Method for manufacturing test piece for adhesion evaluation test and adhesion evaluation method

Abstract

The manufacturing method of a test piece for an adhesion evaluation test includes: a process (S100) of preparing a semiconductor device; and a process (S200) of forming a test piece for an adhesion evaluation test. In the process (S100) of preparing a semiconductor device, the semiconductor device includes: a substrate member; a semiconductor element mounted on the substrate member; and a sealing resin that seals the substrate member and the semiconductor element. In the process (S200) of forming a test piece for an adhesion evaluation test, a test piece for an adhesion evaluation test is formed on the substrate member by the sealing resin of the semiconductor device.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a test piece for an adhesion evaluation test and an adhesion evaluation method. Background Art

[0002] Semiconductor devices such as power modules are used in products such as industrial equipment, household electrical equipment, and information terminals. Generally, in a semiconductor device, for the purpose of protecting and insulating a semiconductor element, a lead frame, an insulating substrate, etc., the semiconductor element, the lead frame, the insulating substrate, etc. are sealed with a sealing resin. For the sealing resin, long-term reliability, reflow heat resistance, high reliability against temperature cycling, etc. are required. Therefore, it is required to quantitatively evaluate the adhesion between the sealing resin and the lead frame, the insulating substrate, etc.

[0003] Generally, as a method for evaluating the adhesion of a sealing resin, a pudding cup test is used. In the pudding cup test, a frustum-shaped test piece made of the same resin as the sealing resin is formed on the surface of a base member. A load is applied to the test piece along the surface of the base member, and the load at the time of breaking the bonded portion of the sealing resin is measured.

[0004] For example, the pudding cup test is described in Japanese Unexamined Patent Application Publication No. 2014-146704 (Patent Document 1).

[0005] In addition, the pudding cup test is also described in SEMI (Semiconductor Equipment and Materials International) Standard G69-0996.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-146704 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In the pudding cup test described in the above-mentioned publication, since a dedicated mold for manufacturing a test piece for the pudding cup test is used, it is difficult to reproduce process conditions such as injection conditions in an actual mass-production mold. Therefore, it is difficult to manufacture a test piece for an adhesion test that directly reflects the phenomena occurring in an actual mass-production mold.

[0011] In addition, in the above-mentioned SEMI Standard G69-0996, a method for manufacturing a test piece for the pudding cup test is not described.

[0012] The present disclosure has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a test piece for an adhesion test and a method for evaluating adhesion that directly reflect the phenomena occurring in an actual mass-production mold.

[0013] Means for Solving the Problems

[0014] The method for manufacturing a test piece for an adhesion evaluation test of the present disclosure includes: a step of preparing a semiconductor device; and a step of forming a test piece for an adhesion evaluation test. In the step of preparing a semiconductor device, the semiconductor device includes: a substrate member; a semiconductor element mounted on the substrate member; and a sealing resin that seals the substrate member and the semiconductor element. In the step of forming a test piece for an adhesion evaluation test, a test piece for an adhesion evaluation test is formed on the substrate member by the sealing resin of the semiconductor device.

[0015] Effects of the Invention

[0016] According to the method for manufacturing a test piece for an adhesion evaluation test of the present disclosure, a test piece for an adhesion evaluation test is formed on the substrate member by the sealing resin of the semiconductor device. Therefore, a test piece for an adhesion evaluation test can be formed on the substrate member by the sealing resin of the semiconductor device formed in an actual mass-production mold. Therefore, it is possible to provide a method for manufacturing a test piece for an adhesion test and a method for evaluating adhesion that directly reflect the phenomena occurring in an actual mass-production mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flowchart showing a method for manufacturing a test piece for an adhesion evaluation test according to Embodiment 1.

[0018] Figure 2 is a perspective view showing a step of preparing a semiconductor device in the method for manufacturing a test piece for an adhesion evaluation test according to Embodiment 1.

[0019] Figure 3 is along Figure 2 a cross-sectional view taken along line III-III.

[0020] Figure 4 is along Figure 2 a cross-sectional view taken along line IV-IV.

[0021] Figure 5 is a cross-sectional view showing a step of forming a test piece for an adhesion evaluation test in the method for manufacturing a test piece for an adhesion evaluation test according to Embodiment 1.

[0022] Figure 6 is showing from Figure 5A cross-sectional view showing a state in which a test piece is formed by further promoting the removal of the sealing resin.

[0023] Figure 7 A perspective view showing a test piece for the adhesion evaluation test of Embodiment 1.

[0024] Figure 8 A top view showing a semiconductor device in which a test piece for the adhesion evaluation test of Embodiment 1 is formed.

[0025] Figure 9 A flowchart showing the adhesion evaluation method of Embodiment 1.

[0026] Figure 10 A cross-sectional view showing a process of measuring the shear peel strength in the adhesion evaluation method of Embodiment 1.

[0027] Figure 11 A cross-sectional view showing a modified example 1 of the manufacturing method of a test piece for the adhesion evaluation test of Embodiment 1.

[0028] Figure 12 It shows from Figure 11 A cross-sectional view showing a state in which a test piece is formed by further promoting the removal of the sealing resin.

[0029] Figure 13 A top view showing a modified example 2 of the manufacturing method of a test piece for the adhesion evaluation test of Embodiment 1.

[0030] Figure 14 A cross-sectional view showing a modified example 3 of the manufacturing method of a test piece for the adhesion evaluation test of Embodiment 1.

[0031] Figure 15 It shows from Figure 14 A cross-sectional view showing a state in which a test piece is formed by removing the mask.

[0032] Figure 16 A cross-sectional view showing a process of preparing a semiconductor device in the manufacturing method of a test piece for the adhesion evaluation test of Embodiment 2.

[0033] Figure 17 A cross-sectional view showing a process of forming a test piece for the adhesion evaluation test in the manufacturing method of a test piece for the adhesion evaluation test of Embodiment 2.

