Nano twin crystal copper electroplating additive and electroplating solution

Abstract

The invention discloses a nano twin-crystal copper electroplating additive and electroplating liquid, in the nano twin-crystal copper electroplating additive, the mass fraction of a component with the molecular weight of more than 100000Da is 0-20%, and the mass fraction of a component with the molecular weight of less than 10000Da is 30-100%. The additive disclosed by the invention has an excellent and stable twin crystal promoting effect, the process stability and repeatability of nano twin crystal copper electroplating are improved, and the process window of electroplating is widened. When the nano twin crystal copper electroplating solution containing the additive is used for electroplating, a (111) preferred orientation nano twin crystal copper plating layer with good structure uniformity, excellent performance and preferred degree greater than 95% can be obtained, and the nano twin crystal copper electroplating solution is beneficial to application in electronic packaging and semiconductor manufacturing.

Description

Technical Field

[0001] The present invention relates to the field of electroplating technology, and more specifically, to a nano-twinned copper electroplating additive and an electroplating solution. Background Art

[0002] Nano-twinned copper is a copper material with nano-scale twin lamellar structures existing inside the grains, having high electrical conductivity, mechanical properties, electromigration resistance performance and stability, and having broad application prospects in electronic packaging and semiconductor manufacturing. Relying on its excellent electrical and mechanical properties, nano-twinned copper is becoming the key to solving the current bottleneck of electroplated copper technology.

[0003] CN102400188B discloses a nano-twinned copper material with a (111) texture, which is prepared by a direct current electro-deposition process. The composition of the electroplating solution used is: 150 - 200 g / L of copper sulfate, adjusting the pH to 0.5 - 1.5, adding 2.5 - 15 mL / L of an aqueous gelatin solution with a concentration of 0.2 - 0.5 wt% and 0.2 - 1.0 mL / L of an aqueous NaCl solution with a concentration of 5 - 25 wt%. CN114875461B discloses a direct current electroplated nano-twinned copper material. The composition of the electroplating solution used is: 20 - 70 g / L of copper ions, 20 - 200 g / L of sulfuric acid, 20 - 80 ppm of chloride ions, 5 - 200 ppm of gelatin, 0.5 - 100 mmol / L of nickel ions and the balance of water. The above patents all use gelatin as an additive for the nano-twinned copper electroplating solution. The addition of gelatin can make the electroplated copper grow a nano-twinned structure and is beneficial to improving the flatness and brightness of the coating.

[0004] However, gelatin is a mixture of polypeptide chains with different molecular weights, and the molecular weight distribution is between several thousand and several hundred thousand. According to the different hydrolysis methods when preparing gelatin, gelatin can be divided into acid-process gelatin, alkali-process gelatin and enzyme-process gelatin. The raw material sources of gelatin are also diverse, such as animal tissues like pigskin, cowhide, fish skin, bones, etc. In the actual process of preparing nano-twinned copper, when using gelatin as an electroplating additive for nano-twinned copper, the preparation process is often unstable and has poor repeatability, and it is impossible to stably obtain a nano-twinned structure, which limits the application of gelatin in the electroplating of nano-twinned copper. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned defects existing in the prior art, and provide a nano-twinned copper electroplating additive and an electroplating solution. The nano-twinned copper electroplating additive has excellent and stable twin-promoting effects, improves the process stability and repeatability of nano-twinned copper electroplating, broadens the electroplating process window, and can obtain a (111) preferred orientation nano-twinned copper coating with good tissue uniformity, excellent performance and a preferred degree greater than 95% by electroplating with a nano-twinned copper electroplating solution containing this additive.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] In the first aspect of the present invention, a nano-twinned copper electroplating additive is provided. The additive is obtained by hydrolyzing or separating collagen, gelatin or their derivatives. The composition of the nano-twinned copper electroplating additive needs to meet the following requirements:

[0008] The mass fraction of components with a molecular weight above 100,000 Da is 0-20%;

[0009] The mass fraction of components with a molecular weight below 10,000 Da is 30%-100%;

[0010] The rest are components with a molecular weight of 10,000-100,000 Da.

