JP2016127219A - Semiconductor device manufacturing method and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method and a semiconductor device, which can inhibit generation of a low-density region at a joining part and inhibit the occurrence of poor insulation.SOLUTION: A semiconductor device manufacturing method comprises: a process of forming an electrode pattern 2 on an insulating substrate 1; a process of applying a rust preventive film 3 to the electrode pattern 2; a process of removing the rust preventive film 3 only on joining parts of a semiconductor chip 7; a process of applying a conductive paste 6 to regions where the rust preventive film 3 is removed and on a surface of the rust preventive film 3 on a peripheral area of the regions where the rust preventive film 3 is removed; a process of arranging the semiconductor chip 7 and heating the conductive paste 6 while applying pressure to form joining parts 6b for joining the semiconductor chip 7 and the electrode pattern 2; and a process of removing sintered layers 6be without application of pressure on the rust preventive film 3 and the joining parts 6b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor device manufacturing method and a semiconductor device using a bonding material containing ultrafine metal particles.

  In recent years, a conductive paste is often used for a joint portion of electronic component mounting. Generally, conductive paste is mixed with high-temperature firing type conductive paste that decomposes and disperses the solvent and dispersant by heating to sinter the conductive powder, and the conductive powder in the polymer. There is a heat-curing type conductive paste that cures the polymer by heating and obtains conductivity by bringing the conductive powders into contact with each other, and the heat-curing type conductive paste is also used as a conductive adhesive. It is attracting attention as a similar joining method and is being developed.

  On the other hand, in the solder used so far, as a soldering method, for example, in Patent Document 1, a resist protective film made of an epoxy resin is formed on a circuit board having an electrode pattern, and a polyethylene-based film is further formed thereon. After attaching the film, use YAG laser (Yttrium Aluminum Garnet laser) to provide openings in the resist protective film and polyethylene film so that part of the electrode pattern is exposed, and then supply solder paste to the film surface. A method of forming solder bumps on an electrode pattern of a substrate by removing the film after the solder paste is filled only in the opening by scraping with a squeegee and the solder is melted in a reflow furnace is disclosed.

  Patent Document 2 discloses a method for soldering a printed wiring board, in which an organic rust inhibitor is applied to a metal surface, and reflow soldering is performed in a low oxygen atmosphere having an oxygen concentration of 15% or less using a low-residue cream solder. A soldering method is disclosed in which post-cleaning is not necessary by performing soldering. Moreover, about the part which does not implement soldering, the method of removing a rust prevention film is disclosed by carrying out the reflow process in air | atmosphere using the flux agent which does not need the post-cleaning of a low residue.

  Furthermore, Patent Document 3 discloses a method of forming a bond with a Cu electrode coated with a rust preventive film made of an organic compound containing N using a solder material of Sn—Ag—Cu alloy. Specifically, a step of coating with a rust preventive film composed of any one of imidazole, benzimidazole, alkylimidazole, benzotriazole, mercaptobenzothiazole, pyrrole, and thiazole, and Ag 2.0 to 3.0 wt%, Cu 0.5 to A method is disclosed in which a solder joint is formed on the coated Cu electrode using a solder material consisting of 0.8 wt%, the remainder Sn and inevitable impurities.

JP 2006-245190 A (paragraphs 0021 to 0034, FIG. 1) JP-A-6-314872 (paragraphs 0016 to 0018) Japanese Patent Laying-Open No. 2007-17576 (paragraph 0021, FIG. 1)

  However, when a conductive paste containing metal ultrafine particles coated with an organic protective film is used as the conductive paste, the conductive paste containing metal ultrafine particles coated with the organic protective film is printed on a screen printing machine or the like. When printing and coating is performed using an apparatus, if there is a portion where the thickness of the conductive paste is thin or not applied at the lower part of the material to be joined, particularly at the end of the material to be joined, the joining pressure at this part is reduced. Since it becomes insufficient, a low density region in which the density of the bonding material is reduced is generated. This low-density region has a higher thermal resistance than a region where the joint is soundly formed, so that the efficiency for conducting the heat generated from the material to be joined is low, and the heat is concentrated as a hot spot. Since this works, there is a problem that the quality of the entire joint is lowered.

  In addition, in order to suppress the occurrence of the low density region as described above, in the step of printing and applying a conductive paste containing metal ultrafine particles coated with the organic protective film using a printing device such as a screen printer, When conductive paste is printed and applied to a larger area than the material to be joined, the occurrence of low density areas can be suppressed, but the portion of the conductive paste material that has not been pressurized by the material to be joined becomes unpressurized. In the manufacturing process of the semiconductor device after the pressurizing and heating bonding, the semiconductor device is separated and released, which causes a problem of causing an insulation failure of the semiconductor device.

