Semiconductor equipment
By employing a mold with protrusions to facilitate the detachment of the encapsulant from the mold, the method addresses the issue of reduced releasability, enhancing productivity by minimizing mold cleaning and release agent application.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-19
AI Technical Summary
The decrease in releasability between resin and mold due to peeling of the release agent leads to manufacturing defects in semiconductor devices, necessitating frequent mold cleaning and reapplication of the release agent, which reduces productivity.
A method involving the use of a mold with protrusions that temporarily pull down and then push up the cured sealing material to improve the release properties, creating a delamination point for easier detachment of the encapsulant from the mold.
This method enhances the release properties between the encapsulant and mold, reducing the frequency of mold cleaning and release agent reapplication, thereby improving productivity.
Smart Images
Figure 2026083424000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a semiconductor device and a method for manufacturing a semiconductor device.
Background Art
[0002] As a method for molding a package of a semiconductor device, as shown in Patent Document 1, a resin sealing method is known in which resin is molded by a mold and a semiconductor element is sealed inside the resin. In this resin sealing method, in order to ensure the releasability between the resin and the mold, a release agent is previously applied inside the mold.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When the release agent peels off due to repeated use of the mold coated with the release agent, the releasability between the resin and the mold decreases. When the resin sealing process is performed in such a state, a part of the resin adheres to the mold. When removing the molded resin from the mold, a part of the resin peels off, and the object to be sealed such as a semiconductor element is exposed from the peeled part. Thus, the decrease in releasability causes manufacturing defects of the semiconductor device. Therefore, regular mold cleaning and reapplication of the release agent are required. For mold cleaning, for example, melamine resin, release property recovery resin, etc. are used, and each cleaning requires a significant amount of time.
[0005] In order to solve the above problems, an object of the present disclosure is to provide a method for manufacturing a semiconductor device in which productivity is improved by improving the releasability between a sealing material and a mold.
Means for Solving the Problems
[0006] A method for manufacturing a semiconductor device according to this disclosure comprises the steps of: filling a mold with a sealing material while an object to be sealed, including a semiconductor element, is placed inside the mold and an opening is made, with at least one projection protruding from the inside of the mold; curing the filled sealing material to seal the object to be sealed; and releasing the cured sealing material from the mold. The step of releasing the sealing material includes the steps of temporarily pulling down the protruding projection and, after temporarily pulling down the projection, using the projection to push up the cured sealing material. [Effects of the Invention]
[0007] The semiconductor device manufacturing method of this disclosure improves productivity by improving the release properties between the encapsulant and the mold.
[0008] The purpose, features, aspects, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings. [Brief explanation of the drawing]
[0009] [Figure 1] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 1. [Figure 2] This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 1. [Figure 3] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 4] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 5] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 6] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 7] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 8] This figure shows the resin encapsulation process in the manufacturing method of a semiconductor device. [Figure 9] This is a plan view showing the configuration of the lower mold used in the semiconductor device manufacturing method in Embodiment 2. [Figure 10] This figure shows the resin encapsulation step in the semiconductor device manufacturing method according to Embodiment 3. [Figure 11] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 4. [Figure 12] This is a plan view showing the configuration of the back surface of the semiconductor device in Embodiment 5. [Figure 13] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 6. [Modes for carrying out the invention]
[0010] <Embodiment 1> Figure 1 is a cross-sectional view showing the configuration of the semiconductor device 101 in Embodiment 1. The semiconductor device 101 includes an insulating sheet 1, a metal plate 2, a semiconductor element 3, leads 4, a sealing material 5, and at least one hole 6. The configuration of the semiconductor device 101 shown in Figure 1 and the following drawings is simplified, and illustrations of wiring and signal terminals electrically connected to the semiconductor element 3 are omitted.
