Substrate for semiconductor device and semiconductor device

Abstract

To provide a substrate for semiconductor device that allows highly flexible setting of surface geometry in a metal part, and enables a larger surface area of metal parts to be secured.SOLUTION: A substrate for semiconductor device has, on a matrix substrate 10, a plurality of metal parts 11 serving as semiconductor element mounting parts 11a and / or electrodes 11b. The metal part 11 has an overhang formed around the entire upper edge periphery. The area of an upper face of the metal part 11 including the overhang is larger than the area of a rear face of the metal part 11 that is in contact with a front face of the matrix substrate 10. The overhang protrudes from the metal part 11 in a direction perpendicular to an axial direction of the metal part 11. In each of the metal parts 11, a protruding amount in the protrusion at any position except a position on a side facing the adjacent metal part 11 is longer than a protruding amount in the protrusion at any position on the side facing the adjacent metal part 11.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a substrate for a semiconductor device, which includes a mother substrate and metal parts serving as semiconductor element mounting parts and electrode parts, and a semiconductor device formed using the substrate for a semiconductor device. [Background technology]

[0002] A semiconductor device in which a semiconductor element is mounted on a substrate (printed circuit board) for supporting the semiconductor element, the semiconductor element is electrically connected to a terminal for external output, and the entire substrate including the semiconductor element is covered with a protective material such as resin, has a limit to how small it can be made due to its structure. In contrast, a semiconductor device in which a metal portion that serves as a semiconductor element mounting portion and an electrode portion is provided, the semiconductor element is mounted on the metal portion, and after processing such as electrical connection, the surface side of the semiconductor element and the metal portion are sealed with a sealing material such as resin, and the metal portion is exposed from the bottom, can be made low in height to save space, and has the advantage of being excellent in terms of heat dissipation, as heat generated by the semiconductor element can be released to the outside through the exposed metal portion, and is therefore increasingly used in the field of small semiconductor devices such as chip size.

[0003] Such semiconductor devices are mainly manufactured through a manufacturing process in which metal parts that will become semiconductor element mounting parts and electrode parts are formed on a conductive mother substrate by plating (electroforming) in a desired number of semiconductor devices at once, the front side of the metal parts that have been subjected to processing such as mounting of semiconductor elements and electrical connection between the semiconductor elements and the electrode parts is sealed with a sealant, and then only the mother substrate is removed and the many integrated semiconductor devices are cut into individual pieces. Examples of manufacturing methods for such semiconductor devices are disclosed in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-9196 A [Patent Document 2] JP 2004-214265 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional method for manufacturing a semiconductor device, as shown in the above-mentioned patent document, when forming metal parts on a mother substrate, a resist layer is formed in advance on the parts of the mother substrate where the metal parts are not to be arranged, so that the metal parts are formed in appropriate positions by electrolytic plating. Metals such as nickel, which are suitable for formation by plating, are used for the metal parts. Then, after dissolving and removing the resist layer with a solvent or the like, the mother substrate and the metal parts formed on its surface are supplied as a substrate for a semiconductor device. Using this substrate for a semiconductor device, mounting of semiconductor elements, wiring, sealing with a sealing material, etc. are performed in the actual manufacturing process of the semiconductor device.

[0006] The present invention has been made to solve the above problems, and has an object to provide a substrate for a semiconductor device that enables further miniaturization of the semiconductor device and increases the formation density of the semiconductor device, and a semiconductor device using this substrate for a semiconductor device.

[0007] However, in conventional processes, it is difficult to strictly control the amount of protrusion of the protruding parts on the upper part of the metal part, so that the distance between the protruding parts is not so narrow that it would hinder subsequent removal of the resist layer, and as a result, it is necessary to arrange the metal parts at wider intervals. This makes it difficult to further miniaturize the semiconductor device and to improve production efficiency by increasing the formation density of the semiconductor device on the semiconductor device substrate.

[0008] The present invention has been made to solve the above problems, and has an object to provide a substrate for a semiconductor device that enables further miniaturization of the semiconductor device and increases the formation density of the semiconductor device, and a semiconductor device using this substrate for a semiconductor device. [Means for solving the problem]

[0009] The substrate for a semiconductor device according to the present invention comprises a metal part 11 which becomes a semiconductor element mounting part 11a and / or an electrode part 11b on a mother substrate 10. A protruding part 11c is formed on the metal part 11. The protruding part 11c has a lower surface which is parallel to a direction perpendicular to the axial direction of the metal part 11, an upper surface which is formed continuously with the upper surface of the metal part 11, and a side surface which is formed between the lower surface and the upper surface.

[0010] Moreover, the side surface of the overhanging portion 11c is parallel to the axial direction of the metal portion 11. Moreover, the height dimension of the overhanging portion 11c is the same as or greater than the width dimension of the overhanging portion 11c.

[0011] A surface metal layer 13 is formed on the upper surface of the metal portion 11 and on the upper surface of the protruding portion 11c, and the thickness of the surface metal layer 13 appears as the side surface of the protruding portion 11c.

[0012] Furthermore, the metal part 11 is formed with the protruding part 11c and / or the protruding part 11c', and this protruding part 11c' has a lower surface parallel to a direction perpendicular to the axial direction of the metal part 11, and an upper surface formed continuous with the upper surface of the metal part 11. In this way, the metal part 11 is formed with the protruding part 11c having a side surface and / or the protruding part 11c' not having a side surface, resulting in a configuration in which different protruding parts are mixed.

[0013] The present invention also relates to a method for manufacturing a substrate for a semiconductor device having a metal portion 11 which becomes a semiconductor element mounting portion 11a and / or an electrode portion 11b on a mother substrate 10, the method comprising the steps of forming a first resist layer 12 of a predetermined pattern for forming the metal portion 11 on the mother substrate 10, forming a second resist layer 16 of a predetermined pattern on the first resist layer 12, and forming the metal portion 11 in an exposed area of ​​the mother substrate 10 which is not covered by the first resist layer 12, wherein in the step of forming the metal portion 11, the metal portion 11 is formed to a predetermined thickness which exceeds the thickness of the first resist layer 12 but does not exceed the thickness of the second resist layer 16, and which includes a portion which contacts the side of the second resist layer 16, thereby forming a protrusion portion 11c in the metal portion 11.