  Even when a conductive paste containing metal ultrafine particles coated with the organic protective film is printed and applied using conventional techniques such as those described in Patent Documents 1 to 3, the edges of the materials to be joined In this case, since the bonding material thickness is reduced, the generation of the low density region cannot be suppressed at the end of the material to be bonded after the pressure heating bonding. In addition, the problem of insulation failure of the semiconductor device due to the release of the conductive paste material in the non-pressurized state cannot be suppressed.

  The object of the present invention is to solve the above-mentioned problems, and even when a conductive paste containing ultrafine metal particles coated with an organic protective film is used for a semiconductor device, the material to be joined An object of the present invention is to provide a semiconductor device manufacturing method and a semiconductor device capable of suppressing the generation of a low-density region at the end of the semiconductor device and suppressing the occurrence of defective insulation of the semiconductor device.

  The method for manufacturing a semiconductor device of the present invention includes a step of forming an electrode pattern on an insulating substrate, a step of forming a rust preventive film on the electrode pattern, and a step of removing the rust preventive film only in a region where the semiconductor element is bonded. , Applying the conductive paste containing ultrafine metal particles on the rust-preventive film and the area where the rust-preventive film has been removed , Pressing the semiconductor element while pressing the conductive paste and heating to form a sintered layer of ultrafine metal particles, bonding the semiconductor element and the electrode pattern, and using a cleaning agent containing a reducing agent And a step of removing the non-pressurized sintered layer on the rust preventive film together with the rust preventive film.

  According to the present invention, by forming the sintered layer sufficiently pressed up to the end of the semiconductor element, it is possible to ensure electrical continuity and suppress the occurrence of the low density region. Moreover, by removing the non-pressurized sintered layer at the periphery of the edge together with the anticorrosive film, the non-pressurized sintered layer at the periphery of the semiconductor element can be easily removed, and the end of the sintered layer It is possible to suppress the occurrence of insulation failure due to the liberation.

It is a fragmentary sectional view which shows the joining process in the manufacturing method of the semiconductor device by Embodiment 1 of this invention. It is a top view of the board | substrate after forming an electrode pattern in the joining process in the manufacturing method of the semiconductor device by Embodiment 1 of this invention. It is a top view of the board | substrate after apply | coating an etching paste in the joining process in the manufacturing method of the semiconductor device by Embodiment 1 of this invention. It is a fragmentary sectional view which shows the joining process in the manufacturing method of the semiconductor device by Embodiment 2 of this invention. It is a fragmentary sectional view which shows the joining process in the manufacturing method of the semiconductor device by Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a bonding step in the method for manufacturing a semiconductor device 101 according to the first embodiment of the present invention. Hereinafter, the manufacturing method of the semiconductor device 101 according to the first embodiment of the present invention will be described with reference to FIG.

  First, as shown in FIG. 1A, an electrode pattern 2 made of Cu is formed at a desired position on the surface of an insulating substrate 1 made of aluminum nitride (hereinafter referred to as AlN). Here, as the insulating substrate 1 made of AlN, a substrate having a thickness of 0.6 mm × length 50 mm × width 70 mm was used. A Cu plate having a thickness of 0.3 mm is joined to the insulating substrate 1 by brazing Ag, and an electrode pattern 2 is formed by a photolithography process and a Cu etching process. FIG. 2 shows a top view of the insulating substrate 1 on which the electrode pattern 2 is formed.

  Next, as shown in FIG. 1B, the insulating substrate 1 on which the electrode pattern 2 is formed is dipped in an aqueous solution containing benzotriazole, then washed with water and dried, so that the surface of the Cu electrode pattern 2 is coated with benzoate. A rust preventive film 3 made of triazole is formed.