[0011] The insulating sheet 1 is formed from a material that has electrical insulation properties and high thermal conductivity. For example, the insulating sheet 1 is epoxy resin. The insulating sheet 1 may also contain fillers such as silicon oxide (SiO2), aluminum oxide (Al2O3), or boron nitride (BN). The back surface of the insulating sheet 1 forms part of the outer surface of the semiconductor device 101. A metal foil (not shown) may be formed on the back surface of the insulating sheet 1. After the semiconductor device 101 is completed, heat dissipation fins can be attached to the metal foil. The metal foil forms a thermal connection between the semiconductor element 3 inside the semiconductor device 101 and the heat dissipation fins outside the semiconductor device 101.
[0012] The metal plate 2 is provided on the surface of the insulating sheet 1. The metal plate 2 is made of a material with excellent thermal conductivity, such as an aluminum alloy or copper.
[0013] The semiconductor element 3 is joined to the metal plate 2 via the joining material 7. That is, the semiconductor element 3 is mounted on the surface of the insulating sheet 1 via the joining material 7 and the metal plate 2. The joining material 7 has conductivity. The joining material 7 is, for example, a soft solder such as solder. The semiconductor element 3 is formed of, for example, a semiconductor such as Si. Alternatively, the semiconductor element 3 is formed of a so-called wide bandgap semiconductor having a larger bandgap than Si, such as SiC, GaN, Ga2O3, diamond. The semiconductor element 3 is a power semiconductor element, a control IC (Integrated Circuit) for controlling the power semiconductor element, or the like. The semiconductor element 3 includes, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a Schottky barrier diode, or the like. Alternatively, the semiconductor element 3 may include an RC-IGBT (Reverse-Conducting IGBT) in which an IGBT and a freewheeling diode are formed in one semiconductor substrate. Two semiconductor elements 3 are mounted on the semiconductor device 101 in the first embodiment. The number of semiconductor elements 3 mounted on the semiconductor device 101 is not limited to two, and the number of semiconductor elements 3 required according to the application of the semiconductor device 101 is mounted.
[0014] The lead 4 is formed of a metal material having a small electrical resistance value. The lead 4 is, for example, a metal frame in which a metal plate such as copper is processed into a predetermined shape. The lead 4 forms an internal circuit of the semiconductor device 101 and is configured to be electrically connectable to a circuit (not shown) provided outside the semiconductor device 101. The lead 4 in the first embodiment extends to the outside of the sealing material 5. In other words, the end portion of the lead 4 protrudes from the sealing material 5 and constitutes an external electrode connectable to an external circuit. Alternatively, although not shown, the external electrode protruding from the sealing material 5 may be provided as a separate component from the lead 4. In that case, the lead 4 is electrically connected to the external electrode by a metal wire or the like.
[0015] A part of the lead 4 is joined to the upper surface of the semiconductor element 3 via the bonding material 8. The bonding material 8 has conductivity. The bonding material 8 is a soft solder such as, for example, solder. The connecting member between the lead 4 and the semiconductor element 3 is not limited to the bonding material 8. Although not shown, the lead 4 may be electrically connected to the semiconductor element 3 via a metal wire. The metal wire is formed of, for example, aluminum (Al), gold (Au), copper (Cu), or the like. Also, although not shown, a part of the lead 4 may be joined to the metal plate 2 via the bonding material 8.
[0016] The encapsulant 5 encapsulates an object to be encapsulated including the surface of the insulating sheet 1, the metal plate 2, a part of the semiconductor element 3, and the lead 4. The encapsulant 5 is formed of a resin having insulation and curability. The encapsulant 5 is formed of, for example, an epoxy resin. The encapsulant 5 may contain a filler having excellent insulation properties such as aluminum oxide (Al2O3), silicon (Si), or the like. The encapsulant 5 is not limited to these materials, and any material having desired physical properties with respect to the elastic modulus, heat resistance, adhesiveness, coefficient of linear expansion, or the like may be used.