[0034] Figure 18 A graph showing the relationship between the laser irradiation time and the shear peel strength in the examples.

[0035] Figure 19 A photograph showing the appearance of the test piece and the appearance of the adhered portion after the shear test.

[0036] Figure 20 It is a cross-sectional view showing the state of unevenness of the sealing resin around the test piece in the embodiment.

[0037] Figure 21 It is a graph showing the relationship between the diameter of the test piece and the shear peel strength in the embodiment.

[0038] Figure 22 It is a photograph showing the appearance after the shear peel test when the diameters of the test pieces are 1.94 mm and 0.9 mm.

[0039] Figure 23 It is a cross-sectional view showing the method for measuring the shear peel strength of the test piece in the embodiment.

[0040] Figure 24 It is a graph showing the relationship between the direction of pressing with the tool and the shear peel strength.

[0041] Figure 25 It is a perspective view showing the shape of the test piece and the direction of pressing with the tool.

[0042] Figure 26 It is a graph showing the relationship between the injection molding speed and the peel rate.

[0043] Figure 27 It is a graph showing the relationship between the injection molding speed and the shear peel strength.

[0044] Figure 28 It is a graph showing the relationship between the peel rate and the shear peel strength.

[0045] Figure 29 It is a cross-sectional view showing the process of preparing the semiconductor device in the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 3.

[0046] Figure 30 It is a cross-sectional view showing the process of forming the test piece for the adhesion evaluation test in the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 3.

[0047] Figure 31 It is a cross-sectional view showing the process of measuring the shear peel strength in the adhesion evaluation method of Embodiment 3. Detailed Embodiments

[0048] Hereinafter, the embodiments will be described based on the drawings. In addition, hereinafter, the same or equivalent parts will be denoted by the same reference numerals, and repeated explanations will not be repeated.

[0049] Embodiment 1.

[0050] Refer to Figures 1 to 10, a method for manufacturing a test piece for the adhesion evaluation test of Embodiment 1 and a method for evaluating adhesion will be described.

[0051] Refer to Figures 1 to 7 , a method for manufacturing a test piece for the adhesion evaluation test of Embodiment 1 will be described. Refer to Figure 1 , the method for manufacturing a test piece for the adhesion evaluation test of Embodiment 1 includes a process S100 of preparing the semiconductor device 1 and a process S200 of forming the test piece 72 for the adhesion evaluation test.

[0052] Refer to Figures 2 to 4 , a process of preparing the semiconductor device in the method for manufacturing a test piece for the adhesion evaluation test of Embodiment 1 will be described. Figure 2 is a perspective view of the semiconductor device 1 in the method for manufacturing a test piece for the adhesion evaluation test of Embodiment 1. In addition, in Figure 2 , in order to easily observe the internal structure, the sealing resin is not shown. Figure 3 is along Figure 2 the III-III line sectional view. Figure 4 is along Figure 2 the IV-IV line sectional view. Figure 4 shows the cross-section of the central part of the lead frame.

[0053] The semiconductor device 1 includes a base member 10, a semiconductor element 20, solder 30, wires 40, 41, and a sealing resin 7. The semiconductor device 1 is, for example, a power module for power use.

[0054] In the present embodiment, the base member 10 is a lead frame 11. The material of the lead frame 11 is, for example, copper. The size of the lead frame 11 is, for example, 120 mm in length, 75 mm in width, and 0.6 mm in thickness. The lead frame 11 includes a die pad 112, main electrode terminals 113, and signal terminals 114 such as gate electrode terminals.

[0055] The semiconductor element 20 is mounted on the base member 10. The semiconductor element 20 is, for example, a power semiconductor element for power use. In the present embodiment, the semiconductor element 20 includes a diode 21 and an IGBT (Insulated Gate Bipolar Transistor). The size of the diode 21 is, for example, 15 mm in length, 13 mm in width, and 0.2 mm in thickness. The size of the IGBT 22 is, for example, 15 mm in length, 15 mm in width, and 0.2 mm in thickness. The diode 21 and the IGBT 22 are die-bonded to the die pad 112 of the lead frame 11 by the solder 30.

[0056] In addition, as the semiconductor element 20, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or the like can be used.

[0057] The semiconductor element 20 can also be a power semiconductor element using silicon (Si). Additionally, the semiconductor element 20 can also be a wide-bandgap compound semiconductor using silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), or the like.

[0058] Two diodes 21 and IGBTs 22 are each bonded to the chip pads 112 of the lead frame 11 using solder 30. The composition ratio of the solder 30 is, for example, 96.5 mass% of tin (Sn), 3 mass% of silver (Ag), and 0.5 mass% of copper (Cu). The melting point of the solder 30 is, for example, 217°C.

[0059] In addition, the composition ratio of the solder 30 can also be, for example, 98.5 mass% of tin (Sn), 1 mass% of silver (Ag), and 0.5 mass% of copper (Cu). Additionally, the composition ratio of the solder 30 can also be, for example, 96 mass% of tin (Sn), 3 mass% of antimony (Sb), and 1 mass% of silver (Ag).

[0060] Alternatively, instead of the solder 30, a copper (Cu)-tin (Sn) paste that disperses copper powder and obtains high heat resistance through isothermal solidification or a nano silver paste that performs bonding using low-temperature firing of nano silver particles can be used.

[0061] The main electrode 211 of the diode 21 and the main electrode 221 of the IGBT 22 are electrically connected to the lead frame 11 using a wire 40. The material of the wire 40 is, for example, aluminum. The diameter of the wire 40 is, for example, 0.3 mm.

[0062] The gate electrode and other signal electrodes 222 of the IGBT 22 are electrically connected to the lead frame 11 using a wire 41. The material of the wire 41 is, for example, aluminum. The diameter of the wire 41 is, for example, 0.15 mm.

