Oxygen-free sintering method of interconnected sample based on copper paste and electronic device

Abstract

The invention provides an oxygen-free sintering method of an interconnection sample based on copper paste and an electronic device, and the oxygen-free sintering method of the interconnection sample based on the copper paste comprises the steps: dissolving a raw material of the copper paste in a solvent to obtain copper paste slurry; wherein the solvent comprises an acid solvent, a reducing solvent and an organic solvent; preparing an interconnection sample through the upper substrate, the lower substrate and the copper paste slurry; and carrying out anaerobic sintering on the interconnected sample. The components of the solvent are changed, the conventional organic solvent is adjusted into the mixed solvent of the acid solvent, the reducing solvent and the organic solvent, so that the acid solvent can remove oxidation films on the surfaces of the copper particles, the reducing solvent can further reduce the oxidation degree of the copper particles, sintering is carried out in an oxygen-free environment, and the yield of the copper particles is improved. In the whole sintering process, oxygen oxidation can be avoided, so that the prepared interconnection sample is good in stability and higher in connection strength.

Description

Technical Field

[0001] The invention relates to the technical field of electronic products, and in particular to an oxygen-free sintering method for interconnection samples based on copper paste and an electronic device. Background Art

[0002] The current interconnect samples are all sintered by an oxidation + reduction method, which has a long sintering process and low preparation efficiency. Summary of the invention

[0003] The present invention aims to solve or improve the technical problems of the traditional sintering method in the prior art, that is, the sintering process takes a long time and the preparation efficiency is low.

[0004] A first aspect of the present invention is to provide an oxygen-free sintering method for an interconnection sample based on copper paste, comprising: dissolving the raw materials of the copper paste in a solvent to obtain a copper paste slurry; wherein the solvent comprises an acidic solvent, a reducing solvent and an organic solvent; preparing an interconnection sample by an upper substrate, a lower substrate and the copper paste slurry; and performing oxygen-free sintering on the interconnection sample.

[0005] The oxygen-free sintering method provided by the present invention first dissolves the raw materials of the copper paste in a solvent to obtain a copper paste slurry, wherein the solvent includes an acidic solvent, a reducing solvent and an organic solvent, and then prepares an interconnection sample through an upper substrate, a lower substrate and the copper paste slurry, and performs oxygen-free sintering on the interconnection sample to obtain a sintered interconnection sample. The present invention changes the composition of the solvent, and adjusts the conventional organic solvent to a mixed solvent of an acidic solvent, a reducing solvent and an organic solvent, so that the acidic solvent can remove the oxide film on the surface of the copper particles, and the reducing solvent can further reduce the oxidation degree of the copper particles, so that sintering is performed in an oxygen-free environment. Since oxidation by oxygen can be avoided during the entire sintering process, the prepared interconnection sample has good stability and higher connection strength. In addition, since there is no oxidation in the entire process, the entire sintering process does not involve reduction sintering, so there is no need to provide reducing gas, which reduces the danger of reducing gas to the experimental operator and the corrosiveness to the equipment, so that the entire preparation process is safer and more environmentally friendly. In addition, since the acidic solvent can remove the oxide layer on the surface of the copper particles, the copper particles prepared by the atomization method purchased on the market can be directly used as raw materials without selecting high-purity copper particles prepared by chemical reduction, which saves time in preparing the copper paste raw materials.

[0006] In the above technical solution, optionally, the acidic solvent includes lactic acid and / or ascorbic acid.

[0007] In this technical solution, lactic acid and / or ascorbic acid can better remove the oxide film on the surface of copper particles and improve the connection strength of interconnected samples.

[0008] In the above technical solution, optionally, the reducing solvent includes isopropanolamine.

[0009] In this technical solution, isopropanolamine can further reduce the oxidation degree of copper particles and improve the connection strength of interconnected samples.

[0010] In the above technical solution, optionally, the organic solvent includes terpineol.

[0011] In this technical solution, pinene alcohol can fully dissolve copper particles and improve the joint connection strength of the interconnected samples.

[0012] In the above technical solution, optionally, the step of performing oxygen-free sintering on the interconnected sample specifically includes: heating the interconnected sample in an oxygen-free environment, heating the interconnected sample at a first preset heating rate, and after the interconnected sample reaches the first preset temperature, keeping the temperature for a first preset time.

