KR101671258B1 - Stacked semiconductor module - Google Patents

Abstract

A pad 15 is provided on the connection surface of the lower module with the upper module of the first substrate 11 and an opening 3 is formed in which the pad 15 is covered by the insulation film 20, The first connection terminal 2 is formed on the lower surface of the first substrate 11 of the lower module and the planar shape of the opening 3 is different from the plane shape of the first connection terminal 2, And the shape of the lower end of the second connection terminal 30 widened to the opening portion 3 is not exposed to the other terminal even when the transmission inspection is performed from the upper side. According to this, it is possible to easily and surely determine whether or not the joint portion is in the nondestructive inspection.

Description

[0001] STACKED SEMICONDUCTOR MODULE [0002]

The present invention relates to a semiconductor module for stacking arranged in the lowest layer when a plurality of semiconductor devices are stacked and a stacked semiconductor module using the same.

There has been developed a package-on-a-package (hereinafter referred to as " package on package ") in which electronic components, in particular, a plurality of semiconductor devices and chips are stacked and integrated in accordance with a demand for miniaturization and high functionality of various electronic apparatuses such as cellular phone apparatuses and digital cameras.

In the mounting of the stacked semiconductor module, there is a problem of improvement in inspection sensitivity due to the increase in the number of steps and high functionality of the connection of the upper and lower packages due to the higher density of one layer. On the other hand, .

Japanese Unexamined Patent Application Publication No. 2004-363126 is known as a conventional stacked semiconductor module. 8A shows a conventional stacked semiconductor module, and a second package PK2 is stacked on the first package PK1.

The external connection terminal 2 is disposed on the lower surface of the first package PK1 and the upper and lower connection terminals 1 are disposed on the upper surface of the first package PK1. In the normal product, the upper and lower connection terminals 1 are bonded on the pad 15a for upper-layer module connection formed on the upper surface of the first package PK1. The shape of the connecting surface of the upper and lower connecting terminals 1 and the shape of the external connecting terminals 2 are both circular and similar shapes. The upper layer module connection pad 15a is circular as shown in Fig. 8 (b).

Japanese Patent Laid-Open Publication No. 2000-208557 discloses a method of forming a land 4 formed on a substrate 11 of a semiconductor device by forming it into a rectangle, an ellipse, an ellipsoid or the like so as to be long in a thermal expansion direction, Thereby improving the connection reliability of the semiconductor device.

Normally, electrical inspection is used for connection determination between upper and lower semiconductor devices. That is, it is general to perform the re-inspection in the state of the upper and lower connection and the state of the laminated finished product which is vertically connected to guarantee the electric power.

In this inspection, the stacked semiconductor module is inserted into the socket of the inspecting device, and the external connection terminal 2 of the first package PK1 is brought into contact with the probe on the socket side by applying a load from above, The conduction determination of the connection portion between the first package PK1 and the second package PK2 is made through the internal wiring of the second package PK2.

However, in such electrical inspection, in the case where the state of bonding between the first package PK1 and the second package PK2 is not a reliable junction, it is difficult to determine whether the first package PK1 ) And the second package (PK2) are temporarily taken into contact with each other, so that it is judged to be "electrically OK" and the inspection may be passed.

Therefore, the upper and lower connecting terminals are not only in contact with each other, but also in the determination of whether or not the upper and lower portions are physically bonded to maintain the connection, X-ray inspection or SAT Scanning Acoustic Tomogaph Has been used.

However, such a penetration test requires a very long time in the visual examination, and it is difficult to determine the presence or absence of the bonding because it is difficult to set the threshold value in the automatic judgment.

Specifically, in the example shown in Figs. 8 (a) and 8 (b), the shape of the pad 15a is circular and the external connection terminal 2 is also circular in the shape of a ball, Even though the module is transmitted from the upper part, the circular shape is the same. In addition, the planar shape of the ball of the upper terminal itself is shown in the non-contact state and the non-contact state with respect to the circular shape of the contact surface in the vertically bonded state, and they have the same shape together. In addition, since the connection terminals of the same shape such as the lowermost terminal and the upper terminal are mixed regardless of the size, even if they are in the unjoined state, they are identical in size and shape to each other and have the same shape as the other connection terminals Therefore, it is difficult to distinguish between the connection points and the other connection terminals.

Japanese Patent Application Laid-Open No. 2000-208557 discloses that the shape of the land 4 is a rectangle as shown in Fig. 9 for the purpose of improving the connection strength of a semiconductor device to a printed circuit board. However, it is apparent that the present invention is not directed to the problem of inspection in which the terminals exist in the upper and lower portions in the laminated state like the stacked type semiconductor module.