When the Cu material is dried, an oxide film does not grow on the surface layer, and the internal protective cuprous oxide film reaches an equilibrium state with a thickness of about 1 to 5 nm. However, since the protective cuprous oxide coating becomes electrically and chemically unstable due to the presence of moisture, organic and inorganic substances, and changes in the environment on the surface of the Cu material, it oxidizes and corrodes the cuprous oxide coating. It is known that it progresses to a copper oxide film and changes color. Therefore, it is possible to prevent oxidation, corrosion, and discoloration of the Cu material by constructing a protective film on the surface of the Cu material. Here, benzotriazole _{(C 6 H 4 N 2 NH} , Benzo triazole: abbreviation BTA) using, constitutes a protective coating consisting of benzotriazole copper salt to the electrode pattern 2 on the surface of Cu. In forming this protective film, since benzotriazole is water-soluble and an aqueous solution can be easily formed, an aqueous solution in which about 5 wt% of benzotriazole is dissolved in 1000 ml of water is used. By immersing the insulating substrate 1 on which the electrode pattern 2 is formed in this solution,
2Cu + 0 ₂ + 4C ₆ H ₄ N ₂ NH → 2 [(C ₆ H ₄ N ₂ N) ₂・ Cu] + 2H ₂ O
It is considered that a film of benzotriazole copper salt (Cu · BTA) is formed on the surface of the copper electrode. Moreover, it is thought that the benzotriazole copper salt forms the following compounds on the polymer depending on the ionic state of copper.
-[(C ₆ H ₄ N ₂ N) ₂ -Cu- (C ₆ H ₄ N ₂ N) ₂ -Cu] _n-
After the formation of the benzotriazole copper salt, the insulating substrate 1 is immersed in a water washing solution to wash the substrate with water, and the insulating substrate 1 is dried by blow drying, whereby a protective coating is formed on the surface of the Cu electrode pattern 2. The rust preventive film 3 made of benzotriazole can be formed.

  Here, since it is necessary that the heat resistance temperature of the rust preventive film is higher than the heating temperature at the time of bonding, the rust preventive film 3 (heat resistant temperature: 200 ° C.) made of benzotriazole copper salt having high heat resistance is used. However, it is not limited to this. If this heat-resistant temperature is satisfied, a rust preventive film other than benzotriazole may be used.

  Subsequently, as shown in FIGS. 1C to 1D, an opening 5 is provided in the rust preventive film 3 using the etching paste 4. Here, a phosphoric acid-based etching paste is used as the etching paste 4 and is etched with the same size as the semiconductor chip 7 as a semiconductor element to be joined to a desired position of the rust preventive film 3 in a later step (see FIG. 1G). Paste 4 is applied (see FIG. 1C). As the semiconductor chip 7, a 10 mm square IGBT (Insulated Gate Bipolar Transistor) is used. After applying the etching paste 4, heat treatment is performed for 30 minutes in an atmosphere of 150 ° C. After the heat treatment, the insulating substrate 1 is immersed in a washing solution and washed with ultrasonic waves for 30 minutes, and the insulating substrate 1 is dried by drying with a hot air blow. Through such an etching process, the opening 5 can be provided in the rust preventive film 3 (see FIG. 1D). FIG. 3 shows a top view after the etching paste 4 is applied. By using the etching paste 4, the etching process for forming the opening 5 can be simplified only by heat treatment, but is not limited thereto. The opening 5 may be provided by using a general photolithography technique or etching technique.

  Next, as shown in FIGS. 1 (e) to 1 (f), the conductive paste 6 for bonding containing metal ultrafine particles coated with an organic protective film is provided with an opening having an area larger than the opening 5. The conductive paste 6a is applied to the opening 5 and its edge in a larger area than the opening 5 by supplying the surface of the mask 10 and moving the squeegee 9 in the direction A to scrape the conductive paste 6. As the conductive paste 6, a conductive paste containing metal ultrafine particles made of Ag having a particle size of about 10 to 20 nm was used. The conductive paste 6 used here does not contain a reducing agent that can remove the Cu anticorrosive film 3. For this reason, since the conductive paste applied to the portion where the rust preventive film 3 has not been removed cannot be metal-bonded to the Cu material of the electrode, it can be easily detached in a subsequent process.

  In addition, it is preferable that the particle diameter of a metal ultrafine particle is 1-100 nm, especially the particle diameter of 1-50 nm generally called a nanoparticle. With these particle sizes, a melting point temperature significantly lower than that in the bulk state can be obtained, and the particles are melted by heating and pressurization, and the particles are sintered together to become a bulk. The melting temperature after becoming bulk is the same as the melting temperature of the metal in the normal bulk state, and the metal ultrafine particles are sintered by heating at a low temperature, and then heated to the melting temperature in the bulk state after sintering. It has the feature of not melting until. Further, the ultrafine metal particles are not limited to Ag, and those composed of at least one selected from Au, Ag, Ni, Cu, Al, Zn, Sn, In, Bi, and Sb are preferable.

