A process for ion plating a thickening layer on the surface of a copper-tin layer

Abstract

The application relates to a process method for ion plating thickening of a copper-tin layer surface, and the process method comprises the following steps: monitoring real-time temperatures of different height positions of a vacuum chamber; when an upper limit target temperature determined according to each real-time temperature reaches a preset upper limit temperature of a temperature interval, a cooling medium gas is input into a gas distribution structure to cool the vacuum chamber; if a lower limit target temperature falls to a preset lower limit temperature of the temperature interval, an air exhaust system is restored to restore the vacuum degree of the vacuum chamber to a preset working vacuum degree; a deposition source is started, ion plating deposition is continuously carried out on the surface of the electroplated copper-tin layer to form a single deposition film layer; and the thickness of the total deposition film layer reaches a target thickness value, so that a corresponding ion plating layer is obtained. The cracking, bulging or surface degradation phenomenon of the copper-tin substrate due to high temperature failure is avoided, so that the binding firmness of the film layer and the use performance of the final product are significantly improved.

Description

Technical Field

[0001] This invention relates to the technical field of surface plating processes, and in particular to a process for ion plating a thickened copper-tin layer. Background Technology

[0002] Currently, in existing ion plating processes, the film layer applied to the copper-tin surface is typically thin, generally less than 1 micrometer, while the common product specifications for copper-tin layers on the market are usually limited to 0.3-0.7 micrometers. In contrast, ion plating layers on stainless steel surfaces often reach 2 micrometers or more. Existing technologies generally directly transfer plating methods used on stainless steel surfaces to copper-tin surfaces. However, due to the excellent high-temperature resistance of stainless steel substrates, the heat and temperature rise generated during ion plating do not adversely affect them, while the temperature resistance of copper-tin substrates is relatively low, generally only able to withstand temperatures below 120°C. To avoid damage to the copper-tin substrate from high temperatures, the industry often adopts the method of reducing the plating thickness to protect the copper-tin layer. However, when the temperature rise of the copper-tin substrate exceeds the tolerance range during ion plating, damage is very likely to occur, such as striped cracks on the film surface, local blistering of the copper-tin layer, or the degradation of the original mirror effect to a matte finish. These problems seriously limit the promotion and application of thicker ion plating processes for copper-tin surfaces. Summary of the Invention

[0003] To address the problems in existing processes where insufficient temperature resistance of the copper-tin layer leads to limited thickness of the ion-plated film, and causes cracking, blistering, and surface failure, this application provides a process for ion-plating a thicker layer on the surface of the copper-tin layer.

[0004] A process for ion plating to thicken a copper-tin layer surface, the process comprising:

[0005] S1. Place the copper-tin plating substrate workpiece in a vacuum chamber with a gas distribution structure, start the pumping system to pump the vacuum chamber to a preset working vacuum level, and adjust the temperature of the vacuum chamber to a reference temperature for ion plating deposition. Determine the corresponding temperature range based on the reference temperature.

[0006] S2. Based on the temperature acquisition devices arranged at the upper, middle and lower height positions of the vacuum chamber, the real-time temperature at different height positions of the vacuum chamber is monitored. When the upper limit target temperature determined according to each real-time temperature reaches the preset upper limit temperature of the temperature range, cooling medium gas is introduced into the gas distribution structure to cool the vacuum chamber, and the working state of the pumping system is adjusted to maintain the residence time of the cooling medium gas in the vacuum chamber and stop the ion plating deposition.

[0007] S3. Determine the lower limit target temperature. If the lower limit target temperature drops to the preset lower limit temperature of the temperature range, restore the pumping system to remove the residual cooling medium gas and restore the vacuum degree of the vacuum chamber to the preset working vacuum degree.

[0008] S4. When the temperature of the vacuum chamber is maintained in the temperature range for a preset threshold duration, the surface of the electroplated copper-tin layer substrate workpiece is cleaned using an ion source.

[0009] S5. After completing the surface cleaning process, start the deposition source and continue to perform ion plating deposition on the surface of the electroplated copper-tin layer to form a single deposition film.

[0010] S6. After a single deposition of the film is completed, repeat the single deposition cycle including steps S2 to S5 until the total thickness of the deposited film reaches the target thickness value, thereby obtaining the corresponding ion plating layer.

