Rare metal reinforced protection process for surface of plastic base material of intelligent terminal

Abstract

The invention relates to the technical field of magnetron sputtering, and discloses an intelligent terminal plastic base material surface rare metal strengthening protection technology which comprises the steps that sputtering pulse ignition time delay of a high-purity cobalt target or a nickel-platinum alloy target is monitored, and discharge energy overshoot caused by target surface magnetic field topological drift is stabilized according to the slope of the rising edge of the starting section of time delay deviation compensation voltage; the sputtering pulse duty ratio is adjusted according to the glass-transition temperature of the plastic base material and the real-time process temperature, and the energy density of the metal atom flow reaching the surface of the base material is maintained in a deposition energy band; according to the method, the mapping relation between deposition energy and base material characteristics is established, so that impact energy is lower than a macromolecular chain segment synergistic motion threshold value, low-temperature compact growth of a strengthened layer is achieved on the premise that thermal degradation of the base material is not triggered, and the physical interlocking anchoring structure is formed on the interface layer. And the interface bonding stability is improved.

Description

Technical Field

[0001] This invention belongs to the field of magnetron sputtering technology, and particularly relates to a rare metal reinforcement and protection process for the surface of plastic substrates for smart terminals. Background Technology

[0002] Currently, magnetron sputtering technology is used to prepare high-purity cobalt or nickel-platinum alloy reinforcement layers on plastic substrates. This is a common method to improve the surface hardness and wear resistance of smart terminal components. It involves the physical process of high-energy metal particles migrating from the target to the substrate in a vacuum environment and eventually nucleating and growing on the substrate surface. Plastic substrates usually have low glass transition temperatures and thermal conductivity, while the preparation of metal films with reinforcement layers requires maintaining high deposition energy projection to ensure the film density and interfacial adhesion. There is an intrinsic physical contradiction between the energy injection required by deposition kinetics and the thermodynamic tolerance boundary of the substrate. Conventional methods mainly rely on adjusting the deposition duty cycle or adding external cooling devices to implement heat management, but this is difficult to suppress the local heat accumulation caused by continuous bombardment of particle streams at the microscopic level, which leads to molecular chain degradation or overall thermal deformation of the substrate surface.

[0003] Besides relying on external cooling and other hardware reinforcements, the precision of process control logic also determines the film quality. For example, Chinese invention patent CN112553624B discloses a method for preparing a black decorative film layer applied to plastics. By adjusting the ratio of staged sputtering and reactive gases, the color stability of the black film layer is improved. However, this control mode based on static parameters or preset step size is difficult to cope with the dynamic interference caused by the topological drift of the magnetic field throughout the life cycle of the target material. When facing magnetic targets such as high-purity cobalt, the nonlinear shift of the plasma ignition phase caused by the loss of the target surface leads to transient discharge energy overshoot. As the sputtering process continues, the target surface raceway pits caused by the loss of the target material cause the magnetic field strength of the target surface to evolve non-uniformly. This magnetic field topological distortion causes the plasma to generate ignition delay fluctuations at the moment of pulse activation, resulting in a severe energy overshoot phenomenon at the leading edge of the pulse waveform. This nonlinear energy characteristic caused by the ignition delay causes the kinetic energy distribution of rare metal atoms to broaden and deviate from the preset range. This not only causes abnormal accumulation of growth stress inside the film layer, but also aggravates the instantaneous impact damage of the particle flow on the surface of the substrate.

[0004] Therefore, the technical problem to be solved by this invention is how to achieve dynamic matching between the sputtered atomic kinetic energy distribution and the thermal relaxation time of the plastic substrate, compensate for the nonlinear influence of the target magnetic field evolution on the particle ignition process, and regulate the film growth stress to improve the interface anchoring performance. Summary of the Invention

[0005] This invention provides a rare metal reinforcement and protection process for the surface of plastic substrates for smart terminals, comprising the following steps: Step S1: Place the plastic substrate in the substrate position within the magnetron sputtering chamber, and install the high-purity cobalt target or nickel-platinum alloy target in the sputtering source position; Step S2: Monitor the pulse leading edge discharge waveform at the output end during each discharge pulse cycle of the sputtering power supply, identify the plasma ignition delay deviation caused by the evolution of the surface etching morphology of the high-purity cobalt target or nickel-platinum alloy target, and adjust the rising edge voltage slope of the pulse voltage start segment in reverse according to the plasma ignition delay deviation to compensate for the transient discharge energy overshoot caused by the drift of the target surface magnetic field topology as the target material is consumed, so that the kinetic energy distribution of sputtered particles reaching the surface of the plastic substrate is maintained within the preset energy bandwidth. Step S3: Obtain the glass transition temperature of the plastic substrate and monitor the instantaneous process temperature on the surface of the plastic substrate. Adjust the duty cycle of the sputtering pulse according to the real-time difference between the glass transition temperature and the instantaneous process temperature to limit the peak value of the instantaneous energy flux density of the metal atom flow to the surface of the plastic substrate within the preset discrete deposition energy band range, so as to ensure that the thermal shock energy generated by the instantaneous energy flux density is lower than the threshold of the cooperative motion of the macromolecular chain segments of the plastic substrate. Step S4: By controlling the off time interval of the sputtering pulse, the residual heat energy carried by the sputtering particles is used to drive metal atoms to diffuse non-impactively in the micropores on the surface of the plastic substrate. By setting the matching parameters of the deposition rate and the heat release cycle, a physical interlocking anchoring structure with root growth characteristics is formed in the interface layer of the plastic substrate.