[0017] The hole 6 is formed in one surface (the lower surface in FIG. 1) of the encapsulant 5. The lower surface of the encapsulant 5 is flush with the surface of the insulating sheet 1 (the back surface in FIG. 1) exposed from the encapsulant 5. The hole 6 has a cylindrical shape. Two holes 6 are provided in the encapsulant 5 in Embodiment 1. The number of the holes 6 is not limited to two, and may be one or three or more.
[0018] FIG. 2 is a flowchart showing a method for manufacturing the semiconductor device 101 in Embodiment 1. FIGS. 3 to 8 are diagrams showing a resin encapsulation process in the method for manufacturing the semiconductor device 101. FIGS. 3 to 8 show schematic cross-sectional views of the semiconductor device 101 and the mold 10 in the resin encapsulation process.
[0019] In this resin encapsulation process, the mold 10 shown in Figure 3 is used. The mold 10 includes an upper mold 10A and a lower mold 10B. Hereinafter, the interior of the mold 10 corresponds to the cavity formed by the upper mold 10A and the lower mold 10B. The lower mold 10B is provided with a sliding projection 11 that leads to the cavity of the mold 10, i.e., the interior of the mold 10. The sliding projection 11 has a cylindrical shape. The mold 10 in Embodiment 1 is provided with two sliding projections 11. The number of sliding projections 11 is not limited to two; there may be one or three or more. The mold 10 is also provided with a sliding pin 12.
[0020] In step S1, the insulating sheet 1 is installed on a portion of the installation surface 10C inside the mold 10. Figure 3 shows the step of installing the insulating sheet 1 inside the mold 10 during the resin encapsulation process. The installation surface 10C on which the insulating sheet 1 is installed corresponds to the cavity of the mold 10, that is, the lower surface inside the mold 10. In other words, the installation surface 10C corresponds to the upper surface of the lower mold 10B. A release agent may be applied to the installation surface 10C of the mold 10. The insulating sheet 1 is installed in a semi-cured state. In step S1, for example, the insulating sheet 1 is installed inside the mold 10 with the tip of the slide projection 11 protruding above the upper surface of the lower mold 10B, that is, above the lower surface inside the mold 10. Alternatively, the insulating sheet 1 may be installed inside the mold 10 with the tip of the slide projection 11 at the same height as or lower than the upper surface of the lower mold 10B. A metal foil (not shown) may be pre-formed on the back surface of the insulating sheet 1 before installation.
[0021] In step S2, the metal plate 2, semiconductor element 3, and lead 4 are placed inside the mold 10. Figure 4 shows the step of placing the metal plate 2, semiconductor element 3, and lead 4 inside the mold 10 during the resin encapsulation process. The metal plate 2, semiconductor element 3, and lead 4 prepared in step S2 are pre-integrated by bonding materials 7 and 8. In other words, the metal plate 2, semiconductor element 3, and lead 4 are prepared as a single component joined to each other by bonding materials 7 and 8. This integrated component is manufactured in another bonding process that is performed beforehand. In that bonding process, the metal plate 2, semiconductor element 3, and lead 4 are heated to a temperature exceeding the melting point of the bonding materials 7 and 8, and the bonding is completed. Then, in step S2, the integrated metal plate 2, semiconductor element 3, and lead 4 are placed on the surface of the insulating sheet 1.
[0022] In step S3, the molten sealant 5 is filled into the mold 10. Figure 5 shows the step of filling the mold 10 with the molten sealant 5 during the resin encapsulation process. First, the upper mold 10A and the lower mold 10B are closed. Then, with the inside of the mold 10 under reduced pressure, the molten sealant 5 is injected. At this time, the sealant 5 is injected into the mold 10 with the sliding protrusions 11 protruding into the inside of the mold 10. The sliding protrusions 11 protrude into the inside of the mold 10 from an area of the installation surface 10C inside the mold 10 where the insulating sheet 1 is not installed. For example, the sliding protrusions 11 protrude approximately 1 mm upward from the installation surface 10C of the lower mold 10B. When the filling of the sealant 5 is complete, the sliding protrusions 11 are covered with the sealant 5.