[0014] The second resist layer 16 is formed so that the inner surfaces of the openings of the predetermined pattern are parallel to a direction perpendicular to the surface direction of the mother substrate 10. Here, "the inner surfaces of the openings of the predetermined pattern of the second resist layer 16 are perpendicular to the surface direction of the mother substrate 10" means that when a straight line (imaginary line) is drawn from the inner surfaces of the openings of the predetermined pattern of the second resist layer 16 toward the surface of the mother substrate 10, it intersects at a right angle.

[0015] Furthermore, a step portion 20 is formed between the inner surface of the opening of the predetermined pattern in the first resist layer 12 and the inner surface of the opening of the predetermined pattern in the second resist layer 16, and the width dimension of the step portion 20 is set to 5 μm or more. Note that there may be a portion where this step portion 20 is not formed, that is, there may be a region where the second resist layer 16 is not formed on the first resist layer 12, and thus, in the step of forming the metal portion 11, the metal layer 11 is formed to a thickness exceeding that of the first resist layer 12, thereby forming a protruding portion 11c' in the metal portion 11.

[0016] The present invention also relates to a semiconductor device comprising a semiconductor element 14 and a metal part 11 which becomes a semiconductor element mounting portion 11a and / or an electrode portion 11b, in which a protrusion 11c is formed in the metal part 11, in which the semiconductor element 14 is mounted on and electrically connected to the metal part 11, and which is sealed with a sealing material 19, and in which the protrusion 11c has a lower surface which is parallel to a direction perpendicular to the axial direction of the metal part 11, an upper surface which is formed continuously with the upper surface of the metal part 11, and a side surface which is formed between the lower surface and the upper surface. Effect of the Invention

[0017] According to the present invention, the adjacent protruding portions 11c can be adjusted to a preset appropriate interval while ensuring the minimum amount of protrusion required for providing the protruding portions 11c with sufficient strength against coming off the sealing material, so that the arrangement interval of the metal portions 11 on the mother substrate 10 can be made smaller than in the past, the semiconductor device formed on the substrate 1 for semiconductor device can be further miniaturized, and the formation density of the semiconductor devices on the substrate 1 for semiconductor device can be increased, thereby making the manufacture of semiconductor devices more efficient. Moreover, the protruding portions 11c can be easily obtained by forming the first resist layer 12 and the second resist layer 16 into the desired shapes. [Brief description of the drawings]

[0018] [Figure 1] 1 is a partially enlarged view of a substrate for a semiconductor device according to a first embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of a substrate for a semiconductor device according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is an explanatory view of a metal portion in the substrate for the semiconductor device according to the first embodiment of the present invention. [Figure 4] FIG. 1 is an explanatory diagram of a semiconductor device according to a first embodiment of the present invention. [Diagram 5] 1A to 1C are diagrams illustrating steps in a method for manufacturing a substrate for a semiconductor device according to a first embodiment of the present invention. [Figure 6] 1A to 1C are diagrams illustrating steps in a method for manufacturing a substrate for a semiconductor device according to a first embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory view of a state of a metal part in the substrate for the semiconductor device according to the first embodiment of the present invention. [Figure 8] 1A to 1C are diagrams illustrating steps in a method for manufacturing a semiconductor device according to a first embodiment of the present invention. [Figure 9] 11 is an explanatory diagram of a metal portion in a substrate for a semiconductor device according to another embodiment of the present invention. [Figure 10] 11 is an explanatory diagram of a semiconductor device according to another embodiment of the present invention. [Figure 11]10A to 10C are explanatory views of steps in a method for manufacturing a substrate for a semiconductor device according to another embodiment of the present invention. [Figure 12] 11 is an explanatory diagram of a substrate for a semiconductor device according to another embodiment of the present invention. FIG. [Figure 13] FIG. 1 is a cross-sectional view showing a conventional substrate for a semiconductor device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (First embodiment) A substrate for a semiconductor device according to a first embodiment of the present invention will be described below with reference to Figures 1 to 3. As shown in the figures, the substrate for a semiconductor device 1 according to this embodiment includes a mother substrate 10 made of a conductive material, and a plurality of metal parts 11 formed on the mother substrate 10 and serving as semiconductor element mounting parts 11a or electrode parts 11b of a semiconductor device 70 manufactured using the substrate for a semiconductor device 1. A surface metal layer 13 is formed on the surface of the metal parts 11 by plating.

[0020] Fig. 2 shows a schematic configuration of a substrate for a semiconductor device, and Fig. 3 shows a schematic configuration of metal part 11, where Fig. 3(A) is a top view, Fig. 3(B) is a cross-sectional view, Fig. 3(C) is a bottom view, and Fig. 3(D) is a perspective view. As shown in Fig. 3, metal part 11 has a protruding part 11c on its periphery, preferably on its upper end periphery, and this protruding part 11c has a lower surface A parallel to a direction perpendicular to the axial direction of metal part 11, an upper surface C formed continuously with upper surface D of metal part 11, and a side surface B formed between the lower surface and the upper surface. Metal part 11 and protruding part 11c are formed in a circular shape when viewed from above. In addition, in Figure 3, a line is drawn at the boundary between the upper surface D of metal part 11 and the upper surface C of protrusion part 11c. This is to clearly show the area of ​​upper surface D of metal part 11 and upper surface C of protrusion part 11c. In reality, upper surface D of metal part 11 and upper surface C of protrusion part 11c are continuous surfaces with no border.

[0021] Moreover, the upper surface C of the overhanging portion 11c is a curved surface. Specifically, the upper surface C of the overhanging portion 11c is a curved surface that is continuously formed from the upper surface D of the metal portion 11 to the side surface B of the overhanging portion 11c. Note that the surfaces of the metal portion 11 (upper surface D, side surface, lower surface) and the surfaces of the overhanging portion 11c (upper surface C, side surface B, lower surface A) may be convex or concave.