[0011] By adopting the above technical solution, the substrate workpiece is arranged in the vacuum chamber and the vacuum degree and temperature are controlled, so that the deposition process is always maintained within the set temperature range. This effectively avoids the problem of excessive film stress due to excessive temperature or insufficient adhesion due to excessive temperature, thus ensuring the deposition stability and consistency of the thickened copper-tin layer.

[0012] Preferably, the cooling medium gas includes nitrogen or helium, wherein the choice of nitrogen or helium is determined based on the residence time in the vacuum chamber.

[0013] By adopting the above technical solution, two different types of cooling medium gas, nitrogen and helium, are introduced and matched according to their retention characteristics, thereby optimizing the cooling efficiency and cooling uniformity, improving the flexibility of the temperature control process, and avoiding the uneven cooling phenomenon caused by a single gas.

[0014] Preferably, the calculation step for the residence time of the cooling medium gas in the vacuum chamber includes:

[0015] Obtain the effective volume V of the vacuum chamber;

[0016] Determine the inlet flow rate Q of the cooling medium gas and the gas type correction factor Kg;

[0017] Based on the effective volume V and the intake flow rate Q, the corresponding residence time t is calculated. The calculation steps for the residence time t are t = (V / Q) × Kg.

[0018] By adopting the above technical solution and establishing a calculation model for residence time, combined with vacuum chamber volume, air flow rate and gas characteristic factors, the residence time of the cooling medium in the vacuum chamber can be accurately assessed, thereby providing a predictable dynamic adjustment means for temperature control and improving the accuracy of cooling regulation.

[0019] Preferably, the step of selecting nitrogen or helium includes:

[0020] Determine the target cooling time, which is the time required to reduce the preset upper limit temperature to the preset lower limit temperature;

[0021] Determine whether the residence time is greater than the target cooling time;

[0022] If the value is greater than the specified value, then the cooling medium gas is determined to be nitrogen.

[0023] If the value is not greater than the specified value, then the cooling medium gas is determined to be helium.

[0024] By adopting the above technical solution, a logic for determining the target cooling time is introduced in the cooling gas selection process to ensure that the appropriate gas type is automatically matched under different cooling requirements. This enables the vacuum chamber to efficiently complete the process of cooling from the upper limit temperature to the lower limit temperature, achieving a balance between rapid response and energy consumption optimization.

[0025] Preferably, the step of determining the corresponding temperature range based on the reference temperature includes:

[0026] Calculate the predicted temperature rise at the upper, middle, and lower height positions of the vacuum chamber;

[0027] The upper limit temperature of each stratification position is calculated by adding the reference temperature and each of the predicted temperature increases;

[0028] The lower limit temperature of each layer is calculated by subtracting the preset temperature control bandwidth from the upper limit temperature of each layer.

[0029] The minimum value among the upper limit temperatures of each layer is determined as the preset upper limit temperature of the temperature range, and the maximum value among the lower limit temperatures of each layer is determined as the preset lower limit temperature of the temperature range.

[0030] By adopting the above technical solution, by predicting the temperature rise at each layer location, setting upper and lower temperature limits for each layer, and using the strictest upper limit and the most lenient lower limit as the overall temperature range, it is possible to effectively avoid film defects caused by local overheating or local undercooling, thereby improving the uniformity and reliability of the overall deposited film.

[0031] Preferably, the step of calculating the predicted temperature rise at the upper, middle, and lower height positions of the vacuum chamber includes:

[0032] Obtain the average heating rate vi at each height position in the previous single deposition cycle, i∈{upper layer, middle layer, lower layer};

[0033] Determine the required deposition time ti at each height position in the current single deposition cycle, where i∈{upper layer, middle layer, lower layer};

[0034] Based on the average heating rate vi and the deposition time ti, the corresponding predicted heating amount T0 is calculated. The formula for calculating the predicted heating amount T0 is T0 = vi × ti.

[0035] By adopting the above technical solution, and by combining the average heating rate of the previous deposition cycle with the current required deposition time, the temperature changes of each layer in the future can be predicted in advance, and the temperature control trend can be estimated in advance to avoid runaway phenomena caused by excessive temperature drift, thereby achieving more proactive process control.

[0036] Preferably, the step of determining the upper limit target temperature based on each of the real-time temperatures includes:

[0037] In each of the real-time temperatures, the maximum temperature value Tmax and the minimum temperature value Tmin are determined. The interlayer temperature difference Tlayer is calculated by subtracting the maximum temperature value Tmax from the minimum temperature value Tmin.

[0038] Calculate the rate of change v0 of the maximum temperature value Tmax within a fixed time window;

[0039] The corresponding upper limit target temperature is calculated based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer.