[0023] In step S4, the inside of the mold 10 is heated under pressure, and the sealant 5 hardens. Figure 6 shows the step in the resin encapsulation process in which the sealant 5 hardens inside the mold 10. By pressurizing the inside of the mold 10, the molten sealant 5 fills the inside of the mold 10 without any gaps. When the sealant 5 is heated to its hardening temperature, the sealant 5 hardens. In this step S4, the object to be encapsulated, including the surface of the insulating sheet 1, the metal plate 2, the semiconductor element 3, and part of the lead 4, is encapsulated. On the other hand, the back surface of the insulating sheet 1 is in contact with the installation surface 10C of the mold 10 and is not covered by the sealant 5. Even after the sealant 5 hardens, the back surface of the insulating sheet 1 is exposed from the bottom surface of the sealant 5. The back surface of the insulating sheet 1 is flush with the bottom surface of the sealant 5. In addition, in this step S4, holes 6 corresponding to the sliding protrusions 11 covered by the sealant 5 are formed in the sealant 5. In Embodiment 1, the holes 6 are formed on the bottom surface of the sealant 5. The shape of hole 6 matches the shape of the sliding projection 11.
[0024] In step S5, the protruding slide projection 11 is pulled down. Figure 7 shows the step in the resin encapsulation process in which the slide projection 11 is pulled down. Here, the tip of the slide projection 11 is pulled down to the lower surface of the lower mold 10B, i.e., the mounting surface 10C. As a result, the hole 6 shown as a cavity in Figure 7 appears. After the encapsulant 5 has hardened, the slide projection 11 is pulled down and a cavity is formed, creating a peeling point between the mold 10 and the encapsulant 5.
[0025] In step S6, the encapsulant 5 is pushed up by the sliding projection 11. Figure 8 shows the step in the resin encapsulation process in which the encapsulant 5 is pushed up by the sliding projection 11. At this time, the upper mold 10A and the lower mold 10B are opened, the lead 4 is lifted by the sliding pin 12, and the encapsulant 5 is further lifted by the sliding projection 11. As a result, the lead 4 is detached from the mold 10, and the encapsulant 5 is released from the mold 10. In other words, the semiconductor device 101 is released from the mold 10.
[0026] In this way, the initial downward movement of the sliding projection 11 in step S5 creates a demolition starting point, and the upward movement of the sliding projection 11 in step S6 allows the semiconductor device 101 to be easily released from the mold 10.
[0027] After steps S1 to S6 described above, the necessary terminals are formed, etc. Furthermore, inspections of appearance, electrical characteristics, etc., are performed, and the semiconductor device 101 is completed.
[0028] To summarize, the method for manufacturing the semiconductor device 101 in Embodiment 1 includes the steps of: filling the mold 10 with a sealing material 5 while the object to be sealed, including the semiconductor element 3, is placed inside the mold 10, which has an opening, with at least one slide projection 11 protruding from the inside of the mold 10; curing the filled sealing material 5 to seal the object to be sealed, including the semiconductor element 3; and releasing the cured sealing material 5 from the mold 10. The step of releasing the sealing material 5 includes the steps of temporarily pulling down the protruding slide projection 11, and after temporarily pulling down the slide projection 11, using the slide projection 11 to push up the cured sealing material 5.
[0029] According to this method of manufacturing the semiconductor device 101, a delamination point is formed between the mold 10 and the encapsulant 5. With this delamination point formed, the sliding projection 11 pushes the encapsulant 5 upward, making it easier to detach the semiconductor device 101 from the mold 10. In other words, the release properties between the resin encapsulant 5 and the mold 10 are improved. As a result, the frequency of cleaning the mold 10 and the frequency of reapplying the release agent are reduced. In addition, the number of times the resin encapsulation process can be performed per cleaning or application of the release agent increases. Reducing the frequency of cleaning the mold 10 and reapplying the release agent improves the productivity of the semiconductor device 101.
