A method suitable for preparing special metal rhodium coating

Abstract

The invention discloses a method suitable for preparing a special metal rhodium coating, and relates to the technical field of rhodium coating preparation. The method is realized by placing three functions of sample surface cleaning, precious metal film deposition and sample cooling in three chambers. When the first batch of samples is transferred to a sputtering chamber or a cooling chamber, the second batch of samples can be cleaned, thereby shortening the working hours. At the same time, a suitable position can be selected to perform sputtering spraying on workpieces, thereby ensuring that the uniformity of the rhodium coating meets the requirements. The invention is simple, effective and easy to use.

Description

Technical Field

[0001] The invention belongs to the technical field of rhodium coating preparation, and specifically relates to a method suitable for preparing a special metal rhodium coating. Background Art

[0002] Compared with other coating methods, magnetron sputtering has advantages such as strong bonding and low cost. However, for the deposition of special thin film materials, traditional sputtering equipment still has many problems, including 1. The bonding force of deposited micron-thick special precious metal films is weak, 2. The surface cleaning, sputtering, and cooling of the workpiece are completed in the same chamber, resulting in a long processing cycle, 3. The equipment operation steps are complicated, which is not conducive to processing and production;

[0003] Moreover, how to control the sputtering thickness of the rhodium coating is also a difficult problem. Based on this, a solution is provided. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art;

[0005] To this end, the present invention proposes a method suitable for preparing a special metal rhodium coating, the method specifically comprising the following steps:

[0006] Sputter cleaning of the workpiece surface;

[0007] For the cleaned workpiece, a rhodium coating is sputtered and sprayed at each of the X selected positions; the number X of the selected positions is determined by the following method:

[0008] Spraying is performed from a selected position, and then the optional values ​​are determined according to the parameters of the spraying performance of the reactive rhodium coating, including thickness difference, occupancy time and deviation, and then the number X of selected positions is determined according to the difference between the optional values ​​corresponding to the two different numbers of selected positions before and after;

[0009] After the first round of sputtering, the workpiece surface is bombarded with argon ions;

[0010] After the workpiece has been bombarded with argon ions, a second round of rhodium coating sputtering is carried out at selected locations.

[0011] Furthermore, after the second round of rhodium coating sputtering spraying is performed on the workpiece, the workpiece needs to be cooled.

[0012] Furthermore, sputter cleaning, sputter spraying and cooling of the workpiece are respectively carried out in chamber one, chamber two and chamber three; chamber one, chamber two and chamber three are connected.

[0013] Furthermore, the argon gas flow rate in the chamber 1 was maintained at 26 sccm, the gas pressure was stabilized at 0.05 mbar, the output power of the RF power supply was set to 200 W, and the workpiece was cleaned for 10 minutes.

[0014] Further, after the RF sputtering cleaning is completed, the argon gas flow rate of chamber one is closed, the vacuum degree of chamber one is adjusted to be below 1E-6 mbar, and then the workpiece is transferred from chamber one to chamber two;

[0015] The workpiece is sputtered in chamber 2, and the environment of chamber 2 is maintained at an argon gas flow value of 10 sccm until the gas pressure is stabilized at 0.0058 mbar.

[0016] Furthermore, the cathodes for sputtering rhodium are two 4-inch circular cathodes, and the target head angle is adjustable so that the target head axis direction faces the center of the workpiece;

[0017] Two DC power supplies are turned on in chamber 2, and the output power is maintained at 500 W; X selected positions are determined in an evenly divided manner on the circumference around the workpiece.

[0018] Furthermore, the workpiece surface was subjected to argon ion bombardment treatment for 5 minutes, and the specific chamber 2 environment was maintained at an argon gas flow rate of 30 sccm until the gas pressure was stabilized at 0.05 mbar and the RF power supply was maintained at an output power of 200 W.

[0019] Furthermore, for the second rhodium coating sputtering, the environment of chamber 2 was kept to turn off the RF power, and the argon flow value was set to 10 sccm until the gas pressure stabilized at 0.0058 mbar; two DC power supplies were turned on, and the output power was controlled to be 500 W.

