JP2006005208A - Semiconductor device and mounting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a semiconductor device on a printed circuit board by a simple method with an optimal amount of resin provided on the protruding electrode surface of the semiconductor device.
A substrate 1 provided with a plurality of wirings, a semiconductor element 2 mounted on the substrate 1 and having wiring pads, and a plurality of wirings of the substrate 1 and wiring pads of the semiconductor element 2 are electrically connected. A semiconductor device comprising a connecting means 3, a plurality of protruding electrodes 4 provided on the opposite side of the substrate 1 from the semiconductor element 2, and a resin 5 provided on the substrate surface between the plurality of protruding electrodes 4. The area of the lower surface provided with the resin 5 is equal to or larger than the area of the substrate surface. Thereby, it is possible to provide an optimal amount of resin, and the resin shape after mounting on the printed circuit board can greatly contribute to the improvement of reliability because it forms a large fillet.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device for applying a resin to a gap between a semiconductor device and a printed circuit board for the purpose of facilitating a mounting process of the semiconductor device on a printed circuit board and improving reliability after mounting, and a mounting method thereof.

  As semiconductor devices are becoming lighter, thinner, and smaller, the connection electrodes of the semiconductor devices are also narrowed, and the electrodes themselves are shifting toward smaller volumes and smaller areas. The same applies to printed circuit board mounting using a semiconductor device, and the electrodes connecting the semiconductor device and the printed circuit board are reduced in volume and area, and there is a danger of lowering the mounting reliability of the board. As means for improving the board mounting reliability, a method of injecting a thermosetting resin into a gap between the semiconductor device and the printed board and heat-curing is generally performed in a printed board mounting manufacturer. Recently, a method of preparing a cured resin on the semiconductor device side in advance has been considered.

  Hereinafter, a conventional thermosetting resin coating method will be described with reference to the drawings.

  11 and 12 are flow charts of a mounting method using a conventional semiconductor device. First, there is a solder printing process in which a solder paste 103 is applied to an electrode pad (not shown) on the printed circuit board 104, and there is a semiconductor device product mounting process in which the semiconductor device 101 is prepared and placed on the printed circuit board 104. There is a reflow process in which the solder paste 103 is melted by heating the entire device 104 and the semiconductor device 101. Normally, the printed circuit board is completed by this process, but after the electrical inspection of the printed circuit board for further improvement in reliability, a process of injecting a so-called underfill 102 into the gap between the semiconductor device 101 and the printed circuit board 104. There is a step of thermally curing the underfill by heating again. Through these steps, the semiconductor device 101 and the printed board 104 are more firmly fixed. In the case of this conventional construction method, it is said that various burdens such as equipment cost, time and manpower are large because the injection and curing steps of the underfill 102 are extra than the normal steps. Furthermore, since the area of the connecting lands tends to be narrowed along with the recent narrowing of the pitch, a so-called solder mask remaining phenomenon in which the solder paste does not come out of the printing mask hole occurs in the above-described solder printing process. In addition, after the reflow, the flux agent contained in the solder paste solidifies and adheres around the solder balls, so that intrusion of the underfill is hindered in the subsequent underfill injection process, and the deepest part of the gap between the semiconductor product and the printed circuit board is reached. It becomes impossible to inject. In addition, since it is necessary to secure a space for injecting underfill, it is necessary to increase the distance between parts of adjacent semiconductor products, which makes high-density design impossible. Therefore, as shown in FIG. 12, a method for applying an underfill resin agent 105 to the semiconductor device 101 in advance and fixing it to a printed circuit board simultaneously with reflow mounting has been described in several documents.

For example, Patent Document 1 has a structure in which a thermoplastic resin is provided between a protruding electrode and a protruding electrode of a semiconductor device.
JP-A-11-297750

  However, there is a fear that the amount of the thermoplastic resin is insufficient in the conventional method, and there is a concern about mounting reliability after reflow heating mounting on a printed board.

  Accordingly, an object of the present invention is to provide a semiconductor device capable of mounting a semiconductor device on a printed circuit board by a simple method with an optimal amount of resin provided on the protruding electrode surface of the semiconductor device, and a mounting method thereof. That is.