Specifically, only the rectangular land shown in Patent Document 2 is applied to the upper and lower connecting terminals, the difference in size between the upper and lower connecting terminals and the shape at each connecting portion is not clear, There is a possibility that the connection terminals of the same shape such as the lowermost terminal and the upper and lower terminals are mixed.

An object of the present invention is to provide a stacking semiconductor module and a stacking type semiconductor module which can easily and surely determine whether or not the joint portion can be judged in the nondestructive inspection, thereby improving quality and reliability.

The semiconductor module for laminating according to the present invention is characterized in that a first semiconductor chip is mounted on one side and a first connection terminal is formed on the other side of the first substrate, And an opening portion opened to expose the pad is formed in an insulating film formed on the one surface of the first substrate so as to cover a part of the pad, And the outer shape of the opening portion is protruded from the first connection terminal in a state in which the first connection terminal and the opening portion are inspected in the lamination direction.

Further, the laminated semiconductor module of the present invention is a laminated type semiconductor module in which a first substrate, on which a first semiconductor chip is mounted, is laminated on a second substrate on which the second semiconductor chip is mounted, A second semiconductor chip mounted on the first semiconductor chip and electrically connected to the second substrate; and a second semiconductor chip mounted on the second semiconductor chip, A method for manufacturing a semiconductor device, the method comprising: forming an opening in the insulating film formed on the one surface of the first substrate so as to expose the pad, the planar shape of the opening being formed in a plane shape of the second connection terminal, The other end of the second connection terminal, one end of which is connected to the second substrate, is melted and solidified to meet the opening and is joined to the pad, And the outer shape of the opening portion is protruded from the second connection terminal and the first connection terminal in the state that the opening and the opening are inspected in the lamination direction.

According to this configuration, the stacked-type semiconductor module has a planar shape of the second connection terminal connecting the lower layer module and the upper layer module, and a planar shape of the first connection terminal formed on the other surface of the first substrate, Wherein the shape of the connecting surface between the end of the first connecting terminal and the pad on the side of the first substrate is different from the shape of the connecting surface between the end of the first connecting terminal and the pad on the side of the first substrate, Or the outer shape of the opening is larger than that of the second connecting terminal and the first connecting terminal, the shape of the lower layer module and the upper layer module is clearly different from the unbonded state to the bonded state. Since the planar shape of the second connection terminal bonded to the pad is not exposed to the other terminal in the penetration test from the upward direction, the shape difference can be easily determined by the penetration inspection from the top have. Therefore, the inspection of the junctions of the upper layer and the lower layer module can be surely performed, and the semiconductor device and module can be supplied as a semiconductor device and a module with high quality and reliability.

Fig. 1 is a cross-sectional view of a laminated semiconductor module (a), a cross-sectional view of a connection surface A, a cross-sectional view of a connection surface B, and a cross-sectional view of a connection surface C according to an embodiment of the present invention.
Fig. 2 is an explanatory diagram of a manufacturing method of a multilayer type semiconductor module in the embodiment.
3 is a cross-sectional view of the lower layer module of the semiconductor device for stacking according to the embodiment.
4 is a plan view of the projection state of the first substrate 11 in this embodiment.
Fig. 5 is a cross-sectional view of a partly unbonded (a) stacked-type semiconductor module in the present embodiment and (b) an image observed when transmission is observed by an X-ray transmission device from an upper direction.
Fig. 6 is an enlarged plan view showing the shape of the opening in this embodiment. Fig.
Fig. 7 is an explanatory diagram of the problem.
8 is a cross-sectional view of the stacked-type semiconductor module described in the conventional example and a top view of a joint surface of the lower module.
9 is a plan view showing a shape of a land described in another conventional example.

Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 7. Fig.

1 (a) shows a stacked semiconductor module of the present invention. Also, the numbers and shapes of the terminals, the electrodes, the wirings, and the like are omitted, or the numbers are easily shown. The same omission or the like is performed in all of the following drawings.

And a second package PK22 is stacked and mounted on the first package PK21. The first semiconductor chip 12 is mounted on the upper surface of the first package PK21 and the second semiconductor chip 22 is mounted on the upper surface of the second substrate 25 of the second package PK22.

Specifically, the second package PK22 is a general-purpose stacking memory device or the like. A second semiconductor chip 22 such as a memory is mounted on a substrate, and the electrodes are electrically connected to each other by wire bonding or flip chip bonding And, in some cases, is sealed or coated with a resin so as to cover the semiconductor chip.

