44results about How to "Reduce short circuit problems" patented technology

The invention relates to a high-temperature resistant micropore thin film material prepared from inorganic fiber, synthetic fiber, natural organic fiber, nano-grade inorganic powder and an adhesive. The thin film material is a non-woven fabric material prepared through one-step molding with a wet papermaking technology combined with a coating technology. The material has a 3-dimensional network structure and porosity higher than 90%. The high-temperature resistant micropore thin film material has an outstanding high-temperature resistance. Under a temperature of 260 DEG C, excellent dimension and structure stabilities of the material are maintained for a long time. The material has excellent liquid absorbency, excellent liquid retaining capacity, and 3-dimensional stereo pores with good uniformity. An average pore size is 0.02-2.5mum. The high-temperature resistant micropore thin film material can be used as lithium ion power battery separation films, super-capacitor separation films, or filtrating materials.

The invention provides an ultrahigh current density electrolysis or electro-deposition groove comprising a groove body, wherein the groove body is provided with a liquid inlet; a flange is arranged at the outer part of the liquid inlet; a panel is arranged on the inner side wall of the groove body; a closed cavity is formed by the panel and the inner side wall of the groove body; the closed cavity is communicated with the liquid inlet in the groove body; the panel is provided with an electrolyte spraying device and a polar plate limiting device; an anode plate and a cathode plate are placed in the groove body; and a liquid discharging device is arranged on the groove body. According to the ultrahigh current density electrolysis or electro-deposition groove disclosed by the invention, a liquid supplying device is formed by the panel, the inner side wall of the groove body and the closed cavity formed by the panel and the inner side wall of the groove body. The liquid supplying device disclosed by the invention is embedded into the inner side wall of the groove body and a liquid supplying manner that the bottom of the e liquid supplying device is parallel to polar plates is utilized so as to guarantee the electrolyte circulation requirements needed by electrolysis or electro-deposition production under the ultrahigh current density; and meanwhile, the polar plates are not contacted with the liquid supplying device which is embedded into the inner side wall of the groove body, so as to guarantee the safety of the liquid supplying device and the production is smoothly and safely operated.

The invention relates to a battery-used separator and a preparation method thereof. The separator comprises a base film; one side of the base film is sequentially provided with a first ceramic coatinglayer and a first polymer coating layer; the other side of the base film is sequentially provided with a second ceramic coating layer and a second polymer coating layer; or, the other side of the base film is only provided with a second polymer coating layer; and the coverage area of the first polymer coating layer and the second polymer coating layer is 10% to 50% of the total area of the base film. A non-full coverage coating polymer coating layer is adopted, and in comparison with a full coverage coating polymer coating layer in the prior art, the risk of separator hole blocking can be reduced by adopting the non-full coverage coating, and the cycle stability of the material is improved. Besides, baking is carried out after coating of a waterborne ceramic coating and a polymer coatingis completed sequentially, and through using the same type of binder, the coating interface between the waterborne ceramic coating and the polymer coating is eliminated, and a product with stronger binding between the coatings can be obtained.

The invention provides an electroluminescent device with high light emitting efficiency, which comprises a transparent substrate, a light scattering layer positioned on the transparent substrate, a surface smooth layer positioned on the light scattering layer and an electroluminescent layer positioned on the surface smooth layer. The electroluminescent device has the following technical effects: 1, light scattering particles are exposed out of an adhesive, each of the light scattering layer and the surface smooth layer is provided with a waved surface, light emitted from the light emitting layer is directly scattered by the waved light scattering particles after passing through the waved surface smooth layer with a high refractive index, parts of light rays which are less than a critical angle are directly emitted out, the light rays which are greater than or equal to the critical angle are reflected back, are reflected again by a reflection electrode layer, passes through the surface smooth layer and are scattered again, another part of light is extracted, and extraction is repeatedly carried out, so that the light extraction efficiency is greatly improved, and the waved surface of the light scattering layer increases an effective light emitting area; 2, the electroluminescent device adopts is simple in preparation process and facilitates scale mass production.

