JP2008258318A - Semiconductor chip, its packaging method and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor chip and its packaging method which facilitate repair work after packaging and also suppress manufacturing cost, and a semiconductor device packaging the semiconductor chip. <P>SOLUTION: A projection electrode 3 is formed on the back of a semiconductor substrate 1. Next, a sealing resin 5 is selectively formed on the back of the semiconductor substrate 1. At least a part of the projection electrode 3 is not covered with the sealing resin 5 and exposed from the outer peripheral direction of the individual semiconductor chip. Next, the semiconductor substrate 1 is cut along a predetermined dicing line DL to be divided into the semiconductor chips 10. Next, the projection electrode 3 is connected to a pad electrode 11, and when heat treatment is applied in this state, the projection electrode 3 is jointed to the pad electrode 11. In this process, the sealing resin 5 in a semi-hardened state is softened so as to be charged into a part between the semiconductor chip 10 and a packaging substrate 12, and the semiconductor chip 10 is bonded to the packaging substrate 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor chip on which a plurality of protruding electrodes are formed, a mounting method thereof, and a semiconductor device on which the semiconductor chip is mounted.

  In recent years, CSP (Chip Size Package) has attracted attention as a new packaging technology. The CSP refers to a small package having an outer dimension substantially the same as the outer dimension of a semiconductor chip. A BGA (Ball Grid Array) type semiconductor device is known as a kind of CSP. A BGA type semiconductor device has a plurality of ball-shaped terminals made of a metal material such as solder arranged on one surface of a package.

  A conventional method for mounting a BGA type semiconductor chip will be described with reference to FIG. Semiconductor substrate 100, a plurality of protruding electrodes 101 formed on one surface (back surface) thereof at regular intervals, and a support 102 (for example, a glass substrate) bonded on the other surface (front surface) of semiconductor substrate 100 ) Is prepared. The back surface of the semiconductor substrate 100 other than the portion where the protruding electrode 101 is formed is covered with an insulating protective film 104 made of a solder resist or the like.

  Subsequently, a mounting substrate 106 having a plurality of pad electrodes 105 made of aluminum or the like formed on the surface is prepared. Next, the semiconductor chip 100 is overlaid on the mounting substrate 106 to connect the protruding electrode 101 and the pad electrode 105, and the semiconductor chip 103 is fixed on the mounting substrate 106. In this step, the protruding electrode 101 is bonded to the pad electrode 105 by being heated and melted. Such a mounting method is generally called a flip chip connection.

  However, with recent miniaturization of semiconductor chips, there are demands such as reducing the size of the protruding electrodes and shortening the pitch of the protruding electrodes as much as possible. For this reason, it may be difficult to ensure mounting strength only by bonding the protruding electrode and the pad electrode. When the mounting strength is not sufficient, if thermal stress or physical stress is concentrated on the joint portion of the bump electrode, cracks occur and reliability cannot be ensured.

  Therefore, when a fine semiconductor chip is mounted, a sealing resin 107 called an underfill as shown in FIG. 5 is used as a material for reinforcing the connection between the semiconductor chip and the mounting substrate. By filling in between, high mounting strength was secured.

  After the semiconductor chip 103 is mounted on the mounting substrate 106, the sealing resin 107 supplies a paste-like sealing resin material around the semiconductor chip 103 using a dispenser nozzle or the like, and the semiconductor chip 103 and the mounting substrate are caused by a capillary phenomenon. The gap is formed by filling a gap between the sealing resin material 106 and the sealing resin material by heat curing. The sealing resin 107 includes an epoxy resin, a silicone resin, a phenol resin, a polyimide resin, an acrylic resin, and the like, but a thermosetting resin including an epoxy resin is generally used from the viewpoint of characteristics and cost.

Techniques related to the present invention are described in, for example, the following patent documents.
JP 2001-284380 A

  However, when the sealing resin 107 is formed as described above, there is a problem as described below. The problem is that when a defect (such as mounting displacement) is found at the joint between the semiconductor chip 103 and the mounting substrate 106 by a reliability inspection after mounting, the repair of the joint is difficult. This is because many sealing resins 107 such as epoxy resins have strong connection strength once heat-treated and cured, and it is extremely difficult to remove the semiconductor chip 103 from the mounting substrate 106 after mounting. Therefore, in such a case, they are often discarded.

