JP2001176902A - Resin sealing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sealing method for improving molding quality without the waste of sealing resin which resin-seals the connection terminal joint face of a semiconductor device. SOLUTION: A molded article 1 where solder balls 2 are jointed is carried into a metallic mold 5 where a metallic mold face clamping the solder ball jointing face is covered by a release film 10. Sealing resin 11 having semi-curing characteristic by an amount for sealing the solder ball jointing face is supplied to the molded article 1. The molded article 1 is clamped and heated by the metallic mold 5. Thus, the head parts of the solder balls 2 are exposed and a solder ball jointing face side is resin-sealed in a semi-curing state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to resin-sealing a connection terminal joining surface of a molded product such as a semiconductor wafer or a circuit board to which connection terminals are joined so that a head on the connection side of the connection terminal is exposed. To a resin sealing method.

[0002]

2. Description of the Related Art A wafer-level semiconductor device having a wiring layer formed on a surface of a semiconductor wafer has been proposed. When manufacturing this semiconductor device in the form of a wafer, a metal post serving as a connection terminal and a solder ball are bonded to the semiconductor wafer, and then a sealing resin is supplied to the connection terminal bonding surface, and then the resin is sealed by compression molding. ing. It is difficult to reliably expose the head of the connection terminal because the connection terminal joint surface is resin-sealed, the flow of the sealing resin is poor, the resin pressure varies, and a narrow gap is sewn while heating. As described above, since the sealing resin flows, the resin is easily cured in the middle, so that the resin thickness of the molded product tends to be non-uniform. Especially when the connection terminal is a solder ball, the exposed head is a curved surface, the height is lower than metal posts, the height is more likely to vary, and the ball pitch is narrower. It was difficult to stop.

[0003] When a solder ball is used as a connection terminal, a semi-curable liquid resin is dropped on the solder ball joint surface of the semiconductor wafer, and the liquid resin is coated up to the peripheral edge of the semiconductor wafer by spin coating. There has been proposed a method in which a semiconductor wafer is heated to semi-harden a sealing resin on a solder ball bonding surface while exposing a head of the solder ball. After resin sealing, the semiconductor wafer is separated into individual semiconductor devices by dicing, and then bonded to the mounting substrate and heated and pressed to melt the semi-cured sealing resin, release voids, and adhere to the mounting substrate surface Then, the solder ball can be bonded to the terminal portion on the mounting board side.

[0004]

However, when a wafer-level semiconductor device is resin-sealed as a molded product, it is difficult to apply a semi-curable liquid resin to the solder ball joint surface and spin coat the semiconductor device. Since the liquid resin overflows from the wafer, wasteful resin is likely to be generated in a large amount (about 80%), and the yield of molded products is significantly reduced.
Manufacturing costs increase. In addition, since the liquid resin is dripped and spin-coated, voids are inherently mixed in the liquid resin, and when the resin flows, the resin density is partially reduced and new voids are easily generated. Variations are likely to occur in the exposed portions of the solder balls due to variations in resin thickness,
Molding quality tends to deteriorate.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a resin sealing method in which a sealing resin for sealing a connection terminal joining surface of a semiconductor device is not wasted and the molding quality is improved. Is to do.

[0006]

To solve the above-mentioned problems, the present invention has the following arrangement. That is, the molded product to which the connection terminals are bonded is carried into a mold having a mold surface for clamping the connection terminal bonding surface covered with a release film, and the connection terminal bonding surface is sealed with the molded product. By supplying a certain amount of semi-curing sealing resin, clamping the molded article with a mold and heating it, the head of the connection terminal is exposed, and the connection terminal joining surface side is semi-cured. It is characterized by sealing. In this case, the molded article may be provided with a resin stopper having a height substantially equal to the height of the connection terminal at the periphery of the connection terminal joining surface to which the connection terminal is joined.

