Anti-aging laser chip electrode protection layer process

Abstract

The present application relates to the technical field of electrode protection layer, in particular to an anti-aging laser chip electrode protection layer process, which comprises the following steps: using No. 1 standard cleaning solution and No. 2 standard cleaning solution to pre-clean the surface of a laser chip wafer, then rinsing with ultrapure water and drying under nitrogen gas flow; using an electron beam evaporation system to sequentially deposit a metal electrode layer on the wafer surface; after deposition, performing patterning treatment by using positive photoresist, and forming an electrode structure by using a wet etching process; then performing surface activation treatment on the electrode structure by using oxygen plasma; coating 3-aminopropyl triethoxysilane solution on the electrode surface by using a spin coating method to form an organic silicon self-assembled passivation layer; performing heat treatment after spin coating; then depositing a zinc aluminum spinel protection layer on the electrode surface to construct a composite surface protection layer; finally, performing heat annealing treatment on the electrode in a nitrogen protective atmosphere to obtain an anti-aging laser chip electrode protection layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrode protection layer, in particular to an anti-aging laser chip electrode protection layer process. BACKGROUND

[0002] As the core active element of high-performance electronic devices, the long-term stable operation capability of laser chips directly determines the reliability and life of the entire system. However, the surface of the chip, especially the electrode area exposed to the environment and laser, is the main weak link of device aging. These electrodes (usually metal contacts) bear complex physical, chemical and electrical stresses, leading to their performance degradation over time.

[0003] During long-term use, the electrode metal layer of the laser chip is easily affected by environmental factors such as high temperature, heat and humidity, oxygen, CO2, etc., resulting in oxidation, migration or interface failure, which seriously affects the performance and life of the laser. Traditional electrode protection layers mostly use SiO2 or Al2O3 films, but have the problems of low oxidation resistance temperature, easy peeling off due to reaction with the metal interface, etc. In view of this, we propose an anti-aging laser chip electrode protection layer process. SUMMARY

[0004] The purpose of the present application is to provide an anti-aging laser chip electrode protection layer process to solve the problems of traditional electrode protection layers mostly using SiO2 or Al2O3 films, but having low oxidation resistance temperature and easy peeling off due to reaction with the metal interface.

[0005] The present application provides an anti-aging laser chip electrode protection layer process, comprising the following steps:

[0006] Step one, using No. 1 standard cleaning solution and No. 2 standard cleaning solution to pre-clean the surface of the laser chip wafer; after cleaning, rinsing twice with ultrapure water and drying under nitrogen gas flow; then using an electron beam evaporation system to deposit a metal electrode layer on the wafer surface in sequence;

[0007] After deposition, using positive photoresist to pattern the wafer, and then using a wet etching process to form an electrode structure;

[0008] Step two, using oxygen plasma to activate the surface of the electrode structure; using spin coating method to coat 3-aminopropyltriethoxysilane solution on the electrode surface to form an organic silicon self-assembled passivation layer with a thickness of 5-10 nanometers; after spin coating, heat treatment at 120℃ for 10 minutes;

[0009] Step three, depositing a zinc-aluminum spinel protection layer on the electrode surface after step two; then building a composite surface protection layer on the zinc-aluminum spinel protection layer;

[0010] Step four, the electrode with completed protective layer is placed in a nitrogen atmosphere for heat annealing treatment to obtain an anti-aging laser chip electrode protective layer.

[0011] As preferred, in step one, the No. 1 standard cleaning solution formula is: ammonia, hydrogen peroxide and water in a mass ratio of 1:1:5;

[0012] The No. 2 standard cleaning solution formula is: hydrochloric acid, hydrogen peroxide and water in a mass ratio of 1:1:6;

[0013] The cleaning temperature is 70-80℃, and the time is 10 minutes.

[0014] As preferred, in step one, the deposition sequence and parameters of the metal electrode layer in the electron beam evaporation system are as follows:

[0015] Titanium layer: thickness of 10 nanometers, evaporation source temperature of 1200℃, and evaporation rate of 0.1-0.2 nanometer / second;

[0016] Platinum layer: thickness of 20 nanometers, evaporation source temperature of 1600℃, and evaporation rate of 0.1-0.15 nanometer / second;

[0017] Gold layer: thickness of 100 nanometers, evaporation source temperature of 1150℃, and evaporation rate of 0.2-0.5 nanometer / second;

[0018] The working voltage is 6-10 kilovolts, and the cooling water temperature is maintained at 20℃.