[0040] By adopting the above technical solution, and by simultaneously considering the maximum temperature, minimum temperature, and interlayer temperature difference, and combining the rate of temperature change over time, a dynamic upper limit target temperature is determined. This enables the control logic to reflect both the highest risk point and the overall temperature distribution balance, thereby improving the rationality of temperature-triggered cooling.

[0041] Preferably, in the step of calculating the corresponding upper limit target temperature based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer, the formula for calculating the upper limit target temperature Tgoal is: Tgoal = Tmax + a × v0 + b × Tlayer;

[0042] Wherein, 'a' is the preset predicted duration of time delay caused by the issuance of the instruction, and 'b' is the penalty coefficient set for the temperature difference between layers.

[0043] By adopting the above technical solution, introducing a time delay compensation factor and an interlayer temperature difference penalty coefficient when calculating the upper limit target temperature, the actual effect of the control action can be reflected more realistically, avoiding overshoot and instability caused by response lag or excessive temperature difference, thereby ensuring the timeliness and effectiveness of the cooling process.

[0044] Preferably, the thickness of the deposited film is 0.2 micrometers, and the thickness of the ion-plated layer is 2 micrometers.

[0045] By adopting the above technical solution, the thickness of the film layer in a single deposition is limited to 0.2 micrometers, and a coating with a total thickness of 2 micrometers is finally formed. This ensures that the thickened layer is stably deposited layer by layer in multiple deposition cycles, avoiding cracking and peeling problems caused by a single thick deposition, thereby obtaining a high-quality copper-tin layer with both density and adhesion.

[0046] In summary, this application includes at least one of the following beneficial technical effects:

[0047] This application deploys temperature acquisition devices at three heights (upper, middle, and lower) within the vacuum chamber to collect temperature data from different spatial levels in real time. Based on this data, an upper and lower target temperature are determined, forming a dynamically comparable temperature range. When the real-time monitored upper target temperature reaches the upper limit of the set temperature range, the system does not continue to force deposition but immediately introduces cooling medium gas through the gas distribution structure. At the same time, the pumping system is adjusted to ensure the residence time of the cooling medium in the vacuum chamber, thereby rapidly reducing the temperature and preventing the substrate from being damaged due to overheating. After the temperature drops to the preset lower limit, a stable working vacuum is maintained by restoring the pumping system. Combined with surface cleaning steps, the effects of adhesion or impurities caused by temperature control and cyclic deposition are eliminated. Finally, the deposition source is restarted within the controlled range for ion plating. This process path of alternating temperature control and deposition breaks through the bottleneck of traditional processes where the copper-tin substrate has insufficient temperature resistance and must limit the deposition thickness. It achieves the gradual accumulation of a thickened ion plating layer with controllable and uniform thickness without damaging the copper-tin substrate structure. While ensuring that the total thickness of the deposited layer meets the standards of similar processes for stainless steel, it avoids cracking, bulging, or surface degradation of the copper-tin substrate due to high-temperature failure, thereby significantly improving the bonding strength of the film and the performance of the final product. Attached Figure Description

[0048] Figure 1 This is a flowchart of a process for ion plating to thicken a copper-tin layer surface according to an embodiment of this application. Detailed Implementation

[0049] The present application will be further described in detail below with reference to the accompanying drawings.

[0050] In one embodiment, such as Figure 1 As shown, this application discloses a process for ion plating to thicken a copper-tin layer surface. The process includes:

[0051] S1. Place the copper-tin plating substrate workpiece in a vacuum chamber with a gas distribution structure, start the pumping system to pump the vacuum chamber to the preset working vacuum level, and adjust the temperature of the vacuum chamber to the reference temperature for ion plating deposition. Determine the corresponding temperature range according to the reference temperature.

[0052] S2. Based on the temperature acquisition devices arranged at the upper, middle and lower height positions of the vacuum chamber, the real-time temperature at different height positions of the vacuum chamber is monitored. When the upper limit target temperature determined according to each real-time temperature reaches the preset upper limit temperature of the temperature range, cooling medium gas is introduced into the gas distribution structure to cool the vacuum chamber, and the working state of the pumping system is adjusted to maintain the residence time of the cooling medium gas in the vacuum chamber and stop the ion plating deposition.

[0053] S3. Determine the lower limit target temperature. If the lower limit target temperature drops to the preset lower limit temperature of the temperature range, restore the pumping system to remove the residual cooling medium gas and restore the vacuum degree of the vacuum chamber to the preset working vacuum degree.