The invention provides a display substrate and a preparation method thereof, a display panel and a display device. A first wiring area, a second wiring area and an under-screen camera area are arranged in a display area of the display substrate. The under-screen camera area is located between the first wiring area and the second wiring area, a transparent cathode layer is arranged in the under-screen camera area, the transparent cathode layer is formed on a substrate of the display substrate, and the transparent cathode layer is electrically connected with a first power supply wiring of the first wiring area and a first power supply wiring of the second wiring area. According to the invention, a power supply signal of the display substrate can directly pass through the under-screen cameraarea; power supply wiring does not need to be wound in the edge of the under-screen camera area; the wiring width of the first power supply wiring of the first wiring area and the wiring width of thefirst power supply wiring of the second wiring area and the wiring distance between the first power supply wiring of the first wiring area and other wiring can be ensured, the power supply wiring voltage drop is reduced, the open circuit problem, the short circuit problem and the inter-wire crosstalk problem are solved, and the power supply voltage difference between the first wiring area and thesecond wiring area is small.

The invention provides a high-breakdown-strength aramid diaphragm as well as a preparation method and application thereof, and relates to the technical field of diaphragms, the high-breakdown-strength aramid diaphragm comprises a base membrane and an aramid coating arranged on one side or two sides of the base membrane; the outer layer of the aramid fiber coating is of a dense porous structure, and the interior of the aramid fiber coating is of a fibrous porous structure; the added value of the air permeability of the aramid fiber coating of the high-breakdown-strength aramid fiber diaphragm is 20-30 s / 100 cc / mu m, and the breakdown strength of the aramid fiber coating of the high-breakdown-strength aramid fiber diaphragm is 0.24-0.3 kv / mu m. On the basis of not abnormally increasing the air permeability of the aramid fiber coating diaphragm, the breakdown strength of the diaphragm can be improved, and the safety performance is improved.

The invention is a manufacturing method of a high-potential gracient ZnO thick-film voltage dependent resistor, belonging to the field of voltage dependent resistor manufacture technology, comprising the steps of: successively depositing membranoid substances on a Al2O3 ceramic plate substrate by screen painting process: a bottom electrode, a ZnO voltage dependent resistor body and a top electrode; and sticking a electrode terminal to the end surfaces of the bottom and top electrodes, characterized in: the slurry for manufacturing the ZnO voltage dependent resistor contains rare-earth metal oxide Y2O3; the ZnO voltage dependent resistor body has a thick-film structure, and a multi-layer film is stacked into a thick film by steps of screen painting process. The method has the advantages of simple process, operation simplicity, low sintering temperature, low equipment requirements, low manufacturing cost, and the ability of manufacturing high performance ZnO thick-film voltage dependent resistor.

The invention provides a display panel. The display panel comprises a first metal layer and a second metal layer which are arranged in sequence, wherein the first metal layer comprises a plurality offirst metal wires, and first gaps among the first metal wires; the second metal layer comprises a plurality of second metal wires which are arranged at intervals; extension directions of the second metal wires are identical to extension directions of the first metal wires; the second metal wires and the first metal wires are arranged in a staggered manner; and orthographic projection areas of thesecond metal wires on the first metal layer are located in first gap areas, so that short circuits between the adjacent second metal wires during preparation of the second metal wires can be avoided.The invention further provides a display panel preparation method, and a display device. The display panel, the display panel preparation method and the display device provided by the invention have the advantage that the problem that short circuits of laminated metal wires are caused by an uneven photoresist coating thickness and incomplete exposure during preparation of the laminated metal wiresis solved.

The invention discloses a polymer composite separator for a lead acid storage battery, and the polymer composite separator comprises the following raw materials by weight: 50-70 parts of polypropylene, 40-60 parts of polyethylene, 5-12 parts of silica, 15-25 parts of maleic anhydride, 1-3 parts of an initiator, 4-8 parts of an additive, 8-15 parts of glass fiber, 10-20 parts of an impregnating compound, 0.8-2 parts of a coupling agent, 1-3 parts of an antioxidant, 2-5 parts of a rare earth material, 10-16 parts of a hydrochloric acid solution and 16-24 parts of a non-ionic surfactant. The polymer composite separator for the lead acid storage battery has the advantages of super-high strength, toughness and permeability resistance, large flexural coefficient, good heat resistance and oxidation resistance, simple preparation method, no high cost equipment investment, low production cost and suitability for industrial production, the polymer composite separator for the lead acid storage battery is used in the lead-acid battery for effectively reducing the short-circuit problem caused by the separator, prolongs the service life of the lead acid storage battery, and widens the application prospect.

