JP4793610B2 - Semiconductor device substrate and semiconductor device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate for a semiconductor device and a method for manufacturing a semiconductor device using the same, and more particularly to a substrate capable of blocking a sealing resin for sealing a semiconductor element in a desired region.
[0002]
[Prior art]
In order to protect a semiconductor element mounted on a lead frame or a wiring board from corrosion or the like, resin sealing is conventionally performed by transfer molding or potting molding. The former forms a large number of packages at once with a mold, and is suitable for resin sealing of a semiconductor element mounted on a lead frame. On the other hand, the latter potting mold is a solution in which a liquid resin is dropped onto a semiconductor element and cured to form a package. Although the mass productivity is inferior to that of a transfer mold, the element does not give excessive heat history or injection pressure. There is no risk of changes in characteristics. Further, as a so-called chip size package (CSP) is required for portable devices and the like, the downsizing of the package is in the direction of further progress. However, when such a small package is formed by transfer molding, a resin flow path such as a gate is narrowed with the miniaturization of the cavity, so that a considerable injection pressure is required. Therefore, there is a possibility of causing various problems such as unfilling of resin, mixing of voids, and breakage of wires. In that respect, the potting mold can reliably apply the resin, and it is not necessary to apply extra stress to the elements and wiring, so there are almost no physical problems, and in that sense, an extremely small package is formed. It can be said that it is suitable for.
[0003]
Hereinafter, a semiconductor substrate used for the potting mold and a method for manufacturing a semiconductor device using the semiconductor substrate will be described with reference to FIGS. 1A is a cross-sectional view showing a state after the potting mold is completed in the manufacturing process of the semiconductor device, FIG. 2B is a top view of FIG. 1A, and FIG. 3C is a perspective view of the finally obtained semiconductor device. Each figure is shown. In this figure, 1 is a substrate, 2a is a metal wiring, 2b is a die pad, 2c is an electrode, 3 is a through hole, 4 is a bonding wire, 5 is a semiconductor element, 6 is a sealing resin, 7 is a resist film, and 8 is a unit. Semiconductor element formation region, 10 is a side through, 11 is a dam, 30 is a collective substrate, and 31 is a semiconductor device.
[0004]
The package of the semiconductor device shown in FIG. 3C is a CSP having an LCC (Lead-less Chip Carrier) structure, and has a side through 10 formed by dividing a through hole 3 on a side surface. The assembly substrate 30 is used for the manufacture, and as shown in the cross-sectional view of FIG. 3A, a circuit pattern composed of metal wiring 2a and a die pad 2b is formed on the surface of the insulating substrate 1, and an electrode 2c is formed on the back surface. A through hole 3 that is formed and electrically connects the metal wiring 2a and the electrode 2c is formed. Further, a resist film 7 or the like as shown is provided as necessary to prevent the resin from entering the through hole 3.
[0005]
Here, the board | substrate 1 is a plate-shaped object which shows the electrical insulation of ceramic type | system | groups, such as glass fiber reinforced plastic type | system | groups, such as glass epoxy and a Teflon glass cloth, and an alumina. The metal wiring 2a, the die pad 2b, and the electrode 2c are formed by depositing / etching copper foil, printing a conductive paste, or the like, and the through hole 3 is formed by plating or the like. A plurality of circuit patterns including the metal wiring 2a and the die pad 2b are formed so that a large number of semiconductor devices can be formed at a time. Since the portion excluding the portion (unit semiconductor formation region 8) that becomes the semiconductor device including this circuit pattern is discarded later, it is kept to a minimum in the sense of improving cost performance. The circuit patterns are formed in a matrix so as to be easily cut and separated for each unit semiconductor formation region 8 (FIG. 3B). For this reason, the substrate 1 generally has a rectangular planar shape.
[0006]
A method of manufacturing a semiconductor device using such a collective substrate 30 is as follows. First, the semiconductor element 5 is mounted, the dam 11 is formed second, the sealing resin 6 is formed third, and finally a single unit is formed. A process of individualizing the semiconductor element 31 is performed.
