JP2008010694A - Substrate for mounting semiconductor, manufacturing method thereof, and mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for mounting a semiconductor and a mounting structure therefor which improve the yield of flip chip mounting of a semiconductor component and which can yield high reliability. <P>SOLUTION: The substrate for mounting semiconductor is provided with a via electrode 8 for interlayer connection in the substrate 3 under an electrode land 4, and a projection 9 is formed on the surface of the electrode land 4 by the via electrode 8. The variety of heights of solder bumps 7 of the semiconductor component 1 is absorbed, mounting with a high yield is available, and, on the other hand, the amount of used solder can be reduced, thereby permitting the prevention of outflow of the solder upon remelting of the same. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit board for mounting a semiconductor component and a mounting structure.

  In recent years, demands for thinning and miniaturization represented by portable devices and the like have been increasing for electronic devices, and there is a strong demand for lowering the mounting structure of electronic components used for them.

  For this reason, the semiconductor component used is not a package having a lead, but a so-called flip chip mounting in which the semiconductor component is mounted on the substrate.

  FIG. 4 shows a cross-sectional view of the flip chip mounting structure. The electrode 102 provided on the surface of the semiconductor component 101 and the opening 105 of the resist 108 on the electrode land 104 formed on the substrate 103 are connected by solder 106.

  In general, a flip chip mounting process by solder connection of semiconductor components is performed as shown in FIG.

  As shown in FIG. 5A, a protrusion made of solder called a solder bump 107 is provided in advance on the surface of the connection electrode 102 of the semiconductor component 101. In addition, in the connection electrode land 104 formed on the substrate 103, an opening 105 in which the metal foil is partially exposed is formed by the applied solder resist material 108 so that the solder spreads only in a predetermined range. Keep it.

  Next, as shown in FIG. 5B, the solder bumps 107 of the semiconductor component are arranged in alignment with the resist openings 105 of the electrode lands 104.

  Next, as shown in FIG. 5C, the substrate and the semiconductor component are heated, the solder bumps 107 are melted, and the solder is wet spread in the openings 105 of the electrode lands on the substrate side, and then cooled and solidified. Joining is completed.

  Further, in order to improve durability against a drop impact or the like, generally, a reinforcing resin 109 is injected and cured in a gap between the semiconductor component 101 and the substrate 103 as shown in FIG.

As prior art document information, for example, the following Patent Document 1 is known.
Japanese Patent Laid-Open No. 02-016756

  As described above, when a semiconductor component is mounted on a substrate, there is a problem that a mounting failure occurs due to variations in the height of solder bumps. The cause of this phenomenon is shown in FIG.

  FIG. 6A shows a state in which the semiconductor component 101 having a variation in solder bump height is arranged on the substrate 103, and in this case, the height of the central solder bump 110 is low.

  Since the central solder bump 110 is low in height, it is located away from the opening 105 of the electrode land on the substrate.

  When the solder is melted in this state, the solder bumps 111 on both sides almost in contact with the surface of the opening 105 of the substrate electrode land spread out on the surface of the opening 105 of the substrate electrode land, resulting in a decrease in height. The central bump 110 also approaches the surface of the opening 105 of the substrate electrode land.

  When the bump height variation is large, the central bump 110 having a low height cannot be brought into contact with the surface of the opening 105 of the substrate electrode land, and remains floating as shown in FIG. As a result, connection failure occurs.

  Also, in general, when the temperature changes, the higher the solder height after the connection between the semiconductor component and the substrate is, the higher the thermal stress is due to the difference in thermal expansion coefficient between the semiconductor component and the substrate. Less distortion and high reliability.

  However, when the amount of solder is increased in order to increase the solder height, another problem occurs.

  That is, a semiconductor component flip-chip mounted on a substrate is mounted on a circuit board together with other components in the final electronic device manufacturer. Since this mounting is generally performed by a solder reflow method, the semiconductor component and the substrate are mounted. The connected solder will also melt again.

  The solder tends to expand when heated, but as shown in FIG. 7, since the periphery of the solder 112 is surrounded by the reinforcing resin 109, the solder is heated to a temperature exceeding the melting point and becomes liquid. As pressure increases, the interface between the substrate and the resin filled between the semiconductor components is peeled off and flows out, resulting in a connection failure. Reference numeral 113 denotes the leaked solder. This phenomenon is more likely to occur as the amount of solder connecting the semiconductor component and the substrate increases.