The invention discloses a cable and a preparation method thereof. The cable comprises at least two conductors twisted together, wherein the conductors are twisted to form a twisted body, and the outside of the twisted body is coated with an insulating layer; each of the conductors is a conducting wire which is coated by the insulating layer and is twisted by at least two core wires; and the twisted direction of the conductors is the same as that of the insulating core wires twisted mutually. The method comprises the following steps: preparing pre-designed single wires for each of the conductors by the conventional method; twisting the core wires of each of the conductors respectively in the same direction, and coating the insulating layer outside the core wires; and coating a jacket for a strengthening cable or other designed cables. The cable ensures that the twisted direction of the conductors is the same as that of the insulating core wires, and can effectively solve the problems of short circuit and open circuit caused by movement, shrinkage and fatigue of the cable, and prolong the service life of the conductors. A load fatigue test shows that the cable has no change after 180,000 times.

The invention discloses a fan-out chip interconnection manufacturing method, which comprises the steps: coating the surface of a fan-out chip with a photoresist or a passivation layer, and opening thephotoresist or the passivation layer covering the PAD region of the fan-out chip to expose the PAD of the fan-out chip; manufacturing an insulating layer on the surface of the fan-out chip, then manufacturing a seed layer above the insulating layer, then coating with an electroplating photoresist, electroplating with a metal to make RDL, then removing the photoresist, and then removing the seed layer; and connecting the other end of the RDL with the internal bonding pad, and remanufacturing an external bonding pad on the internal bonding pad. According to the invention, the size of the remanufactured external bonding pad is increased, and the distance between the bonding pads is increased; and the area and the position of the chip PAD are redefined, so that the difficulty of interconnection between the embedded fan-out chip PAD and the wafer-level RDL can be greatly reduced, the problems of open circuit and short circuit are reduced, and the reliability of the process is improved.

The invention discloses a driving backboard and a manufacturing method thereof. The driving backboard comprises a substrate, a convex point lower metal layer and a microstructure layer; the bump lower metal layer is arranged on the substrate and is used for butt joint with an LED chip; the microstructure layer is arranged on the substrate and is attached to the side wall of the bump lower metal layer; and the upper surface of the microstructure layer is higher than the upper surface of the bump lower metal layer. When the driving backboard is installed, the LED chip is in butt joint with the under bump metal layer, the electrodes of the LED chip and the under bump metal layer are wrapped by the microstructure layer in the bonding process, flowing of bonding metal in a molten state is limited, and short circuit problems on the driving backboard are reduced.

The invention relates to preparation of paint, and aims at providing a preparation method for hydrophobic nanometer modified resin composite paint used for an LED base plate. The method comprises: firstly uniformly dispersing nanometer alpha-Al2O3 and butanol; then adding a silane coupling agent KH560 and ageing, so as to obtain a modified alpha-Al2O3 sol, and performing concentration distillation; uniformly mixing 1H,1H,2H,2H-perfluorooctyltriethoxysilane, n-butanol and formic acid, then adding deionized water, and ageing to obtain a silicon fluoride oligomer sol; and dispersing the former two products, an epoxy resin monomer, 2-butanone, xylene and 2,2,4-trimethyl-1,3-pentanediolmono(2-methylpropanoate), so as to obtain the paint. By introducing alpha-Al2O3 nano-particle into a conventional epoxy resin coating, the heat conductivity of resin is improved, also the excellent coating property and the workability of resin are maximumly kept, and the price is relatively appropriate. The hydrophobicity is substantially improved, and the short circuit problem caused by air moist is reduced. The prepared hydrophobic nanometer modified resin composite paint is suitable for production processing on a conventional production line, and is beneficial improvement on the basis of a conventional epoxy-resin-coated aluminium base plate.

The invention discloses a power adapter module which comprises a shell. A pin changing mechanism is arranged in the shell and comprises grounding pins, electrode pins, a first connecting rod, a buckle plate, a rectangular opening, a transmission rod, an inclined arc groove, a second connecting rod and a first spring. A set of grounding pins penetrates into and is slidably connected to the right end surface of the shell. Two sets of electrode pins are symmetrically arranged below the grounding pins. The transmission rod fixedly connected to the bottom of the first connecting rod moves leftwards, so that the inclined arc groove in the second connecting rod is squeezed by leftward movement of the transmission rod to rotate slowly and stops moving when the buckle plate moves to the leftmost end of the rectangular opening, and at the moment, the second connecting rod stops rotating, and the first connecting rod fixedly connected with the second connecting rod is rotated to a straight state corresponding to a traditional two-hole socket. Therefore, the power adapter can be conveniently changed from a three-pin state to a two-pin state, and the power adapter is suitable for a three-jack socket and a two-jack socket.