[0063] The materials of the wires 40 and 41 can also be, for example, copper (Cu), gold (Au), or Ag (silver). Additionally, the wires 40 and 41 can also be aluminum (Al)-coated copper (Cu) wires.

[0064] In addition, in circuit formation, instead of using wire bonding, ribbon bonding can be used, or semiconductor elements can be directly soldered to a plate-shaped electrode plate.

[0065] The encapsulating resin 7 encapsulates the base member 10, the semiconductor element 20, the solder 30, and the wires 40, 41. After the lead frame 11, the semiconductor element 20, the solder 30, and the wires 40, 41 are held by a mold (not shown), the heated encapsulating resin 7 is pressure-injected and then heated and cured, thereby completing the resin encapsulation. The mold (not shown) is heated to, for example, 170°C. The encapsulating resin 7 is heated to, for example, 170°C. The encapsulating resin 7 is, for example, an epoxy transfer mold resin containing silica filler. The encapsulating resin 7 is heated and cured at 170°C in an oven for 4 hours, for example, after being pressure-injected.

[0066] Refer to Figure 5 and Figure 6 , the process of forming the test piece for the adhesion evaluation test of Embodiment 1 will be described. Figure 5 and Figure 6 are cross-sectional views at the cross-sectional positions corresponding to Figure 4 .

[0067] As Figure 5 and Figure 6 shown, in the process of forming the test piece for the adhesion evaluation test of Embodiment 1, the test piece 72 for the adhesion evaluation test is formed on the base member 10 by the encapsulating resin 7 of the semiconductor device 1.

[0068] As Figure 5 shown, by processing with the laser 6, the test piece 72 is formed from the encapsulating resin 7. The laser 6 is a laser for opening the encapsulating resin. First, the encapsulating resin 7 is removed in a circular shape by using the laser 6 to form a recessed portion 71. The outermost surface diameter of the recessed portion 71 is, for example, 5.0 mm.

[0069] The irradiation device of the laser 6 is, for example, F / Alit manufactured by Shin-Etsu Chemical Co., Ltd. The wavelength of the laser 6 is, for example, 1064 nm. The maximum output of the laser 6 is, for example, 20 W.

[0070] As Figure 6 shown, the removal of the encapsulating resin 7 is further advanced, and when the remaining height of the encapsulating resin 7 becomes, for example, 1.5 mm, the outer peripheral portion is removed while retaining the central portion of the test piece 72. The diameter of the central portion of the test piece 72 is, for example, 1.5 mm. In this way, the test piece 72 is manufactured.

[0071] Refer to Figure 6 and Figure 7, the test piece 72 is formed in the shape of a pudding cup. That is, the test piece 72 is formed in the shape of a frustum of a cone. The diameter D1 of the lead frame interface of the test piece 72 is, for example, 1.94 mm. The diameter D2 of the surface of the test piece 72 is, for example, 1.5 mm. The height H of the test piece 72 is, for example, 1.5 mm.

[0072] Refer to Figure 8 , the semiconductor device 1 formed with the test piece 72 will be described. Around the frustum-shaped test piece 72, there is almost no remaining sealing resin 7. Or, around the frustum-shaped test piece 72, the chip pads 112 are exposed from the sealing resin 7. Figure 8 is a top view of the semiconductor device 1 formed with the test piece 72 in the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 1. In addition, in Figure 8 , for easy observation, a part of the sealing resin 7 is shown by a dotted line, the lead frame 11 inside the sealing resin 7 is shown by a solid line, and the semiconductor element 20 etc. are not shown.

[0073] Next, the adhesion evaluation method of Embodiment 1 will be described.

[0074] In the adhesion evaluation method of Embodiment 1, the adhesion is evaluated using the test piece manufactured by the above manufacturing method of the test piece for the adhesion evaluation test.

[0075] Refer to Figure 9 , the adhesion evaluation method of Embodiment 1 includes: a process S100 of preparing the above semiconductor device 1; a process S200 of forming the above test piece 72 for the adhesion evaluation test; and a process S300 of measuring the shear peel strength.

[0076] The process S100 of preparing the semiconductor device 1 and the process S200 of forming the test piece 72 for the adhesion evaluation test are the same as the above manufacturing method of the test piece for the adhesion evaluation test, so they will not be repeatedly described.

[0077] Refer to Figure 10 , the process of measuring the shear peel strength of Embodiment 1 will be described. In the process of measuring the shear peel strength of Embodiment 1, the shear peel strength is measured using the test piece 72 for the adhesion evaluation test. The semiconductor device 1 provided with the test piece 72 is fixed to the mounting table 80. In this state, the test piece 72 is pressed with the tool 90 until the test piece 72 breaks.

[0078] The device used in the shear peel strength evaluation is, for example, the BondTester DAGE4000 manufactured by DAGE Co., Ltd. The shear peel strength test is carried out, for example, at room temperature. The height of the tip of the tool 90 is set to a height of, for example, 0.04 mm from the lead frame 11. The shear speed of the pressing tool 90 is, for example, 0.3 mm / s. After the test piece 72 breaks, the contact area of each sample is calculated, and the value obtained by dividing the breaking load by the contact area is defined as the shear peel strength (Kg / mm).

[0079] In addition, the shear peel strength test is not limited to room temperature. By carrying out the shear peel strength test at high temperatures such as 50°C and 100°C as required, the adhesion in the actual use environment can be evaluated.

[0080] Next, the effects of this embodiment will be described.

[0081] According to the manufacturing method of the test piece 72 for the adhesion evaluation test of this embodiment, the test piece 72 for the adhesion evaluation test is formed on the base member 10 from the sealing resin 7 of the semiconductor device 1. Therefore, the test piece 72 for the adhesion evaluation test can be formed on the base member 10 from the sealing resin 7 of the semiconductor device 1 formed in the actual mass production mold. Therefore, a manufacturing method of the test piece 72 for the adhesion test that directly reflects the phenomena occurring in the actual mass production mold can be provided.