[0022] Here, the dimensions of the metal portion 11 (semiconductor element mounting portion 11a, electrode portion 11b) and the overhanging portion 11c will be described. As shown in FIG. 3B, the width dimension W1 of the metal portion 11 is preferably 50 μm or more, the height dimension H1 of the metal portion 11 is preferably 20 to 100 μm, the width dimension W2 of the overhanging portion 11c is preferably 5 μm or more, and the height (thickness) dimension H2 of the overhanging portion 11c is preferably in the range of 5 to 50 μm. In addition, the width dimension (overhang length) W2 of the overhanging portion 11c and the height dimension H2 of the overhanging portion 11c preferably satisfy the relationship W2≦H2. This allows the arrangement interval of the metal portion 11 to be reduced while ensuring the strength of the overhanging portion 11c. The outer dimensions of the metal portion 11 and the overhanging portion 11c can be easily set by forming the first resist layer 12 and the second resist layer 16 described later into the desired shapes. In this embodiment, the width dimension W1 of the semiconductor element mounting portion 11a of the metal portion 11 is set to 500 μm, the width dimension W1 of the electrode portion 11b is set to 250 μm, the height dimension H1 of the metal portion 11 is set to 70 μm, the width dimension W2 of the protrusion portion 11c is set to 20 μm, and the height (thickness) dimension H2 of the protrusion portion 11c is set to 30 μm.

[0023] A semiconductor device 70 manufactured using such a substrate 1 for a semiconductor device is configured to include, in addition to the metal portion 11 and surface metal layer 13 obtained from the substrate 1 for a semiconductor device, a semiconductor element 14 mounted on the semiconductor element mounting portion 11a of the metal portion 11, a wire 15 electrically connecting the semiconductor element 14 to the electrode portion 11b of the metal portion 11, and a sealing material 19 covering and sealing the surface side of the metal portion 11 including the semiconductor element 14 and the wire 15, as shown in FIG.

[0024] In this semiconductor device 70, the back surface of the metal portion 11 is exposed from the sealing material 19 at the bottom as an electrode, a heat dissipation pad, or the like (see FIG. 4(B)). The exposed back surface of the metal portion 11 and the back surface of the sealing material 19 that appears as part of the exterior of the device are positioned on approximately the same plane. On each surface of the semiconductor device 70 other than the bottom, only the sealing material 19 that constitutes the exterior of the device is exposed. However, this is not limited to this, and a part of the metal portion 11 (a side portion of the metal portion 11) may be exposed on each surface of the semiconductor device 70 other than the top (front, back, left and right side surfaces, bottom surface).

[0025] The substrate 1 for semiconductor device is manufactured by forming a first resist layer 12 corresponding to the non-arrangement portion of the metal portion 11 on the mother substrate 10, forming a second resist layer 16 for adjusting and controlling the shape of the upper portion of the metal portion 11 (the amount of overhang of the overhang portion 11c), and then forming the metal portion 11 by plating, and removing the first resist layer 12 and the second resist layer 16. The surface metal layer 13 can be formed by plating the surface of the metal portion 11 including the surface of the overhang portion 11c following the formation of the metal portion 11. Here, by forming the surface metal layer 13 on the upper surface C of the overhang portion 11, the thickness of the surface metal layer 13 appears on the side surface B of the overhang portion 11c, but the surface metal layer 13 may be formed on the entire side surface B of the overhang portion 11c. This makes it possible to further expand the area having excellent bonding properties with the wire 15 while ensuring the strength of the overhang portion 11c and the arrangement interval of the metal portion 11. Furthermore, if the surface metal layer 13 is formed on the entire side surface B of the overhanging portion 11c, the thickness of the surface metal layer 13 will appear on the undersurface A of the overhanging portion 11c. In this manner, the surface metal layer 13 may be formed not only on the upper surface C of the overhanging portion 11, but also on a part of or the entire surface of the side surface B and the undersurface A of the overhanging portion 11.

[0026] Furthermore, when manufacturing a semiconductor device using this substrate for semiconductor device 1, the semiconductor element 14 is mounted and wired on the surface side of the metal part 11 of the substrate for semiconductor device 1, and then the substrate for semiconductor device 1 is sealed with a sealing material 19, and the mother substrate 10 is removed from the semiconductor device part (the part sealed with the sealing material) to obtain the semiconductor device 70.

[0027] The mother substrate 10 is formed of a conductive metal plate of stainless steel (e.g., SUS430), aluminum, copper, etc., having a thickness of about 0.1 mm, and constitutes a main part of the substrate 1 for a semiconductor device until it is removed in the manufacturing process of the semiconductor device. At each stage of the manufacturing process of the substrate for a semiconductor device, a first resist layer 12, a second resist layer 16, and a metal part 11 are formed on the front side, and a resist layer 18 is disposed on the back side. When forming the metal part 11, electricity is passed through the mother substrate 10, and the metal part 11 is formed by electrolytic plating on the part of the front surface of the mother substrate 10 that is not covered by the first resist layer 12 and the second resist layer 16 and can be electrically conducted. When the front metal layer 13 is also formed by electrolytic plating, electricity is passed through the mother substrate 10.

[0028] The metal parts 11 are made of nickel or copper suitable for electrolytic plating, or a nickel alloy such as nickel-cobalt, and are formed by electrolytic plating in the parts of the mother substrate 10 that do not have the first resist layer 12. In the substrate 1 for semiconductor device, the metal parts 11 are formed on the surface of the mother substrate 10 in a form in which a combination of a semiconductor element mounting part 11a and an electrode part 11b arranged in the vicinity thereof is regarded as one unit, and a large number of such combinations are arranged in an aligned state in the number of semiconductor devices to be manufactured.

[0029] The metal portion 11 is formed to a thickness (for example, about 20 to 100 μm) that exceeds the thickness of the first resist layer 12, and has a shape having a generally eaves-shaped protruding portion 11c protruding toward the second resist layer 16 at the upper end periphery. The protruding portion 11c is obtained as a shape protruding from the upper end of the metal portion 11 beyond the first resist layer 12 to the second resist layer 16 side by continuing the electrolytic plating even after the metal portion 11 is formed to the thickness of the first resist layer 12, so that the growth of the metal portion 11 progresses not only in the thickness direction (the axial direction of the metal portion 11) but also in the direction toward the second resist layer 16 (the direction perpendicular to the axial direction of the metal portion 11). Here, the growth of the metal portion 11 toward the second resist layer 16 by electrolytic plating can be restricted from growing further in this direction due to the presence of the second resist layer 16, and the interval between the metal portions 11 can be made constant. It should be noted that as the sealing is performed with the sealing material 19, the protruding portion 11c is sandwiched and fixed by the sealing material 19.