[0019] As preferred, in step one, the steps of using positive photoresist for patterning the wafer are as follows: placing the wafer on a spin coating device, spin coating the positive photoresist, and the thickness of the photoresist layer is 1.3-1.5 micrometers; after spin coating, heating at 90℃ for 90 seconds; then using an ultraviolet exposure machine for pattern exposure, the exposure wavelength is 365 nanometers, and the exposure energy is between 80-120 millijoules per square centimeter; after exposure, immersing the wafer in a developing solution for 45-60 seconds; after developing, rinsing with deionized water and drying in a nitrogen gas stream.

[0020] As preferred, in step one, the steps of wet etching process are as follows:

[0021] Gold layer etching: using gold etching solution, room temperature reaction for 30-60 seconds;

[0022] Platinum layer etching: using aqua regia, room temperature immersion for 10-20 seconds;

[0023] Titanium layer etching: using a mixture of hydrogen fluoride and water in a mass ratio of 1:10, room temperature etching for 5-15 seconds;

[0024] After each etching step, rinse with deionized water and dry in a nitrogen gas stream.

[0025] Preferably, the gold etching solution is composed of potassium iodide, iodine and water in a mass ratio of 4:1:40.

[0026] Preferably, in the second step, the flow rate of oxygen plasma is 20-100 standard cubic centimeters per minute, and the activation treatment time is 30-120 seconds.

[0027] The 3-aminopropyl triethoxysilane solution is prepared by adding deionized water into anhydrous ethanol, then adding 3-aminopropyl triethoxysilane dropwise while stirring at a speed of 100-200 rpm; then, hydrolysis is carried out at room temperature and in the dark for 15-30 minutes; and after the hydrolysis is completed, the solution is filtered through a 0.22 micron filter.

[0028] The mass ratio of 3-aminopropyl triethoxysilane, anhydrous ethanol and deionized water is 1:95:4.

[0029] The spin coating speed is 2000-4000 rpm, and the spin coating time is 30-60 seconds.

[0030] Preferably, in the third step, the preparation of the zinc aluminum spinel protective layer is prepared by atomic layer deposition, using dimethyl zinc and triisopropoxy aluminum as metal precursors and water vapor as an oxidant, and the precursors and oxidants are alternately introduced and cyclically reacted 300-800 times at a deposition temperature of 40-60°C to obtain a zinc aluminum spinel protective layer with a thickness of 30-80 nm.

[0031] Preferably, in the third step, the composite surface protective layer comprises: depositing a titanium nitride film on the zinc aluminum spinel layer by magnetron sputtering, with a thickness of 5-20 nm; then, further depositing a magnesium fluoride film on the surface of the titanium nitride layer by electron beam evaporation, with a thickness of 30-100 nm.

[0032] Preferably, in the fourth step, the annealing temperature is 180-220°C, and the holding time is 30-60 minutes.

[0033] Compared with the prior art, the present application has the following advantages:

[0034] In the anti-aging laser chip electrode protection layer process, the stability and service life of the laser chip in a harsh environment such as high temperature and high humidity are significantly improved by constructing a multiple electrode protection structure. Firstly, the interface passivation layer adopts 3-aminopropyl triethoxysilane to form an organic silicon self-assembled film, effectively passivating the metal surface and inhibiting interface reaction and ion migration. Secondly, the zinc aluminum spinel protection layer is dense and uniform, has excellent thermal stability and oxidation resistance, and can effectively block the penetration of external oxygen and water vapor. Finally, the titanium nitride / magnesium fluoride composite protective layer deposited on the surface has conductivity and insulation protection characteristics, further enhancing the electrode's resistance to electromigration, corrosion and aging, and achieving a multi-layer synergistic protection effect. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] The formula of the No. 1 standard cleaning solution is: the mass ratio of ammonia, hydrogen peroxide and water is 1:1:5; the formula of the No. 2 standard cleaning solution is: the mass ratio of hydrochloric acid, hydrogen peroxide and water is 1:1:6.

[0037] The gold etching solution is composed of potassium iodide, iodine and water in a mass ratio of 4:1:40.