[0082] In the manufacturing method of the test piece 72 for the adhesion evaluation test of this embodiment, the test piece 72 is formed from the sealing resin 7 by using the processing of the laser 6. Therefore, the test piece 72 can be formed from the sealing resin 7 by using the processing of the laser. In addition, since the test piece 72 can be formed from the sealing resin 7 by using the processing of the laser, the dimensional accuracy of the test piece 72 can be improved.

[0083] According to the adhesion evaluation method of this embodiment, the test piece 72 for the adhesion evaluation test is formed on the base member 10 from the sealing resin 7 of the semiconductor device 1. Using this test piece 72 for the adhesion evaluation test, the shear peel strength is measured. Therefore, an adhesion evaluation method that directly reflects the phenomena occurring in the actual mass production mold can be provided.

[0084] In this embodiment, it is also possible to manufacture the test piece 72 not only on the chip pad 112 but also on the signal terminal 114. According to this embodiment, the test piece 72 can be manufactured at any position on the lead frame 11, and the adhesion at the pinpoint position of the part where the peeling between the sealing resin 7 and the lead frame 11 is likely to occur can be evaluated in the long-term reliability and reflow heat resistance tests.

[0085] In addition, the lead frame 11 can also be plated with silver (Ag), gold (Au), nickel (Ni), tin (Sn), etc. Generally speaking, it is known that the adhesion to the sealing resin 7 is lower on these plated members than that of copper (Cu). According to the present embodiment, by combining with the plated member, it is possible to evaluate the adhesion at the exact position of the part where the peeling between the sealing resin 7 and the lead frame 11 is likely to occur in the long-term reliability and reflow heat resistance tests.

[0086] In the present embodiment, it is possible to evaluate the adhesion at the part where the product is likely to peel off or the adhesion at the part where the adhesion force of the product is low.

[0087] Moreover, by changing the process conditions during transfer molding and using the present embodiment, it is possible to evaluate the difference in adhesion caused by process conditions that could not be evaluated in the past. Thus, since the appropriate process conditions can be determined before the reliability investment, the development period can be shortened.

[0088] Next, a modified example of the manufacturing method of the test piece for the adhesion evaluation test of the present embodiment will be described.

[0089] Referring to Figure 11 and Figure 12 , a modified example 1 of the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 1 will be described. Figure 11 and Figure 12 are cross-sectional views at the corresponding cross-sectional positions. In modified example 1 of the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 1, as Figure 5 shown, the outer peripheral portion of the test piece 72 is removed from the beginning. As Figure 11 shown, by further removing the sealing resin 7, the test piece 72 is manufactured. In this way, the test piece 72 can also be manufactured by removing only the outer peripheral portion of the test piece 72 from the beginning. Figure 12 shown, the test piece 72 is manufactured by further removing the sealing resin 7. In this way, the test piece 72 can also be manufactured by removing only the outer peripheral portion of the test piece 72 from the beginning.

[0090] Referring to Figure 13 , a modified example 2 of the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 1 will be described. Figure 13 is a top view of the semiconductor device 1 in modified example 2 of the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 1. In addition, in Figure 13 , in order to facilitate observation, a part of the sealing resin 7 is shown by a dotted line, the lead frame 11 inside the sealing resin 7 is shown by a solid line, and the semiconductor element 20, etc. are not shown.

[0091] In Modification 2 of the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 1, the test piece 72 is formed in the shape of an elliptical frustum. The bottom surface and the upper surface of the test piece 72 may also be formed in the shape of an ellipse or a rounded rectangle. Around the test piece 72 having the shape of an elliptical frustum, a state where there is almost no remaining sealing resin 7 or a state where the chip pad 112 is exposed from the sealing resin 7 is achieved.

[0092] In the test piece 72 having the shape of an elliptical frustum, the dimension in the long side direction (major axis) is, for example, 1.5 times the dimension in the short side direction (minor axis).

[0093] In Modification 2 of the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 1, the test piece 72 is formed in the shape of an elliptical frustum. By measuring the shear peel strength in the long side direction of the test piece 72, when evaluating the adhesion in a minute region, it is possible to evaluate the adhesion while removing the increase in strength caused by flexure.

[0094] Refer to Figure 14 and Figure 15 , and Modification 3 of the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 1 will be described. Figure 14 and Figure 15 are cross-sectional views at the cross-sectional positions corresponding to Figure 5 . In Modification 3 of the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 1, the test piece 72 is formed from the sealing resin 7 by processing using the etching solution 110.

[0095] As Figure 14 shown, first, a mask 100 is formed on the sealing resin 7. The mask 100 is formed so as not to cover the periphery of the test piece 72. The etching solution 110 dissolves the sealing resin 7. The sealing resin 7 is etched into a frustum shape using the etching solution 110.

[0096] As Figure 15 shown, after the sealing resin 7 is etched into a frustum shape using the etching solution 110, the mask 100 is removed. Thereby, the test piece 72 having a frustum shape is formed.

[0097] According to Modification 3 of the method for manufacturing the test piece for the adhesion evaluation test of Embodiment 1, the test piece 72 is formed from the sealing resin 7 by processing using the etching solution. Therefore, compared with the case where the test piece 72 is formed from the sealing resin 7 by processing using a laser, the test piece 72 can be manufactured in large quantities at one time.

[0098] Embodiment 2.

[0099] Unless otherwise specified, Embodiment 2 has the same structure, method, and effects as Embodiment 1 described above. Therefore, in Embodiment 2, the same reference numerals are assigned to the same structures as in Embodiment 1, and repeated descriptions are not provided.