[0030] In addition, the semiconductor element mounting portion 11a of the metal portion 11 can be provided with a recess into which the semiconductor element 14 can be inserted and mounted during the manufacture of the semiconductor device. When the semiconductor element 14 is inserted and disposed in this recess, the position of the semiconductor element 14 can be lowered by the depth of the recess compared to the conventional case where the semiconductor element 14 is mounted on the upper surface of the semiconductor element mounting portion. The recess is deep enough to ensure a thickness below the recess that maintains the necessary strength of the semiconductor element mounting portion 11a. In addition, a recess can also be provided in the electrode portion 11b. When the sealing material 19 is sealed in this recess, the upper surface of the electrode portion and the sealing material of the semiconductor device come into contact widely by the recess, improving the support strength of the electrode portion in the semiconductor device and increasing durability. In addition, when a structure is adopted in which the electrode portion is exposed not only to the bottom but also to the side due to the need for mounting the semiconductor device, a recess is provided in the electrode portion 11b and the recess is cut and separated, so that the cutting position is lowered by the depth of the recess, and the amount of metal cut in the cutting process can be reduced, reducing the load on the cutting device associated with the cutting and suppressing deterioration of the blade portion. The shape of the recess is not limited to a bottomed shape, and may be a through-hole shape.

[0031] Most of the metal part 11 is made of nickel or a nickel alloy suitable for electrolytic plating, but the back side of the metal part 11 is provided with a thin film 11d of a metal having better solder wettability than the main material part such as nickel, for example, gold, tin, palladium, solder, etc., in order to allow appropriate soldering during mounting of the semiconductor device (see FIG. 6(B)). The thickness of this thin film 11d is preferably about 0.01 to 1 μm. In addition, the thin film 11d can also be given a function of preventing the metal part 11 from being corroded and deteriorated by an etching solution when the mother substrate 10 is etched away, and in this case, it is preferable to provide a thin film of gold, silver, tin, etc. The formation of the thin film on the back side of the metal part 11 is not limited to before forming the main material part of the metal part 11 by electrolytic plating, but may be formed on the exposed back side of the metal part 11 by plating after the semiconductor device 70 is completed.

[0032] The surface metal layer 13 is formed as a plating film made of a metal, such as gold or silver, that has excellent bonding properties with a gold wire or the like that constitutes the wiring wire 15. The surface metal layer 13 is formed as a plating of a predetermined thickness, for example, about 0.1 to 1 μm in the case of gold plating, and about 1 to 10 μm in the case of silver plating, on the surface of the metal part 11 and the protruding part 11c by a plating bath for each mother substrate 10. When plating the surface metal layer 13, the back side of the mother substrate 10 is covered with a resist layer 18, so that no plating adhesion occurs (see FIG. 6(D)). In this way, by forming the surface metal layer 13 on the upper surface D of the metal part 11 and the upper surface C of the protruding part 11c, the thickness of the surface metal layer 13 appears as the side surface B of the protruding part 11c, so that the surface area of ​​the surface metal layer 13 that has excellent bonding properties with the wire 15 can be increased. When plating the surface metal layer 13, a plating solution corresponding to the metal to be plated is used, for example, a plating solution different from that used for plating the metal portion 11.

[0033] When plating this surface metal layer 13, if the plating is difficult to adhere, it is desirable to first perform a base plating (copper strike plating, silver strike plating, or gold strike plating) on ​​the surface of the metal part 11 before plating the surface metal layer 13, in order to improve the adhesion of the surface metal layer 13 to the metal part 11.

[0034] Next, a method for manufacturing a substrate for a semiconductor device according to this embodiment and a method for manufacturing a semiconductor device using the substrate for a semiconductor device will be described.

[0035] The manufacturing method for a substrate for a semiconductor device can be said to include the steps of forming resist layers 12 and 18 on the front and back of a mother substrate 10, forming a second resist layer 16 on the upper side of the first resist layer 12 in a position where it is desired to suppress the formation of the metal portion 11 formed as the protruding portion 11c, forming the metal portion 11 to a predetermined thickness on the portion of the front surface of the mother substrate 10 that is not covered by the first resist layer 12 and the second resist layer 16, forming a front metal layer 13 on the front surface of the metal portion 11, and removing the first resist layer 12, the second resist layer 16 on the front surface side of the mother substrate 10, and the resist layer 18 on the rear surface side. Each of these steps in manufacturing a substrate for a semiconductor device will be specifically described below.

[0036] First, in order to form the metal parts 11 on the mother substrate 10 by plating, a first resist layer 12 is formed on the mother substrate 10 so as to expose the parts where the metal parts 11 are to be arranged (corresponding to the parts where the metal parts 11 are not arranged). Specifically, a photosensitive resist 12a is formed on the front side of the mother substrate 10 so as to have a predetermined thickness (for example, about 50 μm) corresponding to the metal parts 11 to be formed (see FIG. 5(A)). The photosensitive resist 12a is subjected to processes such as curing by exposure to ultraviolet light and development to remove the resist from the non-irradiated parts while a mask film of a predetermined pattern corresponding to the arrangement positions of the metal parts 11 is placed on the photosensitive resist 12a, thereby forming a first resist layer 12 having an opening pattern corresponding to the parts where the metal parts 11 are not arranged (see FIG. 5(B)). In addition, a photosensitive resist is also formed on the back side of the mother substrate 10 in the same manner as on the front side, and a resist layer 18 is formed over the entire back side through a process such as exposure to light.

