JP6780398B2 - Manufacturing method of resin-sealed power module - Google Patents

Description

The present invention relates to a method for manufacturing a resin-sealed power module used in a semiconductor device that controls a large current and a high voltage.

Power semiconductor devices for high power control used for controlling wind power generation, electric vehicles, hybrid vehicles, etc. generate a large amount of heat, so that a substrate on which such a power semiconductor element is mounted has insulating properties. A substrate for a power module in which a circuit layer made of copper, aluminum, or the like is formed on one surface of an excellent ceramic substrate is used.
Recently, as the current and voltage have increased, the amount of heat generated from the semiconductor element has increased, and it is required to further improve the bonding reliability between the semiconductor element and the substrate for the power module.

Therefore, for example, in Patent Document 1, the semiconductor element and the substrate for the power module on which the semiconductor element is mounted are sealed with a mold resin to disperse the stress generated at the bonding interface, and the semiconductor element and the power module are used. A technique for improving bonding reliability with a substrate is disclosed.
Further, when the power module substrate on which the semiconductor element is mounted is resin-sealed with a mold resin, for example, as disclosed in Patent Document 2, the surface of the power module substrate and the semiconductor element is made of polyimide resin or the like. A primer treatment liquid is applied to form an underlying layer.

Japanese Patent No. 3429921 JP-A-2014-069509

By the way, in a power module provided with a ceramic substrate made of silicon nitride, even if a primer treatment liquid is applied to the surface of the ceramic substrate and dried, a base layer made of a polyimide resin or the like is not sufficiently formed, and the ceramic substrate and the ceramic substrate are formed. There is a problem that the adhesion with the mold resin is lowered. Therefore, there is a possibility that the mold resin may be cracked from the interface portion between the ceramic substrate and the mold resin. In addition, when a cold cycle is applied, the stress dispersion effect of the mold resin does not work, cracks occur at the bonding interface between the ceramic substrate and the circuit layer, and the bonding reliability between the circuit layer and the ceramic is insufficient. There was a risk of becoming.
Further, when the power module substrate has a Cu layer made of copper or a copper alloy and the Cu layer has a resin contact surface in contact with the mold resin, the mold resin and the Cu layer are in close contact with each other. There was a risk that the properties would deteriorate and the Cu layer and the mold resin would peel off.

The present invention has been made in view of the above circumstances, and is a resin having excellent adhesion between a ceramic substrate made of silicon nitride and a mold resin, and a Cu layer made of copper or a copper alloy and a mold resin. An object of the present invention is to provide a method for manufacturing a resin-sealed power module capable of manufacturing a sealed power module.

As a result of diligent studies by the present inventors in order to solve such a problem and achieve the above object, a ceramic substrate made of silicon nitride has a plurality of needle-like particles on its surface. When the primer treatment solution is applied, the primer treatment solution does not sufficiently permeate between the needle-shaped particles and voids are formed, which prevents the underlying layer from forming well and adheres to the mold resin. It turned out to be less sexual. When the power module substrate has a Cu layer made of copper or a copper alloy and the Cu layer has a resin contact surface in contact with the mold resin, the applied primer treatment liquid is dried. In the process, it was found that the adhesion between the Cu layer and the mold resin is lowered by forming a thick oxide film on the oil contact surface of the Cu layer.

The present invention has been made based on the above findings, and the method for manufacturing a resin-sealed power module of the present invention is for a power module in which a circuit layer is formed on one surface of a ceramic substrate made of silicon nitride. A method for manufacturing a resin-sealed power module in which a power module composed of a substrate and a semiconductor element mounted on the circuit layer of the power module substrate is sealed with a mold resin. Has a Cu layer made of copper or a copper alloy, the Cu layer has a resin contact surface in contact with the mold resin, and is an extension surface of at least the bonding interface of the ceramic substrate with the circuit layer. Above, the ceramic substrate surface roughness adjusting step of adjusting the surface roughness of the contact surface with the mold resin within the range of 1.7 μm or more and 2.7 μm or less at the maximum height Ry, and above the circuit layer. The semiconductor element mounting step of mounting the semiconductor element, the primer treatment liquid coating step of applying the primer treatment liquid to the surface of the power module, and the primer treatment liquid drying of drying the applied primer treatment liquid in a non-oxidizing atmosphere. A step and a resin sealing step of sealing the power module with a resin using the mold resin are provided, and after the primer treatment liquid drying step, an oxide film formed on the resin contact surface of the Cu layer is provided. It is characterized in that the thickness is 25 nm or less.