Fig. 2 shows a step of laminating the first package PK21 and the second package PK22. The second package (PK22) is provided with a second connection terminal (30) for bonding with the first package (PK21). Solder balls using solder materials such as SnPb, SnAgCu, SnCu, and SnBi are generally used as the bonding metal constituting the connection terminal 30.

The first package PK21 of the stacking semiconductor module as a lower layer module is configured as shown in Fig.

The first package PK 21 is constituted by a first substrate 11 and a first semiconductor chip 12 mounted on the chip holding surface of the first substrate 11.

In the first semiconductor chip 12, an integrated circuit formation region (not shown) in which semiconductor elements are formed is formed in the central portion of the planar-shaped chip substrate, and a plurality of first chip terminals 23 are arranged on the outside thereof. The first chip terminal 23 is generally formed of the same metal as the metal used for forming the wiring of the integrated circuit, and is formed of aluminum, copper, or a lamination material of aluminum and copper. The surface of the chip substrate is covered with an insulating film (not shown) such as polyimide, except for the region where the first chip terminal 23 is formed. The first chip terminal 23 may be disposed in the integrated circuit formation region. The protruding electrode 24 is formed on the first chip terminal 23 by a known method such as a wire bump method or a plating method.

The protruding electrode 24 formed on the first chip terminal 23 may be a single layer of solder, gold, copper, or nickel, or a laminate composed of two or more layers, and may be a spherical or columnar bump good.

The first substrate 11 has a multilayer wiring structure formed of an aramid resin, a glass epoxy resin, a polyimide resin, a ceramic, or the like. A plurality of first chip connecting terminals 13 are formed on the chip holding surface of the first substrate 11 at positions corresponding to the protruding electrodes 24 formed on the first semiconductor chip 12.

The first semiconductor chip 12 is flip chip mounted on the first substrate 11 and the protruding electrodes 24 of the first semiconductor chip 12 are electrically connected to the first chip connecting terminal 13 by the conductive adhesive 14. [ As shown in Fig. Further, the underfill resin 16 bridges the gap between the first semiconductor chip 12 and the first substrate 11 to reinforce the connection. The connection between the first semiconductor chip 12 and the first substrate 11 may be performed using a method of connecting the non-conductive resin film 16 by the curing shrinkage of the non-conductive resin film instead of the underfill resin 16. [

On the surface (back surface) opposite to the chip holding surface of the first substrate 11, a plurality of first connection terminals 2 for external connection are arranged in an equally spaced lattice. The first connection terminal 2 can be electrically connected to an external substrate (not shown) which is a printed circuit board. A solder material made of SnPb, SnAgCu, SnCu, SnBi, or a ball made of gold, copper, nickel, or the like is mounted as the material of the first connection terminal 2 and reflow- (11). As the first connection terminal 2, a resin ball in which conductivity is imparted by performing metal deposition or the like on the surface layer may be used.

A pad for connecting an upper layer module for connecting to a second package (PK22) as an upper layer module of the stacked semiconductor module is formed on an outer side portion of the holding region of the first semiconductor chip (12) on the chip holding surface of the first substrate (11) (15) are provided. An insulating film 20 such as a solder resist or polyimide covers a part of the pad 15 and a part of the pad 15 is exposed by the opening 3 for connecting the upper layer module. The portion exposed from the opening 3 is subjected to surface treatment by plating such as nickel or plating to prevent oxidation of the lower layer pad. An insulating film 20 such as solder resist or polyimide is formed on the surface (back surface) opposite to the chip holding surface of the first substrate 11 except for the portion where the first connecting terminal 2 is formed.

4 shows details of the first substrate 11 of the first package PK21.

Fig. 4 shows the projection of the first connection terminal 2 in addition to the plan view of Fig.

Here, the opening 3 has a rectangular shape, and since the first connection terminal 2 is a solder ball, the opening 3 has a circular shape, so that the openings 3 have different planar shapes. Moreover, the external shape of the opening portion 3 is larger than the external connection terminal 2.

This embodiment is characterized by the difference in the shape and the size of the opening 3 of the first package PK 21 and the shape of the first connection terminal 2 and therefore the difference between the sizes of the first package PK 21 and the second package PK 22 The connection state can be easily detected by non-contact transmission inspection as described below.