  Subsequently, in order to remove the organic solvent component contained in the conductive paste 6 a, a heat treatment is performed in an atmosphere of about 70 to 120 ° C., and then a semiconductor is formed on the conductive paste 6 a so as to correspond to the opening 5. When the chip 7 is mounted and the semiconductor chip 7 is pressed and heat-treated, the conductive paste 6a is sintered with the ultrafine metal particles as shown in FIG. The portion and the surface electrode portion of the insulating substrate 1 are joined to form a joined portion 6b that is a sintered layer. Here, the organic solvent component is removed by heating and drying the conductive paste 6a formed on the insulating substrate 1 at 80 ° C. for 30 minutes in a warm air drying oven. The bonding condition of the semiconductor chip 7 is heating at 180 ° C. for 30 minutes under a pressure of 10 Mpa. In addition, although the warm air drying oven was used for the removal of an organic solvent component, it is not restricted to this. A thermostatic bath, a hot plate, a heat treatment furnace, or the like may be used.

  When the bonding temperature of the semiconductor chip 7 is 180 ° C., the heat resistance temperature of the formed rust preventive film 3 is 200 ° C. or less, and therefore the end of the conductive paste 6a applied to the portion where the rust preventive film 3 has not been removed. The portion is not metal-bonded to the Cu electrode pattern 2. However, when the bonding temperature is higher than the heat resistance temperature of the rust preventive film 3, even if the conductive paste 6 does not contain a reducing agent capable of removing the rust preventive film 3, the bonding of the semiconductor chip 7 can be performed. Depending on the bonding temperature, the covering effect of the anticorrosive film 3 may be weakened, and a part of the Cu electrode pattern 2 and the conductive paste 6 may exhibit a metal bond, and the removability in a subsequent process may be reduced.

  In the bonding process of the semiconductor chip 7, since the semiconductor chip 7 is directly pressed under high pressure and bonded while applying pressure to the conductive paste 6a, chip cracking and chipping are likely to occur. For this reason, in order to prevent chip cracking and chipping, it is preferable to press with a heat-resistant flexible material such as a PTFE (polytetrafluoroethylene) sheet as a buffer material between the semiconductor chip 7 and the pressure press part. Also in the first embodiment, the PTFE sheet having a thickness of 1 mm is overlaid on the semiconductor chip 7 and then pressurized and heated.

  Next, the insulating substrate 1 is washed with water using a cleaning agent containing a reducing agent and a chelating agent for Cu, thereby removing the rust preventive agent 3 on the surface of the Cu electrode pattern 2 and the rust preventive agent. The end portion 6be of the joining portion 6b formed on the surface 3 without pressure is removed. Furthermore, it is possible to further enhance the cleaning effect by using ultrasonic waves during water cleaning. Here, cleaning was performed using a cleaning agent MC-2000 manufactured by Toyo Aluminum Co., Ltd. as a cleaning agent, but the cleaning agent is not limited thereto. A cleaning agent other than the cleaning agent MC-2000 may be used. As shown in FIG. 1 (h), oxygen atoms on the surface of the electrode pattern 2 of Cu are adsorbed and reduced by the reducing agent contained in the cleaning agent, and the remaining Cu atoms are adsorbed and removed by the chelating agent. The rust preventive film 3 formed on the surface of the Cu electrode pattern 2 and a part of the Cu atomic layer on the surface are removed. As a result, the end portion 6be of the bonding portion 6b formed on the surface without pressure is freely removed in the cleaning liquid, but is formed by pressurization in which metal diffusion bonding is performed with the Cu atom. The portion of the portion 6b and the portion of the bonding portion 6b that are metal-bonded to each other are not removed by the cleaning liquid, and the semiconductor chip 7 that is the bonded material remains bonded to the Cu electrode pattern 2 Will be left behind.

  As described above, according to the manufacturing method of the semiconductor device 101 according to the first embodiment of the present invention, the step of forming the Cu electrode pattern 2 on the insulating substrate 1 and the benzotriazole on the Cu electrode pattern 2 are performed. The step of applying the rust preventive film 3, the step of removing the rust preventive film 3 only in the region where the semiconductor chip 7 is bonded, the region from which the rust preventive film 3 has been removed, and A step of applying a conductive paste 6 containing ultrafine metal particles coated with an organic protective film on the rust preventive film 3 and a semiconductor chip 7 at a position corresponding to the portion of the conductive paste 6 from which the rust preventive film 3 has been removed. A step of pressing the semiconductor chip 7 and heating the conductive paste 6 while applying pressure to form a bonding portion 6b for bonding the semiconductor chip 7 and the electrode pattern 2 by sintering metal ultrafine particles; Contains reducing agent And the step of removing the non-pressurized sintered layer 6be of the bonding portion 6b using the cleaning agent, and thus the electrical continuity can be secured to the end of the semiconductor element. At the same time, the generation of a low density region can be suppressed. Further, the non-pressurized sintered layer at the peripheral portion can be easily removed, and the occurrence of insulation failure due to the release of the end portion of the joint portion can be achieved.