[0100] Referring to Figure 16 and Figure 17 , a method for manufacturing a test piece for the adhesion evaluation test of Embodiment 2 will be described. In addition, unless otherwise specified, the adhesion evaluation method of Embodiment 2 is the same as that of Embodiment 1.

[0101] Referring to Figure 16 , a process of preparing a semiconductor device in the method for manufacturing a test piece for the adhesion evaluation test of Embodiment 2 will be described. Figure 16 is a cross-sectional view of the semiconductor device 1 in the method for manufacturing a test piece for the adhesion evaluation test of Embodiment 2.

[0102] The semiconductor device 1 includes a base member 10, a base plate 14, a semiconductor element 20, solder 30, wires 40, 41, a sealing resin 7, a housing 60, a signal terminal 61, and a main electrode terminal 62.

[0103] In the present embodiment, the base member 10 is a ceramic substrate 15. The ceramic substrate 15 includes a main body portion 15a and conductor layers 15b, 15c. The conductor layers 15b, 15c are respectively attached to both surfaces of the main body portion 15a. The material of the main body portion 15a is, for example, aluminum nitride ceramic. The external dimensions of the main body portion 15a are a length of 35 mm, a width of 65 mm, and a thickness of 0.64 mm. The materials of the conductor layers 15b, 15c are, for example, copper. The external dimensions of the conductor layers 15b, 15c are a length of 31 mm, a width of 61 mm, and a thickness of 0.4 mm.

[0104] The ceramic substrate 15 is joined to the base plate 14 by solder 30. Specifically, the conductor layer 15b of the ceramic substrate 15 is joined to the base plate 14 by solder 30. The material of the base plate 14 is, for example, copper.

[0105] In the present embodiment, the semiconductor element 20 includes a diode 21 and an IGBT 22. The size of the diode 21 is, for example, a length of 13 mm, a width of 10 mm, and a thickness of 0.2 mm. The size of the IGBT 22 is, for example, a length of 13 mm, a width of 13 mm, and a thickness of 0.2 mm. The diode 21 and the IGBT 22 are joined to the conductor layer 15c of the ceramic substrate 15 by solder 30.

[0106] The semiconductor element 20 can also be a power semiconductor element using silicon (Si). Additionally, the semiconductor element 20 can also be a wide-bandgap compound semiconductor using silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc.

[0107] The composition ratio of the solder 30 is, for example, 96% by mass of tin (Sn), 3.5% by mass of silver (Ag), and 0.5% by mass of copper (Cu).

[0108] In addition, the composition ratio of the solder 30 can also be, for example, 98.5% by mass of tin (Sn), 1% by mass of silver (Ag), and 0.5% by mass of copper (Cu). Also, the composition ratio of the solder 30 can also be, for example, 96% by mass of tin (Sn), 3% by mass of antimony (Sb), and 1% by mass of silver (Ag).

[0109] Alternatively, instead of the solder 30, a copper (Cu)-tin (Sn) paste that disperses copper powder and obtains high heat resistance through isothermal solidification or a nano-silver paste that performs bonding using low-temperature firing of nano-silver particles can be used.

[0110] The main electrode 211 of the diode 21 and the main electrode of the IGBT 22 are electrically connected to the main electrode terminal 62 using a wire 40. The material of the wire 40 is, for example, aluminum. The diameter of the wire is, for example, 0.3 mm.

[0111] The signal electrodes such as the gate electrode of the IGBT 22 are electrically connected to the signal terminal 61 using a wire 41. The material of the wire 41 is, for example, aluminum. The diameter of the wire is, for example, 0.15 mm.

[0112] The materials of the wires 40 and 41 can also be, for example, copper (Cu) or gold (Au). Additionally, the wires 40 and 41 can also be aluminum (Al)-coated copper (Cu) wires.

[0113] Furthermore, in circuit formation, instead of using wire bonding, tape bonding can be used, or alternatively, semiconductor elements can be directly soldered to a plate-shaped electrode plate.

[0114] The signal terminal 61 and the main electrode terminal 62 are formed by inserting and embedding in the housing 60. The external dimensions of the housing 60 are, for example, a length of 75 mm, a width of 75 mm, and a thickness of 8 mm.

[0115] Inside the housing 60, a base plate 14, a ceramic substrate 15, a diode 21, an IGBT 22, a solder 30, wires 40 and 41, a sealing resin 7, a signal terminal 61, and a main electrode terminal 62 are arranged.

[0116] In order to insulate and seal the inner side of the housing 60, the inner side of the housing 60 is sealed with a sealing resin 7. The sealing resin 7 is formed by heating and hardening a liquid sealant that fills the inside of the housing 60. The liquid sealant is composed of, for example, an epoxy resin in which silica fillers are dispersed, a softener, an antifoaming agent, a flame retardant, and the like. The liquid sealant is hardened, for example, by heating at 100 °C for 1.5 hours using an oven and then heating at 140 °C for 1.5 hours.

[0117] Refer to Figure 17 , and the process of forming the test piece for the adhesion evaluation test of Embodiment 2 will be described. Figure 17 The cross-section of the part of the semiconductor device 1 without the semiconductor element 20 is shown.

[0118] Through the processing using the laser 6, the test piece 72 is formed from the sealing resin 7. The laser 6 is a laser for opening the sealing resin. First, the sealing resin 7 is removed in a circular shape using the laser 6 to form a recessed portion 71. The outermost surface diameter of the recessed portion 71 is, for example, 5.0 mm.

[0119] The irradiation device of the laser 6 is, for example, F / Alit manufactured by Shin-Etsu Chemical Co., Ltd. The wavelength of the laser 6 is, for example, 1064 nm. The maximum output of the laser 6 is, for example, 20 W.