  In order to solve the above problem, a semiconductor device according to claim 1 of the present invention includes a substrate provided with a plurality of wirings, a semiconductor element mounted on the substrate and having a wiring pad, and a plurality of wirings on the substrate. Connecting means for electrically connecting wiring pads of the semiconductor element; a plurality of electrodes provided on the opposite side of the substrate from the semiconductor element; and a resin provided on a substrate surface between the plurality of electrodes; The area of the lower surface provided with the resin is equal to or greater than the area of the substrate surface.

  The semiconductor device according to claim 2 is a semiconductor device comprising a semiconductor element, a plurality of electrodes provided on the semiconductor element, and a resin provided on a semiconductor element surface between the plurality of electrodes, The area of the lower surface provided with the resin is equal to or greater than the area of the semiconductor element surface.

  A semiconductor device according to a third aspect is the semiconductor device according to the first or second aspect, wherein the resin is either a thermoplastic resin or a thermosetting resin.

  A semiconductor device according to claim 4 is the semiconductor device according to claim 1, 2 or 3, wherein the substrate is a plastic BGA, 42 alloy or copper metal made of an organic substrate or a thin film material made of polyimide resin. A lead frame type BGA made of a frame or a ceramic type BGA made of a ceramic material.

  The semiconductor device according to claim 5 is the semiconductor device according to claim 1, 2, 3, or 4, wherein the electrodes of the semiconductor device are formed on the same surface or buried in the bottom surface on which the resin is provided. did.

  A method for mounting a semiconductor device according to claim 6 is a step of heating and mounting the semiconductor device according to claim 1, 2, 3, 4 or 5 on a printed circuit board, wherein the resin includes a component having an oxide removing effect, Simultaneously with the melting of the resin, the oxide on the electrode of the printed board is removed, and the electrode of the semiconductor device and the electrode of the printed board are connected.

  A method for mounting a semiconductor device according to claim 7 comprises preparing the semiconductor device according to claim 1, 2, 3, 4 or 5 and a solvent having an oxide removing effect, and mounting the semiconductor device on a printed circuit board by heating. In this step, after the solvent is applied onto the electrode of the printed board, the electrode of the semiconductor device and the electrode of the printed board are connected.

  According to the semiconductor device of the first aspect of the present invention, there is provided a substrate provided with a plurality of wirings, a semiconductor element mounted on the substrate and having a wiring pad, a plurality of wirings on the substrate, and a wiring pad of the semiconductor element. An electrically connected connecting means, a plurality of electrodes provided on the opposite side of the substrate from the semiconductor element, and a resin provided on the substrate surface between the plurality of electrodes, the area of the lower surface provided with the resin Is equal to or larger than the area of the substrate surface, so that an optimal amount of resin can be provided. Thereby, since the resin shape after mounting on the printed circuit board forms a large fillet, it can greatly contribute to the improvement of reliability. Further, even if the amount of resin applied is increased, the electrode is not buried in the resin, and an appearance inspection such as an electrical characteristic inspection in which an inspection pin is brought into contact with the electrode or an electrode displacement inspection can be easily performed.

  According to a second aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor element; a plurality of electrodes provided on the semiconductor element; and a resin provided on a semiconductor element surface between the plurality of electrodes. Since the area of the lower surface is equal to or larger than the area of the semiconductor element surface, the same effect as in the first aspect can be obtained in a semiconductor device composed of only semiconductor elements, so-called wafer level package or flip chip package.

  According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, the resin is preferably either a thermoplastic resin or a thermosetting resin. Note that a thermoplastic resin is desirable for the purpose of being able to be easily removed in a so-called repair process of removing a defective semiconductor device after mounting on a printed circuit board.

  5. The semiconductor device according to claim 1, wherein the substrate is a plastic BGA made of a thin film material made of an organic substrate or a polyimide resin, 42 alloy, or a lead frame made of a copper metal frame. A type BGA or a ceramic type BGA made of a ceramic material is desirable.

  According to a fifth aspect of the present invention, in the semiconductor device according to the first, second, third, or fourth aspect, it is desirable that the electrodes of the semiconductor device have the same surface or a recessed shape with respect to the lower surface provided with the resin.