Embodiment 2. FIG.
In the first embodiment, the case where the conductive paste 6a is applied to the peripheral portion of the opening 5 with an area larger than that of the opening 5 is shown. However, in the second embodiment, the conductive paste 6a is conductive to the same area as the electrode pattern. It shows about the case where an adhesive paste is applied.

  FIG. 4 is a cross-sectional view showing a bonding step in the method for manufacturing the semiconductor device 102 according to the second embodiment of the present invention. In the second embodiment of the present invention, in the step of applying the conductive paste, as shown in FIGS. 4E to 4F, the conductive paste for bonding including the ultrafine metal particles covered with the organic protective film is used. 6 is supplied to the surface of the printing mask 11 provided with an opening larger than the opening 5 and to the same area as that of the electrode pattern 2 of Cu, and the squeegee 9 scrapes off the opening 5 and the electrode pattern. The conductive paste 6 a is applied to the surface of 2 with a larger area than the opening 5. The conductive paste 6 used here does not contain a reducing agent that can remove the Cu anticorrosive film 3. For this reason, in this Embodiment 2, even when the electrically conductive paste 6 is apply | coated to the whole surface of the antirust film 3 on the electrode pattern 2, about the non-pressurized sintered layer 6de shown in FIG.4 (g). Since the rust preventive film 3 is not metal-bonded to the Cu material of the electrode pattern 2, as shown in FIG. 4 (h), a reducing agent containing a reducing agent and a chelating agent for Cu were included. By washing with water using a cleaning agent, the rust preventive agent 3 on the surface of the Cu electrode pattern 2 can be removed, and the non-pressurized sintered layer 6de attached on the rust preventive agent 3 can be easily formed. Can be removed. The other bonding steps are the same as those in the manufacturing method of the semiconductor device 101 of the first embodiment, and the description thereof is omitted.

  As described above, according to the manufacturing method of the semiconductor device 102 according to the second embodiment of the present invention, the step of forming the Cu electrode pattern 2 on the insulating substrate 1 and the benzotriazole on the Cu electrode pattern 2 are performed. On the rust preventive film 3 formed on the electrode pattern 2 and the step of removing the rust preventive film 3 only in the region where the semiconductor chip 7 is bonded, the step of applying the rust preventive film 3 A step of applying a conductive paste 6 containing ultrafine metal particles coated with an organic protective film, and a semiconductor chip 7 at a position corresponding to the portion of the conductive paste 6 from which the rust preventive film 3 has been removed. The step of pressing the chip 7 and heating the conductive paste 6 while pressurizing it to form a bonding portion 6b for bonding the semiconductor chip 7 and the electrode pattern 2 by sintering the metal ultrafine particles, and the cleaning including the reducing agent Agent And the step of removing the non-pressurized sintered layer 6de other than the anticorrosive film 3 and the joining portion 6d is used, so that electrical continuity can be ensured up to the semiconductor element end, Generation of a low density region can be suppressed. Further, the non-pressurized sintered layer at the peripheral portion can be easily removed, and the occurrence of insulation failure due to the release of the end portion of the joint portion can be achieved.

Embodiment 3 FIG.
In the first and second embodiments, the case where a rust-preventing film made of benzotriazole is applied as the rust-preventing film 3 is shown. However, in the third embodiment, a case where another rust-preventing film such as imidazole is used. Show.

