.

[0090] Positioning: Use the instrument’s built-in optical microscope to position a single probe and move the indenter precisely to a position 5 μm away from the tip of the probe.

[0091] Indentation test: Set the loading program to apply a load at a constant loading rate of 5 mN / min until the maximum indentation depth reaches 200 nm. After holding at this depth for 10 seconds, unload at the same rate.

[0092] Data Acquisition and Calculation: The instrument automatically records the load-displacement curves throughout the entire loading-unloading process. The nanoscale hardness of the material is calculated from the unloading portion of the curve using the Oliver-Pharr method.

[0093] Repeated testing: For each test object (Example 1, Comparative Examples 1-3), three probes were randomly selected for repeated testing. The hardness value was recorded each time, and the average value was calculated.

[0094] Test results:

[0095] The nanohardness data of the probe tip region obtained after testing each group of samples are recorded in Table 1.

[0096] Table 1: Probe tip hardness test results

[0097] Test object Hardness test 1 (GPa) Hardness test 2 (GPa) Hardness test 3 (GPa) Average hardness (GPa) Example 1 23.8 24.5 22.9 23.7 Comparative Example 1 11.2 10.8 11.5 11.2 Comparative Example 2 21.5 22.1 20.9 21.5 Comparative Example 3 16.2 15.7 16.6 16.2

[0098] Results analysis:

[0099] Test results show that the average hardness value of the probe tip prepared in Example 1 is significantly higher than that of Comparative Example 1 and Comparative Example 3. The probe tip prepared in Comparative Example 2 also obtained a high hardness value, which is close to that of Example 1.

[0100] The above results correspond to the control mechanism of this technical solution. In Example 1, by applying a second voltage pulse with an amplitude of -2.4V, the electric field strength is low. At this time, N-(2-hydroxyethyl)thiourea, with its smaller molecular size, gains adsorption advantage on the cathode surface in a diffusion-controlled manner. This adsorbent, by inhibiting grain growth and promoting the formation of new crystal nuclei, results in a fine-grained structure in the deposited layer, thereby achieving a hardness value of 23.7 GPa. Comparative Example 2, containing this low-pressure preferential adsorbent and deposited at a correspondingly low voltage, also formed a needle tip with high hardness.

[0101] In contrast, the electrolyte in Comparative Example 1 contained no additives, and its deposition process lacked control over grain size, resulting in a conventional coarse-grained tungsten-rhenium alloy with the lowest hardness. While the electrolyte formulation in Comparative Example 3 was the same as in Example 1, a constant voltage of -3.0V was used throughout the deposition process. At this intermediate voltage, the adsorption behavior of the two additives could not be specifically optimized; in particular, the persistent presence of the high-pressure preferential adsorbent interfered with the formation of a fine-grained structure, resulting in a hardness of only 16.2 GPa. These data demonstrate that the mechanical properties of the probe tip can be controlled by combining specific electrolyte components with programmed voltage pulses.

[0102] Test Example 2: Probe Body Flexibility Test

[0103] Test objective:

[0104] This test case aims to quantitatively evaluate the flexibility of probes prepared by different processes in the needle body, and characterizes it by measuring the reaction force under a specific lateral displacement.

[0105] Test subject:

[0106] Probe prepared in Example 1

[0107] Probe prepared in Comparative Example 1

[0108] Probe prepared in Comparative Example 2

[0109] Probe prepared in Comparative Example 3

[0110] Test equipment and methods:

[0111] A micromechanical testing system equipped with a precision force probe was used for the test. The test steps are as follows:

[0112] Sample preparation: Securely mount the substrate with the deposited probe array onto the sample stage of the test system.

[0113] Positioning: Position the individual probe using the system-integrated microscope. Move the flat-headed cylindrical force probe to a position of 50% of the total probe height (i.e., 50 μm from the substrate) and bring it into contact with the probe sidewall.

[0114] Force-displacement test: Control the force probe to move at a speed of 1 μm / s in a direction perpendicular to the probe axis, so that the probe produces a lateral displacement.

[0115] Data acquisition: Continuously record the displacement of the force probe and the reaction force applied to it by the probe. When the lateral displacement of the probe reaches 10 μm, record the corresponding reaction force value at this moment.

[0116] Repeated testing: For each test object (Example 1, Comparative Examples 1-3), three probes were randomly selected for repeated testing. The reaction force value was recorded each time, and the average value was calculated.

[0117] Test results:

[0118] The reaction force data of the probe when the lateral displacement is 10 μm after testing each group of samples are recorded in Table 2.