In the method for manufacturing a resin-sealed power module having this configuration, the surface roughness of at least the extension surface of the bonding interface with the circuit layer of the ceramic substrate and the contact surface with the mold resin is set to the maximum height Ry. Since the ceramic substrate surface roughness adjusting step for adjusting within the range of 1.7 μm or more and 2.7 μm or less is provided, at least a part of needle-like particles existing on the surface of the ceramic substrate should be removed and flattened. In the subsequent step of applying the primer treatment liquid, the primer treatment liquid can be permeated into the inside of the ceramic substrate. Therefore, the underlying layer can be satisfactorily formed by the subsequent primer treatment liquid drying step, and the adhesion between the mold resin and the ceramic substrate can be improved.
Further, after the primer treatment liquid drying step, the thickness of the oxide film formed on the resin contact surface of the Cu layer is set to 25 nm or less, so that the adhesion between the Cu layer and the mold resin is surely improved. It becomes possible.
Since it is industrially very difficult to control the thickness of the natural oxide film formed on the surface of the Cu layer to less than 3 nm, the oxide film formed on the resin contact surface of the Cu layer The thickness is in the range of 3 nm or more and 25 nm or less.

Further, since the primer treatment liquid drying step of drying the applied primer treatment liquid in a non-oxidizing atmosphere is provided, a thick oxide film is formed on the resin contact surface of the Cu layer made of copper or a copper alloy. Can be suppressed, and the adhesion between the Cu layer and the mold resin can be improved.
As described above, since the adhesion between the ceramic substrate and the mold resin and the Cu layer and the mold resin are improved, it is possible to provide a resin-sealed power module having excellent bonding reliability after a cooling / heating cycle. It becomes.

Here, in the method for producing a resin-sealed power module of the present invention, it is preferable to carry out the primer treatment liquid drying step in a low oxygen atmosphere having an oxygen partial pressure of 32 Pa or less.
In this case, it is possible to suppress the formation of a thick oxide film on the resin contact surface of the Cu layer in the primer treatment liquid drying step, and it is possible to reliably improve the adhesion between the Cu layer and the mold resin. ..

Further, in the method for manufacturing a resin-sealed power module of the present invention, it is preferable to carry out the primer treatment liquid drying step in a vacuum atmosphere having a vacuum degree of 150 Pa or less.
In this case, it is possible to suppress the formation of a thick oxide film on the resin contact surface of the Cu layer in the primer treatment liquid drying step, and it is possible to reliably improve the adhesion between the Cu layer and the mold resin. .. In addition, since it is dried in a vacuum atmosphere after the primer treatment liquid application step, even if a small amount of voids are generated when the primer treatment liquid is applied to the ceramic substrate, the voids are kept in the vacuum atmosphere. It can be removed. Therefore, the primer treatment liquid can be more reliably permeated into the ceramic substrate, and the underlying layer can be formed satisfactorily.

According to the present invention, it is possible to manufacture a resin-sealed power module having excellent adhesion between a ceramic substrate made of silicon nitride and a mold resin, and a Cu layer made of copper or a copper alloy and a mold resin. It becomes possible to provide a method for manufacturing a resin-sealed power module.

