JP2002009196A - Manufacturing method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method superior in mass production and capable of inexpensively manufacturing a highly precise, small-sized and thin type semiconductor device in the semiconductor device of a leadless surface mounting type. SOLUTION: In the manufacturing method of the semiconductor device, a resist pattern layer performing prescribed patterning is formed on one face side having conduction of a board, a conductive metal is electrodeposited exceeding the thickness of a resist pattern on an exposure face except for the resist pattern layer, after a semiconductor element mounting metal layer 2a and one or more electrode layers 2b making projection parts on the peripheral edges of the upper ends are independently juxtaposed and formed, the resist pattern layer is removed, a semiconductor element S is mounted on the metal layer 2a, and an electrode L on the semiconductor and the electrode layer 2b are electrically connected. After the mounting part of the semiconductor element S is sealed with a resin layer 4, the board is removed, and a resin sealant in which each rear face of the metal layer 2a and the electrode layer 2b is exposed is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device,
In particular, the present invention relates to a method for manufacturing a resin-encapsulated semiconductor device which can be reduced in size and thickness and can be reduced in cost.

[0002]

2. Description of the Related Art As shown in FIG. 10, a conventional semiconductor device, in particular, a semiconductor device sealed with a resin of a leadless surface mounting method is usually mounted on one surface of a printed board 51 made of glass epoxy or ceramic. Semiconductor element 52
And the plurality of connection electrodes 53 formed on the one surface of the printed board 51 are electrically connected by conductive wires 54 and formed on the back surface of the printed board 51 so as to face the connection electrodes 53. Conductor 5 in which the electrode layer 55 to be formed and the connection electrodes 53 are disposed in the through holes 56, respectively.
The semiconductor device 52 is electrically sealed through an epoxy resin 58 or the like.

[0003]

However, in this kind of conventional semiconductor device, in the manufacturing process,
It is necessary to form the connection electrode 53 on one side of the printed board 51 and the electrode layer 55 on the back side in a state where they are accurately aligned on the printed board 51. In addition, it is necessary that the electrode 53 and the electrode layer 55 formed in alignment with each other are electrically connected without misalignment by the through-holes 56, and precision during manufacturing is required. These demands for accuracy, along with the increase in the number of manufacturing steps for forming the through-holes 56 on the printed circuit board 51 and printing the conductors 57, become a bottleneck for reducing the manufacturing cost, and also cause a problem on the printed circuit board 51 during manufacturing. A region for forming a through hole is required between a large number of semiconductor elements arranged adjacent to each other, which limits the number of semiconductor devices that can be formed and formed on one printed circuit board.

In addition, a relatively thick printed circuit board 51
Since the manufacturing method is such that a semiconductor element is mounted thereon and then sealed with a resin, the presence of the printed board 51 itself hinders miniaturization and thinning of the semiconductor device, and the semiconductor element 52
There is also a disadvantage that heat generated at the time of the operation is easily accumulated in the substrate itself and heat radiation is poor.

An object of the present invention has been proposed to solve such a conventional problem.
Another object of the present invention is to provide a manufacturing method capable of producing a small and particularly thin semiconductor device with excellent mass productivity and at low cost.

[0006]

According to the present invention, there is provided a method of manufacturing a semiconductor device for solving the above-mentioned problems, wherein a predetermined patterning is applied to at least one surface of a substrate having conductivity. The step of forming a resist pattern layer and the step of depositing a conductive metal on the exposed surface of the above-mentioned substrate except for the resist pattern layer, thereby forming a metal layer for mounting a semiconductor element and one or more electrode layers on the substrate independently. Forming the resist pattern layer from the substrate, mounting the semiconductor element on the metal layer, and then electrically connecting the electrode on the semiconductor element to the electrode layer. And sealing the semiconductor element mounting portion on the substrate with a resin layer, and removing the substrate to obtain a resin sealing body in which the back surfaces of the metal layer and the electrode layer are exposed. Feature

According to a second aspect of the present invention, in the step of electrodepositing a conductive metal on a substrate, the conductive metal is electrodeposited beyond the thickness of the resist pattern layer, thereby forming a metal layer and an electrode layer. 2. The method for manufacturing a semiconductor device according to claim 1, wherein an overhang portion is formed at a periphery of an upper end portion of the semiconductor device.