[0054] S4. When the temperature of the vacuum chamber is maintained within the temperature range for a preset threshold duration, the surface of the workpiece with the electroplated copper-tin layer is cleaned using an ion source.

[0055] S5. After completing the surface cleaning process, start the deposition source and continue to perform ion plating deposition on the surface of the electroplated copper-tin layer to form a single deposition film.

[0056] S6. After a single deposition of the film is completed, repeat the single deposition cycle including steps S2 to S5 until the total thickness of the deposited film reaches the target thickness value, thereby obtaining the corresponding ion plating layer.

[0057] In this embodiment, the substrate workpiece is placed in a vacuum chamber. The inner wall of the vacuum chamber is provided with an annular gas distribution structure for introducing cooling medium gas during the process to achieve temperature control. Temperature acquisition devices are arranged in the upper, middle and lower layers of the vacuum chamber, with three thermocouples in each layer. A total of nine temperature acquisition devices are arranged in the entire vacuum chamber for real-time monitoring of the temperature distribution within the vacuum chamber.

[0058] During the ion plating deposition process, when the real-time temperature of any layer reaches the corresponding upper limit target temperature, the central controller sends a control signal to pause the deposition operation and drives the annular gas distribution structure to introduce nitrogen as a cooling medium. The convective heat transfer effect of the gas ensures that the temperature of the vacuum chamber will not continue to rise due to thermal inertia and will gradually decrease. The cooling time is about 10 minutes.

[0059] After cooling is complete, the vacuum system is restarted to restore a high vacuum state, thereby completely removing any residual cooling medium gas and preventing the formation of an adsorption layer on the substrate surface that could affect interfacial adhesion. Subsequently, the substrate surface is cleaned using a strip-shaped ion source at a power of approximately 1 kW for 3 minutes to remove any residual nitrogen and restore the activity of the deposited surface.

[0060] In this embodiment, the deposition process employs a cyclic process, with each cycle including: ion plating deposition for approximately 30 minutes, nitrogen cooling through a ring-shaped gas distribution structure for approximately 10 minutes, and cleaning with a strip-shaped ion source for approximately 3-5 minutes. These steps form a complete cycle, with the deposition thickness controlled at approximately 0.2 micrometers per cycle. After approximately 10 cycles, a copper-tin ion plating layer with a total thickness of approximately 2.0 micrometers is obtained. Testing showed that this plating layer achieves the same performance as high-temperature deposition processes in terms of ion structure density, interface strength, and stability at high temperatures.

[0061] Furthermore, the cooling medium gas includes nitrogen or helium, wherein the choice of nitrogen or helium is determined based on the residence time in the vacuum chamber.

[0062] In this embodiment, either nitrogen or helium is selected as the cooling medium gas and introduced into the gas distribution structure of the vacuum chamber to achieve rapid temperature control during the deposition process. When the upper limit target temperature reaches the set value, the central controller drives the annular gas distribution structure to introduce inert gas, forming a convective heat transfer environment, so that the temperature inside the vacuum chamber can drop in a short time, avoiding temperature overshoot caused by thermal inertia.

[0063] When nitrogen is used as the cooling medium, its large molecular weight and high heat capacity are utilized to provide better heat storage and dissipation under the same pressure conditions. This allows for maintaining temperature uniformity in the vacuum chamber while extending the gas residence time, thus making the cooling process more stable. Nitrogen is relatively inexpensive and widely available, making it suitable for mass production scenarios where cost control is a priority.

[0064] When helium is used as the cooling medium, its small molecular weight, high thermal conductivity, and fast diffusion rate allow it to quickly and uniformly distribute within the vacuum chamber, resulting in more rapid heat exchange and temperature reduction. Helium offers high cooling efficiency and is suitable for applications requiring shorter cycle times, higher deposition efficiency, or stricter temperature fluctuation control. However, its higher price typically limits its use to processes demanding extremely high coating quality and production efficiency.

[0065] Therefore, in this embodiment, the selection of the cooling medium gas is targeted: nitrogen is selected if cost and process stability are given priority; helium is selected if cooling rate and deposition efficiency are given priority. This differentiated selection of the cooling medium allows for flexible adaptation to different application scenarios while ensuring the quality of the deposited film.