It is a schematic explanatory drawing of the resin-sealed power module which is an embodiment of this invention. It is a flow chart of the manufacturing method of the resin-sealed power module which is embodiment of this invention. It is explanatory drawing of the manufacturing method of the power module used in embodiment of this invention. It is explanatory drawing of the manufacturing method of the resin-sealed power module which is an embodiment of this invention. It is a schematic explanatory drawing of the resin sealing power module which is another embodiment of this invention. It is a schematic explanatory drawing of the resin sealing power module which is another embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a resin-sealed power module 50 according to an embodiment of the present invention.
The resin-sealed power module 50 includes a power module 1 including a power module substrate 10 and a semiconductor element 3, and a mold resin 5 for resin-sealing the power module 1.

The power module 1 includes a power module substrate 10 and a semiconductor element 3 bonded to one surface (upper surface in FIG. 1) of the power module substrate 10 via a solder layer 2.
Here, the solder layer 2 is, for example, a Sn-Ag-based, Sn-In-based, or Sn-Ag-Cu-based solder material.

The power module substrate 10 is formed on the ceramic substrate 11, the circuit layer 12 disposed on one surface of the ceramic substrate 11 (upper surface in FIG. 1), and the other surface of the ceramic substrate 11 (lower surface in FIG. 1). It includes an arranged metal layer 13.
The ceramic substrate 11 prevents electrical connection between the circuit layer 12 and the metal layer 13, and is made of silicon nitride (Si ₃ N ₄ ) having high insulating properties in the present embodiment. Here, the thickness of the ceramic substrate 11 is set within the range of 0.2 mm or more and 1.5 mm or less, and in the present embodiment, it is set to 0.32 mm.

As shown in FIG. 3, the circuit layer 12 is formed by joining a copper plate 22 made of copper or a copper alloy to one surface of the ceramic substrate 11. In the present embodiment, an oxygen-free copper rolled plate is used as the copper plate 22 constituting the circuit layer 12. A circuit pattern is formed in the circuit layer 12, and one surface (upper surface in FIG. 1) is a mounting surface on which the semiconductor element 3 is mounted. Here, the thickness of the circuit layer 12 is set within the range of 0.1 mm or more and 1.0 mm or less, and is set to 0.6 mm in the present embodiment.
The circuit layer 12 is connected to the external connection terminal 7 by wire bonding.

As shown in FIG. 3, the metal layer 13 is formed by joining an aluminum plate 23 to the other surface of the ceramic substrate 11. In the present embodiment, the metal layer 13 is formed by joining an aluminum plate 23 made of a rolled aluminum plate having a purity of 99.99 mass% or more (so-called 4N aluminum) to a ceramic substrate 11.
The aluminum plate 23 has a 0.2% proof stress of 30 N / mm ² or less. Here, the thickness of the metal layer 13 (aluminum plate 23) is set within the range of 0.5 mm or more and 6 mm or less, and in the present embodiment, it is set to 2.0 mm.

Then, in the present embodiment, as shown in FIG. 1, the power module substrate 10 and the semiconductor element 3 are sealed with the mold resin 5. As the mold resin 5, for example, an epoxy resin can be applied. Further, a base layer (not shown) is formed on the contact surface of the power module substrate 10 and the semiconductor element 3 with the mold resin 5.

Hereinafter, a method for manufacturing the resin-sealed power module 50 according to the embodiment of the present invention will be described with reference to FIGS. 2 to 4.
As shown in FIG. 2, the method for manufacturing the resin-sealed power module 50 according to the present embodiment is a contact between the power module substrate forming step S01 for forming the power module substrate 10 and the mold resin 5 of the ceramics substrate 11. A ceramic substrate surface roughness adjusting step S02 for adjusting the surface roughness, a semiconductor element mounting step S03 for mounting the semiconductor element 3 on the circuit layer 12 of the power module substrate 10, and a primer treatment on the surface of the power module 1. A primer treatment liquid application step S04 for applying the liquid, a primer treatment liquid drying step S05 for drying the applied primer treatment liquid to form an underlayer, and a resin seal for sealing the power module 1 with a mold resin 5. A stop step S06 is provided.