[0006] Preferably, the rising edge voltage slope of the pulse voltage in step S2 includes: adjusting the pre-ionization current amplitude according to the time constant change of the sputtering power supply output voltage from the no-load peak to the discharge sustaining voltage drop, and inducing the generation of a pre-ionization glow region before the formal sputtering pulse is turned on, so as to lock the plasma ignition phase.

[0007] Preferably, in step S3, the upper limit of the discrete deposition bandgap range is determined by the glass transition temperature of the plastic substrate, and the substrate temperature rise rate caused by the instantaneous energy flux density is lower than the thermal relaxation rate of the plastic substrate molecular chains.

[0008] Preferably, in step S4, a bias pulse synchronized with the phase of the sputtering power supply is applied to the substrate site, so that the rare metal ions in the initial stage of sputtering obtain directional acceleration kinetic energy within a specific phase range of the pulse waveform, inducing metal atoms to penetrate the gaps between the surface molecular chains of the plastic substrate and form embedded anchoring points with a depth of 20nm to 50nm.

[0009] Preferably, step S3 includes feedback adjustment of the duty cycle of the sputtering pulse according to a formula: ,in, The target duty cycle after feedback adjustment. The preset process base duty cycle, The glass transition temperature of the plastic substrate. The instantaneous process temperature of the monitored plastic substrate surface.

[0010] Preferably, in step S2, the wavefront of the pulse voltage is shaped by detecting the impedance fluctuation frequency of the plasma discharge circuit in order to offset the target surface leakage magnetic field strength caused by the increased depth of the etching pits of the high-purity cobalt target or nickel-platinum alloy target, thereby reducing the impact on particle energy broadening.

[0011] Preferably, in step S1, the base vacuum level of the magnetron sputtering chamber is within the range of... Pa to Pa, with a working pressure of 0.1 Pa to 0.8 Pa, and sputtering gases of argon and krypton.

[0012] Preferably, the amplitude of the bias pulse is 50V to 200V, and the start time of the bias pulse has a timing lag of 10μs to 30μs relative to the start edge of the sputtering power supply pulse.

[0013] Preferably, the physical interlocking anchoring structure formed in step S4 is an interlocking layer formed by high-energy particle injection and thermal diffusion coupling, which is used to alleviate the interfacial shear stress caused by the mismatch of elastic modulus between the rare metal reinforcement layer and the plastic substrate.

[0014] Preferably, the process maintains the consistency of particle kinetic energy distribution during the consumption of high-purity cobalt target or nickel-platinum alloy target, and through the cyclic deposition of steps S3 and S4, a rare metal reinforcement layer with a thickness of 100nm to 500nm is grown on the surface of the plastic substrate.

[0015] Compared with existing technologies, the rare metal reinforcement and protection process for the surface of the plastic substrate of the smart terminal of this invention has the following advantages: 1. In rare metal reinforcement protection, by establishing a nonlinear correspondence between the deposition duty cycle and the glass transition temperature of the substrate, the discrete energy flux deposition procedure implemented in this invention ensures that the instantaneous energy flux of metal atoms reaching the substrate surface is always lower than the cooperative motion threshold of macromolecular chain segments. It effectively utilizes the residual heat energy during the pulse shutdown period to guide the metal atoms to diffuse and arrange in the micropores of the plastic surface layer, thereby achieving low-temperature dense growth of the metal reinforcement layer on the substrate surface without inducing thermal deformation and molecular chain rearrangement of the plastic substrate.

[0016] 2. A phase-locked synchronous negative bias pulse is applied to the substrate, which enables the rare metal ions in the initial stage of sputtering to obtain directional kinetic energy pointing to the deep layer of the substrate within a specific phase window. This induces metal atoms to penetrate the surface layer of the plastic molecular chain and form deep anchoring points. This root growth structure formed by electric field relay realizes physical interlocking between the reinforcement layer and the non-metallic substrate, improves the interface stress concentration phenomenon caused by the mismatch between the metal and plastic moduli, and enhances the adhesion stability of the protective layer under dynamic bending conditions.