[0066] Furthermore, the calculation steps for the residence time of the cooling medium gas in the vacuum chamber include:

[0067] Obtain the effective volume V of the vacuum chamber;

[0068] Determine the inlet flow rate Q of the cooling medium gas and the gas type correction factor Kg;

[0069] Based on the effective volume V and the intake flow rate Q, the corresponding residence time t is calculated. The calculation steps for residence time t are t = (V / Q) × Kg.

[0070] In this embodiment, to ensure the accuracy and repeatability of the temperature control process within the vacuum chamber, the central controller introduces a gas type correction coefficient when executing the cooling logic. Its working principle is as follows: When the real-time temperature within the vacuum chamber reaches the upper target temperature determined by the upper, middle, and lower temperature acquisition devices, the gas distribution structure introduces different types of cooling media gases (such as nitrogen or helium) into the vacuum chamber to lower the temperature. However, different gases differ in thermal conductivity, molecular weight, diffusion rate, and specific heat capacity in low-pressure environments. For example, nitrogen has a larger molecular weight and higher heat capacity, resulting in a relatively slower cooling rate but a stable temperature decrease; helium has a smaller molecular weight, faster diffusion rate, and higher cooling efficiency, but its temperature decay curve differs significantly from that of nitrogen under the same pressure and volume conditions.

[0071] If we do not consider the differences in the intrinsic physical properties of these gases and rely solely on the numerical feedback from the temperature sensor to determine the cooling process, the following problems will occur: On the one hand, the hysteresis effect during nitrogen cooling may cause the system to resume deposition prematurely before the temperature is fully balanced; on the other hand, the rapid diffusion during helium cooling may cause a sudden drop in local temperature, but the sensor may not capture the real temperature change of the entire cavity in time, which can easily lead to control errors.

[0072] Therefore, this embodiment introduces a gas type correction coefficient into the temperature control algorithm to correct the real-time temperature signal collected by the sensor, ensuring it remains consistent with the actual average temperature of the cavity. Specifically, the correction coefficient for nitrogen is set as a low-speed heat transfer compensation parameter to offset deviations caused by temperature sensing delay; the correction coefficient for helium is set as a rapid heat transfer attenuation correction parameter to avoid misjudgments caused by sudden temperature drops. In this way, regardless of whether nitrogen or helium is used, the central controller can accurately determine the cooling completion time under conditions close to the actual temperature, and accurately trigger subsequent vacuum recovery and ion source surface cleaning steps.

[0073] Furthermore, the selection step for nitrogen or helium includes:

[0074] Determine the target cooling time, which is the time required to reduce the preset upper limit temperature to the preset lower limit temperature;

[0075] Determine whether the residence time is greater than the target cooling time;

[0076] If the value is greater than the specified value, then the cooling medium gas is determined to be nitrogen.

[0077] If the value is not greater than the specified value, then the cooling medium gas is determined to be helium.

[0078] In this embodiment, residence time reflects the actual time that the cooling medium gas can remain in the vacuum chamber and participate in heat exchange under given effective vacuum chamber volume and inlet flow rate conditions; target cooling time reflects the shortest time required to reduce the temperature from the preset upper limit temperature to the preset lower limit temperature. Comparing the two directly determines whether a candidate gas can complete the necessary cooling task in a single cooling stage under the current process cycle and equipment conditions.

[0079] The gas type correction factor for nitrogen represents its equivalent heat transfer and diffusion characteristics under vacuum chamber conditions. Under the same vacuum chamber volume and inlet flow rate, the residence time obtained using nitrogen is a baseline choice that offers more controllable costs and a more stable temperature field. If the residence time calculated using nitrogen already meets the target cooling time, then choosing nitrogen can ensure temperature convergence while balancing process stability and operating costs. When the residence time of nitrogen is less than the target cooling time, it indicates that under the current vacuum chamber volume and inlet flow rate constraints, a single cooling stage using nitrogen cannot reduce the temperature from the preset upper limit temperature to the preset lower limit temperature within the specified time window. In this case, helium is used. Its gas type correction factor reflects higher heat transfer and diffusion efficiency, resulting in stronger cooling capacity per unit residence time under the same vacuum chamber volume and inlet flow rate conditions. This allows the target cooling time requirement to be met without increasing the residence time, thus ensuring that the cycle time of a single deposition cycle is not prolonged.