[0037] In the process of forming the second resist layer 16, the second resist layer 16 is disposed on the first resist layer 12 formed initially, corresponding to the area where the formation of the metal portion 11 is to be suppressed. Specifically, a photosensitive resist 16a is disposed in close contact with the front surface side of the mother substrate 10 and the first resist layer 12 so as to have a predetermined thickness (for example, about 40 μm) (see FIG. 5(C)). With a mask film of a predetermined pattern corresponding to the position where the formation of the protruding portion 11c is to be suppressed placed on this photosensitive resist 16a, the photosensitive resist 16a is cured by exposure to ultraviolet light, and developed to remove the resist agent in the non-irradiated portion, to form the second resist layer 16 having an opening pattern corresponding to the area where the metal portion 11 is not to be formed (see FIG. 6(A)). The presence of this second resist layer 16 makes it possible to regulate the amount of protrusion of the protruding portion 11c when the metal portion 11 is formed by plating. A step portion 20 is formed between the inner surface of the opening of the predetermined pattern in the first resist layer 12 and the inner surface of the opening of the predetermined pattern in the second resist layer 16 (see FIG. 6(A)), and the desired amount of protrusion can be achieved by setting the width dimension of this step portion 20. The width dimension of the step portion 20 is preferably 5 μm or more, and is set to 20 μm in this embodiment. If the width dimension of the step portion 20 is less than 5 μm, the amount of protrusion is insufficient, making it difficult to obtain the effect of the protrusion portion 11c.

[0038] After the second resist layer 16 is formed, the exposed areas of the surface of the mother substrate 10 that are not covered with the first resist layer 12 and the second resist layer 16 are subjected to a plating pretreatment (acid immersion, cathodic electrolysis, chemical etching, strike plating, etc.). Then, a gold thin film 11d for improving solder wettability is formed on the exposed areas by plating or the like to a thickness of, for example, 0.01 to 1 μm (see FIG. 6(B)). Then, nickel is laminated on the thin film 11d by electrolytic plating to form the metal portion 11 (see FIG. 6(C)).

[0039] In the process of forming the metal portion 11, the metal portion 11 is formed to a predetermined thickness (for example, about 60 μm) that exceeds the thickness of the first resist layer 12 but does not exceed the upper surface of the second resist layer 16, and a substantially eaves-shaped protruding portion 11c that protrudes toward the first resist layer 12 side is formed at the upper end periphery of the metal portion 11 near the first resist layer 12, with a portion that contacts the side surface of the second resist layer 16 (see FIG. 6(C)). The formation range of the protruding portion 11c is restricted by the second resist layer 16 that is arranged so that the metal portion 11 is not formed, so that the protruding amount of the protruding portion 11c is set in advance. In addition, the metal portion 11 is formed in a form in which a combination of a semiconductor element mounting portion 11a and a plurality of electrode portions 11b arranged in the vicinity thereof is regarded as one unit on the surface of the mother substrate 10, and a large number of the combinations are arranged in an aligned state in the number of semiconductor devices to be manufactured.

[0040] After the metal portion 11 has been formed to a predetermined thickness, a surface metal layer 13 is formed on the surface of the metal portion 11 to a predetermined thickness, for example, about 1 to 10 μm in the case of silver plating (see FIG. 6(D)). The first resist layer 12 and the second resist layer 16 have sufficient resistance to the plating solution used in the plating bath, so they do not deteriorate and maintain their function as resist layers, preventing plating from adhering to non-required areas such as the metal portion 11. During plating of the surface metal layer 13, the back side of the mother substrate 10 is covered with the resist layer 18, so no plating is attached thereto.

[0041] After the formation of the front surface metal layer 13, the first resist layer 12, the second resist layer 16 on the front surface side of the mother substrate 10, and the resist layer 18 on the back surface side are each dissolved and removed with a prescribed remover, thereby completing the substrate 1 for the semiconductor device shown in Figure 2.

[0042] In this way, the metal portion 11 is formed beyond the thickness of the first resist layer 12, and therefore a generally eaves-shaped overhanging portion 11c overhanging the first resist layer 12 side is formed at the upper end periphery of the metal portion 11 near the first resist layer 12 (see FIG. 6(C)). At this time, since the second resist layer 16 is disposed on the first resist layer 12, the overhanging portion 11c is formed with a portion contacting the side surface of the second resist layer 16, with its formation range being restricted by the second resist layer 16. As a result, the overhanging amount of the overhanging portion 11c is controlled to a predetermined amount based on the arrangement of the second resist layer 16 that is set in advance. In this case, since each of the adjacent metal portions 11 on the mother substrate 10 has the overhanging portion 11c at the top, and these overhanging portions 11c can be adjusted to a state in which they are spaced apart from each other at a predetermined appropriate interval, the arrangement interval of the metal portions on the mother substrate 10 can be made smaller than in the past. That is, in the conventional process, since the amount of overhang of the overhanging portion of the metal portion cannot be strictly controlled, it was necessary to arrange the metal portions 11 at a wide interval so that the interval between the overhanging portions would not become too narrow to prevent the subsequent removal of the resist, whereas in this embodiment, since the amount of overhang of the overhanging portion 11c can be adjusted by the arrangement of the second resist layer 16, even if the arrangement interval of the metal portions 11 is narrowed, the amount of overhang of the overhanging portion 11c can be suppressed to an extent that the resist can be removed without problems, and the minimum interval between adjacent metal portions 11 can be made an appropriate amount. Also, by adjusting the amount of overhang of the overhanging portion in the metal portion 11 that is opposed to the side surface of the semiconductor device (sealing material 19), it is possible to prevent the metal portion 11 from protruding from the sealing material 19. The intervals between the metal parts 11 can be made small within a range that ensures the minimum amount of overhang required for the overhanging parts 11c to have sufficient strength against coming off, and maintains a state in which the remover for the first resist layer 12 can reach between the metal parts 11 and properly remove the first resist layer 12 (see FIG. 7). By making the side surface B of the overhanging parts 11c parallel to the axial direction of the metal parts 11, the intervals between the metal parts 11 can be made more accurate and appropriate. This makes it possible to further miniaturize the semiconductor device formed on the substrate 1 for semiconductor device, and to increase the formation density of the semiconductor devices on the substrate 1 for semiconductor device, thereby making it possible to efficiently manufacture the semiconductor devices.