[0017] 3. The sputtering power supply is used to perform wavefront shaping operation based on adaptive compensation of ignition delay. By identifying plasma impedance drift caused by target material loss and dynamically adjusting the pulse initiation edge slope, the broadening effect of target surface magnetic field topological distortion on particle energy spectrum is compensated. This ensures that the atomic kinetic energy reaching the substrate surface is always maintained within the preset narrow band distribution range, thereby maintaining the uniformity of film quality throughout the entire life cycle of the target material and avoiding loose film structure or local thermal damage caused by process drift. Attached Figure Description

[0018] Figure 1 This is a flowchart of the rare metal enhanced protection process based on wavefront reconstruction and thermal adaptation of the present invention. Figure 2 This is a comparison chart of the kinetic energy distribution and energy spectrum characteristics of sputtered particles in the experimental group and the control group of this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0020] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0022] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0023] This invention discloses a rare metal reinforcement and protection process for the surface of a plastic substrate for smart terminals. Using magnetron sputtering equipment under a preset vacuum environment, the ignition delay of the sputtering pulse on a high-purity cobalt target or nickel-platinum alloy target is monitored and compensated to mitigate discharge energy overshoot caused by topological drift of the target surface magnetic field. The pulse duty cycle is dynamically adjusted according to the glass transition temperature of the plastic substrate, combined with phase-locked ion-assisted control, to prepare a rare metal reinforcement layer on the surface of the plastic substrate. Before performing the reinforcement and protection process, the plastic substrate is placed in the substrate position within the magnetron sputtering chamber, and the high-purity cobalt target or nickel-platinum alloy target is installed at the sputtering source position. Since the surface of the plastic substrate adsorbs gas molecules or moisture, the base vacuum of the magnetron sputtering chamber is evacuated to 1×10⁻⁶ to remove the adsorbed layer. -5 Pa to 5×10 -4 Argon or krypton gas with a flow rate of 50 sccm to 150 sccm is introduced into the chamber to maintain the working pressure at 0.1 Pa to 0.8 Pa. Plasma glow is generated on the substrate using an RF power supply or a DC bias power supply to perform ion cleaning on the surface of the plastic substrate, providing a physical surface for subsequent chemical anchoring of atoms.

[0024] During the rare metal reinforcement layer deposition stage, to address the target surface magnetic field topology drift problem caused by target material consumption, the system executes an adaptive compensation procedure for ignition delay. Within each discharge pulse cycle of the sputtering power supply, the sensor monitors the discharge waveform at the pulse leading edge of the output terminal, acquiring the time constant change of the sputtering power supply output voltage from the no-load peak to the discharge sustaining voltage drop. The controller's A / D sampling module acquires the output voltage at a frequency of 50MHz and establishes a circular moving average buffer with a length of 10 sampling points to filter out high-frequency electromagnetic noise. The algorithm calculates the derivative of the average voltage within the buffer every 20ns. When the voltage drop slope exceeds 500V / µs and the drop depth reaches 20% of the no-load peak voltage, the logic circuit locks this moment as the plasma ignition start point. By comparing it with the preset reference ignition time, the plasma ignition delay deviation value is calculated. This is used to identify the plasma ignition delay deviation value caused by the surface etching morphology evolution of the high-purity cobalt target or nickel-platinum alloy target, so that the kinetic energy distribution of sputtered particles reaching the plastic substrate surface is maintained within the preset energy bandwidth. The controller adjusts the rising edge voltage slope of the pulse voltage start segment according to the identified plasma ignition delay deviation value Δτ. When an increase in Δτ is detected, the synchronous boost is applied. By inducing a pre-ionization glow region with a duration of 1.5 μs to 5.0 μs before the formal sputtering pulse is turned on, and setting its voltage amplitude to 75% to 85% of the sputtering threshold voltage of a high-purity cobalt target or a nickel-platinum alloy target, the ignition phase of the plasma is locked. Taking a high-purity cobalt target as an example, when the ignition delay increases from the initial 2 μs to 2.5 μs, the controller increases the rising edge voltage slope from 500 V / μs to 650 V / μs, and with a 3 μs pre-ionization step, the full width at half maximum (FWHM) of the particle energy spectrum injected into the substrate is maintained within 8 eV cycles.

[0025] To address the mismatch between deposition energy injection and the thermodynamic tolerance boundary of the plastic substrate, a duty cycle adjustment procedure based on the substrate's thermal relaxation characteristics was implemented to obtain the glass transition temperature of the plastic substrate. The instantaneous process temperature on the surface of the plastic substrate is monitored using an infrared sensor. The system adjusts the duty cycle of the sputtering pulse based on a formula: ,in, The target duty cycle after feedback adjustment. The preset process base duty cycle, The glass transition temperature of the plastic substrate. To monitor the instantaneous process temperature on the surface of the plastic substrate, the glass transition temperature is selected in the specific implementation of this technical solution. For polycarbonate substrates at 150℃, the preset process basic duty cycle is... It is 10% when the instantaneous process temperature When the temperature rises to 60°C, the target duty cycle The automatic adjustment is set to 6%, and the duty cycle is adjusted to ensure that the thermal shock energy generated by the instantaneous energy flux density is lower than the threshold of the coordinated motion of the macromolecular chain segments in the plastic substrate, thus ensuring that the instantaneous temperature rise on the substrate surface is below [the threshold value]. This maintains the energy density of the metal atom flow reaching the substrate surface within the discrete deposition energy band range.

[0026] Procedure for determining the threshold of cooperative motion of macromolecular chain segments in plastic substrates: Determination of the glass transition temperature of plastic substrates using differential scanning calorimetry. With a fixed magnetron power density, the pulse duty cycle was progressively increased in 5% increments to deposit the sample. The intrinsic stress variation curve of the film layer under different duty cycles was monitored using an in-situ thin film stress meter. When the intrinsic stress showed a nonlinear decreasing inflection point with the increase of the duty cycle, the energy input value per unit time corresponding to this point was determined as the threshold value of the cooperative motion of the macromolecular chain segments of the plastic substrate.