[0080] Furthermore, the step of determining the corresponding temperature range based on the reference temperature includes:

[0081] The calculation involves determining the predicted temperature rise at the top, middle, and bottom layers of the vacuum chamber. The reference temperature, obtained by averaging measurements at selected locations within the vacuum chamber, represents the overall process temperature level and serves as the starting point and baseline for calculating the temperature range across the entire vacuum chamber. The predicted temperature rise refers to the potential temperature increase at different heights within the vacuum chamber during the deposition process due to ion bombardment and material deposition. This value is typically calculated based on historical process data or thermal conductivity models and is used to predict the temperature trends of each layer.

[0082] The upper limit temperature for each layer is calculated by adding the reference temperature and each predicted temperature rise. The vacuum chamber, a sealed space used in ion plating to create a low-pressure or high-vacuum environment, is the core of the entire temperature control process, where process gases, the deposition target, and the workpiece all undergo deposition. The upper, middle, and lower layer heights refer to three vertically divided monitoring areas within the vacuum chamber, located at the top, middle, and bottom of the chamber, respectively. This ensures that temperature acquisition and calculation cover the entire chamber space, avoiding distortion from single-point data. The upper limit temperature for each layer is the maximum possible temperature obtained by adding the reference temperature to the predicted temperature rise at that location. It is used to determine the highest temperature boundary that the layer may reach during deposition.

[0083] The lower limit temperature for each layer is calculated by subtracting the preset temperature control bandwidth from the upper limit temperature of each layer. The preset temperature control bandwidth refers to the allowable temperature fluctuation range set manually to ensure process stability. It is usually expressed as a numerical value and is used to correct the upper limit temperature downward in the layer temperature calculation, thereby obtaining a more reasonable lower limit control value. The lower limit temperature of a layer is the lowest allowable temperature boundary at that height position obtained by subtracting the preset temperature control bandwidth from the upper limit temperature of the layer. It is used in conjunction with the upper limit temperature to form a temperature range.

[0084] The minimum value among the upper limit temperatures of each layer is determined as the preset upper limit temperature of the temperature range, and the maximum value among the lower limit temperatures of each layer is determined as the preset lower limit temperature of the temperature range. The temperature range refers to the control range obtained by combining the upper and lower limits of the temperatures of each layer in the vacuum chamber; it determines the triggering conditions for process actions such as the introduction of cooling medium gas, ion plating pause, and restart. The preset upper limit temperature is the minimum value selected from all the upper limit temperatures of each layer as the highest permissible temperature boundary of the entire cavity, ensuring that even the most easily heated areas will not exceed the control range. The preset lower limit temperature is the maximum value selected from all the lower limit temperatures of each layer as the lowest control boundary of the entire cavity, ensuring that even the most difficult-to-cool areas can be included within the effective control range.

[0085] Furthermore, the step of calculating the predicted temperature rise at the upper, middle, and lower height positions of the vacuum chamber includes:

[0086] Obtain the average heating rate vi at each height position in the previous single deposition cycle, i∈{upper layer, middle layer, lower layer}; the average heating rate reflects the rate of temperature rise caused by ion bombardment and energy input in this deposition cycle.

[0087] Determine the required deposition time ti at each height position in the current single deposition cycle, i∈{upper layer, middle layer, lower layer}; the deposition time is determined by the target deposition thickness and deposition rate set by the process.

[0088] Based on the average heating rate *vi* and deposition time *ti*, the corresponding predicted temperature rise *T0* is calculated using the formula *T0 = vi × *ti*. This allows for the prediction of temperature rise trends at various heights during the current deposition cycle. This predicted temperature rise can reflect the potential temperature levels at different heights in advance during process control, guiding subsequent temperature range calculations and the timing of cooling gas introduction, thereby preventing uneven temperature runaway at the upper, middle, and lower levels of the vacuum chamber.

[0089] Furthermore, the step of determining the upper limit target temperature based on each real-time temperature includes:

[0090] At each real-time temperature, the maximum temperature value Tmax and the minimum temperature value Tmin are determined. The interlayer temperature difference Tlayer is calculated by subtracting the maximum temperature value Tmax from the minimum temperature value Tmin.

[0091] Calculate the rate of change v0 of the maximum temperature value Tmax within a fixed time window;

[0092] The upper limit target temperature is calculated based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer.

[0093] Furthermore, in the step of calculating the corresponding upper limit target temperature based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer, the formula for calculating the upper limit target temperature Tgoal is: Tgoal=Tmax+a×v0+b×Tlayer.

[0094] Where a is the preset prediction duration for the time delay caused by the issuance of the command, and b is the penalty coefficient set for the temperature difference between the layers.