(Substrate forming step S01 for power module)
First, as shown in FIG. 3, the copper plate 22 to be the circuit layer 12 and the ceramic substrate 11 are joined (copper plate joining step S11). In the present embodiment, the copper plate 22 to be the circuit layer 12 and the ceramic substrate 11 are joined by using the Ag-Cu-Ti brazing material 24.
Next, as shown in FIG. 3, the aluminum plate 23 to be the metal layer 13 and the ceramic substrate 11 are joined (aluminum plate joining step S12). In the present embodiment, the aluminum plate 23 to be the metal layer 13 and the ceramic substrate 11 are joined to each other by using the Al—Si based brazing material 25.
By the above steps, the power module substrate 10 according to the present embodiment is formed.

(Ceramics substrate surface roughness adjustment step S02)
Next, the surface roughness of at least the extension surface of the bonding interface with the circuit layer 12 of the ceramic substrate 11 and the contact surface with the mold resin 5 is adjusted. In the present embodiment, as shown in FIG. 3, the surface roughness on the extension surface of the bonding interface with the circuit layer 12 and on the extension surface of the bonding interface with the metal layer 13 is adjusted.

In the present embodiment, the surface roughness of the ceramic substrate 11 is adjusted by performing a blast treatment on the surface of the ceramic substrate 11. As the blast particles, SiC particles, Al ₂ O ₃ particles and the like can be used. The particle size of the blast particles is preferably in the range of 13 μm or more and 15 μm or less. Further, the pressure during the blast treatment is preferably in the range of 0.2 MPa or more and 0.25 MPa or less.

By performing the blasting treatment under the above-mentioned conditions, the acicular grains existing on the surface of the ceramic substrate 11 made of silicon nitride are flattened, and the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 is increased. The maximum height Ry (JIS B0601-1994) is adjusted within the range of 1.7 μm or more and 2.7 μm or less.
After the blast treatment, it is preferable that the surface of the ceramic substrate 11 is washed with alkali, acid, water, and dried.

(Semiconductor element mounting process S03)
Next, the semiconductor element 3 is mounted on the circuit layer 12 of the power module substrate 10. In the present embodiment, the circuit layer 12 and the semiconductor element 3 are solder-bonded by using, for example, a Sn-Ag-based, Sn-In-based, or Sn-Ag-Cu-based soldering material. As a result, the power module 1 is formed.

(Primer treatment liquid application step S04)
Next, a primer treatment solution (not shown) is applied to the surface of the power module 1. This primer treatment liquid is capable of forming an underlayer made of a resin having a basic structure such as polyamide, polyimide, or polyamide-imide after drying. As the primer treatment liquid, for example, HL-1200 or H-1210N manufactured by Hitachi Chemical Co., Ltd. can be used. When HL-1200 or H-1210N is used, it is preferable to dilute it 1 to 10 times with a mixed solution of N-methyl-2-pyrrolidone and butyl cellosolve acetate. As a coating method, a method of immersing the power module 1 in a primer treatment liquid for coating, a spin coating, or the like can be used.

(Primer treatment liquid drying step S05)
Next, the applied primer treatment liquid is dried in a non-oxidizing atmosphere to form a base layer made of a resin having a basic structure such as polyamide, polyimide, or polyamideimide on the surface of the power module 1.
Here, in the present embodiment, drying is performed with the oxygen partial pressure in the drying furnace 61 set to a low oxygen atmosphere of 32 Pa or less. Specifically, drying is performed in a vacuum atmosphere with a vacuum degree of 150 Pa or less. By performing the primer treatment liquid drying step S05 in a vacuum atmosphere in this way, it is possible to suppress the thickness of the oxide film formed on the surface of the circuit layer 12 to 25 nm or less after the primer treatment liquid drying step S05. Become. In addition to the vacuum atmosphere, the primer treatment liquid drying step S05 can also be performed in a non-oxidizing atmosphere such as a nitrogen atmosphere or an argon atmosphere. Even in this case, the oxygen partial pressure is preferably 32 Pa or less.