[0038] The 3-aminopropyl triethoxysilane solution is prepared by adding deionized water to anhydrous ethanol, then adding 3-aminopropyl triethoxysilane dropwise while stirring at a speed of 200 rpm; then hydrolyzing at room temperature and in the dark for 30 minutes; and then filtering through a 0.22 micron filter after hydrolysis is complete; the mass ratio of 3-aminopropyl triethoxysilane, anhydrous ethanol and deionized water is 1:95:4.

[0039] The photoresist model is AZ5214, and the developer model is MF-319.

[0040] 3-aminopropyl triethoxysilane CAS No.: 919-30-2; triisopropoxyaluminum CAS No.: 555-31-7; titanium nitride CAS No.: 25583-20-4; magnesium fluoride CAS No.: 7783-40-6; all purchased from Shanghai Yuan Ye Biological Technology Co., Ltd.

[0041] Dimethylzinc CAS No.: 544-97-8, purchased from Hubei Chengfeng Chemical Co., Ltd.

[0042] Example 1: Anti-aging laser chip electrode protection layer process, comprising the following steps:

[0043] Step one, using No. 1 standard cleaning solution and No. 2 standard cleaning solution at 70℃ for 10 minutes to pre-clean the surface of the laser chip wafer; after cleaning, rinse twice with ultrapure water, and dry under nitrogen gas flow; then use an electron beam evaporation system to deposit a metal electrode layer on the wafer surface in sequence;

[0044] Titanium layer: thickness 10 nanometers, evaporation source temperature 1200℃, evaporation rate 0.1 nanometer / second;

[0045] Platinum layer: thickness 20 nanometers, evaporation source temperature 1600℃, evaporation rate 0.1 nanometer / second;

[0046] Gold layer: thickness 100 nanometers, evaporation source temperature 1150℃, evaporation rate 0.2 nanometer / second;

[0047] The working voltage is 6 kilovolts, and the cooling water temperature is maintained at 20℃;

[0048] After deposition, place the wafer on a spin coating device, spin coat positive photoresist, and the thickness of the glue layer is 1.3 microns; after spin coating, heat at 90℃ for 90 seconds; then use a UV exposure machine for pattern exposure, the exposure wavelength is 365 nanometers, and the exposure energy is between 80 millijoules per square centimeter; after exposure, immerse the wafer in the developing solution for 45 seconds; after developing, rinse thoroughly with deionized water and dry under nitrogen gas flow;

[0049] Then use a wet etching process to form an electrode structure;

[0050] Gold layer etching: use gold etching solution, room temperature reaction for 30 seconds;

[0051] Platinum layer etching: use aqua regia, room temperature immersion for 10 seconds;

[0052] Titanium layer etching: use a mixture of hydrogen fluoride and water with a mass ratio of 1:10, room temperature etching for 5 seconds;

[0053] After each etching step, rinse thoroughly with deionized water and dry under nitrogen gas flow;

[0054] Step two, use oxygen plasma to activate the surface of the electrode structure, the flow rate of oxygen plasma is 20 standard cubic centimeters per minute, and the activation treatment time is 30 seconds;

[0055] Use spin coating method to coat 3-aminopropyltriethoxysilane solution on the electrode surface (spin coating speed is 2000 revolutions per minute, spin coating time is 30 seconds), to form a thickness of 5 nanometers of organosilicon self-assembled passivation layer; after spin coating, heat at 120℃ for 10 minutes;

[0056] Step three, using atomic layer deposition on the electrode surface treated in step two, at a deposition temperature of 50℃, the cyclic reaction is carried out for 300 times, and a zinc aluminum spinel protective layer with a thickness of 30 nanometers is obtained;

[0057] Then a titanium nitride film with a thickness of 5 nanometers is deposited on the zinc aluminum spinel layer by magnetron sputtering method, and then a magnesium fluoride film with a thickness of 30 nanometers is further deposited on the surface of the titanium nitride layer by electron beam evaporation;

[0058] Step four, the electrode with the completed protective layer is placed in a nitrogen protective atmosphere for heat annealing treatment, the annealing temperature is 180℃, and the holding time is 30 minutes, and an anti-aging laser chip electrode protective layer is obtained.