[0011] Preferably, in the composition of the nano-twinned copper electroplating additive, the mass fraction of components with a molecular weight above 100,000 Da is 0-10%, the mass fraction of components with a molecular weight below 10,000 Da is 50%-100%, and the rest are components with a molecular weight of 10,000-100,000 Da.

[0012] In the above technical solution, further, the gelatin includes any one or more of acid-processed gelatin, alkali-processed gelatin, and enzyme-processed gelatin.

[0013] In the above technical solution, further, the hydrolysis method includes any one or more of acid-catalyzed hydrolysis, alkali-catalyzed hydrolysis, and enzyme-catalyzed hydrolysis; the separation method includes any one or more of ultrafiltration, dialysis, molecular sieve, gel filtration, and electrophoresis.

[0014] In the second aspect of the present invention, a nano-twinned copper electroplating solution is provided. The nano-twinned copper electroplating solution includes the aforementioned nano-twinned copper electroplating additive.

[0015] In the above technical solution, further, the nano-twinned copper electroplating solution includes copper ions, sulfuric acid, chloride ions, and the nano-twinned copper electroplating additive as described above.

[0016] In the above technical solution, further, the concentration of copper sulfate in the nano-twinned copper electroplating solution is 20-80 g / L; preferably, the concentration of copper ions in the nano-twinned copper electroplating solution is 28-64 g / L; preferably, the copper ions are derived from copper sulfate.

[0017] In the above technical solution, further, the concentration of sulfuric acid in the nano-twinned copper electroplating solution is 5-180 g / L; preferably, the concentration of sulfuric acid in the nano-twinned copper electroplating solution is 10-150 g / L.

[0018] In the above technical solution, further, the concentration of chloride ions in the nano-twinned copper electroplating solution is 3 to 100 mg / L; preferably, the concentration of chloride ions in the nano-twinned copper electroplating solution is 10 to 60 mg / L; preferably, the chloride ions in the nano-twinned copper electroplating solution can be provided by hydrochloric acid and / or sodium chloride.

[0019] In the above technical solution, further, the concentration of the additive in the nano-twinned copper electroplating solution is 5 to 300 mg / L; preferably, the concentration of the additive in the nano-twinned copper electroplating solution is 30 to 200 mg / L.

[0020] The third aspect of the present invention provides a method for electroplating and preparing nano-twinned copper, and the electroplating and preparing method includes: electroplating on a substrate by using the above nano-twinned copper electroplating solution to obtain the nano-twinned copper.

[0021] In the above technical solution, further, the electroplating and preparing method includes: the substrate serves as a cathode, and the anode includes a soluble anode (such as a phosphor copper anode) or an insoluble anode (such as a platinum electrode), and using the nano-twinned copper electroplating solution, electroplating is carried out under the conditions that the electroplating temperature is 10 to 60 °C, the electroplating current density is 1 to 40 A / dm 2 , and the electroplating stirring speed is 400 to 1500 rpm to obtain the nano-twinned copper; the substrate is a conductive material, such as copper, titanium, gold, nickel, aluminum or their alloys.

[0022] The fourth aspect of the present invention provides a nano-twinned copper prepared by using the above electroplating and preparing method.

[0023] In the above technical solution, further, the nano-twinned copper has a strong (111) preferred orientation, and the (111) preferential degree is greater than 95%; the nano-twinned copper includes columnar crystals perpendicular to the substrate; the diameter of the columnar crystals is 0.1 to 20 μm; the inside of the nano-twinned copper contains a high density of horizontal twins, and the twin lamella thickness of the horizontal twins is 1 to 100 nm.

[0024] The fifth aspect of the present invention provides an application of the above nano-twinned copper electroplating additive and the above nano-twinned copper electroplating solution in electronic packaging and semiconductor manufacturing.