[0013] In this technical solution, during the sintering process of the interconnected samples, only oxygen-free sintering is performed, and no reduction sintering is performed, which greatly improves the sintering efficiency. Since there is no need to provide reducing gas, the danger of reducing gas to the experimental operators and the corrosiveness to the equipment are reduced, which makes the entire preparation process safer and more environmentally friendly.

[0014] In the above technical solution, optionally, the first preset heating rate is greater than or equal to 1°C / s and less than or equal to 2°C / s; the first preset temperature is greater than or equal to 200°C and less than or equal to 300°C; the first preset time is greater than or equal to 20min and less than or equal to 40min.

[0015] In this technical solution, controlling the heating rate, insulation temperature and insulation time during the sintering process can better enable the copper particles to form a sintered layer and improve the joint connection strength of the interconnected samples. In addition, since the present invention does not involve the participation of oxygen in the entire sintering step, the formation of an oxide layer is avoided, so that the sintering temperature of the present invention can be relatively low and the sintering time is greatly shortened. Optionally, the first preset heating rate is equal to 1°C / s, 1.5°C / s or 2°C / s, the first preset temperature is 200°C, 240°C, 260°C or 300°C; the first preset time is equal to 20min, 30min or 40min.

[0016] In the above technical solution, optionally, the oxygen-free environment includes a nitrogen environment.

[0017] In this technical solution, oxygen-free sintering is performed in a nitrogen environment to prevent copper particles from being oxidized and improve the strength of the connection joint.

[0018] In the above technical solution, optionally, the step of performing oxygen-free sintering on the interconnected sample specifically includes: placing the interconnected sample in a fixture, applying pressure on the upper surface of the upper substrate toward the lower substrate through the fixture, and placing the interconnected sample under pressure in a sintering furnace for oxygen-free sintering.

[0019] In this technical solution, before the sintering step, pressure is applied to the upper surface of the upper substrate toward the lower substrate through a clamp, which can improve the density of the sintered microstructure, make the sintering preparation process stable and repeatable, and improve the mechanical properties of the joint.

[0020] In the above technical solution, optionally, the mass percentage of the raw material mass of the copper paste to the total mass of the raw material of the copper paste and the solvent is greater than or equal to 75% and less than or equal to 85%.

[0021] In this technical solution, the mass percentage of the raw materials of the copper paste to the total mass of the raw materials and solvent of the copper paste is controlled to be greater than or equal to 75%, and less than or equal to 85%, for example 80%. This can ensure that the raw materials of the copper paste are sufficient, ensure that a stable sintering layer can be formed during the sintering process, improve the density of the microstructure, and improve the mechanical properties of the joint.

[0022] In the above technical solution, optionally, the method for oxygen-free sintering of copper paste-based interconnection samples further includes: after the step of oxygen-free sintering the interconnection samples, cooling the interconnection samples to a second preset temperature at a second cooling rate.

[0023] In this technical solution, after the oxygen-free sintering step, the interconnected sample is cooled to make the structural properties of the connection joint more stable. Optionally, the second cooling rate is greater than or equal to 1°C / s and less than or equal to 2°C / s, such as 1.5°C / s; the second preset temperature is greater than or equal to 25°C and less than or equal to 50°C, such as 40°C.

[0024] The technical solution of the second aspect of the present invention provides an electronic device, including an interconnection sample, which is sintered by the oxygen-free sintering method of the copper paste-based interconnection sample provided by any technical solution of the first aspect of the present invention.

[0025] Since the electronic device provided by the present invention includes an interconnection sample, and the interconnection sample is sintered by the oxygen-free sintering method of the interconnection sample based on copper paste provided by any technical solution of the first aspect, the electronic device of the present invention has all the beneficial effects of the oxygen-free sintering method of the interconnection sample based on copper paste provided by any technical solution of the first aspect of the present invention.