[0059] Example 2: Anti-aging laser chip electrode protective layer process, comprising the following steps:

[0060] Step one, using No. 1 standard cleaning solution and No. 2 standard cleaning solution to pre-clean the surface of the laser chip wafer at 70℃ for 10 minutes; after cleaning, rinse twice with ultrapure water, and dry under nitrogen gas flow; then use an electron beam evaporation system to deposit a metal electrode layer on the wafer surface in turn;

[0061] Titanium layer: thickness 10 nanometers, evaporation source temperature 1200℃, evaporation rate 0.2 nanometers / second;

[0062] Platinum layer: thickness 20 nanometers, evaporation source temperature 1600℃, evaporation rate 0.15 nanometers / second;

[0063] Gold layer: thickness 100 nanometers, evaporation source temperature 1150℃, evaporation rate 0.5 nanometers / second;

[0064] The working voltage is 10 kilovolts, and the cooling water temperature is maintained at 20℃;

[0065] After deposition, the wafer is placed on a spin coating device, and a positive photoresist is spin coated, with a thickness of 1.5 microns; after spin coating, heat at 90℃ for 90 seconds; then use a UV exposure machine for pattern exposure, with an exposure wavelength of 365 nanometers and an exposure energy of 120 millijoules per square centimeter; after exposure, immerse the wafer in a developing solution for 60 seconds; after development, rinse thoroughly with deionized water and dry in a nitrogen gas stream;

[0066] Then use a wet etching process to form the electrode structure;

[0067] Gold layer etching: use gold etching solution, room temperature reaction for 60 seconds;

[0068] Platinum layer etching: use aqua regia, room temperature immersion for 20 seconds;

[0069] Titanium layer etching: using hydrogen fluoride and water mixed solution with mass ratio of 1:10, etching for 15 seconds at room temperature;

[0070] After each step of etching, the electrode was rinsed with deionized water and dried under nitrogen gas flow;

[0071] Step two, using oxygen plasma to activate the surface of the electrode structure, the flow of oxygen plasma is 100 standard cubic centimeter per minute, the activation time is 120 seconds;

[0072] The 3-aminopropyl triethoxysilane solution was coated on the surface of the electrode by spin coating method (spin coating speed is 4000 rpm, spin coating time is 60 seconds), forming a thickness of 10 nanometer of organic silicon self-assembly passivation layer; after spin coating, heat treatment at 120℃ for 10 minutes;

[0073] Step three, using atomic layer deposition on the surface of the electrode treated in step two, the deposition temperature is 50℃, the cycle reaction is 800 times, obtaining a thickness of 80 nanometer of zinc aluminum spinel protective layer;

[0074] Then, using magnetron sputtering method to deposit titanium nitride film on the zinc aluminum spinel layer, the thickness is 20 nanometer; then using electron beam evaporation, further depositing magnesium fluoride film on the surface of the titanium nitride layer, the thickness is 100 nanometer;

[0075] Step four, placing the electrode with completed protective layer into nitrogen protection atmosphere for heat annealing treatment, the annealing temperature is 180℃, the holding time is 30 minutes, obtaining the anti-aging laser chip electrode protective layer.

[0076] Example 3: anti-aging laser chip electrode protective layer process, including the following steps:

[0077] Step one, using No. 1 standard cleaning solution and No. 2 standard cleaning solution to pre-clean the surface of the laser chip wafer at 70℃ for 10 minutes; after cleaning, using ultrapure water to rinse twice, and drying under nitrogen gas flow; then using electron beam evaporation system to deposit metal electrode layer on the wafer surface in sequence;

[0078] Titanium layer: thickness of 10 nanometer, evaporation source temperature is 1200℃, evaporation rate is 0.2 nanometer / second;

[0079] Platinum layer: thickness of 20 nanometer, evaporation source temperature is 1600℃, evaporation rate is 0.1 nanometer / second;

[0080] Gold layer: thickness of 100 nanometer, evaporation source temperature is 1150℃, evaporation rate is 0.4 nanometer / second;

[0081] The working voltage is 8 kilovolts, and the cooling water temperature is maintained at 20℃;

[0082] After the deposition, the wafer is placed on a spin coating device to spin coat a positive photoresist, with a thickness of 1.4 microns; after the spin coating, the wafer is heated at 90°C for 90 seconds; then, a pattern exposure is performed using a UV exposure machine, with an exposure wavelength of 365 nm and an exposure energy of 100 mJ / cm2; after the exposure, the wafer is immersed in a developing solution for 50 seconds; after the development, the wafer is rinsed with deionized water and dried in a nitrogen stream;