[0007]
First, the process of mounting the first semiconductor element 5 includes applying silver paste onto the die pad 2b, die bonding of the semiconductor element 5 with a chip mounter, and bonding wires 4 between the semiconductor element 5 and the metal wiring 2a with a wire bonder. Electrical connection is mainly made. However, the semiconductor element 5 may be a flip chip and a method by flip chip bonding may be employed.
[0008]
In the step of forming the second dam 11, dam material is mainly applied and cured by a dispenser, screen printing, or the like. That is, the dam material is applied along the outer periphery of the substrate 1 at a predetermined distance from the unit semiconductor formation region 8 that is the outermost shell, and is cured at a predetermined temperature to form the dam 11.
[0009]
In the step of forming the third sealing resin 6, a so-called potting mold is performed in which the liquid resin is applied to the region surrounded by the dam 11 and cured.
[0010]
In the final individualization step, as shown in FIG. 3B, dicing lines are determined in a matrix so as to be divided into unit semiconductor device formation regions 8 (one semiconductor device that is not yet divided), and the dicing lines are divided. Are cut with a blade or the like to obtain individual semiconductor devices 31 as shown in FIG.
[0011]
[Problems to be solved by the invention]
However, when potting molding is performed in the third step in the region surrounded by the dam 11 formed in the second step, the liquid resin spreads over the entire inside of the dam as shown by the dotted line in FIG. Therefore, the thickness of the sealing resin 6 may deviate from the design value. This is because the liquid resin tends to become a shape having a smaller surface area due to the surface tension, so that the wetting at the corners of the dam 11 becomes worse.
[0012]
For this reason, the semiconductor device 31 that is separated from the unit semiconductor formation region 8 near the dam 11 does not have a uniform resin thickness as shown in FIG. Furthermore, when the resin-repelled portion 33 becomes larger, the thickness of the semiconductor device 31 becomes thicker than a set value, and all the substrates may be defective.
[0013]
In order to solve this problem, it is conceivable that corners are not formed in the dam 11. However, for that purpose, it is necessary to secure an extra area in the substrate 1, and the cost performance is lowered accordingly. For example, in order to round the corners of the dam 11, the size of the substrate 1 must be increased or the number of unit semiconductor device forming regions 8 must be reduced. If the portion is rounded or chamfered, the number of semiconductor devices that can be taken is reduced.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the invention of the substrate for a semiconductor device according to the present application can be divided into individual semiconductor devices after resin circuit sealing with a liquid resin in which a plurality of circuit patterns capable of mounting semiconductor elements are formed on an insulating plate In the semiconductor device substrate configured as described above, a film having a contact angle with the liquid resin is smaller than that of the insulating plate, and a film surrounding the plurality of circuit patterns in a frame shape is attached, and is superimposed on the film. A semiconductor device substrate characterized in that a dam is formed on the outer side of the film, and the film is exposed inside the dam.
[0015]
With this configuration, since the sealing resin spreads on the film, there is no region where the sealing resin is repelled at the corners of the dam. Therefore, the resin thickness does not deviate from the design value. In addition, the board | substrate for semiconductor devices can be comprised in a normal board | substrate preparation process by employ | adopting solder resists, such as liquid form and a dry film form, as said film | membrane. Further, since the solder resist is a photosensitive material, it can be patterned into a desired shape and can be formed only in a necessary portion.
[0016]
Further, the invention of the method of manufacturing a semiconductor device according to the present application includes mounting the semiconductor element on the semiconductor device substrate, dropping the liquid resin on a region surrounded by the dam so as to cover the semiconductor element, After the liquid resin is cured, it is divided into individual semiconductor devices so as not to incorporate the film.
[0017]
In a semiconductor device manufactured by such a manufacturing method, the resin thickness is as designed, and the resist is not included in the cut surface.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. In these drawings, the same reference numerals as those in FIG. 3 described above denote the same or corresponding elements.