[0026] Additional aspects and advantages of the present invention will become apparent in the following description or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the embodiments of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A preparation flow chart of an oxygen-free sintering method for interconnection samples based on copper paste provided by an embodiment of the present invention is shown; Figure 2 One of the temperature-time relationship diagrams of the oxygen-free sintering method of the copper paste-based interconnection sample provided by the embodiment of the present invention is shown; Figure 3 The second temperature-time relationship diagram of the oxygen-free sintering method of the interconnection sample based on the copper paste provided by the embodiment of the present invention is shown; Figure 4 A microstructure diagram of an interconnection sample prepared by an oxygen-free sintering method of an interconnection sample based on a copper paste provided by an embodiment of the present invention is shown; Figure 5 A printed schematic diagram of an interconnection sample of the present invention is shown; Figure 6 A schematic diagram showing the state of copper particles and solvent before mixing provided by an embodiment of the present invention is shown; Figure 7 A schematic diagram showing a state after copper particles and a solvent are mixed according to an embodiment of the present invention is shown; Figure 8 A structural diagram of an interconnection sample provided by an embodiment of the present invention is shown; Fig. 9 A schematic diagram showing the structure of an electronic device provided by an embodiment of the present invention is shown; Fig.10 A diagram showing the structure of a mounting fixture for interconnection samples of the present invention.

[0028] in, Figures 5 to 10 The corresponding relationship between the reference numerals and component names in the figure is: 1 placing table, 21 upper substrate, 22 lower substrate, 3 printing steel plate, 34 copper paste printing hole, 4 scraper, 5 copper paste slurry, 61 acid solvent, 62 reducing solvent, 63 organic solvent, 64 copper particles, 7 interconnection sample, 8 electronic device, 9 fixture, 91 upper fixture, 92 lower fixture. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above aspects, features and advantages of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments according to the present invention. However, the embodiments according to the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the embodiments according to the present invention is not limited to the specific embodiments disclosed below.

[0031] Embodiment 1

[0032] like Figure 1 As shown, the oxygen-free sintering method of the interconnection sample based on copper paste provided in this embodiment includes the following steps: S102: dissolving 8 g of raw materials of the copper paste in 2 g of a solvent, wherein the solvent is a mixed solvent of lactic acid, isopropanolamine and terpineol; Among them, we need to understand Figure 6 and Figure 7 As shown, the raw material of the copper paste, namely copper particles 64 , an acidic solvent 61 , a reducing solvent 62 , an organic solvent 63 and the copper particles 64 are simultaneously put into a beaker to form a copper paste slurry 5 .

[0033] S104: preparing an interconnection sample by using an upper substrate, a lower substrate and a copper paste slurry; S106: placing the interconnected sample in a sintering furnace, exhausting the air and introducing nitrogen gas, heating the sample from room temperature at a rate of 1°C / s, and maintaining the temperature at 250°C for 30 minutes.

[0034] Embodiment 2

[0035] The sintering steps of this embodiment differ from those of the first embodiment in that the solvent is a mixed solvent of ascorbic acid, isopropanolamine and terpineol, and the remaining steps are the same.

[0036] Embodiment 3

[0037] The difference between the sintering steps of this embodiment and the first embodiment is that in the process of oxygen-free sintering in this embodiment, pressure is applied to the upper surface of the upper substrate in the direction of the lower substrate by a clamp, and oxygen-free sintering is performed on the interconnected samples under pressure.

[0038] Comparative Example 1 The difference between the sintering step of this comparative example and that of Example 1 is that the solvent is terpineol, and the other steps are the same.

[0039] Comparative Example 2 The difference between the sintering step of this comparative example and that of Example 1 is that the solvent is a mixed solvent of ascorbic acid and terpineol, and the other steps are the same.

[0040] Comparative Example 3 The difference between the sintering step of this comparative example and that of Example 1 is that the solvent is a mixed solvent of isopropanolamine and terpineol, and the other steps are the same.