  FIG. 5 is a cross-sectional view showing a bonding step in the method for manufacturing the semiconductor device 103 according to the third embodiment of the present invention. In the third embodiment of the present invention, in the step of applying the conductive paste, as shown in FIG. 5B, in the step of applying the rust preventive film, the insulating substrate 1 on which the electrode pattern 2 is formed is replaced with imidazole, benzoate. Immersion in an aqueous solution containing any one of imidazole, alkylimidazole, mercaptobenzothiazole, pyrrole, and thiazole, followed by washing with water and drying. The rust preventive film 8 made of any one of pyrrole and thiazole is formed. The heat-resistant temperature of the rust preventive film 8 used here is 350 ° C. As described above, it is necessary that the heat resistance temperature of the rust preventive film is higher than the heating temperature at the time of joining. Therefore, in the third embodiment, since the heat resistance temperature of the rust preventive film 8 is higher than the rust preventive film (heat resistant temperature: 200 ° C.) made of benzotriazole, the semiconductor chip 7 is used as the electrode pattern 2 on the insulating substrate 1. In the case of bonding, it is possible to bond at a temperature higher than the bonding temperature in the first and second embodiments. The other bonding steps are the same as those in the manufacturing method of the semiconductor device 101 of the first embodiment, and the description thereof is omitted.

  As described above, according to the manufacturing method of the semiconductor device 103 according to the third embodiment of the present invention, the step of forming the Cu electrode pattern 2 on the insulating substrate 1 and the imidazole and benzoate on the Cu electrode pattern 2 are performed. A step of applying a rust preventive film 8 made of any one of imidazole, alkylimidazole, mercaptobenzothiazole, pyrrole, and thiazole; a step of removing the rust preventive film 8 only in a region where the semiconductor chip 7 is joined; A step of applying a conductive paste 6 containing ultrafine metal particles coated with an organic protective film on the rust preventive film 8 at the periphery of the removed region and the region from which the rust preventive film 8 has been removed; The semiconductor chip 7 is disposed at a position corresponding to the portion from which the rust preventive film 8 has been removed, and the conductive paste 6 is heated while being pressed by pressing the semiconductor chip 7, thereby forming ultrafine metal particles. The step of forming the joint portion 6b for joining the semiconductor chip 7 and the electrode pattern 2 by sintering, and the non-pressurized end portion 6be of the rust preventive film 8 and the joint portion 6b using a cleaning agent containing a reducing agent. Therefore, it is possible to ensure electrical continuity up to the end of the semiconductor element and to suppress the generation of the low density region. Further, the non-pressurized sintered layer at the peripheral portion can be easily removed, and the occurrence of insulation failure due to the release of the end portion of the joint portion can be achieved. Furthermore, the heat resistance at the time of joining can be improved, and the removability of the non-pressurized sintered layer can be improved.

  Further, within the scope of the present invention, the embodiments can be freely combined, or the embodiments can be appropriately modified and omitted.

DESCRIPTION OF SYMBOLS 1 Insulating substrate, 2 Electrode pattern, 3 Antirust film, 4 Etching paste, 6 Conductive paste, 7 Semiconductor chip, 8 Antirust film, 101, 102, 103 Semiconductor device

Claims (7)

Forming an electrode pattern on an insulating substrate;
Forming a rust preventive film on the electrode pattern;
Removing the rust preventive film only in the region where the semiconductor element is bonded;
Applying a conductive paste containing ultrafine metal particles on the antirust film and the region from which the antirust film has been removed;
The semiconductor element is disposed on the conductive paste at a position corresponding to the region from which the rust preventive film has been removed, and the conductive paste is heated while being pressed by pressing the semiconductor element, whereby the ultrafine metal particles Forming a sintered layer and bonding the semiconductor element and the electrode pattern;
And a step of removing the non-pressurized sintered layer on the rust preventive film together with the rust preventive film using a cleaning agent containing a reducing agent.   The step of applying the conductive paste is characterized in that the conductive paste is applied only on the rust preventive film in a region where the rust preventive film is removed and in a peripheral portion of the region where the rust preventive film is removed. Item 12. A method for manufacturing a semiconductor device according to Item 1.   3. The method of manufacturing a semiconductor device according to claim 1, wherein a heat resistance temperature of the rust preventive film is higher than a bonding temperature of the conductive paste.   The semiconductor according to any one of claims 1 to 3, wherein the rust preventive film is made of any one of benzotriazole, imidazole, benzimidazole, alkylimidazole, mercaptobenzothiazole, pyrrole, and thiazole. Device manufacturing method.   The conductive paste contains at least one or more metal ultrafine particles among Au, Ag, Ni, Cu, Al, Zn, Sn, In, Bi, and Sb. A method for manufacturing a semiconductor device according to claim 1.   The method for manufacturing a semiconductor device according to claim 1, wherein an etching paste is used in the step of removing the rust preventive film only in a region where the semiconductor element is bonded.   A semiconductor device manufactured by the method for manufacturing a semiconductor device according to claim 1.

Images