  Further, even if the material of the sealing resin 107 is selected and the semiconductor chip 103 can be removed from the mounting substrate 106, an operation of softening the sealing resin 107 using a local heater such as a heat gun is performed on the mounting substrate 106. An operation of peeling the semiconductor chip 103 so as not to damage peripheral components, an operation of removing the sealing resin 107 remaining on the mounting substrate 106, and the like are necessary. Because of this time and effort, repair work is not easy.

  Further, the formation of the sealing resin 107 in the conventional mounting process has a problem that the manufacturing cost increases.

  SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a semiconductor chip, a mounting method thereof, and a semiconductor device on which the semiconductor chip is mounted, in which repair work after mounting can be easily performed and manufacturing cost can be reduced.

  The present invention has been made in view of the above problems, and its main features are as follows. That is, the semiconductor chip mounting method of the present invention includes a semiconductor substrate, a plurality of projecting electrodes formed on one surface of the semiconductor substrate, and a seal partially formed on the one surface of the semiconductor substrate. A step of forming a semiconductor chip provided with a stop resin, and a mounting substrate having an electrode formed on one surface thereof, and electrically contacting the protruding electrode and the electrode; and The step of softening and bonding the semiconductor chip and the mounting substrate via the sealing resin, and the step of curing the sealing resin thereafter, the step of forming the semiconductor chip includes the protruding electrode It is characterized in that it is performed so that the outside of the surface is exposed.

  The semiconductor chip of the present invention includes a semiconductor substrate, a plurality of protruding electrodes formed on one surface of the semiconductor substrate, and a sealing resin partially formed on one surface of the semiconductor substrate. And the outside of the plurality of protruding electrodes is exposed, and the fluidity of the sealing resin is lowered by the first heat treatment, and the fluidity is lowered by the second heat treatment higher than the first heat treatment. It has the characteristic of increasing.

  The semiconductor device of the present invention includes a semiconductor chip having a plurality of protruding electrodes on one surface, a mounting substrate having electrodes on one surface, and the electrodes are electrically connected to the protruding electrodes; A sealing resin filled in a part of a space between one surface of the semiconductor chip and one surface of the mounting substrate, and at least a part of the protruding electrode or the electrode is the sealing It is exposed from the outside without being covered with resin.

  In the present invention, the sealing resin is selectively formed on the mounting surface side of the semiconductor chip, and the side surface of the protruding electrode is exposed from the outside. Therefore, even after the semiconductor chip is mounted on the mounting substrate, the joint portion of the protruding electrode is exposed from the outside of the semiconductor chip, and repair work can be facilitated by replenishing the exposed material from the exposed portion. Can be done.

  Further, the sealing resin is formed in a lump in the process before obtaining the separated semiconductor chips. Therefore, productivity can be improved and manufacturing cost can be reduced as compared with the conventional method in which the sealing resin is individually formed in the mounting process of the semiconductor chip. Moreover, since the sealing resin of the present invention is partially formed on one surface of the semiconductor chip and the material of the sealing resin can be used efficiently, the manufacturing cost can be suppressed.

  Embodiments of the present invention will be described with reference to the drawings. 1 to 3 are cross-sectional views or plan views sequentially showing a manufacturing process from a manufacturing process of a semiconductor chip to a mounting process of the manufactured semiconductor chip. In the semiconductor chip manufacturing process described with reference to FIGS. 1 and 2, a large number of semiconductor chips are formed in a matrix with dicing lines DL as boundaries, but only a part of them is shown for convenience. explain.

  First, as shown in FIG. 1, a wafer-like semiconductor substrate 1 on which a large number of semiconductor elements (for example, integrated circuits composed of MOS transistors, bipolar transistors, capacitors, etc.) are formed for each chip region is prepared. A support 2 is bonded on the surface of the semiconductor substrate 1 via an adhesive layer (not shown). The support 2 is made of glass or the like, and supports the semiconductor substrate 1 and protects a semiconductor element (for example, a semiconductor integrated circuit composed of a MOS transistor, a capacitor, etc.) formed on the surface of the semiconductor substrate 1. It is.