[0043] Furthermore, by forming the second resist layer 16 following the step of forming the first resist layer 12 on the mother substrate 10, and then forming the metal portion 11, it is possible to control the formation range of the metal portion 11 (projecting portion 11c) that reaches the upper side of the first resist layer 12, and also to form the resist layers 12 and 16 together in advance and form the metal portion 11 in one step (one plating), thereby improving production efficiency. In the above explanation, when forming the first resist layer 12 and the second resist layer 16, the first resist layer 12 is formed and then the second resist layer 16 is formed, but in the step of forming the first resist layer 12, after the photosensitive resist 12a is exposed to light in a predetermined pattern, the photosensitive resist 16a may be formed on the photosensitive resist 12a without developing it, and after the photosensitive resist 16a is exposed to light in a predetermined pattern, the photosensitive resist 12a and the photosensitive resist 16a (unexposed portion) may be developed together. In this case, the photosensitive resist 16a (second resist layer 16) is formed on the photosensitive resist 12a formed on one side of the mother substrate 10, so that the photosensitive resist 16a can be easily formed and the development process can be completed in one step. Furthermore, the photosensitive resist 12a and the photosensitive resist 16a can be formed using resists having different exposure sensitivities. For example, if the photosensitive resist 12a and the photosensitive resist 16a having a lower exposure sensitivity than the photosensitive resist 12a are laminated in order on the mother substrate 10, the state in which the second resist layer 16 is formed on the first resist layer 12 as shown in FIG. 6(A) can be obtained by one exposure and development process. Furthermore, the exposure of the photosensitive resist 12a and the photosensitive resist 16a is performed using a mask having a predetermined pattern formed thereon, but direct exposure may also be performed using a direct writing exposure device.

[0044] Next, a method for manufacturing a semiconductor device using the obtained substrate 1 for a semiconductor device will be described. First, a semiconductor element 14 is mounted on the semiconductor element mounting portion 11a of the metal portion 11 in the substrate 1 for a semiconductor device with an adhesive interposed therebetween, and is adhered and fixed. Furthermore, the electrodes on the surface of the semiconductor element 14 are joined to the corresponding electrode portions 11b by wires 15 such as gold wires, and the semiconductor element 14 and each electrode portion 11b are electrically connected (see FIG. 8(A)). This electrical connection by wiring is performed by an ultrasonic bonding device or the like. Since the surface metal layer 13 is formed on the surface of the electrode portion 11b, the joining with the wire 15 can be ensured, and the reliability of the connection can be improved. This semiconductor element 14 is a so-called chip on which a fine electronic circuit is formed. The adhesive may be solid, viscous, or liquid, and examples of the adhesive include silver paste, resin paste, and die attach film. Although the electrical connection between the semiconductor element 14 and the electrode portion 11b is performed by wire bonding, it may also be performed by flip chip.

[0045] After the connection between the semiconductor element 14 and each electrode portion 11b is completed, the area on the front side of the mother substrate 10 that will become the semiconductor device, including the metal portion 11, etc., is sealed with a sealant 19 such as a thermosetting epoxy resin having high physical strength, and the semiconductor element 14 and the wires 15 are isolated from the outside and protected (see FIG. 8(B)). In detail, the front side of the mother substrate 10 is attached to a mold die that will become the upper die, and the mother substrate 10 plays the role of the lower die, and the sealing is performed in the process of pressing the epoxy resin before hardening that will become the sealant 19 into the mold die, and on the mother substrate 10, a large number of combinations of the semiconductor element mounting portion 11a and the multiple electrode portions 11b that will become one semiconductor device are uniformly sealed while remaining in an aligned state, and a large number of semiconductor devices appear in a connected state. When the semiconductor element 14 is a light-emitting element such as an LED, a light-transmitting material is used.

[0046] Once a large number of connected semiconductor devices have been obtained, the mother substrate 10 is removed, leaving the back side of the metal part 11 exposed at the bottom of each semiconductor device (see FIG. 8(C)). The mother substrate 10, which is made of stainless steel, is removed by physically peeling it off from the semiconductor device. By using stainless steel, which has excellent strength and peelability, as the mother substrate 10, it can be peeled off from the semiconductor device and quickly separated and removed. At this time, by making the sealing material 19 have sufficient physical strength, even when the mother substrate 10 is peeled off and removed, it can maintain its integrated state with the metal part 11 without any damage such as cracks.

[0047] Alternatively, when the mother substrate 10 is made of another metal material, such as a copper material, the mother substrate 10 can be removed by immersing it in an etching solution and dissolving it. In this etching, an etching solution is used that has selective etching properties such that the mother substrate 10 dissolves but the material of the metal portion 11 and the surface metal layer 13 is not damaged. When removing by dissolution, no excessive force is applied to the semiconductor device, so that the probability of adverse effects occurring due to removal of the mother substrate 10 can be reduced.

[0048] At the bottom of the semiconductor device after the mother substrate 10 has been removed, the back side of the exposed metal portion 11 and the back side of the sealing material 19 are positioned on approximately the same plane. After removing the mother substrate 10, the multiple connected semiconductor devices are separated one by one to complete the semiconductor device 70.

[0049] Inside the obtained semiconductor device 70, the upper peripheral edge of metal portion 11 is formed as protrusion 11c that protrudes in a roughly eave-like shape, and when sealed with sealing material 19, this protrusion 11c is surrounded and fixed by the hardened sealing material 19. Therefore, protrusion 11c bites into sealing material 19, which is firmly integrated with the resins adhered to each other, and acts as a resistor against external forces applied to metal portion 11. Even if an external force is applied to the back side of metal portion 11 to separate it from the exterior of the device, such as when stainless steel or the like is used for mother substrate 10 and mother substrate 10 is physically peeled off and removed from the semiconductor device side, protrusion 11c prevents movement of metal portion 11 and prevents misalignment of metal portion 11 with respect to other portions. This improves the yield during manufacturing and increases the strength of the semiconductor device, thereby improving its durability during use and the reliability of the operation of the semiconductor device.