According to a third aspect of the present invention, the overhang length of the overhang portion is in the range of 5 to 20 μm.
Or a method for manufacturing a semiconductor device according to item 2.

According to a fourth aspect of the present invention, there is provided a semiconductor device according to the first aspect, wherein the electrodeposition step is performed after activating the surface of the substrate before the electrodeposition of the conductive metal. It is a manufacturing method of an apparatus.

According to a fifth aspect of the present invention, a plurality of pairs of a metal layer and an electrode layer are formed in parallel on a substrate, and a plurality of semiconductor elements mounted on each metal layer and a plurality of elements of each element are formed. After electrically connecting the electrode layers corresponding to the electrodes, sealing the plural sets of element mounting portions with a continuous resin layer, removing the substrate,
The method for manufacturing a semiconductor device according to claim 1, further comprising a step of cutting into individual resin sealing bodies.

[0011]

According to the present invention, a metal layer for mounting a semiconductor element and an electrode layer are simultaneously formed on a substrate by electroforming.
After the semiconductor element is mounted on the metal layer on the surface of the substrate, the electrode on the element is electrically connected to the electrode layer on the substrate, the element mounting portion is sealed with resin, and only the substrate is removed. Because it is manufactured, the core portion formed by electrodeposition can be laminated very well and it can cope with fine arrangement, and there is no need to use expensive printed boards such as glass epoxy or ceramic as components that constitute semiconductor devices. In addition, the material cost can be reduced, and this type of printed circuit board is not required as a component for mounting a semiconductor element to be sealed with a resin, so that the semiconductor device itself can be significantly reduced in size, particularly, thinner. In addition, since a substrate serving as a matrix for forming a metal layer and an electrode layer by an electroforming process is left until a resin sealing process, which is a subsequent process, and then removed, a metal layer in a subsequent process is removed. It also plays a role of protecting the main surface of each of the electrode layers.

Further, in the electroforming step of electrodepositing a conductive metal on the substrate, the conductive metal is electrodeposited in a so-called overhang over the thickness of the resist pattern layer, so that the metal layer and the electrode layer are electrodeposited. Since the overhanging portion is formed at the periphery of the upper end portion, in the resin sealing step after the removal of the resist pattern layer, since each overhanging portion is located in a bite shape with respect to the resin layer, it is peeled off by this biting effect. When the substrate is peeled off from the resin sealing body side by work or the like, the metal layer and the electrode layer do not stick to the substrate side and are securely separated and remain on the resin sealing body side without being separated. The reliability of the semiconductor device can be improved. In addition, due to the unique overhanging shape formed over the entire periphery of the upper end portion of the metal layer and the electrode layer, upward of moisture invading from the back side of the semiconductor device through the boundary between the metal layer, the electrode layer and the resin layer. Can be prevented, and excellent water resistance can be obtained. In this case, the overhang length of the overhang portion is 5 to 2
Overhanging at the time of electrodeposition so as to be within the range of 0 μm improves the reliability of the substrate removal work due to the reliable biting effect between the overhang portion and the resin layer, and also removes the resist pattern layer before resin sealing. During the process, the metal layer and the electrode layer together with the resist pattern do not float or peel off from the substrate.

In the step before electrodeposition of the conductive metal,
Since the electrodeposition step is performed after the so-called activation treatment of the surface of the substrate, the adhesion between the substrate and the metal layer, which is the electrodeposit, and the electrode layer are improved, and the wire after the semiconductor element is mounted on the metal layer In the connection step, the electrode layer does not drop off or float from the substrate side due to ultrasonic vibration on the bonding apparatus side.