[0027] To address the issue of interfacial thermal stress accumulation caused by the mismatch between the settling window duration and the thermal conductivity of the substrate during the preparation of rare metal reinforcement layers, this invention employs a turn-off time calibration procedure based on the substrate's thermal conductivity coefficient. This process identifies the thermal conductivity coefficient κ of the plastic substrate and determines the characteristic heat transfer length L in the thickness direction. Sensors are used to monitor the surface temperature rise after a single pulse injection, and the instantaneous process temperature on the substrate surface is calculated. The heat dissipation phase duration required for the pulse to fall below the threshold of cooperative motion of macromolecular chain segments is used to determine the turn-off time of the magnetron sputtering pulse. The duration of the static window is determined by establishing a mapping relationship using Formula 3: ,in, The pulse off-time is defined in milliseconds (ms); γ is the heat dissipation shape factor, ranging from 0.8 to 1.2; ρ is the density of the plastic substrate, in milliseconds (ms). ; κ represents the specific heat capacity of the plastic substrate; L represents the characteristic heat transfer length of the substrate; κ represents the thermal conductivity of the plastic substrate, assuming a thermal conductivity κ of 0.19 W / (m⋅K) and a density of 0.19 W / (m⋅K). for In a specific example of the polycarbonate substrate, the system calibrates the turn-off time based on the aforementioned physicochemical parameters. With a duration of 15ms, this procedure establishes a coupled logical relationship between heat conduction rate and heat dissipation method to ensure that the heat load remains within a dynamic heat dissipation balance window during continuous deposition cycles. In process control, the magnetron sputtering power supply adopts a fixed frequency mode, and the target duty cycle is adjusted by dynamically adjusting the pulse width. Determine the pulse turn-off time. As the minimum heat dissipation phase reference for the thermal safety of the substrate, when the target duty cycle obtained by the formula... The off-time determined by multiplying the preset pulse period by less than The control system prioritizes execution based on Based on the heat dissipation interval, extending the pulse cycle limits the instantaneous temperature rise on the substrate surface to a safe range.

[0028] During film growth, to address the issue of insufficient mechanical interlocking depth between rare metal atoms and the non-metallic substrate, the system executes a phase-locked interface control procedure. Within the deposition window of the magnetron sputtering power supply, by controlling the off-time interval of the sputtering pulse, the residual heat energy carried by the sputtered particles drives the metal atoms to diffuse non-impactively within the micropores on the surface of the plastic substrate. Simultaneously, a bias pulse synchronized with the sputtering power supply is applied to the substrate. The amplitude of this bias pulse is 50V to 200V. The lag time of the bias pulse's on-time relative to the sputtering power supply pulse start edge is calculated by dividing the physical linear distance from the target to the substrate by the rare metal atoms. The equivalent drift velocity of metal ions (taken as 4.5 km / s) was obtained. Taking a target-substrate distance of 100 mm as an example, the calculated time for ions to reach the substrate surface was approximately 22.2 μs. Based on this, the system searched for the peak waveform of the ion current within the range of 20 to 25 μs and aligned the rising edge of the bias pulse with this peak moment to ensure that the accelerating electric field accurately acts on the high-flux metal ion cluster, thereby inducing metal atoms to penetrate the gaps between the surface molecular chains of the plastic substrate. The on-time of this phase-locked electric field has a timing lag of 10 μs to 30 μs relative to the starting edge of the sputtering power pulse. This phase-locked electric field relay enables the rare metal atoms to penetrate the surface molecular chain gaps of the plastic substrate in the initial stage of sputtering. Metal ions gain directional acceleration kinetic energy within a specific phase range, inducing metal atoms to penetrate the surface molecular chain gaps of the plastic substrate, forming embedded anchoring points with a depth of 20 nm to 50 nm. To maintain the logical continuity of the plasma cloud during pulse turn-off, a background arc current is provided to the magnetron sputtering equipment within the pulse resting window. The voltage generated is lower than the sputtering threshold voltage of the target material. During this period, residual particles adsorbed on the surface of the plastic substrate are removed by applying a sweeping positive bias pulse using an electric field. Through the repeated cycles of the deposition window and the resting window, a layer with a thickness of 100 nm to 500 nm is grown on the surface of the plastic substrate. The rare metal reinforcement layer, with root growth characteristics, can alleviate the interfacial stress concentration caused by the mismatch between the metal and plastic moduli, and improve the adhesion stability of the protective layer under dynamic bending conditions. The physical interlocking anchoring structure with root growth characteristics is verified: the cross-section of the interface layer is sampled using a focused ion beam, and the penetration morphology of metal atoms in the surface layer of the plastic substrate is observed using a high-resolution transmission electron microscope; metal atoms are discontinuously dispersed in the depth range of 20nm to 50nm below the surface of the plastic substrate, and there is no physical interface between the metal reinforcement layer and the plastic substrate, which determines that the embedded anchoring point and physical interlocking structure are formed.