[0050] The first resist layer 12, the second resist layer 16, and the resist layer 18 are formed of an insulating material that is resistant to dissolution in the plating solution used in plating the metal portion 11 and the surface metal layer 13. The first resist layer 12, the second resist layer 16, and the resist layer 18 can be formed, for example, by disposing an alkali-developable photosensitive film resist by thermocompression bonding or the like, and then performing various processes such as exposure and development. The first resist layer 12, the second resist layer 16, and the resist layer 18 are not limited to the above-mentioned photosensitive resist, and can also be formed by applying a paint that is not altered by the plating solution and can provide a coating film with high strength to a required coating thickness by electrochemical coating or the like on the non-arrangement portion of the metal portion 11 on the mother substrate 10 and a position where the formation of the protruding portion 11c is to be restricted.

[0051] In the above embodiment, the metal part 11 is cylindrical, but it may be a square prism as shown in FIG. 9 or a triangular prism. The outer shape of the lower part of the metal part 11 (the part formed within the thickness of the first resist layer 12) may be different from the outer shape of the upper part and the protruding part 11c of the metal part 11 (the part formed within the thickness of the second resist layer 16). For example, the lower part of the metal part 11 may be formed in a square prism shape, and the upper part and the protruding part 11c of the metal part 11 may be formed in a cylindrical shape. Such a shape can be obtained by forming the opening pattern in the first resist layer 12 in a square shape and the opening pattern in the second resist layer 16 in a circular shape. In this way, the shapes of the metal part 11 and the protruding part 11c can be freely set by forming the opening patterns of the first resist layer 12 and the second resist layer 16 in the desired shapes.

[0052] Also, the second resist layer 16 formed on the first resist layer 12 may be formed partially in order to restrict the amount of overhang of the overhanging portion 11c. This is because it is required to secure as large an area as possible for the surface of the metal portion 11 (semiconductor element mounting portion 11a) in order to prevent the adhesive (paste) used when mounting the semiconductor element 14 on the metal portion 11 (semiconductor element mounting portion 11a) from dropping off the surface of the metal portion 11 (semiconductor element mounting portion 11a), but since the shape and dimensions of the semiconductor device and the position, shape and dimensions of the back surface of the metal portion 11 exposed from the bottom of the semiconductor device (the back surface of the sealing material 19) as an external electrode or heat dissipation pad are determined as specifications, if the shape and dimensions of the front surface of the metal portion 11 are made the same as the shape and dimensions of the back surface of the metal portion 11, the surface area of ​​the metal portion 11 will be small. Therefore, by adopting a configuration in which some overhanging portions have side surface B and others do not, specifically, a configuration in which only overhanging portion 11c that faces the side surface of the semiconductor device (sealing material 19) has side surface B as shown in Fig. 10, a large surface area of ​​metal portion 11 can be ensured. Such a configuration is achieved by partially forming second resist layer 16, that is, in metal portion 11c, the amount of overhang of overhang portion 11c is restricted on the side facing the side surface of the semiconductor device (sealing material 19), and the amount of overhang of overhang portion 11c is not restricted on the side adjacent to metal portion 11. Hereinafter, a method for manufacturing a substrate for a semiconductor device having such a configuration will be described with reference to Fig. 11.

[0053] First, a photosensitive resist 12a is formed on the front side of the mother substrate 10, and the photosensitive resist 12a is exposed, developed, and the like to form a first resist layer 12. Then, a photosensitive resist 16a is formed on the front side of the mother substrate 10 and the first resist layer 12. A resist layer 18 is also formed on the rear side of the mother substrate 10. The steps up to this point are the same as those in the above embodiment (see FIG. 5), so a detailed description is omitted. The photosensitive resist 12a is formed to a thickness of 20 to 40 μm (25 μm in this case), and the photosensitive resist 16a is formed to a thickness of 30 to 80 μm (45 μm in this case). Next, with a mask film of a predetermined pattern corresponding to the position where the formation of the protruding portion 11c is to be suppressed placed on the photosensitive resist 16a, the photosensitive resist 16a is subjected to processes such as curing by exposure to ultraviolet light irradiation and development to remove the resist in the non-irradiated portion, thereby forming a second resist layer 16 having an opening pattern corresponding to the position where the metal portion 11 is not to be formed (see FIG. 11(A)). The presence of this second resist layer 16 makes it possible to regulate the amount of protrusion of the protruding portion 11c when the metal portion 11 is formed by plating, and here, the second resist layer 16 is formed at a position facing the side surface of the semiconductor device (sealant 19). A step portion 20 is formed between the inner surface of the opening of the predetermined pattern in the first resist layer 12 and the inner surface of the opening of the predetermined pattern in the second resist layer 16, and the width dimension of this step portion 20 is the amount of protrusion of the protruding portion 11c, and the width dimension of the step portion 20 is preferably 5 μm or more.

[0054] After the second resist layer 16 is formed, a plating pretreatment (acid immersion, cathodic electrolysis, chemical etching, strike plating, etc.) is performed on the exposed area of ​​the surface of the mother substrate 10 that is not covered with the first resist layer 12 and the second resist layer 16, and then a thin film 11d and a metal portion 11 are laminated and formed on the exposed area (see FIG. 11(B)). Here, the thin film 11d is formed by plating gold to a thickness of 0.01 to 1 μm, and the metal portion 11 is formed by plating nickel to a thickness of 50 to 100 μm on the thin film 11d. At this time, the metal portion 11 is formed to a thickness exceeding the thickness of the first resist layer 12, and in the area where the second resist layer 16 is formed, it is formed to a predetermined thickness (here, 60 μm) that does not exceed the upper surface of the second resist layer 16, and a substantially eaves-like protruding portion 11c that protrudes toward the first resist layer 12 side is formed on the periphery of the upper end of the metal portion 11 close to the first resist layer 12, with a portion that contacts the side surface of the second resist layer 16. The shape of the protrusion differs between the area where the second resist layer 16 is formed and the area where it is not formed. A characteristic feature is that in the area where the second resist layer 16 is formed, a protrusion 11c having a side surface B is formed, while in the area where the second resist layer 16 is not formed, a protrusion 11c' not having a side surface B is formed.