(Resin sealing step S06)
Next, the power module 1 on which the base layer is formed is resin-sealed with the mold resin 5. In this resin sealing step S06, for example, by a transfer mold in which the mold temperature is 160 ° C. to 180 ° C., the molding pressure (injection pressure) is 7 MPa to 15 MPa, the molding temperature is 160 ° C. to 180 ° C., and the molding time is 220 seconds to 260 seconds. It can be sealed with resin.
As described above, the resin-sealed power module 50 according to the present embodiment is manufactured.

According to the method for manufacturing the resin-sealed power module 50 according to the present embodiment having the above-described configuration, the mold resin 5 is on the extension surface of the bonding interface between the circuit layer 12 and the metal layer 13 of the ceramic substrate 11. Since the ceramic substrate surface roughness adjusting step S02 for adjusting the surface roughness of the contact surface with the ceramic substrate within the range of 1.7 μm or more and 2.7 μm or less at the maximum height Ry is provided, it exists on the surface of the ceramic substrate 11. At least a part of the acicular grains to be formed can be removed and flattened. Therefore, in the subsequent primer treatment liquid application step S04, the primer treatment liquid can be sufficiently permeated into the inside of the ceramic substrate 11, and the base layer can be formed satisfactorily. This makes it possible to improve the adhesion between the mold resin 5 and the ceramic substrate 11.

Here, in the ceramic substrate surface roughness adjusting step S02, when the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 is set to less than 1.7 μm at the maximum height Ry, an anchor effect is obtained. This may not be possible and the adhesion between the mold resin 5 and the ceramic substrate 11 may decrease. On the other hand, when the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 exceeds 2.7 μm at the maximum height Ry, the penetration of the primer treatment liquid becomes insufficient and the underlying layer is satisfactorily formed. This may not be possible, and the adhesion between the mold resin 5 and the ceramic substrate 11 may decrease.
From the above, in the present embodiment, the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 is set within the range of 1.7 μm or more and 2.7 μm or less at the maximum height Ry.

In order to further reliably improve the adhesion between the mold resin 5 and the ceramic substrate 11, the lower limit of the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 is set to 2.4 μm at the maximum height Ry. The above is preferable. Further, it is preferable that the upper limit of the surface roughness of the contact surface of the ceramic substrate 11 with the mold resin 5 is 2.6 μm or less at the maximum height Ry.

Further, in the present embodiment, since the primer treatment liquid drying step S05 is carried out in a vacuum atmosphere with a vacuum degree of 150 Pa or less, a small amount of voids may be generated when the primer treatment liquid is applied to the ceramic substrate 11. However, the voids can be removed by holding the ceramic substrate in a vacuum atmosphere, and the primer treatment liquid can be more reliably permeated into the ceramic substrate 11 to form a good base layer.

Further, in the primer treatment liquid drying step S05, when the applied primer treatment liquid is dried in a non-oxidizing atmosphere, a thick oxide film is formed on the resin contact surface of the circuit layer 12 made of copper or a copper alloy. It can be suppressed, and the adhesion between the circuit layer 12 and the mold resin 5 can be improved.
In particular, in the present embodiment, the primer treatment liquid drying step S05 is configured to be carried out in a low oxygen atmosphere having an oxygen partial pressure of 32 Pa or less, and specifically, is carried out in a vacuum atmosphere having a vacuum degree of 150 Pa or less. Therefore, the thickness of the oxide film formed on the resin contact surface of the circuit layer 12 can be limited to 25 nm or less, and the adhesion between the circuit layer 12 and the mold resin 5 can be reliably improved.

Further, in the present embodiment, since the surface roughness of the ceramic substrate 11 is adjusted by performing the blast treatment in the ceramic substrate surface roughness adjusting step S02, at least the needle-like particles existing on the surface of the ceramic substrate 11 are adjusted. It is possible to reliably remove a part and flatten it.