[0020] Furthermore, the value of X is determined as follows:

[0021] SS1: Assume that X selected positions are selected in equal parts around the workpiece in a circular angle;

[0022] SS2: Let X = 1;

[0023] SS3: After sputtering, the workpiece is obtained and sputtering spraying is performed at a selected position on the workpiece;

[0024] SS4: On the workpiece, the thickness of the rhodium coating at several set positions on the workpiece surface is detected to obtain several thickness values ​​Hi, i=1, ..., n, indicating that there are n set positions, and then the maximum value in Hi is subtracted from the minimum value, and the obtained value is marked as the thickness difference;

[0025] SS5: Then get the mean value P of Hi and use the formula to calculate the deviation W of Hi. The specific calculation formula is:

[0026] ;

[0027] SS6: The total spraying time is obtained again. Here, the total spraying time includes two sputtering sprayings, which is marked as occupied time.

[0028] SS7: Then use the formula to calculate the optional value. The specific formula is:

[0029] Optional value = 0.39 × thickness difference + 0.49 × deviation + 0.12 × occupied time;

[0030] SS8: Then, the value of X is increased by 1, and steps SS3 to SS7 are repeated to obtain the optional values ​​of the corresponding number of selected positions, and the newly obtained optional value is marked as optional value 2;

[0031] Then, if the optional value - optional value 2 ≥ X2 is satisfied, the optional value here is deleted and the optional value 2 is re-marked as the optional value; X2 here is a preset value set by the administrator;

[0032] SS9: Repeat step SS8 until no new optional value can be selected, and determine the X value corresponding to the last optional value as the final value of X.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present application separates the three functions of sample surface cleaning, precious metal film deposition and sample cooling into three chambers. When the first batch of samples is transferred to the sputtering chamber or cooling chamber, the second batch of samples can be cleaned, thus shortening the working hours.

[0035] At the same time, a suitable position can be selected to perform sputtering spraying on the workpiece to ensure that the uniformity of the rhodium coating meets the requirements; the sputtering method provided in the present application, compared with the prior art or the control group example provided in the present application, the rhodium coating obtained has stronger bonding force and better adhesion; the present invention is simple, effective, and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of Embodiment 1 of the present invention;

[0037] Figure 2 A flow chart for determining the value of X in the present invention;

[0038] Figure 3 The morphology of the rhodium coating after bending the workpiece prepared by the method of Example 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of obvious cracks appearing on the rhodium coating of the rhodium-plated workpiece after bending obtained in the control group 1 of the present invention. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figure 1-Figure 2 , the present application provides a method suitable for preparing a special metal rhodium coating;

[0042] As an embodiment of the present application, it specifically includes the following steps:

[0043] S1: Set three independent environments with a vacuum degree of 8E-7mbar, marked as chamber 1, chamber 2 and chamber 3 respectively; chamber 1, chamber 2 and chamber 3 are connected;

[0044] S2: Chamber 1 is used to perform RF sputtering cleaning on the surface of the workpiece. The argon flow rate in Chamber 1 is maintained at 26 sccm. The gas pressure is stabilized at 0.05 mbar. The RF power supply is set to an output power of 200 W. The workpiece is cleaned for 10 minutes to remove copper oxides and other adsorbed tiny particles on the surface of the workpiece and improve the bonding strength between the rhodium coating and the copper-based workpiece. The workpiece is a copper-based workpiece.

[0045] After the RF sputtering cleaning is completed, the argon gas flow of chamber one is turned off, the vacuum degree of chamber one is adjusted to below 1E-6 mbar, and then the workpiece is transferred from chamber one to chamber two;

[0046] S3: Sputtering and spraying the workpiece in chamber 2, setting the argon gas flow rate to 10 sccm, and waiting for the gas pressure to stabilize at 0.0058 mbar;

[0047] The cathodes for sputtering rhodium are two 4-inch circular cathodes, and the angle of the target head is adjustable, which is adjusted to the direction of the target head axis toward the center of the workpiece; two DC power supplies are turned on in chamber 2, and the output power is set to 500W; X positions are selected in equal divisions around the workpiece on the circumferential angle, X is a preset value, and four are generally selected; and sputtering and spraying are performed at the corresponding selected positions for 5 minutes, and the workpiece is sprayed at the corresponding position by rotating the workpiece; under the hardware conditions of using two 4-inch small circular cathodes, it can be ensured that the copper-based workpiece surface in the 200mm×210mm tooling is plated with a uniform thickness of rhodium coating; after sputtering, the first sputtering rhodium coating is about 1-1.5 microns thick.