[0083] Then, a wet etching process is used to form the electrode structure;

[0084] Gold layer etching: gold etching solution is used, and the reaction is performed at room temperature for 50 seconds;

[0085] Platinum layer etching: aqua regia is used, and the wafer is immersed at room temperature for 15 seconds;

[0086] Titanium layer etching: a mixture of hydrogen fluoride and water with a mass ratio of 1:10 is used, and the wafer is etched at room temperature for 10 seconds;

[0087] After each etching step, the wafer is rinsed with deionized water and dried in a nitrogen stream;

[0088] Step two: the electrode structure is subjected to surface activation treatment using oxygen plasma, with a flow rate of 60 standard cubic centimeters per minute, and an activation treatment time of 70 seconds;

[0089] A 3-aminopropyltriethoxysilane solution is applied to the electrode surface by spin coating (spin coating speed of 2000 rpm, spin coating time of 40 seconds), forming an organic silicon self-assembled passivation layer with a thickness of 8 nanometers; after the spin coating, the wafer is heat treated at 120°C for 10 minutes;

[0090] Step three: on the electrode surface treated in step two, atomic layer deposition is performed at a deposition temperature of 50°C for 600 cycles, obtaining a zinc aluminum spinel protective layer with a thickness of 60 nanometers;

[0091] Then, a titanium nitride film is deposited on the zinc aluminum spinel layer using a magnetron sputtering method, with a thickness of 10 nanometers; then, a magnesium fluoride film is further deposited on the surface of the titanium nitride layer using an electron beam evaporation method, with a thickness of 50 nanometers;

[0092] Step four: the electrode with the completed protective layer is placed in a nitrogen protective atmosphere for heat annealing treatment, with an annealing temperature of 180°C and an annealing time of 30 minutes, obtaining an anti-aging laser chip electrode protective layer.

[0093] Measurement of electrode corrosion rate: the treated chip sample was placed in a 85℃, 85% RH environment for 1000 hours of aging; after removal, the surface was gently wiped with anhydrous ethanol to remove condensate or salt residue; an optical microscope (200-500x magnification) was used to take pictures of the electrode area on the chip surface; the corrosion area of the electrode area image was identified by ImageJ or other image recognition software, and the area was calibrated; the electrode corrosion rate (%) = corrosion area / total electrode area x 100% was calculated.

[0094] Measurement of contact resistance change rate: the contact resistance value R0 of the initial electrode was measured using a four-probe station or probe station; the sample was aged in a 85℃, 85% RH environment for 1000 hours; the contact resistance R1 was re-measured after aging; the contact resistance change rate (%) = (R1-R0) / R0 x 100% was calculated.

[0095] Measurement of electromigration failure time T 50 : lead wires were introduced in the electrode area, a constant current density (such as 1MA / cm 2 ) was applied to 20-30 samples; a constant temperature of 150℃ was maintained to accelerate electromigration failure; the resistance change of each sample was continuously monitored, and the failure (resistance surge or open circuit) time was recorded; the failure data was statistically analyzed using Weibull distribution or median method, and the failure rate curve was drawn to obtain the T 50 value.

[0096] Measurement of surface roughness change ΔRa: atomic force microscopy (AFM) was used to scan the electrode surface area to obtain the average roughness Ra0 before aging; the sample was aged in a 85℃, 85% RH environment for 1000 hours; AFM was used again to measure the roughness Ra1 after aging; the ΔRa = Ra1-Ra0 was calculated.

[0097] The anti-aging laser chip electrode protection layer prepared in the above Examples 1-3 was used to protect the anti-aging laser chip electrode, and the performance data of the anti-aging laser chip electrode is shown in Table 1:

[0098] Table 1 Performance data of anti-aging laser chip electrode of Examples 1-3

[0099]

[0100] According to the above test experiments, Example 3 is the optimal example;

[0101] Example 4: Compared with Example 3, the difference is that the thickness of the zinc aluminum spinel protection layer is 80 nanometers.

[0102] Example 5: Compared with Example 3, the difference is that the thickness of the zinc aluminum spinel protection layer is 100 nanometers.

[0103] Example 6: The difference between this example and Example 3 is that the thickness of the titanium nitride film is 20 nanometers.

[0104] Example 7: The difference between this example and Example 3 is that the thickness of the titanium nitride film is 30 nanometers.