  Next, a conductive material (for example, solder paste) is screen-printed on a metal layer (for example, aluminum wiring) exposed on the back surface of the semiconductor substrate 1, and the protruding material 3 is formed by reflowing the conductive material by heat treatment. . The protruding electrode 3 is an external connection electrode electrically connected to a large number of semiconductor elements formed on the semiconductor substrate 1. The protruding electrode 3 can also be formed by an electrolytic plating method or a dispensing method (application method) in which a conductive material is applied using a dispenser. The back surface of the semiconductor substrate 1 other than the portion where the protruding electrodes 3 are formed is covered with an insulating protective film 4 made of a solder resist or the like.

  The number of protruding electrodes 3 corresponding to one semiconductor chip region is determined in advance by design. In the design of this embodiment, four protruding electrodes 3 correspond to each corner of the semiconductor chip as shown in FIG. 2A. It is a configuration to be arranged. Further, the pitch of the adjacent protruding electrodes 3 is, for example, about 0.4 mm to 0.65 mm, and the height thereof is, for example, about 0.05 mm to 0.2 mm.

  Next, as shown in FIGS. 2A and 2B, a sealing resin 5 protruding in a columnar shape is selectively formed on the back surface of the semiconductor substrate 1. 2A is a schematic plan view showing a state in which the sealing resin 5 is formed, and FIG. 2B corresponds to a cross-sectional view taken along line XX in FIG. 2A.

  The sealing resin 5 will be described. The sealing resin 5 is changed in state (softened) from a semi-cured state to a paste state by a heat treatment (second heat treatment) to be described later, and is partially filled in a gap between the semiconductor chip 10 and the mounting substrate 12, It serves to reinforce the connection strength between the two.

  Next, the characteristics of the sealing resin 5 will be described. The sealing resin 5 is insulative and is pasty and fluid when applied to the back surface of the semiconductor substrate 1 (first state), but the fluidity is reduced by the first heat treatment. A semi-cured state (second state) is obtained, and the fluidity is increased again by the second heat treatment at a temperature different from the first heat treatment (in this embodiment, a temperature higher than the first heat treatment) to become a paste ( (Third state), and thereafter, it is made of a resin material having a characteristic of being completely cured through a third heat treatment at a temperature higher than that of the second heat treatment and subsequent cooling. Note that the semi-cured state described in the present embodiment may be referred to as a “B stage”. The pasty state here refers to a state with a viscosity of about 5000 to 50000 centipoise (cp), and the semi-cured state refers to an intermediate state between a paste state and a solid state with almost no viscosity. The encapsulating resin 5 used when the inventor conducted verification becomes the above-mentioned semi-cured state by the first heat treatment at about 120 ° C. to 140 ° C., and is pasted again by the second heat treatment at about 160 ° C. to 170 ° C. This is a resin layer that is in a state (third state) and is completely cured by the third heat treatment at about 175 ° C. or higher and the subsequent cooling treatment.

  As the sealing resin 5, a material containing a thermosetting resin (for example, an epoxy resin or a polyimide resin) is preferably used, and the material is not limited as long as it has the above-described state change characteristics. Accordingly, a mixture of a plurality of types of resin layers may be used, and various thermosetting agents and thermoplastic agents may be included. Note that the resin used for the sealing resin 5 may be referred to as a pre-applied sealing resin.

  For example, the sealing resin 5 is formed as follows. First, the paste-like material of the sealing resin 5 is surrounded by the protruding electrodes 3 in the central region of the semiconductor substrate 1 by a screen printing method using a predetermined printing mask and squeegee, a dispenser method using a dispenser, or the like. Selectively apply to the position. The height of the sealing resin 5 from the semiconductor substrate 1 is preferably about the same as that of the protruding electrode 3 (for example, about 0.05 mm to 0.2 mm).