[0030] In Embodiment 1, the downward and upward movements of the slide projection 11 are relative movements to the sealing material 5. For example, the downward movement of the slide projection 11 may be performed by driving the slide projection 11 downward, or by driving the mold 10 upward. Similarly, the upward movement of the slide projection 11 may be performed by driving the slide projection 11 upward, or by driving the mold 10 downward.
[0031] <Embodiment 2> Figure 9 is a plan view showing the configuration of the lower mold 10B used in the semiconductor device manufacturing method in Embodiment 2.
[0032] The number of slide protrusions 11 provided on the mold 10 is two or less. In other words, the number of positions where slide protrusions 11 are provided is two or less. If the mold 10 has multiple cavities and multiple semiconductor devices are manufactured in a single resin encapsulation process, the number of slide protrusions 11 is two or less per cavity.
[0033] The method for manufacturing the semiconductor device in Embodiment 2 is the same as the manufacturing method shown in Embodiment 1. The number of holes 6 formed in the sealing material 5 corresponds to the number of slide protrusions 11. Therefore, the number of holes 6 in the semiconductor device in Embodiment 2 is two or less.
[0034] In this second embodiment of the manufacturing method, a delamination point is formed between the mold 10 and the sealing material 5 in step S5. Therefore, even if the number of slide protrusions 11 is two or less, the sealing material 5 can be easily released from the mold 10. In particular, in Figure 9, two slide protrusions 11 are provided diagonally across the internal space of the mold 10, which facilitates delamination. Also, since the number of slide protrusions 11 is two or less, the design of the mold 10 is simple.
[0035] <Embodiment 3> Figure 10 shows the resin encapsulation step of the semiconductor device manufacturing method in Embodiment 3. Figure 10 shows the step in the resin encapsulation process in which the encapsulating material 5 is pushed up by the sliding projection 31.
[0036] The sliding projection 31 has a shape in which its diameter gradually narrows towards the tip of the sliding projection 31. In other words, the sliding projection 31 has a tapered shape. The number of sliding projections 31 may be two or less, as in Embodiment 2.
[0037] Furthermore, the hole 36 formed on the lower surface of the sealing material 5 has a shape in which the diameter of the hole 36 gradually decreases towards the back of the hole 36. In other words, the hole 36 has a tapered shape. This is because the shape of the sliding projection 31 is reflected in the shape of the hole 36.
[0038] The method for manufacturing the semiconductor device in Embodiment 3 is the same as the manufacturing method shown in Embodiment 1.
[0039] The frictional force between the tapered slide projection 31 and the sealing material 5 is smaller than the frictional force between the cylindrical slide projection 31 and the sealing material 5. Therefore, in the step S5 in which the slide projection 31 is pulled down from the sealing material 5, it is possible to pull down the slide projection 31 with less driving force. As a result, problems such as the slide projection 31 becoming stuck in the hole 36 of the sealing material 5 and being unable to be pulled down from the sealing material 5 are prevented. The semiconductor device manufacturing method in Embodiment 3 is more productive than the manufacturing methods in Embodiments 1 and 2.
[0040] <Embodiment 4> Figure 11 is a cross-sectional view showing the configuration of the semiconductor device 104 in Embodiment 4.
[0041] The semiconductor device 104 of Embodiment 4 is manufactured by the manufacturing method shown in Embodiment 1.
[0042] The holes 6 provided on the lower surface of the sealing material 5 are cylindrical in shape. There is one or more holes 6. The holes 6 are formed in the processes shown in steps S3 and S4. The holes 6 are formed with an opening on one surface of the sealing material 5 that is flush with the surface of the insulating sheet 1 exposed from the sealing material 5, and have a bottom inside the sealing material 5. In step S6, the sliding projection 11 enters the hole 6 and pushes up the sealing material 5. The release properties between the sealing material 5 and the mold 10 are improved. The frequency of cleaning the mold 10 and the frequency of reapplying the release agent are reduced. As a result, the productivity of the semiconductor device 104 is improved.