Further, according to the resin-sealed power module 50 of the present embodiment, it is manufactured by the manufacturing method of the resin-sealed power module 50 of the present embodiment described above, and the ceramic substrate 11, the mold resin 5, and the circuit are manufactured. Since the adhesion between the layer 12 and the mold resin 5 is improved, the bonding reliability after the cooling / heating cycle is excellent.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the invention.
For example, in the present embodiment, the circuit layer is made of copper or a copper alloy, and the metal layer is made of aluminum or an aluminum alloy. However, the circuit layer may be made of aluminum or an aluminum alloy. The metal layer may be made of copper, a copper alloy, or the like. A Cu layer made of copper or a copper alloy and in contact with the mold resin may be formed on the power module substrate.

Further, as in the resin-sealed power module 150 shown in FIG. 5, the circuit layer 112 and the metal layer 113 may have a laminated structure of Al layers 112A and 113A and Cu layers 112B and 113B. In this case, it is sufficient to prevent the oxide film from being thickly formed on the contact surface of the Cu layers 112B and 113B that comes into contact with the mold resin 5. In this case, the thickness of the Cu layers 112B and 113B may be in the range of 0.1 mm to 6.0 mm.

Further, as in the resin-sealed power module 250 shown in FIG. 6, the circuit layer 212 is a die pad portion 231 of the lead frame 230 made of copper or a copper alloy, and the lead portion 232 has a structure protruding to the outside of the mold resin 5. It may have been done. In this case, it is sufficient to prevent the oxide film from being thickly formed on the contact surface of the lead frame 230 that comes into contact with the mold resin 5.

Further, in the present embodiment, the ceramic substrate and the copper plate have been described as being joined by using an Ag-Cu-Ti brazing material, but the present invention is not limited to this, and an Ag-Ti brazing material is used. It may be joined, or the copper plate and the ceramics may be joined by the DBC method.

Further, in the present embodiment, the ceramic substrate and the aluminum plate have been described as being bonded by using an Al—Si brazing material, but the present invention is not limited to this, and the transient liquid phase bonding method (Transient Liquid Phase Bonding) is not limited to this. ), Casting method, metal paste method, etc. may be used for joining.

A comparative experiment conducted to confirm the effectiveness of the present invention will be described.

A ceramic substrate (40 mm × 40 mm × thickness 0.32 mm) made of silicon nitride (Si ₃ N ₄ ) is prepared and blasted under the conditions shown in Table 1, and the surface roughness of the ceramic substrate is shown in Table 1. Adjusted to.
The surface roughness of the ceramic substrate after the blast treatment was measured using a surface roughness measuring machine SV-400 (manufactured by Mitutoyo Co., Ltd.) with a reference length Lr = 0.8 mm and an evaluation length Ln = 4 mm.
After the blast treatment, alkaline washing was carried out at 50 ° C. for 82 seconds using a 5% NaOH aqueous solution, acid washing, water washing and drying were carried out at room temperature for 30 seconds using a 5% HCl aqueous solution.
Then, a copper plate (37 mm × 37 mm × thickness 0.3 mm) made of oxygen-free copper (C1020) is joined to one surface and the other surface of the blasted ceramic substrate to form a circuit layer and a metal layer. did. Then, an IGBT element (13 mm × 10 mm × thickness 0.6 mm) as a semiconductor element was solder-bonded onto the circuit layer to obtain a power module. A Sn-Ag-Cu system was used as the solder material.

Then, the primer treatment solution shown in Table 1 was applied to the power module, and the primer treatment solution was dried under the conditions shown in Table 1 to form an underlayer. As the primer treatment solution, HL-1200 manufactured by Hitachi Chemical Co., Ltd. was diluted 2-fold with a mixed solution of N-methyl-2-pyrrolidone and butyl cellosolve acetate (35:65 (volume ratio)) to obtain power. The module was dipped in a primer treatment solution and applied.