[0105] Example 8: The difference between this example and Example 3 is that the thickness of the magnesium fluoride film is 100 nanometers.

[0106] Example 9: The difference between this example and Example 3 is that the thickness of the magnesium fluoride film is 150 nanometers.

[0107] Comparative Example 1: The difference between this comparative example and Example 3 is that no organosilicon self-assembled passivation layer is added.

[0108] Comparative Example 2: The difference between this comparative example and Example 3 is that no titanium nitride / magnesium fluoride composite protective layer is added.

[0109] Comparative Example 3: The difference between this comparative example and Example 3 is that no zinc aluminate spinel protective layer is added.

[0110] The protective layers for anti-aging laser chip electrodes prepared in Examples 3-9 and Comparative Examples 1-3 above are used to protect anti-aging laser chip electrodes, and the performance data of the anti-aging laser chip electrodes are shown in Table 2:

[0111] Table 2 Performance data of anti-aging laser chip electrodes of Examples 3-9 and Comparative Examples 1-3

[0112]

[0113] As can be seen from Table 2, as the thickness of the zinc aluminate spinel protective layer increases from 60 nanometers (Example 3) to 80 nanometers (Example 4) and 100 nanometers (Example 5), the electrode corrosion rate increases from 1.2% to 1.4% and 2.1%, the contact resistance change rate increases from 0.7% to 0.9% and 1.2%, the T 50 decreases from 1610h to 1580h and 1320h, and ΔRa increases from 0.8 to 0.9 and 1.4. The reason for the performance decline is that zinc aluminate spinel is a dense and chemically stable ceramic material that can effectively passivate and protect the electrode from corrosion. When the thickness increases, the stress accumulation and microcracks in the material increase, resulting in a decrease in the interfacial adhesion between the protective film and the metal electrode, which in turn induces problems such as localized corrosion, film peeling, etc. In addition, an excessively thick protective layer also forms a charge block at the micro level, resulting in an increase in the contact resistance and a decrease in the electromigration failure time.

[0114] Further from Table 2, as the thickness of the titanium nitride film gradually increases from 10 nm (Example 3) to 20 nm (Example 6) and 30 nm (Example 7), the electrode corrosion rate increases to 1.6% and 2.8%, respectively, the contact resistance change rate increases from 0.7% to 1.1% and 1.9%, and the T 50 As the thickness of the titanium nitride film gradually increases from 10 nm (Example 3) to 20 nm (Example 6) and 30 nm (Example 7), the electrode corrosion rate increases to 1.6% and 2.8%, respectively, the contact resistance change rate increases from 0.7% to 1.1% and 1.9%, and the T

[0115] As the thickness of the magnesium fluoride film increases from 50 nm (Example 3) to 100 nm (Example 8) and 150 nm (Example 9), the electrode corrosion rate increases to 1.5% and 2.5%, the contact resistance change rate increases to 1.0% and 1.7%, and the T 50 As the thickness of the magnesium fluoride film increases from 50 nm (Example 3) to 100 nm (Example 8) and 150 nm (Example 9), the electrode corrosion rate increases to 1.5% and 2.5%, the contact resistance change rate increases to 1.0% and 1.7%, and the T

[0116] In Comparative Example 1, compared with Example 3, no organic silicon self-assembled passivation layer is added, which leads to obvious deterioration of the electrode in terms of corrosion, contact resistance, and electromigration performance. The electrode corrosion rate is as high as 5.9%, which is much higher than the 1.2% of Example 3. The contact resistance change rate increases to 3.7%, and the T 50The significant decrease to 780h is only half of that of Example 3, and the surface roughness change ΔRa also increases to 1.7, indicating that the passivation effect is insufficient; the core role of the self-assembled passivation layer of organosilicon is to form a dense covalent bond layer with the metal surface through the functional groups in the silane coupling molecules, forming a stable hydrophobic barrier; the self-assembled layer has high chemical inertness, and can effectively block the penetration path of corrosion media such as water, ions and oxygen, thereby significantly reducing the anodic dissolution rate of the metal surface; without the passivation layer, the metal surface is exposed to the electrolytic environment, and an electrochemical microcell is easily formed, which aggravates local corrosion; at the same time, the lack of ordered and dense coverage of the surface oxide layer will lead to metal grain coarsening and uneven surface, which in turn leads to an increase in ΔRa and an increase in contact resistance fluctuations; this surface deterioration will further induce migration path short circuits, making T 50 greatly shortened.