[0119] Table 2: Results of probe body flexibility test

[0120] Test object Reaction force measured in μN Reaction force test 2 (μN) Reaction force test 3 (μN) Mean reaction force (μN) Example 1 51.3 48.8 52.1 50.7 Comparative Example 1 89.6 92.5 90.2 90.8 Comparative Example 2 85.4 88 86.9 86.8 Comparative Example 3 70.2 68.9 71.6 70.2

[0121] Results analysis:

[0122] Test data show that the probe prepared in Example 1 exhibits a significantly lower average reaction force than all comparative examples when producing the same lateral displacement, indicating its superior flexibility. Comparative Examples 1 and 2 show the highest and most similar reaction force values. The reaction force value of Comparative Example 3 falls between that of Example 1 and Comparative Examples 1 and 2.

[0123] This result directly corresponds to the synthesis mechanism of the flexible root and needle body in this technical solution. In Example 1, by applying a first voltage pulse with an amplitude of -3.6V, the high electric field strength drives charged poly(diallyldimethylammonium chloride) molecules to preferentially migrate and adsorb onto the cathode surface due to electrophoresis. The steric hindrance effect generated by this polymer adsorbent hinders the dense packing of metal atoms, resulting in a microstructure with relatively coarse grains and low internal stress in the deposited layer. This structure gives the probe body low bending stiffness.

[0124] In contrast, the electrolytes in Comparative Examples 1 and 2 did not contain a high-pressure preferential adsorbent, thus failing to achieve the aforementioned mechanism at any voltage. Their deposit structures were relatively dense, resulting in higher probe stiffness. While the electrolyte formulation in Comparative Example 3 was complete, the constant voltage of -3.0V used failed to maximize the electrophoretic effect of the high-pressure preferential adsorbent, and its adsorption was somewhat suppressed. Therefore, the resulting probe flexibility fell between that of Example 1 and the other comparative examples. This data confirms that the combination of specific electrolyte components and programmed high-voltage pulses is the reason for achieving the required probe flexibility.

[0125] Test Example 3: Probe Abrasion Resistance and Electrical Stability Test

[0126] Test objective:

[0127] This test case aims to quantitatively evaluate the wear resistance and contact resistance stability of probes prepared by different processes after undergoing repeated mechanical contact cycles.

[0128] Test subject:

[0129] Probe prepared in Example 1

[0130] Probe prepared in Comparative Example 1

[0131] Probe prepared in Comparative Example 2

[0132] Probe prepared in Comparative Example 3

[0133] Test equipment and methods:

[0134] The test was conducted using a semi-automatic probe station with an integrated precision source measurement unit (SMU). The test object was a standard silicon wafer with a 1μm thick aluminum layer on its surface. The test procedures are as follows:

[0135] Sample preparation: Mount the substrate with the probe to be tested deposited on the probe chuck, and place the aluminum pad wafer test piece on the stage.

[0136] Initial contact resistance measurement: The probe is lowered until its tip contacts the aluminum pad surface. An overdrive distance of 5 μm is applied. A constant current of 1 mA is applied through the SMU, and the contact resistance value at this point is measured and recorded as R. initial .

[0137] Contact cycle test: At the same point on the aluminum pad, the probe is controlled to perform 100,000 consecutive contact-separation cycles. In each cycle, the probe contacts the aluminum pad with a set overdrive distance, holds for 10ms, and then lifts off.

[0138] Final contact resistance measurement: After 100,000 cycles, at the same test point, an overdrive distance of 5 μm was applied again, and the contact resistance value at this time was measured using a constant current of 1 mA, denoted as R. final .

[0139] Data Calculation and Repetition: Calculate the rate of change of contact resistance. The formula is: Rate of Change (%) = ((R) / (R)) final -R initial ) / R initial ()×100%. For each test object, three probes were randomly selected for a complete and repeated test. The rate of change was recorded each time, and the average value was calculated.

[0140] Test results:

[0141] The probe contact resistance change rate data obtained after testing each group of samples are recorded in Table 3.

[0142] Table 3: Results of Contact Resistance Stability Test

[0143] Test object <![CDATA[R initial (mΩ)]]> <![CDATA[R final (mΩ)]]> Rate of change in resistance (%) Example 1 145.2 158.9 9.4 Comparative Example 1 151.7 488.3 221.9 Comparative Example 2 148.3 210.6 42 Comparative Example 3 149.8 265.1 77

[0144] Results analysis:

[0145] Test results show that the probe prepared in Example 1 exhibits the lowest rate of change in contact resistance after 100,000 contact cycles. The probe prepared in Comparative Example 1 shows the highest rate of change in contact resistance. The rates of change in resistance in Comparative Examples 2 and 3 are significantly higher than those in Example 1.

[0146] The contact resistance stability exhibited by the probe in Example 1 is a direct reflection of the high hardness and high wear resistance of its tip region. This tip was fabricated by inducing a fine-grained structure with a low-pressure preferential adsorbent under a second voltage pulse (-2.4V). As shown in Example 1, this structure possesses high nanoscale hardness, effectively resisting wear and plastic deformation under repeated mechanical impacts, thereby maintaining the stability of the tip's geometry and conductive contact area, ultimately keeping the change in contact resistance at a low level.