[0048] S4: Set the argon gas flow rate to 30 sccm, wait for the gas pressure to stabilize at 0.05 mbar, and use the RF power supply at an output power of 200 W to perform argon ion bombardment on the workpiece surface for 5 minutes;

[0049] S5: Perform a second rhodium coating sputtering, the coating is about 1-1.5 microns thick; turn off the RF power supply, set the argon flow rate to 10 sccm, and control the gas pressure to be stable at 0.0058 mbar; turn on two DC power supplies, and control the output power to be 500 W;

[0050] After the selected X positions, sputter again for 5 min;

[0051] Plasma bombardment treatment is added between the first and second rhodium plating layers to reduce the film internal stress of the rhodium coating with a total thickness of 2-4 microns on the surface of the copper-based workpiece and improve the bonding strength of the rhodium coating.

[0052] The positions selected in step S3 and step S5 are X positions, which are determined in the following manner:

[0053] SS1: Assume that X selected positions are selected in equal parts around the workpiece in a circular angle;

[0054] SS2: Let X = 1;

[0055] SS3: After sputtering, the workpiece is obtained, and after sputtering spraying is performed at a selected position on the workpiece, the workpiece is then inspected for thickness. The thickness inspection is performed using existing technology, so it will not be described in detail here.

[0056] SS4: On the workpiece, the thickness of the rhodium coating at several set positions on the workpiece surface is detected to obtain several thickness values ​​Hi, i=1, ..., n, indicating that there are n set positions, and then the maximum value in Hi is subtracted from the minimum value, and the obtained value is marked as the thickness difference;

[0057] SS5: Then get the mean value P of Hi and use the formula to calculate the deviation W of Hi. The specific calculation formula is:

[0058] ;

[0059] SS6: The total spraying time is obtained again. Here, the total spraying time includes two sputtering sprayings, which is marked as occupied time.

[0060] SS7: Then use the formula to calculate the optional value. The specific formula is:

[0061] Optional value = 0.39 × thickness difference + 0.49 × deviation + 0.12 × occupied time;

[0062] SS8: Then, the value of X is increased by 1, and steps SS3 to SS7 are repeated to obtain the optional values ​​of the corresponding number of selected positions, and the newly obtained optional value is marked as optional value 2;

[0063] Then, if the optional value - optional value 2 ≥ X2 is satisfied, the optional value here is deleted and the optional value 2 is re-marked as the optional value; X2 here is a preset value set by the administrator;

[0064] SS9: Repeat step SS8 until no new optional value can be selected, and determine the X value corresponding to the last optional value as the final value of X;

[0065] S6: turn off the DC power output of chamber 2, set the argon gas flow rate to 0, and then pump the vacuum degree of chamber 2 to below 1E-6 mbar, take out the sputtered workpiece from chamber 2 and transfer it to chamber 3 for cooling;

[0066] S7: Turn off the vacuum pumping function of the cooling chamber, and take out the cooled rhodium-plated workpieces after the vacuum is broken in the cooling chamber. After the above step 3 is completed, the vacuum pumping function of the cooling chamber can be turned off, and the second batch of copper-based workpieces can be placed after the vacuum is broken in the sample chamber.

[0067] Control group:

[0068] Preparation of rhodium-plated coating in control group 1: The steps are basically the same as those in Example 1, except that the workpiece is not subjected to argon ion bombardment treatment between two rhodium-plated coatings in the sputtering chamber.

[0069] Preparation of rhodium-plated coating in control group 2: The steps are basically the same as those in Example 1, except that when sputtering the rhodium-plated coating, the rotation angle of the sample stage in the sputtering chamber is always maintained at a selected position;

[0070] Preparation of rhodium-plated coating in control group 3: The steps are basically the same as those in Example 1, except that the rhodium-plated process of the workpiece starts with surface cleaning in chamber 1, transfers to rhodium-plated coating in chamber 2, and then transfers from chamber 2 back to chamber 1 to complete cooling and removal. Only after removal can the second batch of workpieces be placed.

[0071] Rhodium was plated according to the magnetron sputtering rhodium plating coating method described in Example 1 and Control Groups 1, 2, and 3, and the results were as follows:

[0072]

[0073] like Figure 3 As shown, in Example 1, the rhodium coating of the rhodium-plated workpiece obtained after bending has no cracks, and the rhodium thickness distribution within the range of 200mm×210mm is within the range of 2-3.5 microns, and the thickness distribution is relatively uniform. The average time for each batch under the multi-batch process is about 1.5h.

[0074] like Figure 4 As shown, the rhodium coating of the rhodium-plated workpiece obtained in control group 1 showed obvious cracks after bending.

[0075] The control group 2 obtained rhodium-plated workpieces, and the rhodium thickness distribution within the range of 200mm×210mm was all in the range of 1-5 microns, and the thickness distribution was uneven.