A plurality of pairs of metal layers and electrode layers are formed in parallel on a substrate, and a plurality of semiconductor elements mounted on each metal layer and an electrode layer corresponding to an electrode of each element are electrically connected. After the electrical connection, multiple sets of element mounting parts are sealed with a continuous resin layer, the substrate is removed, and then cut into individual resin sealing bodies. Can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 to 3 show a first embodiment in the case of manufacturing a semiconductor device according to the present invention. 1A and 1B show a leadless surface-mount type semiconductor device according to the present invention. FIG. 1A is a sectional view, and FIG.
Is a bottom view. In the figure, S is a semiconductor element, which is bonded and mounted on the metal layer 2a. L denotes an electrode formed on the semiconductor element S, and the metal layer 2a
And a corresponding electrode layer 2b, which is provided independently and side by side, and is electrically connected by a conductive wire 3 such as gold. The mounting portion of the semiconductor element S is sealed with a resin layer 4 made of a thermosetting epoxy resin or the like, thereby forming a resin sealing body in which the back surfaces of the metal layer 2a and the electrode layer 2b are exposed.

FIGS. 2 and 3 show a method of manufacturing the above-described semiconductor device for each step. FIG. 2A shows a conductive metal plate such as stainless steel, aluminum, or copper, for example, S in the case of this embodiment.
Laminating about 50 μm thick alkaline type photosensitive film resist on both sides of a 0.1 mm thick substrate 1 formed by US430, etc.
2B, and then a double-sided exposure by ultraviolet irradiation with a film F having a predetermined pattern disposed on the photosensitive resist layer 5 on one side of the substrate 1 as shown in FIG. As shown in FIG. 2 (c), a resist pattern layer 6 having a predetermined pattern formed on one side of the substrate 1 and a cured resist layer 5 formed on the back side are obtained.

Next, the exposed surface of the substrate 1 which is not covered with the resist pattern layer 6 on one side is subjected to a surface activation treatment such as removal of a surface oxide film by chemical etching or a well-known chemical treatment with chemicals as necessary. After that, the substrate 1 is electroformed, and as shown in FIG. 2D, an electrodeposit of a conductive metal is grown from the exposed surface defined by the resist pattern layer 6 of the substrate 1 to form a metal layer for mounting a semiconductor. Plural sets are formed in parallel with one or more independent electrode layers 2b as pairs for each of the metal layers 2a and 2a. As the electrodeposit, nickel, nickel-cobalt alloy copper, and other various metals can be considered. In the present embodiment, a matte bath of nickel sulfamate is used, and Electrodeposited with a thickness of 40-50 μm. The step of the surface activation treatment is not an essential step.

Next, if necessary, the surface of each of the metal layers 2a and the electrode layers 2b is coated with 0.3% of gold plating or the like for improving the binding force.
By removing the resist pattern layer 6 and the resist layer 5 from both sides of the substrate 1, the thickness of FIG.
The state shown in FIG. As a method for removing the resist, a method for removing swelling with an alkali solution or the like is conceivable.

Next, as shown in FIG. 3A, the semiconductor element S is bonded and mounted on the metal layer 2a by a known method, and the electrode L on the semiconductor element S is connected to the corresponding electrode layer 2b. Are connected by an ultrasonic bonding device or the like using a conductive wire 3 such as a gold wire as shown in FIG. Here, when the wires 3 are connected, a separating force from the bonding device acts on each electrode layer 2b, and the electrode layers 2b tend to float up from the substrate 1. However, as described above, before the electroforming process, Since the adhesion between the substrate 1 and the electrodeposition layer is improved in advance by performing the surface activation treatment on the exposed surface, the electrode layer 2b at the time of connection is formed.
Can be effectively prevented from falling off and rising, and the defective product formation rate during the manufacturing process can be reduced.

Next, as shown in FIG. 3C, the portion on which the semiconductor element S is mounted on the substrate 1 is molded with a resin layer 4 such as a thermosetting epoxy resin, and a resin sealing body is formed on the substrate 1.
More specifically, a plurality of sets of semiconductors are formed by mounting one surface of the substrate 1 on a mold (upper die) and press-fitting an epoxy resin into the mold by a cavity. The element mounting portion is continuously sealed by the resin layer 4. In this case, the substrate 1 itself functions as a lower mold at the time of resin molding. In addition, when a plurality of substrates 1 are arranged in parallel at the time of molding and epoxy resin is press-fitted between each substrate 1 and the upper mold through a liner, a large number of resin sealing can be performed efficiently. It is.