[0095] In this embodiment, real-time temperatures are collected at the upper, middle, and lower layers of the vacuum chamber. The maximum temperature value Tmax and the minimum temperature value Tmin are selected, and their difference is calculated to obtain the interlayer temperature difference Tlayer. The interlayer temperature difference Tlayer is introduced to reflect the non-uniformity of temperature distribution within the vacuum chamber. When the interlayer temperature difference Tlayer is large, it indicates a significant temperature gradient between the upper and lower layers. If only the maximum temperature value Tmax is used as the criterion, the risk of local overheating caused by temperature distribution differences may be ignored. By superimposing the interlayer temperature difference Tlayer when calculating the upper limit target temperature and combining it with a penalty coefficient b for weighting, the threshold for triggering cooling can be actively reduced when the internal temperature distribution of the vacuum chamber is uneven, thereby effectively avoiding local overheating and ensuring the stability of the deposition process.

[0096] Subsequently, the maximum temperature value Tmax is continuously sampled within a fixed time window, and its rate of change v0 is calculated. The introduction of the rate of change v0 is to anticipate the dynamic upward trend of the vacuum chamber temperature. If Tmax rises rapidly in a short period of time, even if it has not yet exceeded the preset upper limit temperature of the temperature range, the temperature may rapidly exceed the safety threshold in subsequent periods due to thermal inertia. Therefore, by combining the prediction duration a with weighted compensation of the rate of change v0, the calculation result of the upper limit target temperature can reflect the future temperature change trend in advance, ensuring that the cooling medium gas can intervene in time before the temperature actually reaches the dangerous value.

[0097] Based on the above principles, the calculation formula for the upper limit target temperature Tgoal is set as Tgoal=Tmax+a×v0+b×Tlayer, where the maximum temperature value Tmax reflects the current actual highest temperature, the rate of change v0 reflects the dynamic trend of temperature rise, and the interlayer temperature difference Tlayer reflects the temperature uniformity in the vacuum chamber. The three factors work together to form a comprehensive criterion that takes into account the current state, future trend, and spatial distribution, thereby providing a more reliable control basis for the cooling triggering of the gas distribution structure.

[0098] Specifically, the lower limit target temperature is determined based on real-time temperature monitoring results inside the vacuum chamber. Specifically, real-time temperature acquisition devices are installed at the top, middle, and bottom levels of the vacuum chamber. As each real-time temperature gradually decreases during the cooling phase of the deposition process, the maximum temperature value is used as the criterion for analysis. Only when this maximum temperature value has decreased to the preset lower limit temperature of the temperature range and remains stable without rising within a preset threshold time is the entire vacuum chamber considered to have reached a sufficiently uniform and safe cooling state. This determination method avoids premature resumption of deposition operations due to incomplete heat dissipation in local areas, effectively reducing the risk of secondary temperature rise due to thermal inertia. By using the maximum temperature value as the criterion, it can be ensured that the overall ambient temperature of the vacuum chamber has decreased to the target range. This ensures the interfacial bonding stability and process repeatability of the deposited film during subsequent steps such as evacuation, surface cleaning, and re-deposition, improving the performance of the obtained ion-plated layer in terms of thickness uniformity, interfacial adhesion, and ion structure consistency.

[0099] Furthermore, the thickness of the deposited film is 0.2 micrometers, and the thickness of the ion-plated layer is 2 micrometers.

[0100] In this embodiment, during the ion plating process, the duration of the deposition cycle and the cooling interval are controlled so that the thickness of the deposited film layer formed in each single deposition cycle is approximately 0.2 micrometers. After accumulating multiple deposition cycles, the overall thickness of the ion-plated layer gradually increases, and when approximately ten deposition cycles are completed, the final thickness of the ion-plated layer is approximately 2 micrometers. This thickness setting ensures that the film layer maintains density and uniformity in its microstructure, while also guaranteeing the strong interfacial bonding between the film layer and the substrate. This allows for the acquisition of the same ion structure and performance indicators as high-temperature deposition without relying on continuous high-temperature deposition.