Further, the mold surface including the cavity concave portion of the mold is covered with a release film, a molded product is accommodated in the cavity concave portion, and the connection terminal joint surface is sealed with the connection terminal joint surface of the molded product. By supplying an amount of semi-curable sealing resin, clamping the molded article with a mold and heating it, the head of the connection terminal is exposed and the resin between the connection terminals is semi-cured. It is characterized by sealing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the present embodiment, a resin encapsulation for manufacturing a wafer-level semiconductor device in which a wiring layer is formed on the surface of a semiconductor wafer and connection terminals such as solder balls and metal posts that are electrically connected to the wiring layer are formed. The method will be described. 1 is an explanatory diagram showing an example of a resin sealing process, FIG. 2 is an explanatory diagram showing a process from a resin-sealed semiconductor wafer to a substrate mounting process of a semiconductor device, and FIG. 3 is a device configuration according to another example of FIG. FIG. 4 is an explanatory view showing a resin sealing process used, FIG. 4 is an explanatory view showing a resin sealing process according to another example, and FIG. 5 is a plan view seen from a solder ball joining surface side of a circuit board.

Referring to FIG. 1, a resin sealing method for a semiconductor wafer will be described together with its apparatus configuration. Reference numeral 1 denotes a molded article, on which a wiring layer is formed on a semiconductor wafer having a diameter of about 200 to 300 mm, and a solder ball 2 is joined to a part of the wiring layer as a connection terminal. The molded article 1 is carried into a mold 5 composed of an upper mold 3 and a lower mold 4 and clamped. The upper die 3 is suspended from the upper die base 7 by a spring 6 so as not to apply excessive clamping pressure in order to clamp the solder ball joint surface. The upper die 3 and the lower die 4 have heaters 8 and 9 incorporated therein.

A release film 10 covers the parting surface of the upper mold 3 so that the upper mold 3 does not directly contact the sealing resin 11. The release film 10 has heat resistance enough to withstand the heating temperature of the mold 5 and is easily peeled off from the mold surface, and is a film material having flexibility and extensibility, for example, PTFE, E
TFE, PET, FEP, fluorine impregnated glass cloth, polypropylene, polyvinylidene chloride and the like are preferably used. The release film 10 is stretched in close contact with the upper mold 3 by sucking air from suction holes formed in the parting surface of the upper mold 3. The release film 10 may be configured such that a long film is continuously supplied to a mold by a release film supply mechanism (not shown), or a film that has been cut into strips in advance may be used. good. When the long release film 10 is used, the release film supply mechanism also needs to move up and down with the opening and closing operation of the upper die 3.

As the sealing resin 11, a resin having a semi-curing property by heating is preferably used. This sealing resin 1
1 may be a solid resin tablet, a granular resin, a powdery resin, or a liquid resin. Further, the molded article 1 may be provided with metal posts so as to be directly electrically connected to the electrode terminals of the semiconductor wafer. In this case, a resin stopper may be provided on the peripheral edge or the outer peripheral surface of the semiconductor wafer.

Next, the resin sealing process will be described. A resin stopper 12 is formed on the periphery of the solder ball joint surface of the molded article 1 to which the solder ball 2 is joined, at a height substantially equal to the height of the solder ball 2. When the resin stopper 12 is sealed with the mold 5 by the resin,
The sealing resin 11 is provided to prevent the overflow of the sealing resin 11 spread around the peripheral portion of the semiconductor wafer by preventing the overflow, and to apply the required resin pressure to the sealing resin 11 so as to spread it evenly. The resin stopper 12 may be formed by dropping a thermosetting resin on the periphery of the semiconductor wafer by potting in advance, or may be formed by attaching a resin material such as polyimide or elastomer. In addition, since the resin stopper 12 is formed at a portion that is removed when dicing the semiconductor wafer, there is almost no influence on the quality of the molded product.

The molded article 1 is carried into a mold 5 in which the parting surface of the upper mold 3 is covered with a release film 10. Then, a semi-curing sealing resin 11 is supplied to the solder ball joint surface of the molded article 1, and the molded article 1 is clamped by the mold 5. At this time, the sealing resin 11 is clamped by the mold 5 while being heated by the heaters 8 and 9, so that a uniform resin pressure is applied to the peripheral edge of the semiconductor wafer and spread uniformly. Further, since the sealing resin 11 is dammed at the peripheral edge by the resin stopper 12, the sealing resin 11 does not overflow from the mold 5. Also, since the head of the solder ball 2 is quantitatively covered with the release film 10, the head can be reliably exposed. By applying heat and pressure by the mold 5, the solder ball bonding surface of the semiconductor wafer exposes the head of the solder ball 2, and the sealing resin 11 is brought into a semi-cured state.