Next, as shown in FIG. 3D, by removing the substrate 1 from the resin sealing body, a plurality of sets of the back surfaces of the metal layer 2a and the electrode layer 2b are exposed on the bottom surface of the resin sealing body. In addition, the respective back surfaces of the metal layer 2a and the electrode layer 2b and the resin layer 4
Are substantially flush with each other. As a method for removing the substrate 1, besides a method for forcibly removing the substrate 1 such as peeling the substrate 1 from the resin sealing body, for example, depending on a material constituting the substrate 1 and the like, The method also includes a method of dissolving and removing the substrate 1 with a solvent or the like having no influence. After this step, if necessary, a thin film of a conductive gold layer such as gold or silver is mounted on only the back surface of each electrode layer 2b or the electrode layer 2b and the metal layer 2a by a known method such as flash plating. It may be formed in a thickness of 0.3 to 0.5 μm.

Next, as shown in FIG. 3E, a dicing step of cutting and separating the pair of semiconductor elements along the cutting line XX as shown in FIG. The semiconductor device is completed.

(Second Embodiment) Next, in the step of electrodepositing a conductive metal on the substrate 1, the conductive metal is electrodeposited beyond the thickness of the resist pattern layer 6, thereby forming the metal layer 2a.
And overhanging portions 11, 11 on the periphery of the upper end of electrode layer 2b.
Will be described.

That is, in the present invention, in the electroforming step of FIG. 2D, the electrodeposited metal may be formed by electrodeposition by pressing the electrodeposited metal within the thickness range of the resist pattern layer 6. Is the electrodeposited metal (metal layer 2a,
The electrode layer 2b) is electrodeposited beyond the thickness of the resist pattern layer 6 that regulates the electrodeposition range, so-called overhang, so that the metal layer 2a and the electrode layer 2b are removed after the resist pattern layer 6 is removed as shown in FIG. The overhanging portions 11, 11 having a cross-sectional eaves shape are formed on the periphery so as to be integrally formed. In particular, this overhang 11,
The overhang length T of 11 is preferably in the range of 5 to 20 μm.

As described above, the metal layer 2a and the electrode layer 2b
If the overhang portions 11 are formed on the periphery of the resin layer 4 in a resin-sealed state by the resin layer 4 in a later step, the resin layer 4 is in a state where the overhang portions 11 are positioned in a recessed shape as shown in FIG. Due to the hardening, the metal layer 2a and the electrode layer 2b surely remain on the resin layer 4 side when the substrate 1 is peeled and removed during the peeling operation of the substrate 1 from the resin sealing body due to the biting effect. In addition, it does not stick together with the substrate 1 and is separated from the substrate 1, which can effectively prevent displacement and dropout, thereby improving the yield in the manufacturing process. Furthermore, the presence of the overhang portion 11 having a unique eaves shape allows the metal layer 2a
In addition, there is also an effect of preventing moisture and the like entering from a minute gap between the resin layer 4 on the back surface side of the electrode layer 2b and the upper portion, that is, the connection portion and the semiconductor element mounting portion, from connecting to the semiconductor element S and the wire. It is also possible to improve the water resistance at each location and to improve the reliability of the completed semiconductor device itself.

As for each overhanging portion 11, as a result of an experiment conducted by the applicant, the length T grows substantially in proportion to the height at which the resist pattern layer 6 overhangs beyond the thickness thereof. Its length T is 5 μm
Below this, the biting effect on the resin layer 4 at the time of molding is weak, and when the substrate 1 is peeled off, the metal layer 2a and the electrode layer 2b are slightly but adhered to the substrate 1 side and are separated from each other, resulting in displacement or chipping. Since a phenomenon is observed, it is preferable to set the length to be longer than this. If the length exceeds 20 μm, the resist pattern layer 6 swells when the resist pattern layer 6 is removed by swelling with an alkaline solvent during removal of the resist pattern layer 6 after the electrodeposition step. The resist pattern layer 6 is overhanging part 1
Electrodeposited metal via 1 and 11 (metal layer 2a, electrode layer 2b)
There is a possibility that the substrate may be lifted from the substrate 1. Therefore, it is preferable that the distance be set in the range of 5 to 20 μm in consideration of these points.