[0041] The interconnected samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to mechanical tensile property tests, and the test standard was GB / T 1450.1-Test method for interlaminar shear strength of fiber reinforced plastics. The test results are shown in Table 1 below: test Shear Strength Embodiment 1 28MPa Embodiment 2 30MPa Embodiment 3 27MPa Comparative Example 1 22MPa Comparative Example 2 23MPa Comparative Example 3 21MPa Table 1 As can be seen from Table 1, in Examples 1 to 3 of the present invention, a mixed solvent of an acidic solvent 61, a reducing solvent 62 and an organic solvent 63 is used, so that the acidic solvent 61 can remove the oxide film on the surface of the copper particles 64, and the reducing solvent 62 can further reduce the oxidation degree of the copper particles 64. In this way, sintering is performed in an oxygen-free environment. During the entire sintering process, the copper particles 64 can be prevented from being oxidized by oxygen. Figure 8 As shown, the prepared interconnection sample 7 has good stability and higher shear strength, while in comparative example 1, the solvent is only pineol, so during the sintering process, the copper particles 64 are easily oxidized and the shear strength is the lowest. In comparative examples 2 and 3, the solvent contains only one of isopropanolamine and ascorbic acid, which cannot completely avoid the formation of oxide film on the surface of the copper particles 64. Although the shear strength is slightly improved compared with comparative example 1, it is far less than the shear strength of the interconnection sample 7 prepared in the embodiment.

[0042] Another embodiment of the present invention provides an oxygen-free sintering method for an interconnection sample based on copper paste. Specifically, the raw materials of the copper paste are dissolved in a solvent to obtain a copper paste slurry 5; wherein the solvent includes an acidic solvent 61, a reducing solvent 62 and an organic solvent 63; an interconnection sample 7 is prepared by an upper substrate 21, a lower substrate 22 and the copper paste slurry 5; and the interconnection sample 7 is subjected to oxygen-free sintering.

[0043] The oxygen-free sintering method provided by the present invention first dissolves the raw materials of the copper paste in a solvent to obtain a copper paste slurry 5, wherein the solvent includes an acidic solvent 61, a reducing solvent 62 and an organic solvent 63, and then prepares an interconnection sample 7 through the upper substrate 21, the lower substrate 22 and the copper paste slurry 5, and performs oxygen-free sintering on the interconnection sample 7 to obtain the sintered interconnection sample 7. The present invention changes the composition of the solvent, and adjusts the conventional organic solvent 63 to a mixed solvent of an acidic solvent 61, a reducing solvent 62 and an organic solvent 63, so that the acidic solvent 61 can remove the oxide film on the surface of the copper particles 64, and the reducing solvent 62 can further reduce the oxidation degree of the copper particles 64, so that the sintering is performed in an oxygen-free environment, and since it can avoid being oxidized by oxygen during the entire sintering process, the prepared interconnection sample 7 has good stability and higher connection strength. In addition, in the whole process, since there is no oxidation, the whole sintering process does not involve reduction sintering, so there is no need to provide reducing gas, which reduces the danger of reducing gas to the experimental operator and the corrosion to the equipment, making the whole preparation process safer and more environmentally friendly. In addition, since the acidic solvent 61 can remove the oxide layer on the surface of the copper particles 64, the copper particles 64 prepared by the atomization method purchased on the market can be directly used as raw materials, without the need to select high-purity copper particles 64 prepared by chemical reduction, which saves time in preparing the raw materials of the copper paste.

[0044] In the above embodiment, optionally, the acidic solvent 61 includes lactic acid and / or ascorbic acid.

[0045] In this embodiment, lactic acid and / or ascorbic acid can better remove the oxide film on the surface of the copper particles 64 and improve the connection strength of the interconnection sample 7 .

[0046] In the above embodiment, optionally, the reducing solvent 62 includes isopropanolamine.

[0047] In this embodiment, isopropanolamine can further reduce the oxidation degree of copper particles 64 and improve the connection strength of interconnection sample 7 .

[0048] In the above embodiment, optionally, the organic solvent 63 includes terpineol.

[0049] In this embodiment, pinene alcohol can fully dissolve the copper particles 64 and improve the joint connection strength of the interconnection sample 7 .

[0050] In the above embodiment, optionally, the step of performing oxygen-free sintering on the interconnect sample 7 specifically includes: heating the interconnect sample 7 in an oxygen-free environment, heating the interconnect sample 7 at a first preset heating rate, and after the interconnect sample 7 reaches the first preset temperature, keeping the temperature for a first preset time.

[0051] In this embodiment, during the sintering process of the interconnected sample 7, only oxygen-free sintering is performed, and reduction sintering is not performed, which greatly improves the sintering efficiency. Since there is no need to provide reducing gas, the danger of reducing gas to the experimental operator and the corrosiveness to the equipment are reduced, which makes the entire preparation process safer and more environmentally friendly.