[0019]
FIG. 1A is a side sectional view showing an embodiment according to the invention of a substrate for a semiconductor device. As shown in the figure, a film 12 is deposited on the substrate 1, and a dam 11 is formed on the substrate 1 so as to be partially exposed without covering the entire film 12. Further, as shown in a plan view in FIG. 1B, the film 12 is formed in a frame shape surrounding a portion where the semiconductor device is formed, and is exposed between the dam 11 and the unit semiconductor formation region 8 with a certain width. ing.
[0020]
The film 12 is preferably a polymer film that enhances the surface activity of the liquid resin, for example, and is made of a material having better wettability than the substrate 1. In this example, a solder resist is employed. The solder resist is mainly used as a protective film for protecting the metal wiring or the like of a printed wiring board built in an electronic device, but is less deteriorated with time and does not impair reliability even if left in a semiconductor device. In addition, as a method for depositing the solder resist, there are a method of spray coating a liquefied material and a method of laminating the material in a film form.
[0021]
Next, a method for manufacturing a semiconductor device using such a collective substrate 40 will be described. As described above, since the dam 11 is formed in advance as a part of the collective substrate 40 together with the film 12, the step of forming the dam is omitted. Also, the semiconductor element is first mounted, but since it is the same as in the prior art, the description is omitted and the process of forming the sealing resin will be described.
[0022]
2A and 2B are a side sectional view and a plan view showing a state in which the sealing resin 6 is formed on the collective substrate 40 shown in FIG. The sealing resin 6 is formed by dropping a liquid resin into a region surrounded by the dam 11 with a dispenser or the like and curing it at a predetermined temperature. When the liquid resin is dropped on the center of the collective substrate 40, the liquid resin initially spreads almost on a circle and is in the short side direction of the collective substrate 40 closest to the dropping point (the vertical direction of the drawing in FIG. 2B). Reach up to dam 11. Subsequently, the liquid resin further wets and spreads in the long side direction (the left-right direction in FIG. 2B), but the supply of the liquid resin stops halfway. This is because in order to make the thickness of the package constant, the supply of a predetermined amount must be stopped, and the productivity becomes worse if the supply time is lengthened. After the supply of the liquid resin from the dispenser is stopped, the kinetic energy generated by the drop between the collective substrate 40 and the syringe discharge port cannot be used as an urging force, and the plane of the collective substrate 40 is caused by the gravity applied to the liquid resin itself. It spreads up. Accordingly, when the liquid resin is almost spread over the entire surface, the shape of the liquid resin is a thin layer, and the surface is almost horizontal except for the vicinity of the corner of the dam 11, so that it tends to be thinner and spread by gravity. The force and the surface tension of the liquid resin itself are balanced. If the liquid resin is completely balanced at this point, in order for the liquid resin to spread further, the level of the surface activity between the liquid resin and the collective substrate 40 (strictly, the substrate 1) is high, that is, the wettability is good. Is a condition. Since no countermeasure has been taken in the past, a resin repelling portion 33 was generated as shown in FIG. 3B, but in this embodiment, a liquid resin and a film 12 having good wettability are deposited on this portion. Because it is, it will spread further wet. Even if the conventional resin repelling part 33 is not completely covered by the film 12, the liquid resin flows around the film 12 from the two sides of the corner of the dam 11, so that the entire surface can be wetted. In order to expect such an effect, if the liquid resin is a general epoxy resin, the width of the film 12 made of solder resist exposed from the dam 11 to the inside may be about 5 mm.
[0023]
After forming the sealing resin 6 in this way, dicing lines are determined in a matrix so as to be divided into the unit semiconductor device forming regions 8 shown in FIG. 2B, and cut along the dicing lines with a blade or the like. As shown in FIG. 2C, an individual semiconductor device 31 is obtained. At this time, the semiconductor device 31 is cut so as not to incorporate the film 12. This is the reason why the film 12 is deposited in advance avoiding the region to be the semiconductor device 31.