[0120] The removal of the sealing resin 7 is further advanced, and when the remaining height of the sealing resin 7 becomes, for example, 1.5 mm, the outer peripheral portion is removed while retaining the central portion of the test piece 72. The diameter of the central portion of the test piece 72 is, for example, 1.5 mm. In this way, the test piece 72 is manufactured.

[0121] The test piece 72 is formed in the shape of a pudding cup. That is, the test piece 72 is formed in the shape of a frustum of a cone. The diameter of the lead frame interface of the test piece 72 is, for example, 1.94 mm. The diameter of the surface of the test piece 72 is, for example, 1.5 mm. The height of the test piece 72 is, for example, 1.5 mm.

[0122] Next, the effects of the present embodiment will be described.

[0123] According to the manufacturing method of the test piece 72 for the adhesion evaluation test of the present embodiment, similarly to Embodiment 1, a manufacturing method of the test piece 72 for the adhesion test that directly reflects the phenomena occurring in the actual mass-production mold can be provided.

[0124] According to the adhesion evaluation method of the present embodiment, a test piece 72 for adhesion evaluation is formed on the base member 10 by the sealing resin 7 of the semiconductor device 1. The shear peel strength is measured using the test piece 72 for adhesion evaluation. Therefore, similarly to Embodiment 1, an adhesion evaluation method that directly reflects the phenomena occurring in an actual mass-production mold can be provided.

[0125] Example

[0126] Hereinafter, the example will be described. In the example, unless otherwise specified, it has the same structure, method, and effect as those of the above-described Embodiment 1. Therefore, in the example, the same reference numerals are given to the same structures as those of the above-described Embodiment 1, and the description will not be repeated.

[0127] A method for manufacturing the test piece for adhesion evaluation in the example will be described.

[0128] First, the semiconductor device 1 is prepared. In the example, the semiconductor device 1 includes a lead frame 11, a diode 21, an IGBT 22, solder 30, wires 40, 41, and a sealing resin 7.

[0129] The material of the lead frame 11 is copper. The dimensions of the lead frame 11 are a length of 120 mm, a width of 75 mm, and a thickness of 0.6 mm.

[0130] The dimensions of the diode 21 are a length of 15 mm, a width of 13 mm, and a thickness of 0.2 mm. The dimensions of the IGBT 22 are a length of 15 mm, a width of 15 mm, and a thickness of 0.2 mm. The diode 21 and the IGBT 22 are chip-bonded to the chip pads 112 of the lead frame 11 by the solder 30.

[0131] The composition ratio of the solder 30 is 96.5 mass% of tin (Sn), 3 mass% of silver (Ag), and 0.5 mass% of copper (Cu). The melting point of the solder 30 is 217°C.

[0132] The main electrode 211 of the diode 21 and the main electrode 221 of the IGBT 22 are electrically connected to the lead frame 11 using the wire 40. The material of the wire 40 is aluminum. The diameter of the wire 40 is 0.3 mm.

[0133] The signal electrode 222 such as the gate electrode of the IGBT 22 is electrically connected to the lead frame 11 using the wire 41. The material of the wire 41 is aluminum. The diameter of the wire 41 is 0.15 mm.

[0134] After the lead frame 11, semiconductor element 20, solder 30, and wires 40 and 41 are held by a mold (not shown), the heated encapsulating resin 7 is pressure-injected and then heat-cured, thereby completing resin encapsulation. The mold (not shown) is heated to 170°C. The encapsulating resin 7 is heated to 170°C. The encapsulating resin 7 is an epoxy transfer molding resin containing silica filler. After being pressure-injected, the encapsulating resin 7 is heat-cured at 170°C in an oven for 4 hours.

[0135] Next, a test piece 72 for the adhesion evaluation test is formed. The encapsulating resin 7 is removed in a circular shape using a laser 6 to form a recess 71. The outermost surface diameter of the recess 71 is 5.0 mm.

[0136] The irradiation device of the laser 6 is F / Alit manufactured by Shin-Etsu Chemical Co., Ltd. The wavelength of the laser 6 is 1064 nm. The maximum output of the laser 6 is 20 W.

[0137] The removal of the encapsulating resin 7 is further advanced, and when the remaining height of the encapsulating resin 7 becomes 1.5 mm, the outer peripheral portion is removed while retaining the central portion of the test piece 72. The diameter of the central portion of the test piece 72 is 1.5 mm.

[0138] The test piece 72 is formed in the shape of a pudding cup. That is, the test piece 72 is formed in the shape of a frustum of a cone. The diameter D1 of the lead frame interface of the test piece 72 is 1.94 mm. The diameter D2 of the surface of the test piece 72 is 1.5 mm. The height H of the test piece 72 is 1.5 mm.

[0139] Next, the adhesion evaluation method in the embodiment will be described.

[0140] In the adhesion evaluation method of the embodiment, the adhesion is evaluated using a test piece manufactured by the above-described method for manufacturing a test piece for the adhesion evaluation test.

[0141] In the adhesion evaluation method of the embodiment, the shear peel strength is measured using the above-described test piece for the adhesion evaluation test.

[0142] The semiconductor device 1 provided with the test piece 72 is fixed to a mounting table 80. In this state, the test piece 72 is pressed with a tool 90 until the test piece 72 breaks.

[0143] The device used in the shear peel strength evaluation is the bond tester DAGE4000 manufactured by DAGE Co., Ltd. The shear peel strength test is carried out at room temperature. The height of the tip of the tool 90 is set to a height of 0.04 mm from the lead frame 11. The shear speed of the pressing tool 90 is 0.3 mm / s.

[0144] Refer to Figure 18The relationship between the laser irradiation conditions and the shear peel strength was studied. Figure 18 It is a graph showing the relationship between the laser irradiation conditions (the resin residue amount around the test piece) and the shear peel strength. The irradiation time of the laser was changed, and the shear peel strength of the test piece 72 was studied. The height of the test piece 72 is 1.5 mm. The diameter of the lead frame 11 interface of the test piece 72 is 1.94 mm.