Next, in FIG. 2, the semiconductor wafer 13 is cut by a dicing saw 30, and individual semiconductor devices 14 are obtained. This semiconductor device 14 is mounted on a mounting device 15
And mounted on the mounting board 16 as an alignment. At this time, the semiconductor device 14 is heated and pressurized by the mounting device 15 to melt the semi-cured sealing resin 11, escape the voids, adhere to the mounting substrate 16, and cure the solder ball 2. Side terminal part. Thereby, the resin sealing of the solder ball joint surface of the semiconductor device 14 can be performed without any gap, and the resin sealing (underfill molding) and the substrate mounting can be performed simultaneously.

According to the above resin sealing method, the molded article 1 to which the solder balls 2 are joined is carried into the mold 5 in which the mold surface for clamping the solder ball joint surface is covered with the release film 10. And a molding resin 1 having a semi-curing property sufficient to seal the solder ball joint surface to the molded article 1.
1 is supplied, and the molded article 1 is clamped and heated by the mold 5 so that the resin can be sealed in a semi-cured state without wasting the sealing resin 11, thereby improving the yield of the molded article. Also, manufacturing costs are reduced. In particular, when a resin stopper 12 having a height substantially equal to the height of the solder ball 2 is formed on the periphery of the solder ball joining surface to which the solder ball 2 is joined, the product 1 The sealing resin 11 spread over the peripheral edge of the sealing resin 11 is prevented from overflowing and can be uniformly spread by applying a required resin pressure to the sealing resin 11, and the configuration of the mold 5 is simplified. Can be In addition, since the release film 10 is clamped by the stretched mold 5 and sealed with resin, the solder ball joining surface where the height tends to fluctuate and the pitch between the balls tends to be narrow is secured to the head of the solder ball 2. And can be resin-sealed. Also,
Since the semi-curing sealing resin 11 is semi-cured by being heated and pressurized by the mold 5, there is no possibility that voids are generated in the sealing resin 11, and there is little variation in resin thickness, so that molding quality is improved. Can be done. In this embodiment,
Although a semiconductor wafer has been described as the molded article 1,
It is also possible to similarly perform resin sealing using a circuit board or the like on which a wiring layer is formed and solder balls are joined.

Although the above embodiment has been described with reference to the apparatus configuration in which the solder ball bonding surface of the molded article 1 is oriented upward and mounted on the mold 5 and clamped, as shown in FIG. 1 may be mounted on the mold 5 so that the solder ball bonding surface faces downward.

Specifically, the lower mold 4 of the mold 5
Are covered by a release film 10. A resin stopper 12 is formed at the periphery of the solder ball joining surface of the molded article 1 at a height substantially equal to the height of the solder ball 2. The resin encapsulation process will be described. First, a semi-curable encapsulating resin 11 is supplied to a lower mold 4 covered with a release film 10, and then the molded article 1 is turned upside down with the solder ball bonding surface facing downward. Is held by suction on the parting surface by a vacuum suction mechanism or the like. And
The molded article 1 is clamped by the mold 5 and heated and pressed. At this time, the sealing resin 11 is clamped by the mold 5 while being heated by the heaters 8 and 9, so that a uniform resin pressure is applied to the peripheral edge of the semiconductor wafer and spread uniformly. Further, since the sealing resin 11 is dammed at the peripheral edge by the resin stopper 12, the sealing resin 11 does not overflow from the mold 5. Also, since the head of the solder ball 2 is quantitatively covered with the release film 10, the head can be reliably exposed.

Next, another resin sealing method will be described together with the configuration of the resin sealing device. Note that the same members as those in the above-described embodiment are denoted by the same reference numerals, and the description is referred to. In this embodiment,
A method of resin-sealing a molded article 1 in which a solder ball 2 is joined to a circuit board 17 on which a wiring layer is formed as shown in FIG. 4 will be described.