[0076] Control group 2 obtained rhodium-plated workpieces, and the average time for each batch under the multi-batch process was about 3 hours.

[0077] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A method for preparing a special metal rhodium coating, characterized in that: The method specifically comprises the following steps: Sputter cleaning of the workpiece surface; For the cleaned workpiece, a rhodium coating is sputtered and sprayed at each of the X selected positions; the number X of the selected positions is determined by the following method: Spraying is performed from a selected position, and then the optional values ​​are determined according to the parameters of the spraying performance of the reactive rhodium coating, including thickness difference, occupancy time and deviation, and then the number X of selected positions is determined according to the difference between the optional values ​​corresponding to the two different numbers of selected positions before and after; After the first round of sputtering, the workpiece surface is bombarded with argon ions; After the workpiece has been bombarded with argon ions, a second round of rhodium coating sputtering is carried out at selected locations; The value of X is determined as follows: SS1: Assume that X selected positions are selected in equal parts around the workpiece in a circular angle; SS2: Let X = 1; SS3: After sputtering, the workpiece is obtained and sputtering spraying is performed at a selected position on the workpiece; SS4: On the workpiece, the thickness of the rhodium coating at several set positions on the workpiece surface is detected to obtain several thickness values ​​Hi, i=1, ..., n, indicating that there are n set positions, and then the maximum value in Hi is subtracted from the minimum value, and the obtained value is marked as the thickness difference; SS5: Then get the mean value P of Hi and use the formula to calculate the deviation W of Hi. The specific calculation formula is: ; SS6: The total spraying time is obtained again. Here, the total spraying time includes two sputtering sprayings, which is marked as occupied time. SS7: Then use the formula to calculate the optional value. The specific formula is: Optional value = 0.39 × thickness difference + 0.49 × deviation + 0.12 × occupied time; SS8: Then, the value of X is increased by 1, and steps SS3 to SS7 are repeated to obtain the optional values ​​of the corresponding number of selected positions, and the newly obtained optional value is marked as optional value 2; Then, if the optional value - optional value 2 ≥ X2 is satisfied, the optional value here is deleted and the optional value 2 is re-marked as the optional value; X2 here is a preset value set by the administrator; SS9: Repeat step SS8 until no new optional value can be selected, and determine the X value corresponding to the last optional value as the final value of X.

2. A method for preparing a special metal rhodium coating according to claim 1, characterized in that: After the second round of rhodium coating sputtering, the workpiece needs to be cooled.

3. A method for preparing a special metal rhodium coating according to claim 1, characterized in that: Sputtering cleaning, sputtering spraying and cooling of the workpiece are respectively carried out in chamber one, chamber two and chamber three; chamber one, chamber two and chamber three are connected.

4. A method for preparing a special metal rhodium coating according to claim 3, characterized in that: The argon flow rate in chamber 1 was maintained at 26 sccm, the gas pressure was stabilized at 0.05 mbar, the output power of the RF power supply was set to 200 W, and the workpiece was cleaned for 10 minutes.

5. A method for preparing a special metal rhodium coating according to claim 4, characterized in that: After the RF sputtering cleaning is completed, the argon gas flow of chamber one is turned off, the vacuum degree of chamber one is adjusted to below 1E-6 mbar, and then the workpiece is transferred from chamber one to chamber two; The workpiece is sputtered in chamber 2, and the environment of chamber 2 is maintained at an argon gas flow value of 10 sccm until the gas pressure is stabilized at 0.0058 mbar.

6. A method for preparing a special metal rhodium coating according to claim 5, characterized in that: The cathode for sputtering rhodium is two 4-inch circular cathodes, and the target head angle is adjustable, so that the target head axis direction faces the center of the workpiece; Two DC power supplies are turned on in chamber 2, and the output power is maintained at 500 W; X selected positions are determined in an evenly divided manner on the circumference around the workpiece.

7. A method for preparing a special metal rhodium coating according to claim 3, characterized in that: The workpiece surface was subjected to argon ion bombardment for 5 minutes. Specifically, the environment of chamber 2 was maintained at an argon gas flow rate of 30 sccm until the gas pressure was stabilized at 0.05 mbar and the RF power supply was maintained at an output power of 200 W.

8. A method for preparing a special metal rhodium coating according to claim 7, characterized in that: During the second sputtering of the rhodium coating, the environment of chamber 2 was kept by turning off the RF power supply and setting the argon flow rate to 10 sccm until the gas pressure stabilized at 0.0058 mbar; the two DC power supplies were turned on and the output power was controlled to be 500 W.

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