  Next, for example, heat treatment (first heat treatment) at about 120 ° C. to 140 ° C. is performed to make the paste-like material in a semi-cured state (second state). The sealing resin 5 is formed at a position surrounded by the protruding electrodes 3 as in the present embodiment so that at least the outer side 6 of the protruding electrodes 3 is exposed without being covered with the sealing resin 5. . In other words, at least a part of the side surface of the protruding electrode 3 is not covered with the sealing resin 5 and is exposed from the outer peripheral direction of each semiconductor chip region. In addition, as long as the outer side 6 of the protruding electrode 3 is exposed, there is no limitation on the planar shape, number, and formation position of the sealing resin 5.

  Next, the semiconductor substrate 1 and the support 2 are cut along a predetermined dicing line DL and divided into chip-like semiconductor chips 10. As a method of dividing the semiconductor chip 10, there are a dicing method, an etching method, a laser cutting method, and the like.

  Next, as shown in FIG. 3, a mounting substrate 12 on which a pad electrode 11 made of aluminum or the like is formed is prepared. The mounting substrate 12 is a substrate on which the semiconductor chip 10 is mounted, and is made of, for example, glass / epoxy resin or phenol resin. The pad electrode 11 is a part of a wiring pattern electrically connected to a circuit element formed on the mounting substrate 12.

  Next, after the separated semiconductor chip 10 is sucked and held by a predetermined bonding tool (not shown), the protruding electrode 3 and the pad electrode 11 are aligned. Next, the protruding electrode 3 and the pad electrode 11 are brought into contact with each other, and pressure and heat are applied to the bonding tool in this state. Then, the protruding electrode 3 or the pad electrode 11 is melted, and the protruding electrode 3 and the pad electrode 11 are joined (second heat treatment). In order to improve the electrical connection and bonding strength between the protruding electrode 3 and the pad electrode 11, a conductive adhesive such as a solder material may be applied in advance between the corresponding protruding electrode 3 and the pad electrode 11. .

  During the second heat treatment, the sealing resin 5 is softened (dissolved) from a semi-cured state to become a paste and is filled between the semiconductor chip 10 and the mounting substrate 12. Is bonded via the paste-like sealing resin 5. The term “filling” as used herein means that a part between the semiconductor chip 10 and the mounting substrate 12 is filled, and a part of the protruding electrode 3 or the pad electrode 11 is not covered with the sealing resin 5 and is mounted on the mounting substrate 12. It is exposed from the outer peripheral direction. The conditions for the second heat treatment are changed according to the material and characteristics of the sealing resin 5, and are performed under conditions of, for example, about 160 ° C to 170 ° C.

  Next, after further raising the temperature (third heat treatment, for example, 175 ° C. or higher), the paste-like sealing resin 5 is cured by cooling.

  Through the above steps, the semiconductor device 20 in which the semiconductor chip 10 is mounted on the mounting substrate 12 is completed. The mounting strength of the semiconductor device 20 is reinforced by the completely cured sealing resin 5 formed between the semiconductor chip 10 and the mounting substrate 12.

  In this embodiment, the column-shaped sealing resin 5 in a semi-cured state is collectively formed for each semiconductor chip region in a process before obtaining individual semiconductor chips. Therefore, productivity can be improved and manufacturing cost can be reduced as compared with the conventional method in which the sealing resin is individually formed in the mounting process of the semiconductor chip. Moreover, since the sealing resin of the present invention is selectively formed on one surface of the semiconductor chip and the material of the sealing resin can be used efficiently, the manufacturing cost can be suppressed.

  2A and 2B, when the separated semiconductor chip 10 is obtained, the outer side 6 of the protruding electrode 3 is not covered with the sealing resin 5, and the outer peripheral direction of the semiconductor chip 10 is obtained. Is exposed from. Therefore, even if the semiconductor chip 10 undergoes a mounting process, the protruding electrode 101 and the pad electrode 105 are not all covered with the sealing resin 107 as in the conventional structure (see FIG. 5), but as shown in FIG. The side surface of the joint portion between the protruding electrode 3 and the pad electrode 11 is exposed from the outside of the semiconductor device 20. Therefore, even if a poor electrical connection (mounting misalignment, etc.) is found at the joint between the protruding electrode 3 and the pad electrode 11 by a subsequent reliability test, a conductive material (for example, solder) is present at the joint. Can be replenished. That is, repair work can be performed without removing the semiconductor chip from the implementation substrate after mounting, and problems such as poor connection can be easily solved.