  According to the method for mounting a semiconductor device according to claim 6 of the present invention, the resin has an oxide removal effect in the step of heat mounting the semiconductor device according to claim 1, 2, 3, 4 or 5 onto the printed circuit board. As the resin melts, the oxide on the printed circuit board electrode is removed and the electrode of the semiconductor device is connected to the printed circuit board electrode. It can be improved and the mounting process on the printed circuit board can be facilitated. In this case, the semiconductor device and the printed board can be easily connected by exhibiting a so-called flux effect that removes the oxide on the electrode of the printed board simultaneously with the melting of the resin.

  According to a method for mounting a semiconductor device according to a seventh aspect of the present invention, the semiconductor device according to the first, second, third, fourth or fifth aspect and a solvent having an oxide removing effect are prepared, and the semiconductor device is printed. In the process of heat mounting on the substrate, the solvent is applied onto the electrode of the printed circuit board, and then the electrode of the semiconductor device and the electrode of the printed circuit board are connected. The mounting reliability after reflow heating mounting on the board can be further improved, and the mounting process on the printed board can be facilitated.

  Embodiments of a semiconductor device and a mounting method thereof according to the present invention will be described below with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a plan view of the semiconductor device viewed from the protruding electrode surface side, and FIG. 3 is an enlarged view of a portion A in FIG.

  As shown in FIG. 1 to FIG. 3, a substrate 1 provided with a plurality of wirings, a semiconductor element 2 mounted on the substrate 1 and having wiring pads, a plurality of wirings on the substrate 1, and wiring pads of the semiconductor elements 2 Connecting means 3 (stud bump bonding method is shown in FIG. 1), a plurality of protruding electrodes 4 provided on the opposite side of the semiconductor element 2 on the substrate 1, and a plurality of protruding electrodes 4 There is a semiconductor device 6 in which either one of a thermoplastic resin or a thermosetting resin 5 is provided on the substrate surface, and the area of the lower surface on which the resin 5 is provided is equal to or larger than the area of the substrate surface. It has become. With this configuration, the resin shape after mounting on the printed board forms a large fillet, which can greatly contribute to the improvement of reliability.

  FIG. 4 is an enlarged view corresponding to part A of FIG. 1, and shows a case different from FIG. As shown in FIG. 4, the resin 5 provided in the semiconductor device 6 is configured to protrude to the side surface of the substrate 1 in order to secure a large fillet after the printed circuit board is mounted. With this configuration, the protruding electrode 4 is not buried in the resin 5 even when the amount of the resin 5 applied is increased. Therefore, the external appearance such as an electrical characteristic inspection in which the inspection pin is brought into contact with the protruding electrode 4 and a positional deviation inspection of the protruding electrode 4 is performed. Inspection is also easy.

  In this embodiment, the substrate 1 used for the semiconductor device 6 is an organic substrate made of several metal layers, a polyimide film to which a metal layer is attached, a lead frame made of a metal plate such as 42 alloy or copper, tungsten And a ceramic with a metal layer typified by molybdenum or the like attached thereto, and the base material is selected according to a so-called package shape configured in accordance with the purpose of the semiconductor device. A detailed package shape will be described later with reference to the drawings (fourth embodiment).

  In this embodiment, the protruding electrode is often a metal ball having a diameter of about 0.2 mm to about 0.8 mm, and the metal composition does not use lead in accordance with recent environmental problems in addition to tin-lead eutectic solder. Examples include so-called lead-free solder. In some cases, a bump electrode called a bump having a smaller diameter is used. Note that the protruding electrodes may be recessed on the same surface or embedded with respect to the lower surface provided with the resin.

  In this embodiment, it is desirable that the resin 5 is either thermoplastic or thermosetting, but the purpose is that the defective semiconductor device can be easily removed in a so-called repair process after mounting the printed circuit board. If so, a thermoplastic resin is desirable. In recent years, thermosetting resins that can be repaired have been developed.

  A second embodiment of the present invention will be described with reference to FIGS. 5 and 6 are side views of the semiconductor device mounting method according to the first embodiment of the present invention.