[0101] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A process for ion plating to thicken a copper-tin layer, characterized in that, The process for ion plating a thickened copper-tin layer includes: S1. Place the copper-tin plating substrate workpiece in a vacuum chamber with a gas distribution structure, start the pumping system to pump the vacuum chamber to a preset working vacuum level, and adjust the temperature of the vacuum chamber to a reference temperature for ion plating deposition. Determine the corresponding temperature range based on the reference temperature. S2. Based on the temperature acquisition devices arranged at the upper, middle and lower height positions of the vacuum chamber, the real-time temperature at different height positions of the vacuum chamber is monitored. When the upper limit target temperature determined according to each real-time temperature reaches the preset upper limit temperature of the temperature range, cooling medium gas is introduced into the gas distribution structure to cool the vacuum chamber, and the working state of the pumping system is adjusted to maintain the residence time of the cooling medium gas in the vacuum chamber and stop the ion plating deposition. S3. Determine the lower limit target temperature. If the lower limit target temperature drops to the preset lower limit temperature of the temperature range, restore the pumping system to remove the residual cooling medium gas and restore the vacuum degree of the vacuum chamber to the preset working vacuum degree. S4. When the temperature of the vacuum chamber is maintained in the temperature range for a preset threshold duration, the surface of the electroplated copper-tin layer substrate workpiece is cleaned using an ion source. S5. After completing the surface cleaning process, start the deposition source and continue to perform ion plating deposition on the surface of the electroplated copper-tin layer substrate workpiece to form a single deposition film layer. S6. After a single deposition of the film is completed, repeat the single deposition cycle including steps S2 to S5 until the total thickness of the deposited film reaches the target thickness value, thereby obtaining the corresponding ion plating layer. The step of determining the corresponding temperature range based on the reference temperature includes: Obtain the average heating rate vi at each height position in the previous single deposition cycle, i∈{upper layer, middle layer, lower layer}; Determine the required deposition time ti at each height position in the current single deposition cycle, where i∈{upper layer, middle layer, lower layer}; Based on the average heating rate vi and the deposition time ti, the corresponding predicted heating amount T0 is calculated. The formula for calculating the predicted heating amount T0 is T0 = vi × ti. The reference temperature and each of the predicted heating amounts are added together to calculate the upper limit temperature of the stratification at each height position. The lower limit temperature of each layer is calculated by subtracting the preset temperature control bandwidth from the upper limit temperature of each layer. The preset temperature control bandwidth refers to the allowable temperature fluctuation range set manually to ensure process stability. The minimum value among the upper limit temperatures of each layer is determined as the preset upper limit temperature of the temperature range, and the maximum value among the lower limit temperatures of each layer is determined as the preset lower limit temperature of the temperature range. The step of determining the upper limit target temperature based on each of the aforementioned real-time temperatures includes: In each of the real-time temperatures, the maximum temperature value Tmax and the minimum temperature value Tmin are determined. The interlayer temperature difference Tlayer is calculated by subtracting the maximum temperature value Tmax from the minimum temperature value Tmin. Calculate the rate of change v0 of the maximum temperature value Tmax within a fixed time window; The corresponding upper limit target temperature is calculated based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer; In the step of calculating the corresponding upper limit target temperature based on the maximum temperature value Tmax, the rate of change v0, and the interlayer temperature difference Tlayer, the formula for calculating the upper limit target temperature Tgoal is: Tgoal = Tmax + a × v0 + b × Tlayer. Wherein, 'a' is the preset prediction duration for the time delay caused by the issuance of the instruction, and 'b' is the penalty coefficient set for the temperature difference between the layers.

2. The process for thickening a copper-tin layer by ion plating according to claim 1, characterized in that, The cooling medium gas includes nitrogen or helium, wherein the choice of nitrogen or helium is determined based on the residence time in the vacuum chamber.

3. The process for thickening a copper-tin layer by ion plating according to claim 2, characterized in that, The calculation steps for the residence time of the cooling medium gas in the vacuum chamber include: Obtain the effective volume V of the vacuum chamber; Determine the inlet flow rate Q of the cooling medium gas and the gas type correction factor Kg; Based on the effective volume V and the intake flow rate Q, the corresponding residence time t is calculated. The calculation steps for the residence time t are t = (V / Q) × Kg.

4. The process for thickening a copper-tin layer by ion plating according to claim 2, characterized in that, The step of selecting nitrogen or helium includes: Determine the target cooling time, which is the time required to reduce the preset upper limit temperature to the preset lower limit temperature; Determine whether the residence time is greater than the target cooling time; If the value is greater than the specified value, then the cooling medium gas is determined to be nitrogen. If the value is not greater than the specified value, then the cooling medium gas is determined to be helium.

5. The process for thickening a copper-tin layer by ion plating according to claim 1, characterized in that, The thickness of the single-deposited film is 0.2 micrometers, and the thickness of the ion-plated layer is 2 micrometers.

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