[0147] Comparative Example 1, lacking additives in its electrolyte, had a low tip hardness, resulting in severe wear during cyclic testing. This led to changes in contact area and accumulation of surface oxides, causing a sharp increase in contact resistance. Comparative Example 2, while having a higher tip hardness, had a rigid needle body (as shown in Test Example 2), generating a greater impact force upon contact, accelerating tip wear, and thus maintaining a high resistance change rate. Comparative Example 3, prepared using a single voltage, had insufficient tip hardness and lower wear resistance than Example 1, resulting in a significantly higher resistance change rate. These data confirm that programmable voltage control, creating a gradient structure of a flexible needle body and an ultra-hard tip on a single probe, is the reason why the probe maintains stable electrical performance during long-term use.

Claims

1. A novel semiconductor test probe manufacturing process, characterized in that, Includes the following steps: S1. Electrolyte preparation steps: A voltage-responsive functional gradient ionic liquid electrolyte is prepared in an inert atmosphere. The composition and concentration of the electrolyte are as follows: Ionic liquid solvent: 1-Butyl-3-methylimidazolium tetrafluoroborate; Metal precursors: anhydrous tungsten hexachloride at a concentration of 0.05–0.20 mol / L and anhydrous rhenium trichloride at a concentration of 0.01–0.05 mol / L; Low-pressure preferred adsorbent: N-(2-hydroxyethyl)thiourea at a concentration of 100–500 ppm; High-pressure preferred adsorbent: poly(diallyldimethylammonium chloride) at a concentration of 50–300 ppm; S2. Programmed in-situ synthesis step: A substrate with a conductive base is used as the anode, and a microelectrode is used as the cathode. The conductive base and the microelectrode are immersed in the voltage-responsive functional gradient ionic liquid electrolyte prepared in step S1. By applying a preset voltage pulse between the microelectrode and the conductive base, a tungsten-rhenium alloy is deposited layer by layer on the conductive base to form a probe. This step specifically includes: S2.1 Synthesis of flexible root and needle body: A first voltage pulse with a pulse amplitude of -3.2V to -4.0V is applied to cause the high-voltage preferential adsorbent to be preferentially adsorbed and deposited to obtain the flexible root and needle body of the probe; S2.2 Synthesis of superhard needle tip: A second voltage pulse with a pulse amplitude of -2.0V to -2.8V is applied to cause the low-pressure preferential adsorbent to be preferentially adsorbed, and the superhard needle tip of the probe is obtained by deposition at the flexible root and the tip of the needle body. S3. Post-processing steps: Clean and dry the substrate with the probe deposited.

2. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, The preparation method of the low-pressure preferential adsorbent is as follows: Thiourea was reacted with 2-chloroethanol under reflux in anhydrous ethanol solvent. After the reaction was completed, the solvent was removed by rotary evaporation, and then N-(2-hydroxyethyl)thiourea was obtained by recrystallization and vacuum drying.

3. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, The preparation method of the high-pressure preferential adsorbent is as follows: Using diallyl dimethyl ammonium chloride as a monomer and ammonium persulfate as an initiator, a free radical polymerization reaction was carried out in deionized water. After the reaction was completed, the poly(diallyl dimethyl ammonium chloride) was obtained by dialysis purification and freeze drying.

4. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, In the step of combining the flexible root and the needle body, the pulse width of the first voltage pulse is 100μs to 500μs, and the pulse interval is 200μs to 1000μs.

5. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, In the synthesis step of the superhard needle tip, the pulse width of the second voltage pulse is 50 μs to 200 μs, and the pulse interval is 100 μs to 500 μs.

6. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, Between the synthesis steps of the flexible root and the needle body and the synthesis steps of the superhard needle tip, there is also a synthesis step of a transition layer: by linearly or stepwise reducing the amplitude of the applied voltage pulse from the amplitude range of the first voltage pulse to the amplitude range of the second voltage pulse, a transition layer is deposited between the flexible root and the needle body and the superhard needle tip.

7. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, The microelectrode is made of tungsten or platinum-iridium alloy wire, with a tip curvature radius of 50 nm to 200 nm.

8. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, The conductive base is a double-layer structure disposed on a silicon dioxide insulating layer, with a titanium attachment layer of 10-30nm thickness at the bottom and a gold conductive layer of 50-100nm thickness at the top.

9. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, The cleaning process in the post-processing step is as follows: the substrate is ultrasonically cleaned sequentially using acetonitrile and isopropanol.

10. The novel semiconductor test probe manufacturing process according to claim 1, characterized in that, In the programmed in-situ synthesis step, the Z-axis position of the microelectrode is retracted upward by 0.1 nm to 0.5 nm in each pulse cycle according to a preset growth model.