Next, a mold resin was molded into the power module on which the base layer was formed by a transfer mold. The transfer molding was performed at a mold temperature of 170 ° C., a molding pressure (injection pressure) of 10 MPa, a molding temperature of 170 ° C., and a molding time of 240 seconds. The material of the mold resin is shown in Table 1.
Then, after-cure was performed in the air under the condition of holding at 180 ° C. for 4 hours to cure the mold resin.

Regarding the thickness of the oxide film on the surface of the circuit layer, the thickness of the oxide film was measured by using XPS (Model-5600LS manufactured by ULVAC-PHI) on the cross section of the circuit layer before the transfer mold after the base layer was formed. .. The evaluation results are shown in Table 1.

Further, the obtained resin-sealed power module was loaded with a cooling / heating cycle of -40 ° C × 5 minutes ← → 125 ° C × 3 minutes and 3000 cycles, and a ceramic substrate and a mold resin, a circuit layer (Cu layer) and a mold resin were applied. The peeling rate with and was evaluated.
The peeling rate was evaluated by measuring the interface between the ceramic substrate and the mold resin and the interface between the circuit layer (Cu layer) and the mold resin using an ultrasonic flaw detector (INSIGHT-300 manufactured by Insight Co., Ltd.). In the binarized image obtained by the ultrasonic flaw detector, the peeled portion is displayed in white, so the ratio of the white part area to the reference area was defined as the peeling rate. The reference area was defined as the area of the portion of the ceramic substrate on which the circuit layer (Cu layer) was not formed when measuring the interface between the ceramic substrate and the mold resin. When measuring the interface between the circuit layer (Cu layer) and the mold resin, the area of the circuit layer (Cu layer) (37 mm × 37 mm) was used.
The evaluation results are shown in Table 1.

In Comparative Example 1 in which the surface roughness Ry of the ceramic substrate exceeded 2.7 μm and Comparative Example 2 in which the surface roughness Ry was less than 1.7 μm, the peeling at the interface between the mold resin and the silicon nitride after the thermal cycle was large. Further, in Comparative Example 3 in which the thickness of the oxide film on the surface of the circuit layer exceeded 25 nm, the peeling at the interface between the resin and the circuit layer became large.
On the other hand, in Examples 1 to 8 of the present invention, it was confirmed that a resin-sealed power module having less interfacial peeling after a thermal cycle and excellent adhesion can be obtained.

1 Power module 3 Semiconductor element 5 Molded resin 10 Power module substrate 11 Ceramic substrate 12 Circuit layer (Cu layer)
50 Resin-sealed power module

Claims (3)

A power module composed of a power module substrate having a circuit layer formed on one surface of a ceramic substrate made of silicon nitride and a semiconductor element mounted on the circuit layer of the power module substrate is made of a mold resin. A method for manufacturing a sealed resin-sealed power module.
The power module substrate has a Cu layer made of copper or a copper alloy, and the Cu layer has a resin contact surface in contact with the mold resin.
The surface roughness of at least the extension surface of the bonding interface with the circuit layer of the ceramic substrate and the contact surface with the mold resin is within the range of 1.7 μm or more and 2.7 μm or less at the maximum height Ry. Ceramic substrate surface roughness adjustment process to be adjusted and
A semiconductor element mounting process for mounting the semiconductor element on the circuit layer,
The primer treatment liquid application step of applying the primer treatment liquid to the surface of the power module, and
A primer treatment liquid drying step of drying the applied primer treatment liquid in a non-oxidizing atmosphere,
A resin sealing step of resin-sealing the power module using the mold resin, and
With
A method for manufacturing a resin-sealed power module, characterized in that the thickness of the oxide film formed on the resin contact surface of the Cu layer is 25 nm or less after the primer treatment liquid drying step. The method for manufacturing a resin-sealed power module according to claim 1, wherein the primer treatment liquid drying step is carried out in a low oxygen atmosphere having an oxygen partial pressure of 32 Pa or less. The method for manufacturing a resin-sealed power module according to claim 1 or 2, wherein the primer treatment liquid drying step is carried out in a vacuum atmosphere having a vacuum degree of 150 Pa or less.

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