[0055] After forming the metal portion 11, a surface metal layer 13 is formed on the surface of the metal portion 11 (see FIG. 11(C)). Here, the surface metal layer 13 is formed by plating silver to a thickness of 1 to 10 μm. After forming the surface metal layer 13, the first resist layer 12, the second resist layer 16, and the resist layer 18 on the front and back sides of the mother substrate 10 are removed, thereby completing the substrate 1 for a semiconductor device (see FIG. 11(D)).

[0056] Regarding the manufacturing method of a semiconductor device using the substrate 1 for semiconductor device thus obtained, as in the above embodiment (see FIG. 8), a semiconductor element 14 is mounted on the semiconductor element mounting portion 11a, the electrodes of this semiconductor element 14 are joined to the corresponding electrode portions 11b by wires 15 to electrically connect the semiconductor element 14 to the electrode portions 11b, and then the semiconductor device is sealed with a sealing material 19, and the mother substrate 10 is removed and cut out one by one as a semiconductor device, thereby completing the semiconductor device for use. As a result, even if the position, shape and dimensions of the exposed back surface of the metal portion 11 at the bottom of the semiconductor device (back surface of the sealing material 19) are specified as an external electrode or a heat dissipation pad, the surface shape of the metal portion 11 can be freely set, and a large surface area of ​​the metal portion 11 can be ensured.

[0057] The surface area of ​​the metal portion 11 can be increased by reducing the shape (width) of the second resist layer 16 (increasing the width of the step portion 20). However, if the shape (width) of the second resist layer 16 is made too small, it may be difficult to remove the first resist layer 12 formed under the second resist layer 16. Therefore, in consideration of productivity, the manufacturing method shown in FIG. 11 is preferable. In the semiconductor device shown in FIG. 10 and the substrate for semiconductor device shown in FIG. 11(D), the second resist layer 16 is partially formed to restrict the protrusion amount of the protrusion portion 11c on the side facing the side surface of the semiconductor device (sealing material 19). However, as shown in FIG. 12, the protrusion amount of the protrusion portion 11c may be restricted on the side adjacent to the metal portion 11. In this case, by restricting the side adjacent to the metal portion 11 (semiconductor element mounting portion 11a and electrode portion 11b), the arrangement interval of the metal portion 11 can be reduced while the surface area of ​​the metal portion 11 can be increased. [Explanation of symbols]

[0058] 1 Substrate for semiconductor device 10 Motherboard 11 Metal Part 11a Semiconductor element mounting section 11b Electrode part 11c Overhang (first overhang) 11c' Overhang (second overhang) 11d thin film 12 First resist layer 13 Surface metal layer 14 Semiconductor elements 15 Wire 16 Second resist layer 18 Resist layer 19 Encapsulating materials 20 Step 70 Semiconductor Devices

Claims

1. A substrate for a semiconductor device comprising a mother substrate (10) and a plurality of metal portions (11) serving as semiconductor element mounting portions (11a) and / or electrode portions (11b), A protruding portion is formed on the entire upper peripheral edge of the metal portion (11), The area of ​​the upper surface of the metal portion (11), including the protruding portion, is formed to be larger than the area of ​​the rear surface of the metal portion (11) that is in contact with the front surface of the mother substrate (10); The protruding portion is formed to protrude from the metal portion (11) in a direction perpendicular to the axial direction of the metal portion (11), In each of the metal parts (11), the amount of protrusion of the protruding portion at a position other than the side facing the adjacent metal part (11) is the same as the amount of protrusion of the protruding portion at the position other than the side facing the adjacent metal part (11). A substrate for a semiconductor device, which is formed longer than the amount of overhang of the overhanging portion.

2. The metal portion (11) has an upper peripheral edge formed with protruding portions (11c, 11c') having different shapes, The protruding portion (11c) has a lower surface parallel to a direction perpendicular to the axial direction of the metal portion (11), an upper surface formed continuously with the upper surface of the metal portion (11), and a side surface formed between the lower surface and the upper surface, The protruding portion (11c') has a lower surface parallel to a direction perpendicular to the axial direction of the metal portion (11) and an upper surface formed continuously with the upper surface of the metal portion (11), The substrate for a semiconductor device according to claim 1, characterized in that in each of the metal portions (11), the protrusion portion (11c) is formed on the side facing the adjacent metal portion (11), and the protrusion portion (11c') is formed in a position other than the side facing the adjacent metal portion (11).

3. A semiconductor device comprising a semiconductor element (14) and a metal portion (11) serving as a semiconductor element mounting portion (11a) and / or an electrode portion (11b), the semiconductor element (14) and the metal portion (11) are electrically connected to each other, and the semiconductor element (14) and the metal portion (11) are sealed with a sealing material (19), A protruding portion is formed on the entire upper peripheral edge of the metal portion (11), The area of ​​the upper surface of the metal portion (11) including the protruding portion is formed larger than the area of ​​the back surface of the metal portion (11) exposed from the bottom surface of the sealing material (19), The protruding portion is formed to protrude from the metal portion (11) in a direction perpendicular to the axial direction of the metal portion (11), A semiconductor device characterized in that, in each of the metal portions (11), the amount of protrusion of the protrusion portion at a position other than the side facing the adjacent metal portion (11) is formed to be longer than the amount of protrusion of the protrusion portion on the side facing the adjacent metal portion (11).

4. The metal portion (11) has an upper peripheral edge formed with protruding portions (11c, 11c') having different shapes, The protruding portion (11c) has a lower surface parallel to a direction perpendicular to the axial direction of the metal portion (11), an upper surface formed continuously with the upper surface of the metal portion (11), and a side surface formed between the lower surface and the upper surface, The protruding portion (11c') has a lower surface parallel to a direction perpendicular to the axial direction of the metal portion (11) and an upper surface formed continuously with the upper surface of the metal portion (11), The semiconductor device according to claim 3, characterized in that in each of the metal portions (11), the protrusion portion (11c) is formed on the side facing the adjacent metal portion (11), and the protrusion portion (11c') is formed at a position other than the side facing the adjacent metal portion (11).

Images