[0117] In Comparative Example 2, no titanium nitride / magnesium fluoride composite protective layer was added, and the electrode corrosion rate increased to 7.8%, the contact resistance change rate increased significantly to 4.3%, and the electromigration failure time T 50 was shortened to 570h, and the surface roughness change ΔRa increased to 2.9, all of which showed that the lack of a composite protective layer seriously damaged the overall stability of the system; titanium nitride has excellent chemical stability and density, and can effectively block water vapor and Cl - corrosive ions, and its high hardness and low resistance characteristics can also provide a good electrical connection interface; while magnesium fluoride is a typical wide-bandgap fluoride with excellent electrical insulation and interface band matching characteristics, it is often used in composite structures to enhance the interface potential barrier, suppress electron tunneling effects, and reduce leakage current; the lack of a titanium nitride layer (conductivity) causes the electrode surface to oxidize to form a high-resistance Cu2O layer, resulting in an increase in contact resistance; the lack of a magnesium fluoride layer allows water vapor to enter the interface, exacerbating the oxidation reaction; in addition, the metal surface is prone to form an oxide and a hole accumulation region, resulting in an increase in Ra value and an increase in contact interface instability, ultimately leading to rapid fluctuations in contact resistance and a sharp decrease in T 50 .

[0118] In Comparative Example 3, without adding a zinc aluminum spinel protective layer, the electrode corrosion rate increased to 11.2%, the contact resistance change rate was as high as 6.5%, and T 50The sudden drop is 490h, and the surface roughness change ΔRa is 3.4; the zinc-aluminum spinel is a typical spinel structure oxide, has excellent chemical stability and thermal stability, low surface energy, good electrical insulation, can be well combined with the metal electrode and form a dense ceramic type protective layer on the surface; its high lattice density can effectively fill the micro-pores and defects on the electrode surface, prevent the infiltration of ionic liquid or moisture; at the same time, due to its strong interface bonding force, it is not easy to peel off or crack, so it can maintain the stability of the interface structure for a long time; after the layer is lacking, the bare metal or other protective layer surface is easy to form a crack channel, so that the corrosion medium quickly penetrates to cause the rapid expansion of the local corrosion point, and the electrode failure rate is accelerated, T 50 The sudden drop is 490h, and the surface roughness change ΔRa is 3.4; the zinc-aluminum spinel is a typical spinel structure oxide, has excellent chemical stability and thermal stability, low surface energy, good electrical insulation, can be well combined with the metal electrode and form a dense ceramic type protective layer on the surface; its high lattice density can effectively fill the micro-pores and defects on the electrode surface, prevent the infiltration of ionic liquid or moisture; at the same time, due to its strong interface bonding force, it is not easy to peel off or crack, so it can maintain the stability of the interface structure for a long time; after the layer is lacking, the bare metal or other protective layer surface is easy to form a crack channel, so that the corrosion medium quickly penetrates to cause the rapid expansion of the local corrosion point, and the electrode failure rate is accelerated, T

[0119] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. An anti-aging laser chip electrode protection layer process, characterized in that, The method comprises the following steps: Step 1: the surface of the laser chip wafer is pre-cleaned by using a No. 1 standard cleaning solution and a No. 2 standard cleaning solution; after cleaning, the wafer is rinsed twice with ultrapure water and dried under a nitrogen gas flow; then, a metal electrode layer is deposited on the wafer surface by using an electron beam evaporation system; After the deposition is completed, the wafer is subjected to a patterning treatment by using a positive photoresist, and then a wet etching process is used to form an electrode structure; Step 2: the electrode structure is subjected to a surface activation treatment by using an oxygen plasma; A 3-aminopropyltriethoxysilane solution is coated on the electrode surface by using a spin coating method to form an organic silicon self-assembled passivation layer with a thickness of 5-10 nanometers; after the spin coating, the wafer is subjected to a heat treatment at 120℃ for 10 minutes; Step 3: a zinc-aluminum spinel protective layer is deposited on the electrode surface after the treatment in Step 2; then, a composite surface protection layer is constructed on the zinc-aluminum spinel protective layer; Step 4: the electrode with the constructed protective layer is subjected to a heat annealing treatment in a nitrogen protective atmosphere to obtain an anti-aging laser chip electrode protection layer.