[0029] Example 1: In the specific production process of the high-conductivity electromagnetic shielding layer for smart terminals, a layer with a thickness of 0.5mm and a glass transition temperature of... A polycarbonate substrate at 145℃ was placed on the substrate of a magnetron sputtering apparatus. The sputtering source was a high-purity cobalt target with a cumulative execution time of 150 hours and an 8mm deep raceway crater on its surface. Due to the local thinning of the target material, the topological shift of the target surface magnetic field caused by the target material thinning resulted in an increase in the plasma ignition delay deviation Δτ of the discharge circuit to 3.2μs. If the predetermined driving parameters were maintained, the nonlinear hysteresis of plasma ignition would induce a transient energy overshoot at the pulse leading edge, causing the kinetic energy of rare metal particles to broaden and exceed the thermal damage threshold of the polycarbonate substrate. To eliminate the discharge energy overshoot, the system implemented adaptive ignition delay compensation by monitoring the dropout inflection point of the sputtering power supply output voltage and adjusting the voltage slope of the rising edge of the pulse voltage initiation segment. The initial 400V / μs was adjusted to 580V / μs. Based on this, a pre-ionized glow region with a duration of 2.5μs and an amplitude of 80% of the sputtering threshold voltage was induced before the main sputtering pulse was activated. This wavefront shaping operation provided a pre-ionized plasma channel for the subsequent main discharge pulse, making the discharge energy release curve more gradual and locking the plasma ignition phase. As a result, the energy spectrum bandwidth of the sputtered particles injected into the polycarbonate plastic substrate surface was limited to within 8eV, avoiding microscopic thermal damage to the substrate caused by uncontrolled energy distribution. As the deposition process continued, the infrared sensor monitored the instantaneous process temperature on the polycarbonate plastic substrate surface. The temperature rose from room temperature to 72°C.

[0030] To address the technical limitations of heat accumulation and substrate thermal sensitivity during high-energy atomic deposition, the system adjusts the target duty cycle of the sputtering pulse in real time based on a formula. , ,in, The target duty cycle after feedback adjustment. The preset process base duty cycle, The glass transition temperature of the plastic substrate. To monitor the instantaneous process temperature on the surface of the plastic substrate, the process base duty cycle is... The initial energy flux density was automatically adjusted from 12% to 6.04%. This adjustment process dynamically reduced the energy flux density on the substrate surface per unit time by shortening the energy injection time and extending the thermal relaxation window. Even under continuous high-intensity sputtering conditions, the instantaneous temperature rise on the surface of the polycarbonate plastic substrate remained below its glass transition temperature. This allows the nucleation environment of sputtered particles to be controlled below the threshold of cooperative motion of macromolecular chain segments. During the preparation of a 120nm thick high-purity cobalt reinforced layer, the system initiates phase-locked interface modulation. A synchronous bias pulse with an amplitude of 120V and a lag of 20μs relative to the start edge of the sputtering power pulse is applied to the substrate. The peak ion current in the middle of the sputtering pulse is used to provide directional kinetic energy to the ions in the early stage of nucleation through electric field relay. The rare metal particle flow penetrates the gaps between the molecular chains on the surface of the plastic substrate and generates physical interlocking points with a depth of 35nm. During the pulse turn-off, the background arc current maintains the ionization of the plasma cloud. Combined with the scanning positive bias pulse, residual particles adsorbed at the interface are removed. Finally, a dense high-purity cobalt reinforced layer with root anchoring characteristics is formed on the surface of the polycarbonate plastic substrate. Its interface bonding strength meets the adhesion stability under dynamic bending conditions.

[0031] Example 2: An experimental environment was established using a vacuum magnetron sputtering deposition system, which has advantages over... The vacuum chamber's ultimate background pressure was controlled, the substrate temperature control resolution reached 0.1℃, and the bias power supply pulse response frequency was set to 200kHz. Both the experimental and control groups used high-purity cobalt targets with a purity of 99.99%. The plastic substrate was a 1.0mm thick polymethyl methacrylate (PMMA) sheet. The glass transition temperature of this PMMA sheet was... The temperature was 105℃, and data acquisition was based on a physical experimental platform; the voltage slope of the pulse rising edge at the beginning of the sputtering power supply was considered. Perform calibration procedures, rising edge voltage slope The value of is affected by the fluctuation of plasma ignition impedance. The technical trade-off is that increasing the slope can shorten the ignition delay, but an excessively high slope will cause a discharge current spike at the pulse leading edge. Based on the relationship between the ignition delay deviation Δτ and the evolution of plasma density, when the target material consumption is detected to cause an increase in Δτ, the plasma ignition phase is locked within a preset range, and the rising edge voltage slope is... The rise time voltage slope increases synchronously with the increase of the ignition delay deviation value Δτ. Under specific operating conditions, when the ignition delay deviation value Δτ of the high-purity cobalt target shifts from 2μs to 4μs, the rise time voltage slope increases. The compensation was increased from the initial 450V / μs to 620V / μs, where, Δτ is the rise edge voltage slope, in V / μs; Δτ is the ignition delay deviation, in μs. The experimental group adopted the aforementioned complete process. Control group 1 removed the ignition delay adaptive compensation procedure and fixed the pulse start edge slope at 450V / μs. Control group 2 removed the phase-locked bias pulse. Control group 3 set the sputtering pulse duty cycle to 6%, which is higher than the target duty cycle calculated according to the formula. That is, 4.7%, which is to simulate an industrial electromagnetic environment by superimposing radio frequency noise with a signal-to-noise ratio of 15dB on the bias circuit.