[0043] <Embodiment 5> Figure 12 is a plan view showing the configuration of the back surface of the semiconductor device 105 in Embodiment 5.
[0044] The holes 6 provided on the lower surface of the sealing material 5 are cylindrical in shape, similar to Embodiment 1. The number of holes 6 is two or less, similar to Embodiment 2. The insulating sheet 51, similar to insulating sheet 1, extends to the area where there are no holes 6. Although not shown in the illustration, the metal plate, similar to metal plate 2, also extends to the area where there are no holes 6. In other words, in Embodiment 5, the insulating sheet 51 and the metal plate extend to the area other than the holes 6 provided on the lower surface of the sealing material 5 in a plan view.
[0045] The semiconductor device 105 of Embodiment 5 is manufactured by the manufacturing method shown in Embodiment 1. Also, similar to Embodiment 2, the number of slide protrusions 11 provided on the mold 10 is two or less. In other words, the positions where the slide protrusions 11 are provided are two or less.
[0046] In addition to the same effects as in Embodiment 2, the area of the insulating sheet 51 and the metal plate is increased, which expands the heat dissipation area. This improves the design margin of the semiconductor device 105.
[0047] <Embodiment 6> Figure 13 is a cross-sectional view showing the configuration of the semiconductor device 106 in Embodiment 6.
[0048] The hole 36 provided on the lower surface of the sealing material 5 has a shape in which the diameter of the hole 36 gradually decreases towards the back of the hole 36. In other words, the hole 36 has a tapered shape. The hole 36 is conical or frustoconical.
[0049] The semiconductor device 106 of Embodiment 6 is manufactured by the manufacturing method shown in Embodiment 3. That is, the slide projection 31 provided on the mold 10 has a shape in which its diameter gradually tapers towards the tip of the slide projection 31.
[0050] In step S6, when the slide projection 31 pushes the sealant 5 out of the mold 10, the tapered shape of the hole 36 increases the surface area of the slide projection 31 that contacts the sealant 5. That is, the contact area between the two increases, making it easier for the sealant 5 to be released from the mold 10. As a result, the frequency of cleaning the mold 10 and the frequency of reapplying the release agent are reduced. The number of times the resin encapsulation process can be performed per cleaning or per application of the release agent increases. As a result, the productivity of the semiconductor device 106 is improved.
[0051] Although this disclosure has been described in detail, the above description is illustrative and not limiting in all respects. It is understood that countless variations not illustrated are conceivable.
[0052] This disclosure allows for the free combination of each embodiment, and enables the modification or omission of each embodiment as appropriate. [Explanation of symbols]
[0053] 1 Insulating sheet, 2 Metal plate, 3 Semiconductor element, 4 Lead, 5 Encapsulating material, 6 Hole, 7 Bonding material, 8 Bonding material, 10 Mold, 10A Upper mold, 10B Lower mold, 10C Mounting surface, 11 Slide projection, 12 Slide pin, 31 Slide projection, 36 Hole, 51 Insulating sheet, 101 Semiconductor device, 104-106 Semiconductor device.
Claims
1. An insulating sheet on which an object to be encapsulated, including a semiconductor element, A sealing material for sealing the object to be sealed, The sealing material comprises at least one hole formed therein, A semiconductor device wherein the aforementioned hole is formed on one surface of the sealing material that is flush with the surface of the insulating sheet exposed from the sealing material, and has an opening and a bottom within the sealing material.
2. The semiconductor device according to claim 1, wherein the at least one hole is two or fewer holes.
3. The insulating sheet and the semiconductor element are further provided with a metal plate, The semiconductor device according to claim 2, wherein the insulating sheet and the metal plate extend in a plan view to an area other than the hole provided on one surface of the sealing material.
4. The semiconductor device according to any one of claims 1 to 3, wherein the hole has a shape in which the diameter of the hole gradually decreases toward the back of the hole.