  In order to solve the above problems, a semiconductor mounting substrate of the present invention is a substrate having electrodes arranged corresponding to connection electrodes on a semiconductor component to be mounted, and an interlayer connection via electrode is provided under the electrodes. A projection is formed on the electrode surface by the via electrode.

  In the semiconductor mounting substrate of the present invention, even when the solder bump provided on the semiconductor component to be mounted has a height variation, the protrusion provided on the surface of the substrate electrode land absorbs the bump height variation, and the connection failure is caused. Hard to occur.

  Further, due to the effect of the protrusions on the surface of the substrate electrode land, the amount of solder necessary to maintain the distance between the semiconductor component and the substrate is reduced, and when the solder is remelted, the molten solder does not easily flow out.

  In addition, in forming a projection on the electrode land surface on the substrate, the metal foil for forming the electrode is formed into a projection shape by the interlayer connection via electrode provided under the electrode. Is not added, and has an effect that a highly reliable mounting structure can be easily provided.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view for explaining a mounting structure of a semiconductor mounting substrate and a semiconductor component, which is an example of the first embodiment of the present invention.

  In the present embodiment, as shown in FIG. 1, the connection electrode 2 provided on the surface of the semiconductor component 1, the opening 6 of the solder resist 5 provided on the electrode land 4 formed on the substrate 3, and However, it is in a state of being connected by the solder 7, and in the opening 6 of the solder resist 5 provided on the electrode land 4, there is a protrusion 9 formed by pushing up the interlayer connection via electrode 8.

  A method for realizing this structure will be described with reference to the drawings.

  FIG. 2 is a diagram illustrating the steps for manufacturing the semiconductor mounting substrate of the present invention.

  FIG. 2A shows a state in which the through hole 11 is provided in the insulating substrate 10 and the paste electrode material 12 is filled in the through hole 11.

  The paste electrode material 12 was made of copper paste and filled in the through holes 11 by a mask printing method.

  The paste electrode material 12 has a shape protruding from the surface of the insulating substrate 10 and can be easily formed by utilizing the thickness of the printing mask.

  Next, as shown in FIG. 2B, metal foil, here, copper foil 13 is installed on both surfaces of the insulating substrate 10.

  Next, FIG. 2C shows a state where the insulating substrate 10 and the copper foil 13 in the above state are mounted on a hot press apparatus (not shown) and pressed.

  In the present embodiment, the flat plate material 14 shown on the upper surface is a flexible sheet, and the flat plate material 15 shown on the lower surface is a rigid sheet.

  For example, a sheet of synthetic rubber, urethane resin, silicone resin, fluorine resin, or the like can be used for the flat plate member 14 having flexibility. The rigid flat plate 15 can be made of a metal material such as stainless steel or a ceramic material. Thus, since the flat plate material 14 side has flexibility, the paste electrode material 12 is laminated with the flat plate material 14 side raised as shown in FIG.

  In the present invention, when a so-called prepreg containing a semi-cured epoxy resin is used for the insulating substrate 10, the copper foil 13 can be bonded to the insulating substrate 10 without using an adhesive.

  When the insulating substrate 10 and the paste electrode material 12 are cured by heating in the pressed state, the copper foil 13 is etched into a predetermined pattern, and the solder resist 5 is formed into a predetermined pattern. Thus, a substrate is obtained in which the vias 8 for interlayer connection of the substrate 3 are formed with protrusions 9 formed by pushing up the copper foil in the openings 6 of the solder resist 5 provided on the electrode lands 4.

  In the present embodiment, in the flat plate material shown in FIG. 2C, only the upper surface of the substrate 3, that is, the flat plate material 14 on one side is a flexible sheet, but the flat plate materials 14 and 15 on both sides of the substrate 3. May be a flexible sheet. When mounting semiconductor components on both sides of the substrate 3, via electrodes 8 having protrusions 9 are required on both sides of the substrate 3. In FIG. 2C, the flat plate members 14 and 15 on both sides are flexible sheets. The configuration consisting of:

  By using the substrate obtained in FIG. 2D for semiconductor mounting, it is possible to mount with high yield even when the solder bumps of the semiconductor component have height variations. This effect will be described with reference to FIG.