[0032] Experimental data shows that, in an environment with noise disturbance, the experimental group stabilized the full width at half maximum (FWHM) of the metal ion kinetic spectrum at 7.5 eV through an ignition delay compensation mechanism. Control group 1, lacking energy wavefront reconstruction, experienced a broadened ion kinetic spectrum to 22 eV. Uncontrolled impacts of high-energy particles caused microcracks with depths ranging from 5 μm to 15 μm to appear on the surface of the polymethyl methacrylate (PMMA) sheet. In the interfacial bonding performance evaluation, the experimental group achieved a physical interlocking depth of 42 nm for metal atoms on the substrate surface through phase-locked electric field relay, achieving an adhesion grade of 0. The test standard was based on GB / T9286-1998. Control group 2, lacking the directional kinetic energy generated by the phase-synchronized electric field, had an average interlocking depth of only 4 nm, resulting in an adhesion grade decrease to 3. Verification of the gradient effect of duty cycle adjustment showed that when the real-time process temperature of the PMMA sheet... When the temperature rises from room temperature to 55°C, the target duty cycle Dynamic downsampling was performed. Within this working window, the substrate surface remained flat. In control group 3, due to excessive duty cycle, the energy flux density on the substrate surface exceeded the threshold of cooperative motion of macromolecular chain segments, and thermal shrinkage deformation was observed on the substrate surface, with a shrinkage rate of 2.3%. This proves that the parameter range determined by the formula is the inflection point that balances the deposition rate and the thermal safety of the substrate. The formula is shown below: ,in, The target duty cycle after feedback adjustment; The preset process base duty cycle; The glass transition temperature of the plastic substrate. The instantaneous process temperature on the surface of the plastic substrate was monitored, and the above comparative data were used to demonstrate the engineering reliability of this process in dealing with target etching and protecting heat-sensitive substrates.

[0033] Example 3: This example combines Figures 1 to 2 This describes a rare metal reinforcement and protection process for the surface of a plastic substrate used in smart terminals, such as... Figure 1 As shown, the rare metal reinforcement and protection process for the surface of the plastic substrate of the smart terminal begins at the process start point, entering the substrate and target assembly stage in step S1. This step specifically involves placing the plastic substrate on the substrate site and installing a high-purity cobalt target or nickel-platinum alloy target. The process then proceeds to step S2, discharge energy wavefront reconstruction. During this process, the system monitors the discharge waveform at the pulse leading edge and identifies the plasma ignition delay deviation value. Based on the obtained data, the rising edge voltage slope is adjusted in reverse according to the ignition delay deviation value. Next, the process proceeds to step S3, deposition energy flux thermal adaptation, by obtaining the glass transition temperature. And monitor instantaneous process temperature Thus achieving based on and The control logic for adjusting the sputtering pulse duty cycle by adjusting the differential ratio is then executed. Step S4, interface physical interlocking and anchoring, is then performed. The non-impact diffusion is driven by controlling the turn-off time interval, and the final output is the process result of forming a rare metal reinforcement layer with root growth characteristics.

[0034] like Figure 2 As shown, the chart constructs a two-dimensional coordinate system with particle kinetic energy as the horizontal axis and relative intensity as the vertical axis. The physical quantity on the horizontal axis is labeled as eV, and the physical quantity on the vertical axis is labeled as %. The chart contains two sets of comparative data curves. The solid line with circular nodes represents the kinetic energy distribution of the experimental group. This curve shows a peak concentration characteristic in a specific low-energy range. The dashed line with square nodes represents the kinetic energy distribution of the control group. This curve shows a wider energy distribution range and a shift towards the high-energy region.

[0035] Example 4: In the high-load continuous production of electromagnetic shielding layers for smart terminals, the high-purity cobalt target in the magnetron sputtering equipment is in the middle to late stage of its life cycle. The magnetic field on the target surface is non-uniformly distorted due to the physical displacement of the magnets and the wear of the pole shoes. In addition, the frequency converter in the production site generates conducted electromagnetic noise with a signal-to-noise ratio of 12dB, causing glitches in the voltage waveform at the output of the sputtering power supply. The system executes a waveform characteristic derivative analysis program to determine the plasma ignition phase, and the controller collects the output voltage sequence of the sputtering pulse in real time at a sampling frequency of 50MHz. It calculates the instantaneous voltage change rate δ between adjacent sampling points. When the instantaneous voltage change rate δ exceeds the preset negative voltage drop threshold for three consecutive sampling periods, the output voltage sequence is... The first sampling point was determined as the voltage drop inflection point, which corresponds to the plasma ignition start point. By calculating the time difference between this ignition start point and the moment the power drive command was issued, the plasma ignition delay deviation value Δτ was determined. The system calculates the target rising edge voltage slope based on the calibrated linear compensation operator. The calculation formula is as follows: ,in, The target rising edge voltage slope after feedback adjustment, in V / μs; The reference slope set for the initial process is taken as 420V / μs in this specific example; α is the voltage slope compensation factor, determined by measuring the rate of change of discharge impedance of the vacuum chamber under no-load conditions, and its value is... Δτ is the determined plasma ignition delay deviation value, in μs.