The invention discloses a method for adding a solder resist bridge between narrow IC pads on a thick copper PCB, and belongs to the technical field of printed circuit boards. The method comprises thefollowing steps: manufacturing an outer layer circuit of the PCB; printing a first layer of ink on the surface of the PCB with the outer layer circuit; carrying out exposure and development on the first layer of ink, and exposing places which do not need to be covered with the ink and not reserving the ink between the adjacent IC pads to form first solder resist windowing; printing a second layerof ink on the surface of the PCB with the outer layer circuit; exposing and developing the second layer of ink, forming a solder resist bridge and forming second solder resist windowing, wherein the size of the second solder resist windowing is greater than that of the first solder resist windowing; and baking until the ink is completely cured. The solder resist bridge of a relatively thin thickness is manufactured under the condition that the thick copper wire section can be covered by enough thick solder resist ink so that the solder resist bridge can stand stably in a narrow IC interval andcannot pollute IC pads on two sides; and the problem of solder short circuit caused by excessively narrow IC pads can be reduced so that the yield of SMT assembly is improved.

The invention discloses a solar energy-saving street lamp which comprises a shell. The surface of the shell is wrapped with a waterproof material structure layer, the waterproof material structure layer is fixed to the shell, a lamp shell body is arranged in the shell, and the shell is detachably connected with the lamp shell body; a lamp panel is arranged in the lamp shell body, and a lamp strip is connected to the lamp panel and is powered with a solar panel arranged on the upper surface of the waterproof material structure layer and a solar storage battery arranged in the lamp shell body; and a protection plate is connected to the lower surface of the waterproof material structure layer. By means of the solar energy-saving street lamp, water flow can be effectively prevented from permeating, and the problem of internal element short circuits caused by water flow permeating is solved; meanwhile, the good protection performance can be achieved through the solar energy-saving street lamp, and the borne external force action force is larger; and in addition, the column height of the solar energy-saving street lamp can be adjusted according to the current requirement.

The invention discloses a test circuit of a display panel and a display device. The test circuit comprises a plurality of test wires, a plurality of first active switches and a protection circuit, wherein the test wires comprise a high level signal test wire, a low level signal test wire and at least one test signal wire; the first active switch controls the on and off of the test signal line, the low-level signal test line and the high-level signal test line; the high-level signal test line is also connected with the control end of each first active switch; the protection circuit comprises a control signal input end and a control signal output end, the control signal input end is connected with the high-level signal wire and the low-level signal wire, and the control signal output end is connected with the control end of each first active switch; when the display panel works normally, the protection circuit receives a low-level signal on the low-level signal line and outputs a control signal to control the first active switch to be turned off. According to the scheme, the problem of short circuit of test wiring is solved.

The invention provides an electric boiling pot which comprises a pot body, a pot cover rotationally installed on the upper end of the pot body and a plugging handle located at the center of the bottom of the pot cover, wherein a photoelectric liquid-level sensing device is installed on the plugging handle; the photoelectric liquid-level sensing device comprises a photoelectric liquid-level sensor used to collect liquid level information in the port body and an infrared emitter used to wirelessly send the liquid level information in the pot body; the lower end face of the photoelectric liquid-level sensor stretches into the pot body by 2-4 cm; a signal receiving device is installed on the lower end of the outer wall of the pot body; a vertically disposed L-shaped supporting rod is connected to the upper part of the signal receiving device; a connecting pillar which is perpendicular to a horizontal rod of the L-shaped supporting rod and disposed downwards is firmly installed on the end part of the horizontal rod of the L-shaped supporting rod; and an electric magnet is firmly installed on the bottom of the connecting pillar. The electric boiling pot provided by the invention has the advantages that the structure is simple; use is convenient; and pot spilling can be prevented effectively.