[0052] In the above embodiment, optionally, the first preset heating rate is greater than or equal to 1°C / s and less than or equal to 2°C / s; the first preset temperature is greater than or equal to 200°C and less than or equal to 300°C; the first preset time is greater than or equal to 20 minutes and less than or equal to 40 minutes.

[0053] In this embodiment, the heating rate, insulation temperature and insulation time during the sintering process are controlled, so that the copper particles 64 can form a sintering layer better and improve the joint connection strength of the interconnected sample 7. In addition, since the present invention does not involve the participation of oxygen in the entire sintering step, the formation of an oxide layer is avoided, so that the sintering temperature of the present invention can be relatively low and the sintering time is greatly shortened. Optionally, the first preset heating rate is equal to 1°C / s, 1.5°C / s or 2°C / s, the first preset temperature is 200°C, 240°C, 260°C or 300°C; the first preset time is equal to 20min, 30min or 40min.

[0054] In the above embodiment, optionally, the oxygen-free environment includes a nitrogen environment.

[0055] In this embodiment, oxygen-free sintering is performed in a nitrogen environment to prevent the copper particles 64 from being oxidized and improve the strength of the connection joint.

[0056] In the above embodiment, optionally, the step of performing oxygen-free sintering on the interconnection sample 7 specifically includes: placing the interconnection sample 7 in a fixture 9, applying pressure to the upper surface of the upper substrate 21 in the direction of the lower substrate 22 through the fixture 9, such as Fig.10 As described above, the fixture 9 includes an upper fixture 91 and a lower fixture 92, and the interconnection sample 7 in a compressed state is placed in a sintering furnace for oxygen-free sintering.

[0057] In this embodiment, before the sintering step, pressure is applied to the upper surface of the upper substrate 21 toward the lower substrate 22 by the clamp 9, so that the density of the sintered microstructure is improved, the sintering preparation process is stable and repeatable, and the mechanical properties of the joint are improved.

[0058] In the above embodiment, optionally, the mass percentage of the raw material mass of the copper paste to the total mass of the raw material of the copper paste and the solvent is greater than or equal to 75% and less than or equal to 85%.

[0059] In this embodiment, the mass percentage of the raw material mass of the copper paste to the total mass of the raw material and the solvent of the copper paste is controlled to be greater than or equal to 75%, and less than or equal to 85%, which can ensure that the raw material consumption of the copper paste is sufficient, ensure that a stable sintering layer can be formed during the sintering process, improve the density of the microstructure, and improve the mechanical properties of the joint.

[0060] In the above embodiment, optionally, the method for oxygen-free sintering of interconnection samples based on copper paste further includes: after the step of oxygen-free sintering the interconnection sample 7 , cooling the interconnection sample 7 to a second preset temperature at a second cooling rate.

[0061] In this embodiment, after the oxygen-free sintering step, the interconnection sample 7 is cooled to make the microstructure and performance of the connection joint more stable. Optionally, the second cooling rate is greater than or equal to 1°C / s and less than or equal to 2°C / s, for example, 1.5°C / s; the second preset temperature is greater than or equal to 25°C and less than or equal to 50°C, for example, 40°C.