[0036] For the condition where the plasma ignition delay deviation Δτ increases to 3.5μs, the system adjusts the target rising edge voltage slope based on the aforementioned linear mapping logic. The compensation was adjusted to 717.5 V / μs, and the voltage amplitude of the pre-ionization glow discharge region was adjusted to 82% of the high-purity cobalt target sputtering threshold voltage, so that the pre-ionized electron density in the chamber was maintained at... The energy spectrum distribution of rare metal ions injected into the polycarbonate substrate surface exhibits a narrow banding characteristic, with its energy peak stabilizing at 12 eV. The instantaneous energy flux density on the polycarbonate substrate surface remains below the threshold of cooperative motion of macromolecular chain segments. The high-purity cobalt reinforcement layer generates a dense fibrous crystal structure on the polycarbonate substrate surface and forms a physical interlocking structure with a depth of 30 nm to 45 nm at the interface layer. As a result, the bonding strength between the reinforcement layer and the polycarbonate substrate exhibits high batch uniformity and does not cause uncontrolled jumps in process parameters due to target magnetic field drift or environmental electromagnetic interference.

[0037] Example 5: In a specific nickel-platinum alloy reinforced layer production deployment scenario, to accommodate the differences in secondary electron emission coefficients of different batches of nickel-platinum alloy targets, the system executes a pre-deployment calibration procedure. Before starting deposition, the vacuum chamber pressure is stabilized at 0.5 Pa, the output bias voltage of the magnetron sputtering power supply is increased in 5V increments, and the current density change of the discharge circuit is recorded using a current monitoring module. When the current density first reaches 1×10⁻⁶, the system... -3 A / cm 2 At that time, the voltage value corresponding to that moment is determined as the sputtering threshold voltage of the nickel-platinum alloy target. The system obtains the unit area heat capacity constant of the polyimide substrate through offline testing, and based on the discrete relationship between the heat capacity constant and the thermal conductivity rate, determines the process basic duty cycle. The initial setting is 8.5%, and the final setting is based on the determined sputtering threshold voltage. Calculate the voltage amplitude range of the pre-ionization glow region to smooth out the discharge overshoot caused by batch impedance fluctuations by setting the voltage envelope.

[0038] When applying enhanced protection technology to the surface of polyphenylene sulfide (PPS) substrates, the system executes a deployment parameter fine-tuning procedure. Using an infrared thermal imaging unit, the equilibrium temperature curve of the substrate surface is acquired at pulse duty cycle gradients ranging from 5% to 15%. The derivative of the equilibrium temperature with energy injection duration is calculated to identify the critical injection power value that causes a nonlinear temperature rise on the substrate surface, and the basic duty cycle of the process is calibrated. Combined with the glass transition temperature of the substrate and the instantaneous process temperature of the substrate surface monitored. The system startup time is 60 seconds for simulating deposition action to verify the feedback gain, thus enabling the measured process temperature under continuous pulse impact. The deviation from the predicted temperature rise trajectory is kept within 2.0℃, so that the combination of substrates and target materials with different physical properties has certain control parameters, eliminating the difference in deposition quality caused by the initial reference fluctuation in the industrial production environment.

[0039] Example 6: In an industrial production scenario where a reinforcing layer is prepared on the surface of a liquid crystal polymer plastic substrate with a complex three-dimensional structure using a high-purity cobalt target, in order to maintain the continuity of the plasma cloud during pulse turn-off and to mitigate the instability during the transition from arc discharge to glow discharge, the system executes a background arc current. The calibration procedure involves maintaining the sputtering power supply in DC mode and gradually reducing the output current under a vacuum chamber operating pressure of 0.5 Pa. The critical point where the voltage waveform exhibits high-frequency oscillations and the glow center contracts is monitored, and the corresponding current intensity is determined as the instability sustaining current. The background arc current is determined according to the formula. Execution value: ,in, Background arc current, in amperes (A); The measured instability sustaining current is expressed in A; β is the ionization sustaining coefficient, ranging from 1.2 to 1.5, determined by the ratio of the emission spectral intensity at 450 nm wavelength within the vacuum chamber to the peak value of the main pulse; in the specific deployment of this technical solution, the measured... With a current of 0.15A and β set to 1.35, the background arc current was calculated. The execution value is 0.20A, which ensures that the cathode target surface maintains a self-sustaining discharge state at the moment the main pulse is turned off, eliminating the re-ignition impact caused by the complete dissipation of charge.