(Third Embodiment) In the embodiment shown in FIGS. 7A and 7B, different pairs of adjacent electrode layers 2b, 2b are used for a semiconductor element S on a metal layer 2a disposed on the left and right sides thereof. The semiconductor element S is mounted, connected to a wire, sealed with the resin layer 4, and then sealed with a final cutting line XX (X
In the step of dicing along (1-X1, X2-X2), the electrode layers 2b, 2b are cut at the connecting central portion and separated into individual semiconductor device sides. The arrangement of the electrode layers 2b, 2b can be efficiently performed by bringing them closer to each other, so that the number of pieces to be taken from one substrate 1 can be increased, which is suitable for mass production and cost reduction.

(Fourth Embodiment) As shown in FIGS. 8 (a) and 8 (b), when one or both of the back surfaces of the electrodeposited metal layer 2a and the electrode layer 2b are sealed with resin, It is also possible to have a configuration in which the bottom surface of each of the metal layer 2a and the electrode layer 2b is protruded (the embodiment shows a configuration in which both the metal layers 2a and the electrode layers 2b are protruded slightly). As a manufacturing method in this case, as shown in FIG. 9A, the metal layer 2a,
A concave portion 2 having a size of, for example, about 5 to 15 μm is formed at a position corresponding to the portion where the electrode layer 2 b is formed, in accordance with the amount of protrusion.
1 is formed by etching or pressing. Subsequent steps are the same as the ordinary steps of the present application, but also in this case, it is preferable that the overhanging portion is applied over the height of the resist pattern layer 6 to perform electrodeposition to provide the overhang portion 11. After the resist pattern layer 6 is removed, the substrate 1 is removed after each step of mounting the semiconductor element S, connecting wires, and sealing the resin layer 4 as shown in FIG. This is reflected as the amount of protrusion of the back surface of the metal layer 2a and the back surface of the electrode layer 2b with respect to the back surface of the resin layer 4, and is formed so as to protrude from the back surface of the resin layer 4. Finally, dicing is performed along the cutting line XX to complete individual resin sealing bodies. Of course, after that, a thin film of gold, silver, or the like may be formed on the back surface of each metal layer 2a or electrode layer 2b by flash plating.

(Other Embodiments) In the fourth embodiment, one or both of the rear surface of the metal layer 2a and the rear surface of the electrode layer 2b are slightly projected from the rear surface of the resin layer 4 when the resin is sealed. In this case, the back surface of the electrodeposited layer may be slightly recessed from the back surface of the resin layer 4. In this case, the substrate 1 may be formed in advance by etching, pressing or the like so that only the position corresponding to the metal layer 2a and the electrode layer 2b on one surface side of the substrate 1 is projected. It may be the same.

[0030]

As described above, according to the present invention,
This eliminates the need to use a printed circuit board, which was conventionally required as a component of a semiconductor device, and can reduce material costs and various processing costs, as well as reduce the size of the semiconductor device itself, especially the thickness. is there. In addition, since the part for mounting the semiconductor element and the electrode part for external derivation are formed by electroforming, the precision is extremely good, it can correspond to fine arrangement, and it corresponds to other pins due to the high density of semiconductors Is what you can do. Further, since the metal layer on which the semiconductor element S is mounted is exposed from the back surface of the resin layer, the heat dissipation is excellent.