  FIG. 3 illustrates the steps of mounting a semiconductor component having solder bumps with variations in height on the substrate of the present invention.

  FIG. 3A shows a state in which the opening 6 of the substrate land of the present invention and the solder bumps 16 to 18 on the semiconductor component 1 are aligned and arranged. Here, since the solder bumps vary in height, the solder bumps 16 and 18 are substantially in contact with the protrusion 9 of the board land portion, but the solder bump 17 having a low height is not in contact.

  In this embodiment, the via electrode 8 of the substrate 3 in FIG. 3 is provided with the protrusions 9 on one side. However, when the semiconductor component is mounted on both sides, the via electrode 8 is provided with the protrusions 9 on both sides. It becomes composition.

  FIG. 3B illustrates the state at the time when the solder starts to melt in the above-described state. As the solder melts, the solder bumps 16 and 18 begin to get wet with the protrusions 9 on the board land, and the gap between the semiconductor component 1 and the board 3 becomes narrower.

  At this time, the solder wets and spreads on the side surfaces of the protrusions 9 of the board land portion, so that the gap between the semiconductor component 1 and the substrate 3 can be made significantly larger than that without the protrusions 9 and the height is low. The solder bumps 17 are also surely in contact with the protrusions 9 on the board land portion.

  When the solder bumps 17 and the projections 9 on the board land portion come into contact with each other, the melted solder 7 starts to spread rapidly on the board land portions, and as a result, as shown in FIG. Spreads to the opening 6 of the substrate land, and a reliable connection is obtained.

  Further, as shown in FIG. 3C, after the mounting is completed, the protrusion 9 of the board land portion enters the solder 7, and the height of the solder 7 can be maintained even if the amount of the solder 7 is small. Therefore, when the height of the solder 7 is the same, it can be mounted with a smaller amount of solder than when there is no projection 9 on the board land portion.

  As a result, the distance between the substrate 3 and the semiconductor component 1 can be increased without increasing the amount of solder, the reliability can be improved, and the amount of solder is small, so that when the solder is melted again The effect that solder outflow can be prevented occurs.

  The substrate for semiconductor mounting and the semiconductor mounting structure of the present invention can mount semiconductor components with high yield and can withstand remelting of solder. High reliability is obtained, and it is useful as a substrate for small electronic devices and a mounting structure.

Sectional drawing of the semiconductor component mounting part in Embodiment 1 of this invention Process explanatory drawing of the semiconductor component mounting board | substrate in Embodiment 1 of this invention Semiconductor component mounting process explanatory drawing in Embodiment 1 of this invention Sectional view of conventional semiconductor component mounting part Illustration of conventional semiconductor component mounting process Illustration of conventional semiconductor component mounting process Sectional drawing for demonstrating the subject of the conventional mounting structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor component 2 Connection electrode 3 Board | substrate 4 Electrode land 5 Solder resist 6 Opening part 7 Solder 8 Via electrode 9 Protrusion 10 Insulating board 11 Through-hole 12 Paste electrode material 13 Copper foil 14 Flat plate material 15 Flat plate material 16, 17, 18 Solder bump

Claims (4)

A substrate having an electrode land arranged corresponding to a connection electrode on a semiconductor component to be mounted, and an interlayer connection via electrode in the substrate is provided under the electrode land, and a projection is formed on the surface of the electrode land by the via electrode. Substrate for semiconductor mounting. A semiconductor mounting structure in which an electrode land on the substrate and a connection electrode on a semiconductor component are connected by solder. A step of providing a through hole in the insulating substrate, a step of filling the through hole with a paste electrode material in a shape protruding from the surface of the insulating substrate, and pressing a metal foil on both surfaces of the insulating substrate. The manufacturing method of the board | substrate for semiconductor mounting which consists of the process which adhere | attaches while hardening a paste-form electrode material. In the step of adhering while pressing the metal foil to both surfaces of the insulating substrate, at least one side of the surface in contact with the metal foil on the both surfaces in the apparatus for pressing the metal foil is a flexible member, Manufacturing method for industrial use.

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