[0040] When the system faces the task of removing adsorbed particles from deep pores in liquid crystal polymer plastic substrates, it executes an online calibration program for the scanning positive bias pulse parameters. Within the pulse settling window, a progressively increasing positive bias voltage is applied. A Langmuir probe is used to measure the rate of decrease in residual ion flux on the substrate surface, identifying the peak positive voltage required to achieve dynamic equilibrium of the surface potential. ,Will By setting the voltage within the range of 30V to 80V and making the pulse width of the positive bias pulse account for 15% to 25% of the main pulse off time, the particles deposited during the resting period are driven to detach from the substrate surface by directional electrostatic repulsion. The test results showed that the density of the reinforcement layer in the deep holes of the liquid crystal polymer plastic substrate was increased by 12.5%, and the surface roughness Ra of the reinforcement layer was reduced from 0.45μm to 0.22μm, so that the reinforcement layer maintains a stable interfacial bonding state under high temperature and high humidity environment.

[0041] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A rare metal reinforcement and protection process for the surface of a plastic substrate for smart terminals, characterized in that, Includes the following steps: Step S1: Place the plastic substrate in the substrate position within the magnetron sputtering chamber, and install the high-purity cobalt target or nickel-platinum alloy target in the sputtering source position; Step S2: Monitor the pulse leading edge discharge waveform at the output end during each discharge pulse cycle of the sputtering power supply, identify the plasma ignition delay deviation caused by the evolution of the surface etching morphology of the high-purity cobalt target or nickel-platinum alloy target, and adjust the rising edge voltage slope of the pulse voltage start segment in reverse according to the plasma ignition delay deviation to compensate for the transient discharge energy overshoot caused by the drift of the target surface magnetic field topology as the target material is consumed, so that the kinetic energy distribution of sputtered particles reaching the surface of the plastic substrate is maintained within the preset energy bandwidth. Step S3: Obtain the glass transition temperature of the plastic substrate and monitor the instantaneous process temperature on the surface of the plastic substrate. Adjust the duty cycle of the sputtering pulse according to the real-time difference ratio between the glass transition temperature and the instantaneous process temperature to limit the peak instantaneous energy flux density of the metal atom flow to the surface of the plastic substrate within the preset discrete deposition energy band range. Step S4: By controlling the off time interval of the sputtering pulse, the residual heat energy carried by the sputtering particles is used to drive metal atoms to diffuse non-impactively in the micropores on the surface of the plastic substrate. By setting the matching parameters of the deposition rate and the heat release cycle, a physical interlocking anchoring structure with root growth characteristics is formed in the interface layer of the plastic substrate.

2. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, The adjustment of the rising edge voltage slope of the pulse voltage in step S2 includes: adjusting the pre-ionization current amplitude according to the time constant change of the sputtering power supply output voltage from the no-load peak to the discharge sustaining voltage drop, and inducing the generation of a pre-ionization glow region before the formal sputtering pulse is turned on, so as to lock the plasma ignition phase.

3. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, In step S3, the upper limit of the discrete deposition band range is determined by the glass transition temperature of the plastic substrate, and the substrate temperature rise rate caused by the instantaneous energy flux density is lower than the thermal relaxation rate of the plastic substrate molecular chains.

4. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, In step S4, a bias pulse synchronized with the sputtering power supply is applied to the substrate site, so that the rare metal ions in the initial stage of sputtering obtain directional acceleration kinetic energy within a specific phase range of the pulse waveform, inducing metal atoms to penetrate the gaps between the surface molecular chains of the plastic substrate and form embedded anchoring points with a depth of 20nm to 50nm.

5. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, Step S3 includes feedback adjustment of the duty cycle of the sputtering pulse according to the formula: ,in, The target duty cycle after feedback adjustment. The preset process base duty cycle, The glass transition temperature of the plastic substrate. This refers to the instantaneous process temperature of the monitored plastic substrate surface.

6. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, In step S2, the wavefront of the pulse voltage is shaped by detecting the impedance fluctuation frequency of the plasma discharge circuit in order to offset the target surface leakage magnetic field strength caused by the increased depth of the etching pits of the high-purity cobalt target or nickel-platinum alloy target, thereby reducing the impact on particle energy broadening.

7. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, In step S1, the background vacuum level of the magnetron sputtering chamber is within the range of: Pa to Pa, with a working pressure of 0.1 Pa to 0.8 Pa, and sputtering gases of argon and krypton.

8. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 4, characterized in that, The bias pulse amplitude ranges from 50V to 200V, and the start time of the bias pulse has a timing lag of 10μs to 30μs relative to the start edge of the sputtering power supply pulse.

9. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, The physical interlocking anchoring structure formed in step S4 is an interlocking layer formed by high-energy particle injection and thermal diffusion coupling, which is used to alleviate the interfacial shear stress caused by the mismatch of elastic modulus between the rare metal reinforcement layer and the plastic substrate.

10. The rare metal reinforcement and protection process for the surface of a smart terminal plastic substrate according to claim 1, characterized in that, The process maintains the consistency of particle kinetic energy distribution during the consumption of high-purity cobalt or nickel-platinum alloy targets. Through cyclic deposition in steps S3 and S4, a rare metal reinforcement layer with a thickness of 100 nm to 500 nm is grown on the surface of the plastic substrate.

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