[0024]
Since the collective substrate 40 described above has the above-described configuration, even if the thin spreading force of the liquid resin in the resin sealing process is reduced, the outer peripheral portion of the spreading range (the range surrounded by the dam 11). Since there is a film that wets well with the liquid resin, the film spreads to every corner and the resin repelling portion does not occur. The determination that the wetness is good is made based on the contact angle. If the contact angle is small, it is determined that the wettability is good. Here, the contact angle refers to an angle formed by the imaginary tangent plane and the horizontal plane when the imaginary tangent plane at the point where the liquid resin surface stationary on the horizontal plane contacts the horizontal plane is considered.
[0025]
In addition, the constant application of the dam material by the dispenser requires a certain technique because there is a fluctuation in pressure due to a change in the viscosity of the dam material in the syringe over time, a fluctuation in the filling amount, etc. Therefore, the purchaser can reduce costs such as development costs.
[0026]
Further, in the method of manufacturing a semiconductor device using the collective substrate 40, the collective substrate 40 on which the dam is formed in advance is put into the assembly process, so that the subsequent dam forming step is omitted. In addition, since the above-described film 12 is formed, the liquid resin spreads over the entire surface, improving the manufacturing yield. Since the film 12 does not remain in the semiconductor device 31 after the division, it is not necessary to consider interface peeling with the sealing resin 6 during dicing. That is, only those having good wettability with the liquid resin can be selected without being restricted by the elasticity of the film 12.
[0027]
In this embodiment, the collective substrate 31 for a semiconductor device has been described. However, the present invention can also be applied to a semiconductor device in which the dam 11 needs to be manufactured for each semiconductor element 5, and a semiconductor device in which a plurality of dams are provided on a substrate. Is the same. Further, although the dam 11 is formed so as to overlap the film 12, the configuration circumscribing the film 12 is the same because the film 12 is exposed inside the region surrounded by the dam 11.
[0028]
【The invention's effect】
As described above, according to the present invention, by applying a film made of a material having a smaller contact angle than the substrate to the inside of the dam 11, the liquid resin spreads on the film, and the liquid resin is spread at the corners of the dam. There is no area to be repelled. Thereby, the thickness of the sealing resin does not deviate from the design value, and the manufacturing yield of the semiconductor device is improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a semiconductor device substrate and a semiconductor device according to the present invention.
FIG. 2 is a view showing a semiconductor device substrate according to the present invention and a resin application example of the semiconductor device.
FIG. 3 is a diagram showing a conventional semiconductor device substrate having an LCC structure and a semiconductor device.
[Explanation of symbols]
1: substrate (insulating plate), 2a: metal wiring, 2b: die pad, 2c: electrode, 3: through hole, 4: bonding wire, 5: semiconductor element, 6: sealing resin, 7: dry film solder resist 8: Ag paste, 10: Side-through, 11: Dam, 12: Solder resist, 30: Collective substrate, 31: Semiconductor device, 33: Resin repelling part, 40: Collective substrate

Claims (2)

A plurality of circuit patterns on which a semiconductor element can be mounted on an insulating plate is formed, and a semiconductor device substrate configured to be separable into individual semiconductor devices after resin sealing with a liquid resin,
A film having a contact angle with the liquid resin made of a material smaller than that of the insulating plate, a film surrounding the plurality of circuit patterns in a frame shape is attached, and a dam is formed on the film so as to overlap or circumscribe the film. A substrate for a semiconductor device, wherein the film is exposed inside the dam. A substrate for a semiconductor device in which a plurality of circuit patterns on which a semiconductor element can be mounted is formed on an insulating plate, and is configured to be separable into individual semiconductor devices after resin sealing with a liquid resin, which is in contact with the liquid resin A film having a corner smaller than that of the insulating plate, a film surrounding the plurality of circuit patterns in a frame shape is attached, and a dam is formed on the film so as to overlap or circumscribe the film. On the semiconductor device substrate with the exposed film,
  The semiconductor element is mounted, and the liquid resin is dropped on a region surrounded by the dam so as to cover the semiconductor element. After the liquid resin is cured, the semiconductor element is divided into individual semiconductor devices so as not to incorporate the film. A method for manufacturing a semiconductor device, comprising:

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