[0062] Another embodiment of the present invention provides a low-pressure, low-temperature, oxygen-free sintering method for preparing a copper paste using copper particles 64, the method comprising the following steps: Step 1: Prepare copper paste slurry 5 using copper particles 64: stir and mix micron-sized pure copper particles 64 and acidic solvent 61 for multiple times, then wash with reducing solvent 62 to obtain copper particles 64, and then stir and mix with organic solvent 63 and copper particles 64 for multiple times to obtain copper paste, wherein the mass percentage of pure copper particles 64 in the copper paste is 75%-85%; Step 2, preparing the printed steel plate 3: using modeling software to model the printed steel plate 3, reserving edge positioning holes for the lower substrate 22 on the printed steel plate 3, and then reserving copper paste printing holes 34 for coating copper paste, and then obtaining the corresponding printed steel plate 3 by laser printing or other methods, wherein the thickness of the printed steel plate 3 can be 0.05mm-0.2mm; Step 3: Prepare interconnection sample 7 using printed steel plate 3 and copper paste 5: Figure 5 As shown, the printed steel plate 3 is placed on the placement table 1, the lower substrate 22 is placed under the printed steel plate 3, and the lower substrate 22 is fixed at a specified position through the edge positioning holes of the printed steel plate 3. Then, the copper paste slurry 5 obtained above is applied to the corresponding lower substrate 22 from the position of the copper paste printing hole 34 by a scraper 4 through a screen printing method, and the copper paste slurry 5 is repeatedly applied to evenly distribute the copper paste slurry 5 and to be in the same plane as the upper plane of the printed steel plate 3. The printed steel plate 3 is gently removed, and finally the upper substrate 21 is placed on the lower substrate 22 accordingly; Step 4, oxygen-free sintering: Place the interconnection sample 7 on the sintering furnace platform, remove air and introduce nitrogen gas to prevent oxygen from oxidizing the copper paste in the sintering furnace, and heat up at a rate of 1°C / s-2°C / s from room temperature. During the heating process, the organic solvent 63 evaporates. After reaching the set sintering temperature of 200°C-300°C, keep warm for 20min-40min. Step 5: Cooling: Place the interconnection sample 7 in a sintering furnace and cool it down from a high temperature at a rate of 1°C / s-2°C / s. Reduce the temperature to 40°C, remove the gas in the cavity, fill with hot nitrogen to keep the pressure balance in the cavity, and cool down for 30min-50min. Among them, in step 4 and step 5, the heating process is as follows Figure 2 As shown, the interconnection sample 7 is first heated to 300°C at a heating rate of 1°C / s-2°C / s, then kept at this temperature for 20min-40min, and then cooled to 40°C at a cooling rate of 1°C / s-2°C / s to obtain the interconnection sample 7, or the heating process is as follows Figure 3 As shown, the interconnection sample 7 is first heated to 250°C at a heating rate of 1°C / s-2°C / s, then kept warm for 20min-40min, and then cooled to 40°C at a cooling rate of 1°C / s-2°C / s to obtain the interconnection sample 7.

[0063] Step 6: Obtaining the interconnection sample 7: Opening the sintering furnace cavity, obtaining the interconnection sample 7 after sintering, wherein the microstructure of the fracture surface of the interconnection sample 7 after shearing is as follows: Figure 4 As shown, Figure 4 In the figure, (a), (b) and (c) are cross-sectional microstructure diagrams at three different scales.

[0064] Among them, the acidic solvent in step 1 includes lactic acid, ascorbic acid, etc., the reducing solution is isopropanolamine, and the organic solvent 63 is pineneol.

[0065] The modeling software in step 2 can be CAD, SolidWorks, etc. The thickness of the printed steel plate 3 is equal to the thickness of the copper paste coated on the lower substrate 22. The edge positioning holes are set at the main corners of the lower substrate 22, and if it is a quadrilateral, it is the four vertices.

[0066] In step three, the upper substrate 21 and the lower substrate 22 are both copper blocks with copper surfaces, simulating a chip with a copper layer on the bottom and a DBC substrate with a copper layer on the top, to achieve full copper packaging.

[0067] In step 4, the interconnection sample 7 is placed under the iron block, and a certain pressure is applied to the interconnection sample 7 to promote the sintering of the copper paste and the contact between the copper paste and the substrate.

[0068] The sintering process of step 4 and step 5 is carried out under nitrogen.

[0069] Step 6: Before opening the cavity, the volatile gas of the organic solvent 63 and the nitrogen mixture in the cavity are removed, and the cavity is opened after the air pressure in the cavity is balanced by filling with hot nitrogen.