[0025] During the copper electrodeposition process, gelatinous additives will undergo periodic adsorption and desorption on the cathode surface, resulting in potential oscillations, which in turn lead to periodic accumulation and relaxation of stress, thus forming a twin structure. The present invention discovers that among gelatinous additives, components with high molecular weight (above 100,000 Da) have too many adsorption sites and a strong binding force with the cathode, making it impossible to desorb in a timely manner, which will significantly inhibit the acquisition of nano-twin structures; components with low molecular weight (below 10,000 Da) have fewer adsorption sites and a weak binding force with the cathode, and are prone to periodic adsorption and desorption, so they have a significant twin-promoting effect; the remaining components with medium molecular weight (10,000 - 100,000 Da) can also produce periodic adsorption and desorption, but the effect is significantly weaker than that of components with low molecular weight (below 10,000 Da), and have a relatively weak twin-promoting effect. Therefore, the present invention proposes to reduce the proportion of components with high molecular weight (above 100,000 Da) that have a twin-inhibiting effect, and at the same time increase the proportion of components with low molecular weight (below 10,000 Da) that have a twin-promoting effect, so that this specific composition of additives can play an excellent and stable twin-promoting role, improve the process stability and repeatability of nano-twin copper electroplating, broaden the electroplating process window. Electroplating with a nano-twin copper electroplating solution containing this additive can obtain a nano-twin copper coating with good tissue uniformity, excellent performance, and a (111) preferred orientation degree greater than 95%.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The nano-twin copper electroplating additive provided by the present invention has an excellent and stable twin-promoting effect, improves the process stability and repeatability of nano-twin copper electroplating, broadens the electroplating process window. Electroplating with a nano-twin copper electroplating solution containing this additive can obtain a nano-twin copper coating with excellent performance.

[0028] (2) The nano-twin copper coating prepared by the present invention has good tissue uniformity, has a strong (111) preferred orientation, and the (111) preferred orientation degree is greater than 95%. It contains columnar crystals perpendicular to the substrate, and the grain interior contains a high density of horizontal twins. The nano-twin copper coating has the characteristics of high conductivity, mechanical properties, high resistance to electromigration, oxidation resistance, and thermal stability, and can be applied to technical fields such as electronic packaging and integrated circuit manufacturing, including wafer-level electroplating, substrates, carrier plates, and application scenarios that require electroplating such as PCBs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an FIB diagram of the cross-sectional microstructure of the growth direction of the nano-twin copper coating obtained in Example 1.

[0030] Figure 2(a) is the EBSD IPF orientation map of the top microstructure of the nanocrystalline twin copper coating prepared in Example 1, Figure 2 (b) is the EBSD inverse pole figure of the top microstructure of the nanocrystalline twin copper coating prepared in Example 1.

[0031] Figure 3 (a) is the EBSD IPF orientation map of the top microstructure of the nanocrystalline twin copper coating prepared in Example 2, Figure 3 (b) is the EBSD inverse pole figure of the top microstructure of the nanocrystalline twin copper coating prepared in Example 2.

[0032] Figure 4 (a) is the EBSD IPF orientation map of the top microstructure of the nanocrystalline twin copper coating prepared in Example 3, Figure 4 (b) is the EBSD inverse pole figure of the top microstructure of the nanocrystalline twin copper coating prepared in Example 3.

[0033] Figure 5 (a) is the EBSD IPF orientation map of the top microstructure of the nanocrystalline twin copper coating prepared in Example 4, Figure 5 (b) is the EBSD inverse pole figure of the top microstructure of the nanocrystalline twin copper coating prepared in Example 4.

[0034] Figure 6 is the FIB image of the cross-sectional microstructure of the copper coating growth direction prepared in Comparative Example 1.

[0035] Figure 7 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 1, Figure 7 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 1.

[0036] Figure 8 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 2, Figure 8 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 2.

[0037] Figure 9 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 3, Figure 9 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 3.