[0145] The irradiation conditions of the laser are the following conditions (a), (b), and (c). In condition (a), the remaining thickness of the sealing resin around the test piece is 0 mm or more and 0.07 mm or less. In condition (b), the copper lead frame is exposed from the sealing resin around the test piece. In condition (c), excessive laser is irradiated around the test piece. For each condition, the average value and the standard deviation σ were calculated based on seven (n = 7) measurement values. In condition (a), the standard deviation σ is 0.15 (σ = 0.15). In condition (b), the standard deviation σ is 0.16 (σ = 0.16). In condition (c), the standard deviation σ is 0.45 (σ = 0.45). However, in condition (c), after the copper lead frame was exposed, the laser was irradiated twice around the test piece with an intensity capable of removing the sealing resin with a thickness of about 0.5 mm in one irradiation.

[0146] Figure 19 The appearance of the produced test piece 72 and the appearance of the adhered part after the shear peel test are shown. In condition (c), traces of burning of the copper lead frame were observed around the test piece 72. However, the copper lead frame was not cut into a concave shape, and there was no difference in the overall shape from condition (b).

[0147] The average value hardly changed under each condition. On the other hand, under condition (c), the deviation of the measurement values became larger. Thus, since the laser was continuously irradiated even after the copper lead frame was exposed, heat was generated at the interface between the sealing resin and the lead frame, and the adhesion force might decrease.

[0148] It can be seen that by making the thickness of the sealing resin remaining around the test piece 0 mm or more and 0.07 mm or less, a measurement result with a smaller deviation can be obtained. Herein, the thickness of the sealing resin remaining around the test piece being 0.07 mm means that, as Figure 20 shown, there are irregularities in the sealing resin around the test piece, and the maximum value of the protruding part is 0.07 mm.

[0149] Refer to Figure 21 The relationship between the diameter of the test piece and the shear peel strength was studied. Figure 21It is a graph showing the relationship between the diameter of the test piece and the shear peel strength. Five specifications of test pieces were prepared. Among the five specifications, the diameters D1 of the lead frame 11 interfaces of the test piece 72 were 1.94 mm, 1.74 mm, 1.43 mm, 1.24 mm, and 0.9 mm respectively. Seven test pieces of each of the five specifications were prepared. Shear peel tests were conducted on each test piece. For each of the five specifications, the average value of the shear peel strength was calculated. As a result, the smaller the diameter D1 of the lead frame 11 interface of the test piece 72, the greater the shear peel strength. That is, there is a tendency that the smaller the contact area, the greater the increase in the shear peel strength.

[0150] Figure 22 The appearance after the shear peel test in the cases where the diameter D1 is 1.94 mm and 0.90 mm is shown. If the appearances after the shear peel test in the cases where the diameter D1 is 1.94 mm and 0.90 mm are compared, in the case where the diameter D1 is 1.94 mm, it is generally a mode of interfacial peeling. In contrast, in the case where the diameter is 0.90 mm, a mode of cohesive peeling is confirmed. From this, it can be speculated that when the pudding cup of the test piece is thinner, it will flex with respect to the load applied from the tool, and stress will be applied to the inside of the pudding cup separately from the interface. In addition, in interfacial peeling, peeling occurs at the interface and the copper lead frame is completely exposed. Further, in cohesive peeling, damage occurs in the main body part of the resin.

[0151] Figure 23 It is a cross-sectional view showing the measurement method of the shear peel strength of the test piece 72. It can be considered that when the diameter of the test piece 72 is small, it is easy to generate flexure of the test piece 72 up to the height where the tool 90 contacts, and the shear peel strength is measured to be large. It is known that there is a tendency that the greater the height at which the tool 90 actually contacts is increased for measurement, the greater the shear peel strength becomes.

[0152] Refer to Figure 24 and Figure 25 , the relationship between the direction of pressing with the tool and the shear peel strength in the case where the upper surface and the bottom surface of the test piece 72 are set to a rounded rectangular shape is compared. In Figure 24 , the relationship between the direction of pressing with the tool and the shear peel strength is compared. Figure 25 The shape of the test piece 72 and the direction of pressing with the tool are shown. The shear peel strength when pressing from the short side direction of the test piece 72 is greater than the shear peel strength when pressing from the long side direction. By setting the test piece 72 as an elliptical frustum, specifically, by setting the upper surface and the bottom surface to a rounded rectangular shape, and thus pressing the test piece 72 from the long side direction with the tool, even if the bottom area of the test piece 72 is small, the influence of flexure can be excluded.

[0153] Figure 26 The relationship between the injection molding speed and the peel rate is shown in the case of encapsulating parts with the resin injection molding speed changed and performing a reflow heat resistance test. In Figure 26 , an SAT (Scanning Acoustic Tomograph) image of a part of a copper lead frame is shown. The peel rate is defined as the ratio of the peeled area to the entire area of the copper lead frame. In addition, the injection molding speed represents a value with a median of 1.0. No clear correlation was obtained between the injection molding speed and the peel rate, and it is likely affected by physical property values of materials such as the gelation time of the resin.

[0154] The shear peel strength before the reflow heat resistance test of the encapsulating parts with the resin injection molding speed changed was evaluated. A pudding cup was made at the position where the generation rate of peeling in the reflow heat resistance test was high. Due to the limitation of the area of the copper lead frame, the diameter D1 of the pudding cup was set to 0.9 mm.

[0155] Figure 27 The relationship between the resin injection molding speed and the shear peel strength is shown. It can be seen that the shear peel strength changes with respect to the resin injection molding speed.