The invention provides a gapless contact type intelligent card chip module, an intelligent card and a manufacturing method for the intelligent card chip module. The gapless contact type intelligent card chip module comprises a chip module body and a plurality of contacts, wherein a dielectric layer is arranged on the surface of the chip module body; the contacts are embedded in the dielectric layer; and the two adjacent contacts are isolated by the dielectric layer. The intelligent card chip module has the advantages that the contacts are embedded in the dielectric layer, so that the contacts are firmer and unlikely to fall off, the module is firmer and unlikely to deform, the short-circuit problems caused by the environment are reduced, and the anti-pollution capability is improved.

The invention relates to the preparation of coatings, and aims to provide a method for preparing hydrophobic nano-modified resin composite coatings for LED substrates. The method comprises: first uniformly dispersing nanometer α-Al2O3 and butanol; then adding silane coupling agent KH560 for aging to obtain modified α-Al2O3 sol, concentrated distillation; tridecafluorooctyltriethoxysilane, n- Mix butanol and formic acid, add deionized water, and age to obtain fluorosilane oligomer sol; mix the first two products, epoxy resin monomer, methyl ethyl ketone, xylene and 2,2,4-trimethyl- 1,3‑Pentanediol monoisobutyrate is dispersed to give a coating. The present invention introduces α-Al2O3 nanoparticles into the traditional epoxy resin coating to improve the thermal conductivity of the resin, while retaining the excellent coating and processability of the resin to the greatest extent, and the price is relatively good. The hydrophobic performance is significantly improved, which reduces the problem of short circuits caused by humid air. It is suitable for production and processing on existing production lines, and is a beneficial improvement to traditional epoxy resin-covered aluminum substrates.

The invention is a manufacturing method of a high-potential gracient ZnO thick-film voltage dependent resistor, belonging to the field of voltage dependent resistor manufacture technology, comprising the steps of: successively depositing membranoid substances on a Al2O3 ceramic plate substrate by screen painting process: a bottom electrode, a ZnO voltage dependent resistor body and a top electrode; and sticking a electrode terminal to the end surfaces of the bottom and top electrodes, characterized in: the slurry for manufacturing the ZnO voltage dependent resistor contains rare-earth metal oxide Y2O3; the ZnO voltage dependent resistor body has a thick-film structure, and a multi-layer film is stacked into a thick film by steps of screen painting process. The method has the advantages ofsimple process, operation simplicity, low sintering temperature, low equipment requirements, low manufacturing cost, and the ability of manufacturing high performance ZnO thick-film voltage dependentresistor.

The invention relates to a high-temperature resistant micropore thin film material prepared from inorganic fiber, synthetic fiber, natural organic fiber, nano-grade inorganic powder and an adhesive. The thin film material is a non-woven fabric material prepared through one-step molding with a wet papermaking technology combined with a coating technology. The material has a 3-dimensional network structure and porosity higher than 90%. The high-temperature resistant micropore thin film material has an outstanding high-temperature resistance. Under a temperature of 260 DEG C, excellent dimension and structure stabilities of the material are maintained for a long time. The material has excellent liquid absorbency, excellent liquid retaining capacity, and 3-dimensional stereo pores with good uniformity. An average pore size is 0.02-2.5mum. The high-temperature resistant micropore thin film material can be used as lithium ion power battery separation films, super-capacitor separation films, or filtrating materials.

The invention relates to a clamping type electric heater cover plate. The clamping type electric heater cover plate comprises a display screen and a top cover which are matched with each other, and further comprises a connecting structure which is arranged on the display screen and the top cover and used for connecting the display screen with the top cover, and a waterproof structure which is arranged on the top cover and used for realizing the waterproofing of the interior. By matching a buckle with a buckle groove and matching a groove with a top block, the display screen and the top cover are connected, the connecting effect is good, and detachment is convenient. An inner circle protrudes upwards to form a groove circle which is used for containing a small amount of water stains after water enters and evaporating the water during work, so a small amount of water stains entering an electric heater are dried during work, the internal circuit short-circuit problem caused by the permeation of the water stains is reduced, and safety is improved.

The invention relates to a three-dimensional nonvolatile memory and a manufacturing method thereof. The three-dimensional nonvolatile memory comprises a substrate, a charge storage structure, a laminated structure and a channel layer. The charge storage structure is disposed on the substrate. The laminated structure is arranged on one side of the charge storage structure and comprises a pluralityof insulating layers, a plurality of grids, a buffer layer and a barrier layer. The insulating layers and the gates are alternately stacked. The buffer layer is arranged between each grid and the charge storage structure and on the surface of the insulating layers. The barrier layer is arranged between each grid and the buffer layer. The end portion of the grid is protruded in a direction away from the channel layer with respect to the end portion of the barrier layer.