Further, in the electroforming step of electrodepositing the conductive metal on the substrate, the conductive metal may be overhanged and electrodeposited by overhanging beyond the thickness of the resist pattern layer. It is possible to intentionally form an eave-shaped overhang 11 on the periphery of the upper end of the electrode layer 2b. In this case, in the resin sealing step after removing the resist pattern layer 6, each overhang is formed on the resin layer. 11 is bite-shaped, the metal layer 2
a, the binding force between the electrode layer 2b and the resin layer 4 is improved, and not only the quality after commercialization is improved, but also important components such as the metal layer 2a and the electrode layer 2b are separated when the substrate is separated in a later process. Without sticking to the side and being separated, it is surely left on the resin sealing body side, which can effectively prevent displacement and omission, etc.
The reliability of the semiconductor device can be improved. Also,
The unique shape of the overhang-like overhanging portion 11 prevents water and the like from entering, and also has the effect of increasing the creepage distance, thereby improving the water resistance and moisture resistance to the connection portion and the semiconductor element side. is there.

[Brief description of the drawings]

FIG. 1A is a sectional view showing an embodiment of a semiconductor device according to the present invention, and FIG. 1B is a rear view thereof.

FIGS. 2A to 2E are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIGS. 3A to 3E are cross-sectional views illustrating a method for manufacturing the semiconductor device following FIG. 2E.

FIG. 4 is a cross-sectional view (partially enlarged view) illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view (a partially enlarged view) illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 6 is a sectional view illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 7A is a perspective top view illustrating a method for manufacturing a semiconductor device according to a third embodiment of the present invention, and FIG. 7B is a cross-sectional view thereof.

FIG. 8A is a sectional view of a semiconductor device according to a fourth embodiment of the present invention, and FIG. 8B is a rear perspective view thereof.

FIGS. 9A and 9B are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a conventional semiconductor device.

[Explanation of symbols]

 Reference Signs List 1 substrate 2a metal layer 2b electrode layer 4 resin layer 6 resist pattern layer S semiconductor element

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Noriyuki Numata, Inventor 4680, Ikata, Fukuoka, Tagawa-gun, Fukuoka Prefecture Inside Kyushu Hitachi Maxell Co., Ltd. (72) Inventor Hiroshi Kimura 1-2-7 Ecchujima, Koto-ku, Tokyo Trek 5F061 AA01 BA03 CA21 CB13

Claims (5)

[Claims] 1. A substrate 1 having conductivity on at least one surface.
Forming a resist pattern layer 6 with a predetermined patterning on the one surface side, and electrodepositing a conductive metal on an exposed surface of the substrate 1 excluding the resist pattern layer 6, thereby forming A step of independently forming a metal layer 2a for mounting a semiconductor element and one or more electrode layers 2b in parallel, a step of removing the resist pattern layer 6 from the substrate 1, and a step of forming a semiconductor element on the metal layer 2a. After installing S,
A step of electrically connecting an electrode on the semiconductor element to the electrode layer 2b, a step of sealing the semiconductor element S mounting portion on the substrate 1 with a resin layer 4, and a step of removing the substrate 1 Obtaining a resin sealing body in which the back surfaces of the layer 2a and the electrode layer 2b are exposed. 2. In the step of electrodepositing a conductive metal on the substrate 1, the conductive metal is electrodeposited beyond the thickness of the resist pattern layer 6 so that the upper edge of the metal layer 2a and the electrode layer 2b is formed. An overhanging portion is formed.
13. The method for manufacturing a semiconductor device according to item 5. 3. The overhang length of the overhang portion 11 is 5 to 2
3. The method for manufacturing a semiconductor device according to claim 1, wherein the range is 0 μm. 4. The method according to claim 1, wherein the step of depositing the conductive metal comprises:
2. The method for manufacturing a semiconductor device according to claim 1, wherein the electrodeposition step is performed after activating the surface of the semiconductor device. 5. A plurality of pairs of a metal layer 2a and an electrode layer 2b are formed in parallel on a substrate 1, and a plurality of semiconductor elements mounted on each metal layer 2a and electrodes corresponding to the electrodes of each element. Layer 2b
2. The method according to claim 1, further comprising the steps of: after electrically connecting the device, sealing a plurality of sets of element mounting portions with a continuous resin layer 4, removing the substrate 1, and cutting the individual resin sealing bodies. The manufacturing method of the semiconductor device described in the above.