In FIG. 3, the molded article 1 is an upper mold 18.
Then, it is carried into a mold die 20 composed of a lower mold 19 and clamped. The lower mold 19 is formed with a cavity recess 21 for accommodating the molded article 1. The cavity concave portion 21 is formed such that the movable clamp portion 23 is urged upward by a spring 24 around the lower mold base 22 and is floating supported. When the mold 20 is clamped, the movable clamp 23 is pushed down by the upper mold 18 so that excessive clamping pressure is not applied. It is preferable that an air vent groove (not shown) for releasing air in the cavity concave portion 21 to the outside is formed on the clamp surface side of the movable clamp portion 23. The upper mold 18 and the lower mold 19 have heaters 25, 26,
Is built-in.

The parting surface of the upper mold 18 and the parting surface of the lower mold 19 including the cavity recess 21 are respectively covered with the release film 10 so that the mold 20 does not directly contact the sealing resin 11. It has become. The release film 10 is stretched in close contact with the mold surface by sucking air from suction holes formed in the parting surface of the mold 20. In the cavity concave portion 21, air is sucked using the gap 27 between the lower mold base 22 and the movable clamp portion 23,
It is preferable to stretch and stick to the cavity concave portion 21.
The release film 10 may be configured such that a long film is continuously supplied to a mold by a release film supply mechanism (not shown), or a film that has been cut into strips in advance may be used. good. When the long release film 10 is used, it is necessary that the release film supply mechanism on the movable side, for example, the upper mold side also moves up and down with the opening and closing operation of the upper mold 18.

Next, the resin sealing process will be described. The molded article 1 to which the solder balls 2 are joined is carried into the cavity recess 21 in which the parting surface of the mold 20 is covered with the release film 10. And
The molding resin 1 is clamped by the mold 20 by supplying a sufficient amount of semi-curing sealing resin 11 for sealing the solder ball bonding surface to the solder ball bonding surface of the molding 1. At this time, the sealing resin 11 is clamped to the mold 20 while being heated by the heaters 25 and 26, so that a uniform resin pressure is applied to the peripheral edge of the circuit board 17 and spread uniformly. Also, since the sealing resin 11 is dammed at the periphery by the movable clamp portion 23, the sealing resin 11
Does not overflow from the mold 20. Also, since the head of the solder ball 2 is quantitatively covered with the release film 10, the head can be reliably exposed. By applying heat and pressure by the mold 20, the solder ball bonding surface of the circuit board 17 exposes the head of the solder ball 2, and the sealing resin 11 is brought into a semi-cured state.

Next, in the same manner as in FIG. 2, the circuit board 17 is cut by a dicing saw 30 to separate the semiconductor devices from each other. Then, the semiconductor devices are carried into the mounting device 15 and mounted on the mounting substrate 16 as alignment. I do. At this time, the semiconductor device is heated and pressurized by the mounting device 15 to melt the semi-cured sealing resin 11, release the voids, adhere to the mounting substrate 16 and harden, and fix the solder balls 2 on the mounting substrate 16 side. Can be joined to the terminal portion. Thereby, the resin sealing of the solder ball joint surface of the semiconductor device can be performed reliably without any gap, and the resin sealing (underfill molding) and the substrate mounting can be performed simultaneously.

According to the above resin encapsulation method, the molded article 1 to which the solder ball 2 has been joined is housed in the cavity concave portion 21 and a sufficient amount of semi-curing sealing resin for sealing the solder ball joint surface. Supply 11 and release film 10
Is heated and clamped by the mold 20 having the tension applied thereto, and the sealing resin 11 can be used in a semi-cured state without waste, thereby improving the yield of the molded product and reducing the manufacturing cost. I do. Also, since the release film 10 is clamped by the stretched mold 20 and resin-sealed, the solder ball joint surface where the height tends to fluctuate and the pitch between the balls tends to be narrow is secured to the head of the solder ball 2. And can be resin-sealed. Further, since the semi-curing sealing resin 11 is semi-cured by being heated and pressurized by the mold 20, there is no possibility that a void is generated in the sealing resin 11, and the resin thickness has little variation. Quality can be improved. In this embodiment, the circuit board 17 is used as the molded article 1.
However, it is also possible to similarly perform resin sealing using a semiconductor wafer or the like on which a wiring layer is formed and solder balls are joined.