[0156] Figure 28 Combined with Figure 26 and Figure 27 , the correlation between the shear peel strength and the peel rate in the reflow heat resistance test is shown. A negative correlation was observed between the shear peel strength and the peel rate. By measuring the shear peel strength using this method, the peel rate in the reflow heat resistance test can be predicted.

[0157] Embodiment 3.

[0158] Unless otherwise specified, Embodiment 3 has the same structure, method, and effects as Embodiment 1 above. Therefore, in Embodiment 3, the same reference numerals are used for the same structures as in Embodiment 1 above, and no repeated description is given.

[0159] Refer to Figures 29 to 31 , and the manufacturing method and adhesion evaluation method of the test piece for the adhesion evaluation test of Embodiment 3 will be described.

[0160] Refer to Figure 29 and Figure 30 , and the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 3 will be described. Refer to Figure 29 , and the process of preparing the semiconductor device in the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 3 will be described. Figure 29 is a cross-sectional view of the semiconductor device 1 in the manufacturing method of the test piece for the adhesion evaluation test of Embodiment 3. AsFigure 29 As shown, in semiconductor device 1, an insulating sheet 18 including an insulating member 16 and a metal member 17 is disposed under the chip pad 112. The insulating member 16 is an epoxy resin. The insulating member 16 is configured in a sheet shape. The insulating member 16 has insulating properties. The material of the metal member 17 is, for example, copper or aluminum.

[0161] Refer to Figure 30 to describe the process of forming a test piece for the adhesion evaluation test of Embodiment 3. Figure 30 The cross-section of the part of the semiconductor device 1 without the semiconductor element 20 is shown. As Figure 30 shown, in the part where the chip pad 112 is not disposed, a test piece 72 is formed by laser 6 in such a manner as to include the sealing resin 7 and the insulating member 16. In this way, a test piece 72 for the adhesion evaluation test is formed on the insulating member 16 under the base member 10 by the sealing resin 7 of the semiconductor device 1.

[0162] Refer to Figure 31 to describe the process of measuring the shear peel strength in the adhesion evaluation method of Embodiment 3. Similar to Embodiments 1 and 2, as Figure 31 shown, the test piece 72 is pressed by a tool 90. At this time, the height 120 of the tool 90 is lower than the thickness 130 of the insulating member 16. The height 120 of the tool 90 is, for example, 0.1 mm lower than the thickness 130 of the insulating member 16. Thus, the shear strength at which the interface between the insulating member 16 and the metal member 17 is damaged can be confirmed.

[0163] After sealing the insulating sheet 18 with the sealing resin 7, it is necessary to ensure the adhesion between the insulating member 16 and the metal member 17. However, when evaluating the adhesion between the insulating member 16 and the metal member 17 after sealing, it is a general method to confirm the presence or absence of peeling by ultrasonic testing or the like after the reliability test. As an evaluation of adhesion, it is difficult to quantitatively confirm the presence or absence of deterioration.

[0164] By the shear test method of the present embodiment, the influence of the injection process conditions of the sealing resin 7 on the adhesion strength of the interface between the insulating member 16 and the metal member 17 can be confirmed. Thus, since appropriate process conditions can be determined, the material development period of the insulating member 16 can be shortened.

[0165] The above-described embodiments can be appropriately combined.

[0166] It should be considered that the embodiments and examples disclosed herein are illustrative in all respects and not restrictive. The scope of the present disclosure is not represented by the above description, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0167] Description of Reference Numerals

[0168] 1 semiconductor device, 6 laser, 7 sealing resin, 10 base member, 11 lead frame, 14 base plate, 15 ceramic substrate, 16 insulating member, 17 metal member, 18 insulating sheet, 20 semiconductor element, 21 diode, 30 solder, 40, 41 wire, 60 housing, 72 test piece, 80 stage, 90 tool, 100 mask, 110 etching solution, 120 height, 130 thickness.

Claims

1. A method for manufacturing a test piece for a tightness evaluation test, wherein, The manufacturing method of the test piece for the close contact evaluation test includes: a process of preparing a semiconductor device, the semiconductor device including a substrate member, a semiconductor element mounted on the substrate member, and a sealing resin for sealing the substrate member and the semiconductor element; and a process of forming the test piece for the close contact evaluation test on the substrate member or an insulating member under the substrate member from the sealing resin of the semiconductor device by removing the sealing resin in a portion of the semiconductor device where there is no semiconductor element when observed in a direction perpendicular to the plane direction of the substrate member, when observed in a direction perpendicular to the plane direction of the substrate member, the test piece does not overlap with the semiconductor element.

2. The manufacturing method of the test piece for the close contact evaluation test according to claim 1, wherein the insulating member is a sheet-shaped epoxy resin, and further includes a metal member, the metal member is disposed under the insulating member.

3. The manufacturing method of the test piece for the close contact evaluation test according to claim 1, wherein the test piece is formed in the shape of an elliptical frustum.

4. The manufacturing method of the test piece for the close contact evaluation test according to claim 1 or 3, wherein the test piece is formed from the sealing resin by processing using a laser.

5. The manufacturing method of the test piece for the close contact evaluation test according to claim 1 or 3, wherein the test piece is formed from the sealing resin by processing using an etching solution.

6. A method for evaluating tightness, wherein, The close contact evaluation method includes: a process of preparing a semiconductor device, the semiconductor device including a substrate member, a semiconductor element mounted on the substrate member, and a sealing resin for sealing the substrate member and the semiconductor element; a process of forming a test piece for the close contact evaluation test on the substrate member or an insulating member under the substrate member from the sealing resin of the semiconductor device by removing the sealing resin in a portion of the semiconductor device where there is no semiconductor element when observed in a direction perpendicular to the plane direction of the substrate member; and a process of measuring the shear peel strength using the test piece for the close contact evaluation test, when observed in a direction perpendicular to the plane direction of the substrate member, the test piece does not overlap with the semiconductor element.

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