[0038] Figure 10 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 4, Figure 10 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 4.

[0039] Figure 11 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 5, Figure 11 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 5.

[0040] Figure 12 (a) is the EBSD IPF orientation map of the top microstructure of the copper coating prepared in Comparative Example 6, Figure 12 (b) is the EBSD inverse pole figure of the top microstructure of the copper coating prepared in Comparative Example 6. Detailed implementation manners

[0041] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0042] Example 1

[0043] A nano-twinned copper electroplating additive, the preparation method includes: weighing 1 g of alkaline gelatin derived from cowhide and dissolving it in 100 mL of deionized water, heating it in a water bath to 60 °C and stirring to completely dissolve it to obtain a gelatin solution; using an ultrafiltration membrane with a cut-off molecular weight of 50000 Da to ultrafilter the gelatin solution to obtain the nano-twinned copper electroplating additive, the mass fraction of components with a molecular weight above 100000 Da is 3%, the mass fraction of components with a molecular weight below 10000 Da is 70%, and the rest are components with a molecular weight of 10000-100000 Da.

[0044] A nano-twinned copper electroplating solution, including the following components: 70 g / L of copper sulfate, 150 g / L of sulfuric acid, 20 ppm of chloride ions, 50 ppm of the nano-twinned copper electroplating additive provided in this example; the solvent is deionized water; wherein, the chloride ions are provided by sodium chloride. The preparation method of the nano-twinned copper electroplating solution includes: mixing copper sulfate, sulfuric acid, sodium chloride, the nano-twinned copper electroplating additive provided in this example and deionized water according to the foregoing ratio, and stirring evenly to obtain the nano-twinned copper electroplating solution.

[0045] Using the nano-twinned copper electroplating solution provided in this example to electroplate and prepare nano-twinned copper, using a titanium plate as the cathode and a soluble phosphorus copper anode as the anode, immersing the two in the nano-twinned copper electroplating solution provided in this example for electroplating, and the electroplating conditions are: constant temperature 25 °C, current density 3 A / dm 2 , and the speed of magnetic stirring is 600 rpm.

[0046] The cross-sectional microstructure of the growth direction of the nano-twinned copper coating prepared in this example is as Figure 1As shown, the cross-sectional structure of the nanocrystalline twin copper coating is columnar crystals perpendicular to the substrate. The diameter of the columnar crystals is about 2 - 4 μm, and there are high-density horizontal twins inside the grains. The thickness of the twin lamellae is 50 nm. The crystal orientation information of the nanocrystalline twin copper coating can be obtained by electron backscatter diffraction technology. As Figure 2 shown, the prepared nanocrystalline twin copper coating has a strong (111) preferred orientation, and the degree of (111) preference is 98.6%.

[0047] Example 2

[0048] A nanocrystalline twin copper electroplating additive, the preparation method includes: weighing 0.5 g of collagen and dissolving it in 100 mL of deionized water, heating it in a water bath to 60 °C and stirring to completely dissolve it to obtain a collagen solution; adding sodium hydroxide to adjust the pH to 10 - 12, heating to 90 °C, and hydrolyzing for 20 h under stirring conditions to obtain the nanocrystalline twin copper electroplating additive. The mass fraction of components with a molecular weight above 100,000 Da is 16%, the mass fraction of components with a molecular weight below 10,000 Da is 35%, and the rest are components with a molecular weight of 10,000 - 100,000 Da.

[0049] A nanocrystalline twin copper electroplating solution includes the following components: 90 g / L of copper sulfate, 120 g / L of sulfuric acid, 30 ppm of chloride ions, and 60 ppm of the nanocrystalline twin copper electroplating additive provided in this example; the solvent is deionized water; wherein, the chloride ions are provided by sodium chloride. The preparation method of the nanocrystalline twin copper electroplating solution includes: mixing copper sulfate, sulfuric acid, sodium chloride, the nanocrystalline twin copper electroplating additive provided in this example and deionized water according to the aforementioned ratio, and stirring evenly to obtain the nanocrystalline twin copper electroplating solution.