[0070] The invention provides a low-pressure, low-temperature, oxygen-free sintering method for preparing copper paste using copper particles 64, and the specific steps are: preparing copper paste, preparing a printed steel plate 3, printing, preparing an interconnection sample 7, oxygen-free sintering, and cooling. Compared with the copper paste sintered sample sintered under pressure or low pressure in an oxidizing-reducing atmosphere, the copper paste interconnection sample 7 obtained by the invention does not need to undergo the steps of oxidizing sintering and sintering in a reducing gas, which reduces the danger of reducing gas to the experimental operator and the corrosiveness to the equipment. Sintering in a nitrogen environment can isolate oxygen from oxidizing the copper paste, and the operation process is safe and low-cost. Compared with the method of chemical reduction to prevent the oxidation of copper particles 64, for example, the method of preparing copper paste after replacing copper particles 64 with a solution containing copper ions, the step of replacing copper particles 64 is simplified, and copper particles 64 that are easily available on the market after atomization can be selected, which saves the materials and time required for preparing copper paste. At the same time, the efficiency of preparing copper paste is improved. The optimized copper paste is then prepared by changing the solution, so that the copper particles are in the liquid and isolated from oxygen, which is convenient for the formation of the sintering layer. The preparation process is simplified, and the time for preparing the interconnection sample 7 is greatly shortened. Compared with the use of organic solvent 63 to prepare copper paste, an acidic solvent can be used to remove the oxide film on the surface of copper particles 64. The copper paste is then prepared using a reducing agent and an organic solvent 63 to reduce the degree of oxidation of copper particles 64, which is beneficial to the subsequent sintering process. The introduction of nitrogen during the sintering process can prevent the copper particles 64 from being oxidized by oxygen. The method has good stability and repeatability, and there is no need to polish the interconnection substrate to remove the oxide film, which expands the scope of application.

[0071] like Fig. 9 As shown, an embodiment of the second aspect of the present invention provides an electronic device 8, including an interconnection sample 7, and the interconnection sample 7 is sintered by the oxygen-free sintering method of the copper paste-based interconnection sample provided by any embodiment of the first aspect of the present invention.

[0072] Since the electronic device 8 provided by the present invention includes the interconnection sample 7, and the interconnection sample 7 is sintered by the oxygen-free sintering method of the interconnection sample based on copper paste provided by any embodiment of the first aspect, the electronic device 8 of the present invention has all the beneficial effects of the oxygen-free sintering method of the interconnection sample based on copper paste provided by any embodiment of the first aspect of the present invention.

[0073] In the embodiments according to the present invention, the terms "first", "second", and "third" are only used for description and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments according to the present invention can be understood according to specific circumstances.

[0074] In addition, although each operation is described in a specific order, this should be understood as requiring such operation to be performed in a specific order or in a sequential order, or requiring that all illustrated operations should be performed to obtain desired results. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present invention. Some features described in the context of a separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation can also be implemented in multiple implementations individually or in any suitable sub-combination mode.

[0075] Although the subject matter has been described in the language of specific structural features and / or method logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.

[0076] The above are only preferred embodiments according to the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various modifications and changes may be made according to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. An oxygen-free sintering method for interconnection samples based on copper paste, characterized in that: include: Dissolving the raw materials of the copper paste in a solvent to obtain a copper paste slurry, wherein the solvent includes an acidic solvent, a reducing solvent and an organic solvent; Prepare the interconnection sample by using an upper substrate, a lower substrate and the copper paste slurry; The interconnect samples were subjected to oxygen-free sintering.

2. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The acidic solvent includes lactic acid and / or ascorbic acid.

3. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The reducing solvent includes isopropanolamine.

4. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The organic solvent includes terpineol.

5. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The step of performing oxygen-free sintering on the interconnection sample specifically comprises: In an oxygen-free environment, the interconnected sample is heated to increase the temperature of the interconnected sample at a first preset heating rate, and after the interconnected sample reaches the first preset temperature, the temperature is kept constant for a first preset time.

6. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 5, characterized in that: The first preset heating rate is greater than or equal to 1°C / s and less than or equal to 2°C / s; The first preset temperature is greater than or equal to 200° C. and less than or equal to 300° C.; The first preset duration is greater than or equal to 20 minutes and less than or equal to 40 minutes.

7. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 5, characterized in that: The oxygen-free environment includes a nitrogen environment.

8. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The step of performing oxygen-free sintering on the interconnection sample specifically comprises: The interconnection sample is placed in a fixture, and pressure is applied to the upper surface of the upper substrate toward the lower substrate through the fixture. The interconnection sample under pressure is placed in a sintering furnace for oxygen-free sintering.

9. The oxygen-free sintering method of the copper paste-based interconnection sample according to claim 1, characterized in that: The mass percentage of the raw material mass of the copper paste to the total mass of the raw material of the copper paste and the solvent is greater than or equal to 75% and less than or equal to 85%.

10. An electronic device, characterized in that: include: An interconnection sample is sintered by the oxygen-free sintering method of the copper paste-based interconnection sample according to any one of claims 1 to 9.

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