2. The anti-aging laser chip electrode passivation process of claim 1, wherein, In Step 1, the No. 1 standard cleaning solution has a formula of ammonia, hydrogen peroxide and water with a mass ratio of 1:1:5; The No. 2 standard cleaning solution has a formula of hydrochloric acid, hydrogen peroxide and water with a mass ratio of 1:1:6; The cleaning temperature is 70-80℃, and the time is 10 minutes.

3. The anti-aging laser chip electrode passivation process of claim 1, wherein, In Step 1, the deposition sequence and parameters of the metal electrode layer deposited by using the electron beam evaporation system are as follows: Titanium layer: thickness of 10 nanometers, evaporation source temperature of 1200℃, and evaporation rate of 0.1-0.2 nanometer / second; Platinum layer: thickness of 20 nanometers, evaporation source temperature of 1600℃, and evaporation rate of 0.1-0.15 nanometer / second; Gold layer: thickness of 100 nanometers, evaporation source temperature of 1150℃, and evaporation rate of 0.2-0.5 nanometer / second; The working voltage is 6-10 kilovolts, and the cooling water temperature is maintained at 20℃.

4. The anti-aging laser chip electrode passivation process of claim 1, wherein, In Step 1, the steps of patterning the wafer by using the positive photoresist are as follows: the wafer is placed on a spin coating device, and the positive photoresist is spin coated with a thickness of 1.3-1.5 micrometers; after the spin coating, the wafer is heated at 90℃ for 90 seconds; then, the wafer is subjected to a pattern exposure by using an ultraviolet exposure machine with an exposure wavelength of 365 nanometers and an exposure energy of 80-120 millijoules per square centimeter; after the exposure, the wafer is immersed in a developing solution for 45-60 seconds; After the developing is completed, the wafer is rinsed with deionized water and dried in a nitrogen gas flow.

5. The anti-aging laser chip electrode passivation process of claim 1, wherein, In Step 1, the steps of the wet etching process are as follows: Gold layer etching: gold etching solution is used for reaction at room temperature for 30-60 seconds; Platinum layer etching: aqua regia is used for immersion at room temperature for 10-20 seconds; Titanium layer etching: a mixed solution of hydrogen fluoride and water with a mass ratio of 1:10 is used for etching at room temperature for 5-15 seconds; After each etching step, the wafer is rinsed with deionized water and dried in a nitrogen gas flow.

6. The anti-aging laser chip electrode passivation process of claim 5, wherein, The gold etching solution is composed of potassium iodide, iodine and water with a mass ratio of 4:1:

40.

7. The anti-aging laser chip electrode passivation process of claim 1, wherein, In Step 2, the flow rate of the oxygen plasma is 20-100 standard cubic centimeters per minute, and the activation treatment time is 30-120 seconds; 3-aminopropyltriethoxysilane solution is prepared by adding deionized water into anhydrous ethanol, then adding 3-aminopropyltriethoxysilane dropwise while stirring at a speed of 100-200 rpm; then hydrolyzing at room temperature in the dark for 15-30 minutes; and then filtering through a 0.22 micron filter after hydrolysis is complete; The mass ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water is 1:95:4; The spin coating speed is 2000-4000 rpm, and the spin coating time is 30-60 seconds.

8. The anti-aging laser chip electrode passivation process of claim 1, wherein, In the third step, the preparation step of the zinc aluminum spinel protective layer is as follows: the zinc aluminum spinel protective layer is prepared by atomic layer deposition, dimethyl zinc and triisopropoxy aluminum are used as metal precursors, water vapor is used as an oxidant, the precursors and the oxidant are alternately introduced at a deposition temperature of 40-60℃, and the cycle reaction is performed for 300-800 times to obtain a zinc aluminum spinel protective layer with a thickness of 30-80 nm.

9. The anti-aging laser chip electrode passivation process of claim 1, wherein, In the third step, the composite surface protective layer comprises: a titanium nitride film is deposited on the zinc aluminum spinel layer by magnetron sputtering, with a thickness of 5-20 nm; then a magnesium fluoride film is further deposited on the surface of the titanium nitride layer by electron beam evaporation, with a thickness of 30-100 nm.

10. The anti-aging laser chip electrode passivation process of claim 1, wherein, In the fourth step, the annealing temperature is 180-220℃, and the holding time is 30-60 minutes.

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