[0050] Using the nanocrystalline twin copper electroplating solution provided in this example to electroplate and prepare nanocrystalline twin copper, using a titanium plate as the cathode and a soluble phosphorus copper anode as the anode, and immersing the two in the nanocrystalline twin copper electroplating solution provided in this example for electroplating. The electroplating conditions are: constant temperature of 30 °C, current density of 5 A / dm 2 , and the speed of magnetic stirring is 1000 rpm.

[0051] The nanocrystalline twin copper coating prepared in this example contains columnar crystals perpendicular to the substrate. The diameter of the columnar crystals is about 2 - 3 μm, and there are high-density horizontal twins inside the grains. The thickness of the twin lamellae is 52 nm. The coating has a strong (111) preferred orientation, and the degree of (111) preference is 97.8%. As Figure 3 shown.

[0052] Example 3

[0053] A nano-twinned copper electroplating additive, the preparation method of which includes: weighing 1 g of acid-processed gelatin derived from pigskin and dissolving it in 100 mL of deionized water, heating it in a water bath to 60 °C and stirring to completely dissolve it to obtain a gelatin solution; adding sulfuric acid to adjust the pH to 1-2, heating to 80 °C, and hydrolyzing for 6 h under stirring conditions to obtain the nano-twinned copper electroplating additive, where the mass fraction of components with a molecular weight above 100,000 Da is 8%, the mass fraction of components with a molecular weight below 10,000 Da is 65%, and the rest are components with a molecular weight of 10,000-100,000 Da.

[0054] A nano-twinned copper electroplating solution, which includes the following components: 100 g / L of copper sulfate, 100 g / L of sulfuric acid, 50 ppm of chloride ions, and 80 ppm of the nano-twinned copper electroplating additive provided in this example; the solvent is deionized water; among them, the chloride ions are provided by sodium chloride. The preparation method of the nano-twinned copper electroplating solution includes: mixing copper sulfate, sulfuric acid, sodium chloride, the nano-twinned copper electroplating additive provided in this example, and deionized water according to the aforementioned ratio, and stirring evenly to obtain the nano-twinned copper electroplating solution.

[0055] Using the nano-twinned copper electroplating solution provided in this example to electroplate and prepare nano-twinned copper, using a copper plate as the cathode and a soluble phosphorus copper anode as the anode, and immersing the two in the nano-twinned copper electroplating solution provided in this example for electroplating. The electroplating conditions are: constant temperature of 30 °C, current density of 6 A / dm 2 , and the speed of magnetic stirring is 900 rpm.

[0056] The nano-twinned copper coating prepared in this example contains columnar crystals perpendicular to the substrate. The diameter of the columnar crystals is about 1-3 μm. There are high-density horizontal twins inside the grains. The thickness of the twin lamellae is 62 nm. The coating has a strong (111) preferred orientation, and the (111) preferred degree is 96.9%, as Figure 4 shown.

[0057] Example 4

[0058] A nano-twinned copper electroplating additive, the preparation method of which includes: weighing 1 g of enzyme-processed gelatin derived from fish skin and dissolving it in 100 mL of deionized water, heating it in a water bath to 60 °C and stirring to completely dissolve it to obtain a gelatin solution; adjusting the pH to 7-8, keeping the temperature constant at 37 °C, and hydrolyzing for 10 h in the presence of trypsin to obtain the nano-twinned copper electroplating additive, where the mass fraction of components with a molecular weight above 100,000 Da is 0, the mass fraction of components with a molecular weight below 10,000 Da is 90%, and the rest are components with a molecular weight of 10,000-100,000 Da.