  As shown in FIG. 5, the mounting method uses the semiconductor device 6 of the first embodiment. Here, in the step of heating and mounting the ball grid array 7 on the printed circuit board 8, a plurality of the mounting methods provided on the printed circuit board 8 are used. The wiring pads (electrodes) 9 are opposed to the protruding electrodes 4 of the semiconductor device 6 and are placed on the printed circuit board 8 while being aligned and mounted by heating reflow. It is desirable that the resin 5 contains a so-called flux agent having an oxide removing action, so that the surfaces of the wiring pads 9 and the protruding electrodes 4 can be activated during preheating for reflow mounting. Preheating usually requires a furnace temperature of around 140 ° C to around 180 ° C and an elapsed time of several tens of seconds to several minutes. It is suitable for the size of the printed circuit board, the size and number of mounted components, and the solder paste composition. It is necessary to select the conditions. At the time of the main heating in the reflow mounting, the viscosity of the resin 5 is preferably as low as possible so that the so-called self-alignment effect in which the protruding electrodes 4 of the semiconductor device 6 align themselves with the wiring pads 9 of the printed circuit board 8 can be exhibited. When the main heating for reflow mounting is passed, the protruding electrode 4 is bonded to the wiring pad 9 between the metals, and then the resin 5 is solidified and the semiconductor device 6 and the printed board 8 are fixed.

  Further, as shown in FIG. 6, when the resin 5 does not contain a flux agent, the flux agent 10 is preliminarily applied mainly on the wiring pads 9 of the printed circuit board 8 before the semiconductor device 6 is mounted on the printed circuit board 8. Apply. Alternatively, a method of applying and transferring a flux agent to the protruding electrode 4 immediately before mounting the semiconductor device 6 on the printed circuit board 8 (not shown) may be used. For the purpose of improving the reliability after mounting the printed circuit board, it is desirable that the resin 5 forms a fillet that extends not only to the gap between the semiconductor device 6 and the printed circuit board 8 but also to the side surface of the semiconductor device. It's better to do it. The configuration is as described above with reference to FIGS.

  A third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a side view of the semiconductor device manufacturing method according to the third embodiment of the present invention.

  As shown in FIG. 7, in the semiconductor device 6 of the first embodiment, the liquid resin 11 may be used as long as it is mainly composed of the resin 5 component. As a merit of the liquid resin 11, it is possible to freely control the coating amount according to the size of the semiconductor device 6 (semiconductor elements and the like not shown) and according to the size of the protruding electrodes (not shown). The application location can also be freely selected.

  A fourth embodiment of the present invention will be described with reference to FIGS. 8 to 10 are side views showing examples of different package shapes in the semiconductor device according to the fourth embodiment of the present invention.

  The semiconductor device 14 shown in FIG. 8 is called a plastic type BGA or an OMPAC type BGA. The semiconductor element 2 is mounted on an organic substrate 15 in which several metal layers and a resin layer are laminated in order, and the organic thin wires 16 are used to A wiring pad (not shown) of the substrate 15 and an electrode pad (not shown) of the semiconductor element 2 are electrically connected and protected mainly by an epoxy-based sealing resin 25, and is opposite to the semiconductor element 2. This surface is provided with a solder ball 4 and a resin 5 similar to that of the first embodiment of the present invention. The organic substrate 15 becomes a so-called tape type BGA by using a polyimide film to which a metal layer is attached.

  The semiconductor device 17 shown in FIG. 9 is called a lead frame type BGA. The semiconductor element 2 is mounted on a lead frame 18 made of a metal plate such as 42 alloy or copper, and the lead frame 18 and the semiconductor element 2 are connected by a thin metal wire 16. An electrode pad (not shown) is electrically connected and is mainly protected by an epoxy-based sealing resin 25, and the solder ball 4 and the first electrode of the present invention are provided on the lead frame 18 on the surface opposite to the semiconductor element 2. A resin 5 similar to that of the first embodiment is provided.

  The semiconductor device 19 shown in FIG. 10 is called a wafer level package, and is provided on the semiconductor element 2, the plurality of protruding electrodes 20 provided on the semiconductor element 2, and the semiconductor element surface between the plurality of protruding electrodes 20. A semiconductor device including the resin 5, wherein an area of a lower surface on which the resin 5 is provided is equal to or greater than an area of a semiconductor element surface. In this case, the protruding electrode 20 is provided on the electrode pad of the semiconductor element 2, and the same resin 5 as that of the first embodiment of the present invention is provided on the same surface as the protruding electrode 20. The semiconductor device may be a flip chip package.