Although the preferred embodiment of the present invention has been described in various ways, the present invention is not limited to the above-described embodiment, and the molded article 1 is limited to the semiconductor wafer 13 and the circuit board 17. Instead, for example, a wiring board to which an IC chip is bonded may be used. Various substrates such as a resin substrate and a tape substrate can be used as the substrate used as the molded article 1, or a metal plate serving as a heat sink may be laminated on the substrate. It is needless to say that the modification can be made.

[0025]

According to the resin sealing method of the present invention,
To the molded product to which the connection terminals are joined, supply a sufficient amount of semi-curing sealing resin to seal the connection terminal joint surface, and clamp the clamp surface with a mold that is covered with a release film. By applying heat and pressure, the sealing resin can be sealed in a semi-cured state without waste, thereby improving the yield of molded products and reducing the manufacturing cost. In addition, since the release film is clamped by a stretched mold and sealed with resin, the height tends to vary and the pitch between terminals is narrow (particularly in the case of solder balls).
The connection terminal joint surface can be sealed with resin by reliably exposing the head of the connection terminal. In addition, since the semi-curing sealing resin is semi-cured by being heated and pressed by the mold, there is no risk of voids in the sealing resin, and there is little variation in resin thickness, so molding quality is improved. Can be done. In addition, when the molded product has a resin stopper at about the same height as the connection terminal at the periphery of the connection terminal joining surface to which the connection terminal is joined, the resin spreads over the periphery of the molded product. Damping the encapsulating resin to prevent it from overflowing,
The required resin pressure can be applied to the sealing resin so that the resin can be uniformly spread out, and the configuration of the mold can be simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of a resin sealing process.

FIG. 2 is an explanatory diagram showing a process from a resin-sealed semiconductor wafer to a substrate mounting process of a semiconductor device.

FIG. 3 is an explanatory view showing a resin sealing process using an apparatus configuration according to another example of FIG. 1;

FIG. 4 is an explanatory view showing a resin sealing process according to another example.

FIG. 5 is a plan view of the circuit board as viewed from a solder ball joining surface side.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Molded product 2 Solder ball 3, 18 Upper die 4, 19 Lower die 5, 20 Mold die 6, 24 Spring 7 Upper die base 8, 9, 25, 26 Heater 10 Release film 11 Sealing resin 12 Resin stopper DESCRIPTION OF SYMBOLS 13 Semiconductor wafer 14 Semiconductor device 15 Mounting device 16 Mounting substrate 17 Circuit board 21 Cavity recess 22 Lower mold base 23 Movable clamp part 27 Gap 30 Dicing saw

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29L 31:34 H01L 23/12 L F-term (Reference) 4F202 AD08 AD19 AH33 CA09 CB01 CB12 CK41 CK75 CM72 CP01 CQ06 4F204 AD08 AD19 AH33 FA01 FB01 FB17 FN12 FQ38 5F061 AA01 BA03 BA07 CA21 CB02 DA01 DA06

Claims (5)

[Claims] 1. A molded product to which connection terminals are joined is carried into a mold having a mold surface for clamping the connection terminal joining surface covered with a release film, and the connection terminal is joined to the molded product. Supplying a sufficient amount of semi-curing sealing resin to seal the surface, clamping the molded article by the molding die and heating, thereby exposing the head of the connection terminal and joining the connection terminal. A resin sealing method, wherein the surface side is sealed with a resin in a semi-cured state. 2. The resin molding according to claim 1, wherein the molded article is provided with a resin stopper having a height substantially equal to the height of the connection terminal at a periphery of the connection terminal joining surface to which the connection terminal is joined. 2. The resin sealing method according to 1. 3. The resin sealing method according to claim 1, wherein a solder ball is connected as a connection terminal to the connection terminal bonding surface of the molded article. 4. A mold surface including a cavity recess of a mold is covered with a release film, a molded product is accommodated in the cavity recess, and the connection terminal joining surface is sealed with a connection terminal joining surface of the molded product. By supplying a sealing resin having a semi-curing property in an amount to be stopped, by clamping and heating the molded article by the mold, the head of the connection terminal is exposed and the space between the connection terminals is reduced by half. A resin sealing method characterized by sealing with a resin in a cured state. 5. The resin sealing method according to claim 4, wherein a solder ball is connected as a connection terminal to the connection terminal bonding surface of the molded article.