[0059] A nano-twinned copper electroplating solution, comprising the following components: 130 g / L of copper sulfate, 60 g / L of sulfuric acid, 60 ppm of chloride ions, and 100 ppm of the nano-twinned copper electroplating additive provided in this example; the solvent is deionized water; wherein, the chloride ions are provided by sodium chloride. The preparation method of the nano-twinned copper electroplating solution includes: mixing copper sulfate, sulfuric acid, sodium chloride, the nano-twinned copper electroplating additive provided in this example and deionized water according to the foregoing ratio, and stirring evenly to obtain the nano-twinned copper electroplating solution.

[0060] Using the nano-twinned copper electroplating solution provided in this example to electroplate and prepare nano-twinned copper, using a titanium plate as the cathode and an insoluble platinum electrode as the anode, immersing the two in the nano-twinned copper electroplating solution provided in this example for electroplating, and the electroplating conditions are: constant temperature of 40 °C, current density of 10 A / dm 2 , and the speed of magnetic stirring is 1200 rpm.

[0061] The nano-twinned copper coating prepared in this example contains columnar crystals perpendicular to the substrate. The diameter of the columnar crystals is about 1-2 μm. There are high-density horizontal twins inside the grains. The thickness of the twin lamellae is 75 nm. The coating has a strong (111) preferred orientation, and the (111) preferred degree is 97.4%, as Figure 5 shown.

[0062] Comparative Example 1

[0063] Compared with Example 1, the difference in this comparative example is only that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is unseparated alkaline gelatin derived from cowhide, and the mass fraction of the components with a molecular weight above 100,000 Da is 70%, and the mass fraction of the components with a molecular weight below 10,000 Da is 5%, and the rest are components with a molecular weight of 10,000-100,000 Da.

[0064] Applying the nano-twinned copper electroplating solution of this comparative example, the cross-sectional microstructure in the growth direction of the prepared copper coating is as Figure 6 shown, and the copper coating does not contain a twin structure, and the crystal orientation is as Figure 7 shown. The prepared copper coating has a random orientation and fine grain size.

[0065] Comparative Example 2

[0066] Compared with Example 2, the difference in this comparative example is only that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is collagen without alkali-catalyzed hydrolysis, and the mass fraction of the components with a molecular weight above 100,000 Da is 95%, and the mass fraction of the components with a molecular weight below 10,000 Da is 0, and the rest are components with a molecular weight of 10,000-100,000 Da.

[0067] Using the nano-twinned copper electroplating solution of this comparative example, the obtained copper coating has a random orientation, small grain size, and does not contain a twin structure, as Figure 8 shown.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 2 is only that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is collagen hydrolyzed by alkali catalysis, and the mass fraction of components with a molecular weight above 100,000 Da is 15%, and the mass fraction of components with a molecular weight below 10,000 Da is 25%, and the rest are components with a molecular weight of 10,000 - 100,000 Da.

[0070] Using the nano-twinned copper electroplating solution of this comparative example, the obtained copper coating has a random orientation, small grain size, and does not contain a twin structure, as Figure 9 shown.

[0071] Comparative Example 4

[0072] The difference between this comparative example and Example 3 is only that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is acid-processed gelatin derived from pigskin that has not been hydrolyzed by acid catalysis, and the mass fraction of components with a molecular weight above 100,000 Da is 50%, and the mass fraction of components with a molecular weight below 10,000 Da is 20%, and the rest are components with a molecular weight of 10,000 - 100,000 Da.

[0073] Using the nano-twinned copper electroplating solution of this comparative example, the obtained copper coating has a random orientation, small grain size, and does not contain a twin structure, as Figure 10 shown.

[0074] Comparative Example 5

[0075] The difference between this comparative example and Example 3 is only that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is acid-processed gelatin derived from pigskin that has been hydrolyzed by acid catalysis, and the mass fraction of components with a molecular weight above 100,000 Da is 35%, and the mass fraction of components with a molecular weight below 10,000 Da is 50%, and the rest are components with a molecular weight of 10,000 - 100,000 Da.

[0076] Using the nano-twinned copper electroplating solution of this comparative example, the obtained copper coating has a random orientation, small grain size, and does not contain a twin structure, as Figure 11 shown.