  As described above, according to the present embodiment, the repair work after mounting can be performed more easily than in the past, and the semiconductor chip and its mounting method with reduced manufacturing costs, and the semiconductor device mounted with the semiconductor chip are provided. Can be provided.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be changed without departing from the gist thereof. For example, although the support 2 is bonded to one surface of the semiconductor chip in the above-described embodiment, the present invention can be applied to a semiconductor chip to which the support 2 is not bonded. Further, the numbers and shapes of the protruding electrodes 3 and the sealing resin 5 are not limited to the above-described embodiments. Therefore, three protruding electrodes 3 and sealing resin 5 may be formed on one surface of the semiconductor substrate 1 as shown in FIG. 4A, or one surface of the semiconductor substrate 1 as shown in FIG. 4B. A flat projection electrode 3a and a sealing resin 5a may be formed thereon. The present invention is widely applicable as a technique in which a protruding electrode is formed on one surface of a semiconductor chip and the chip is mounted on a mounting substrate.

It is sectional drawing explaining the semiconductor device which mounted the semiconductor chip concerning the embodiment of the present invention, its mounting method, and a semiconductor chip. 1A and 1B are a plan view and a cross-sectional view illustrating a semiconductor chip, a mounting method thereof, and a semiconductor device mounted with the semiconductor chip according to an embodiment of the present invention. It is sectional drawing explaining the semiconductor device which mounted the semiconductor chip concerning the embodiment of the present invention, its mounting method, and a semiconductor chip. It is a top view which shows the example of a change of this invention. It is sectional drawing explaining the mounting method of the conventional semiconductor chip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Support body 3, 3a Protrusion electrode 4 Protective film 5, 5a Sealing resin 6 (Outside of protrusion electrode) 10 Semiconductor chip 11 Pad electrode 12 Mounting substrate 20 Semiconductor device 100 Semiconductor substrate 101 Protrusion electrode 102 Support body 103 Semiconductor Chip 104 Protective film 105 Pad electrode 106 Mounting substrate 107 Sealing resin

Claims (6)

Forming a semiconductor chip comprising: a semiconductor substrate; a plurality of protruding electrodes formed on one surface of the semiconductor substrate; and a sealing resin partially formed on the one surface of the semiconductor substrate. When,
Prepare a mounting board with electrodes on one side,
Electrically contacting the protruding electrode and the electrode, and softening the sealing resin to bond the semiconductor chip and the mounting substrate via the sealing resin;
And then curing the sealing resin,
The method of mounting a semiconductor chip, wherein the step of forming the semiconductor chip is performed such that the outside of the protruding electrode is exposed. The sealing resin is
Formed through a step of forming a paste-like resin on one surface of the semiconductor substrate, and then a step of semi-curing the resin by applying a first heat treatment;
The step of bonding the semiconductor chip and the mounting substrate through the sealing resin,
Including a step of increasing the fluidity of the sealing resin by performing a second heat treatment at a temperature higher than that of the first heat treatment,
The method for mounting a semiconductor chip according to claim 1, wherein the step of curing the sealing resin includes a step of performing a third heat treatment higher than the second heat treatment. A semiconductor substrate;
A plurality of protruding electrodes formed on one surface of the semiconductor substrate;
A sealing resin partially formed on one surface of the semiconductor substrate,
The outside of the plurality of protruding electrodes is exposed,
The semiconductor chip is characterized in that the fluidity is lowered by the first heat treatment, and the fluidity is increased by the second heat treatment at a temperature higher than that of the first heat treatment. The semiconductor chip according to claim 3, wherein the sealing resin is surrounded by the plurality of protruding electrodes. A semiconductor chip having a plurality of protruding electrodes on one surface;
A mounting substrate comprising an electrode on one surface, wherein the electrode is electrically connected to the protruding electrode;
A sealing resin filled in a part of a space between one surface of the semiconductor chip and one surface of the mounting substrate;
The semiconductor device, wherein the protruding electrode or at least a part of the electrode is exposed from the outside without being covered with the sealing resin. The semiconductor device according to claim 5, wherein the sealing resin is surrounded by the plurality of protruding electrodes.

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