The invention provides an efficient low-resistance separator for high-liquid-content gas-liquid two-phase flow, and belongs to the field of separators. The efficient low-resistance separator for the high-liquid-content air-liquid two-phase flow comprises a gas-liquid two-phase inlet, a gravity sedimentation chamber, a first-stage cyclone tube, a liquid collecting chamber, a liquid collecting chamber draining port, a second-stage cyclone tube, a gas exhausting port, an air exhausting chamber and the like, and is used for gas-liquid separation on high-liquid-content gas. According to the separator, an operation mode that the cyclone tubes at the same stage are connected in parallel and the cyclone tubes at different stages are connected in series is performed in one separator, namely, a plurality of cyclone tubes are connected in parallel to form a stage, and cyclone tubes at two stages are synchronously arranged, so that the separation efficiency is effectively improved while the processing capacity of the device is improved; in addition, the separator can be adapted to the working condition of high-liquid-content gas-liquid two-phase flow; two stages of guide blades connected in series are arranged in each cyclone tube at each stage, so that the separation capacity of the cyclone tubes at each stage can be improved; and meanwhile, the cyclone production synergistic effect between the two-stage guide blades connected in series can be realized, so that the resistance is low, and the requirements on pressure in a following process can be met.

The invention provides a manufacturing method of a printed circuit board and the printed circuit board. The manufacturing method of the printed circuit board comprises the following steps: providing a core board; the core plate comprises an insulating substrate, and a plurality of bonding pads are arranged on a first surface and / or a second surface opposite to the first surface of the insulating substrate; and laminating a dielectric layer on one side of the insulating substrate provided with the plurality of bonding pads to form a lamination layer which is at least partially embedded among the plurality of bonding pads. According to the method, the probability of falling of the lamination layer can be greatly reduced, and the probability of short circuit among the bonding pads during surface mounting of electronic components is further effectively reduced; meanwhile, the thickness of the pressing layer can be controlled within a certain range, the thickness of the pressing layer is effectively reduced, and miniaturization design of products is facilitated.

An ultrahigh current density electrolysis or electro-deposition groove comprises a groove body. The groove body is provided with a liquid inlet; a flange is disposed outside the liquid inlet; a panel is disposed on an inner wall of the groove body; a closed cavity is formed by the panel and the inner wall of the groove body; the closed cavity is communicated with the liquid inlet on the groove body; the panel is provided with an electrolyte spraying device and a polar plate limiting device; an anode plate and a cathode plate are placed in the groove body; and a liquid discharging device is disposed on the groove body. In the present invention, a liquid supplying device is formed by the panel, the inner wall of the groove body, and the closed cavity formed by the panel and the inner wall of the groove body. According to the present invention, the liquid supplying device is embedded into the inner wall of the groove body, and a liquid supplying manner in which the bottom of the liquid supplying device is parallel to a polar plate is utilized to ensure an electrolyte circulation requirement of electrolysis or electro-deposition production with an ultrahigh current density; in addition, the polar plate does not contact the liquid supplying device embedded into the inner wall of the groove body, so that the safety of the liquid supplying device is ensured and the production is smoothly and safely operated.

The invention provides a metal interconnection structure, a preparation method thereof and a semiconductor device. The metal interconnection structure comprises a substrate, an etching stop layer and a protection layer which are sequentially arranged in a laminated mode, a contact hole penetrating through the protection layer and the etching stop layer, and a diffusion barrier layer, wherein the contact hole comprises a first part and a second part, the first part penetrates through the protection layer and extends into the etching stop layer, and the second part is arranged in the etching stop layer and is connected with the first part of the contact hole; the inclination angle of the side wall of the first part of the contact hole relative to the bottom of the contact hole is smaller than the inclination angle of the side wall of the second part of the contact hole relative to the bottom of the contact hole; and the diffusion barrier layer covers the side wall and the bottom of the contact hole. The connection part of the first part and the second part of the contact hole is located at the etching stop layer, transition is smooth, a sharp angle cannot be formed, the coverage of the diffusion barrier layer is good, and the short circuit problem between the interconnection structures is greatly reduced.