[0077] Comparative Example 6

[0078] This comparative example is different from Example 4 only in that: the nano-twinned copper electroplating additive in the nano-twinned copper electroplating solution is enzymatically hydrolyzed gelatin derived from fish skin without trypsin catalysis, the mass fraction of components with a molecular weight above 100,000 Da is 60%, the mass fraction of components with a molecular weight below 10,000 Da is 20%, and the rest are components with a molecular weight of 10,000 - 100,000 Da, such as Figure 12 shown.

[0079] Using the nano-twinned copper electroplating solution of this comparative example, the prepared copper coating has a random orientation, small grain size, and does not contain a twin structure.

[0080] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. A nano twinned copper electroplating additive, characterized in that: The nano twinned copper electroplating additive is obtained by hydrolyzing or separating collagen, gelatin or a derivative thereof; The components of the nano twinned copper electroplating additive need to meet the following requirements: The mass fraction of components with a molecular weight of more than 100,000 Da is 0 to 20%; The mass fraction of components with molecular weight below 10000Da is 30% to 100%; The rest are components with molecular weights ranging from 10,000 to 100,000 Da.

2. The nano twinned copper electroplating additive according to claim 1, characterized in that: The mass fraction of components with a molecular weight of more than 100,000 Da is 0-10%, the mass fraction of components with a molecular weight of less than 10,000 Da is 50%-100%, and the rest are components with a molecular weight of 10,000-100,000 Da.

3. The nano twinned copper electroplating additive according to claim 1, characterized in that: The gelatin includes one or more of acid-processed gelatin, alkaline-processed gelatin, and enzymatic-processed gelatin; the hydrolysis method includes one or more of acid-catalyzed hydrolysis, alkaline-catalyzed hydrolysis, and enzyme-catalyzed hydrolysis; the separation method includes one or more of ultrafiltration, dialysis, molecular sieve, gel filtration, and electrophoresis.

4. A nano twinned copper electroplating solution, characterized in that: The nano-twinned copper electroplating solution comprises the nano-twinned copper electroplating additive according to claim 1.

5. The nano-twinned copper electroplating solution according to claim 4, characterized in that: The nano twin copper electroplating solution comprises copper ions, sulfuric acid and chloride ions.

6. The nano-twinned copper electroplating solution according to claim 5, characterized in that: The concentration of copper ions in the nano-twinned copper electroplating solution is 20-80 g / L; preferably, the copper ions are derived from copper sulfate; The concentration of sulfuric acid in the nano-twinned copper electroplating solution is 5 to 180 g / L; The concentration of chloride ions in the nano-twinned copper electroplating solution is 3-100 mg / L; preferably, the chloride ions are derived from hydrochloric acid and / or sodium chloride; The concentration of the additive in the nano-twinned copper electroplating solution is 5-300 mg / L.

7. A method for preparing nano-twinned copper by electroplating, characterized in that: The electroplating preparation method comprises: electroplating on a substrate using the nano-twin copper electroplating solution as described in any one of claims 4 to 6 to obtain the nano-twin copper.

8. The electroplating preparation method according to claim 7, characterized in that: The electroplating temperature is 10-60°C; The stirring speed of the electroplating solution is 400-1500 rpm; The current density of the electroplating is 1 to 40 A / dm 2 .

9. A nano twinned copper material, characterized in that: Prepared by any method of claims 7-8, the nano-twin copper has a strong (111) preferred orientation, the (111) preference degree is greater than 95%, the nano-twin copper comprises columnar crystals perpendicular to the substrate, the diameter of the columnar crystals is 0.1 to 20 μm, the nano-twin copper contains high-density horizontal twins, and the twin layer thickness of the horizontal twins is 1 to 100 nm.

10. Use of the nano-twin copper electroplating additive according to any one of claims 1 to 3 and the nano-twin copper electroplating solution according to any one of claims 4 to 6 in electronic packaging and semiconductor manufacturing.

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