  These are representative semiconductor devices. However, the embodiments of the present invention are not limited to these semiconductor devices, and are not only semiconductor devices having protruding electrodes, but also land types without protruding electrodes, so-called lands. It can also be applied to a grid array type LGA. In this case, since the gap between the semiconductor device after mounting on the printed circuit board and the printed circuit board becomes very narrow, it is necessary to provide an appropriate amount of resin corresponding to the gap. In some cases, the resin may not be provided on the entire land portion of the semiconductor device, but only on portions other than the land portion.

  As described above, by using the present invention, it is possible to provide the optimum amount of resin, the mounting reliability after reflow heating mounting on the printed circuit board can be further improved, and the mounting process on the printed circuit board is easy. Can be.

  The semiconductor device and the mounting method thereof according to the present invention can provide an optimal amount of resin, can further improve mounting reliability after reflow heating mounting on a printed circuit board, and can perform a mounting process on the printed circuit board. It has an effect that it can be easily performed, and is useful as a means for improving the reliability of a semiconductor device mounted on a printed circuit board.

1 is a side view of a semiconductor device according to a first embodiment of the present invention. FIG. 2 is a plan view of the semiconductor device of FIG. It is the A section enlarged view of FIG. It is an enlarged view of another example corresponding to the A section of FIG. It is a side view of the mounting method of the semiconductor device of a 1st embodiment of the present invention. It is a side view of another example of the mounting method of the semiconductor device of the 1st Embodiment of this invention. It is a side view of the manufacturing method of the semiconductor device of the 3rd Embodiment of this invention. It is a side view which shows the example from which a package shape differs in the semiconductor device of the 4th Embodiment of this invention. It is a side view which shows the example from which a package shape differs in the semiconductor device of the 4th Embodiment of this invention. It is a side view which shows the example from which a package shape differs in the semiconductor device of the 4th Embodiment of this invention. It is a side view of the mounting method using the conventional semiconductor device. It is a side view of another example of the mounting method using the conventional semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Semiconductor element 3 Connection means 4 Projection electrode 5 Resin 6 Semiconductor device 7 Ball grid array type package (BGA)
8 Printed circuit board 9 Wiring pad 10 Flux agent 11 Liquid resin 12 Dent 13 Dam 14 Semiconductor device 15 Organic substrate 16 Metal thin wire 17 Semiconductor device 18 Lead frame 19 Semiconductor device 20 Protruding electrode 101 Semiconductor device 102 Underfill 103 Solder paste 104 Printed circuit board 105 Underfill resin agent

Claims (7)

  A substrate provided with a plurality of wirings, a semiconductor element mounted on the substrate and having a wiring pad, a connection means for electrically connecting the plurality of wirings of the substrate and the wiring pads of the semiconductor element, and the substrate A semiconductor device comprising a plurality of electrodes provided on the opposite side of the semiconductor element and a resin provided on a substrate surface between the plurality of electrodes, wherein an area of a lower surface provided with the resin is A semiconductor device having an area equal to or greater than the area of the substrate surface.   A semiconductor device comprising a semiconductor element, a plurality of electrodes provided on the semiconductor element, and a resin provided on a semiconductor element surface between the plurality of electrodes, wherein an area of a lower surface provided with the resin is A semiconductor device having an area equal to or greater than the area of the semiconductor element surface.   The semiconductor device according to claim 1, wherein the resin is one of a thermoplastic resin or a thermosetting resin.   The substrate is a plastic BGA made of an organic substrate or a thin film material made of polyimide resin, a lead frame type BGA made of a 42 alloy or copper metal frame, or a ceramic type BGA made of a ceramic material. The semiconductor device according to 1, 2 or 3.   5. The semiconductor device according to claim 1, wherein the electrodes of the semiconductor device are formed in the same surface or a recessed shape with respect to the lower surface provided with the resin.   6. The step of heat-mounting the semiconductor device according to claim 1, 2, 3, 4, or 5 on a printed circuit board, wherein the resin includes a component having an oxide removing effect, and at the same time as the resin melts, on the electrode of the printed circuit board A method for mounting a semiconductor device, comprising removing the oxide and connecting the electrode of the semiconductor device and the electrode of the printed circuit board.   6. A step of preparing the semiconductor device according to claim 1, 2, 3, 4 or 5 and a solvent having an oxide removing effect, and heating and mounting the semiconductor device on a printed circuit board. A method for mounting a semiconductor device, comprising: connecting an electrode of the semiconductor device and an electrode of the printed circuit board after coating on the substrate.

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