By melting and solidifying the second package PK22 with the reflow heating above the melting point of the material of the connection terminal 30 while keeping the second package PK22 mounted on the first package PK21 thus constructed as shown in Fig. 2, The lower end of the connection terminal 30 is soldered to the pad 15 on the first package PK 21 side and the first package PK21 is electrically connected to the second package PK22 through the connection terminal 30. [

The molten connecting terminal 30 is wetted in a shape corresponding to the shape of the opening portion 3 and is expanded and coagulated, so that the bottom face has substantially the same shape as the opening shape of the opening portion 3. 1 (b) is a cross-sectional view of the connection surface A of the second package PK22 and one connection terminal 30 in the stacked semiconductor module thus formed. Fig. 1 (c) Fig. 1D is a cross-sectional view of a connection face C of the first package PK21 and one first connection terminal 2. Fig.

The quadrangle of the opening portion 3 in the case of the normal bonding state satisfied with the solidified component of the connection terminal 30 as described above allows the connection terminal 30 to be formed in such a manner that when the stacked semiconductor module is observed through the X- Since the outline of the rectangular opening of the opening 3 is larger than that of the first connection terminal 2 in the observation of transmission from the upper part such as an X-ray, An image of the connection surface of the connection terminal 30 is not exposed even if the connection terminal 30 overlaps the first connection terminal 2 of the connection terminal 30, The rectangular shape of the first connection terminal 2 projected from the shape of the first connection terminal 2 located below the first connection terminal 2 can be observed.

On the other hand, if the bonding failure occurs as in the case of non-bonding in which a wetting failure occurs or P in the left side of the connection terminal 30 shown in Fig. 5 (a), the bottom surface of the connection terminal 30 contacts the opening 3 A circular bottom surface close to the shape of the original connection terminal 30 is formed. When the laminated semiconductor module with poor bonding is observed through the X-ray transmission device or the like from the upper direction, the aperture 3 and the pad itself are thin, with a thickness of 10 占 퐉 to 20 占 퐉, Only the unconnected terminal image of the connection terminal 30 having a relatively thick thickness, for example, a thickness of 100 mu m or more, is sharply reflected as a circular shape. 5 (b) shows an example of detection of the defective junction P (Fig. 5 (b)).

5 (a) and 5 (b), it is possible to confirm the square shape as the normal bonding and the circular shape as the shape of the original connection terminal at the time of non-bonding, It is possible to easily detect the connection state of the second package PK22. Therefore, by stacking the stacked semiconductor module using the first package PK21 having the structure shown in FIG. 3 as a lower layer module, a highly reliable stacked semiconductor module can be realized by a simple inspection process.

In the above-described embodiment, the case where the opening 3 has a rectangular shape has been described as an example. However, a polygon having a larger number of corners than a square may be used. Specific examples thereof are shown in Figs. 6 (a) to 6 (e).

6 (a) is a cross-sectional view when the shape of the opening 3 is a square, Fig. 6 (b) 6 (d) shows a case where the shape of the opening portion 3 is square and arcs protruding inward toward the corner portion are imparted. In Fig. 6 (e), the shape of the opening portion 3 is a part Is a deformed elliptical shape. In any case, the outer shape of the polygon of the opening portion 3 is made larger than the diameter of the first connection terminal 2. In this way, a cross, a shape formed by arcing in each corner, a pentagon, a polygon including an arc in a part of the sides, or a polygon having a curved but angular shape may be used.

In addition, it is possible to reduce the number of resist residues and foreign substances as compared with a case where arcs are not provided at the corner portions of the openings 3 by providing arcs in the corner portions of the openings 3, which is effective.

The size of the opening 3 may be any size as long as it surrounds the entire diameter of the first connection terminal 2, and the size of the opening 3 may not be exposed. For example, in practice, it is preferable that the unevenness level of the external terminal diameter is about 0.01 mm or less, and the unevenness of the opening size is about 0.01 mm, so that the terminal average diameter is preferably 0.015 mm or more larger than the terminal diameter. As a result, it is possible to confirm the connection surface at the opening without revealing almost all the external connection terminal diameters.

More specifically, a polygonal shape such as a quadrangle larger than? 0.315 mm may be set for a ball diameter of about? 0.3 mm. Further, when the opening portion 3 and the first connection terminal 2 are viewed on the projection plane, if the straight portion or the corner portion of the polygonal shape of the opening portion 3 is seen, the difference between the opening portion 3 and the circular shape is clear and easy to understand.

In the lower layer module, the pitch of the opening portion 3 of the upper layer module and the pitch of the first connection terminal 2 may be the same. 7, the external connection terminals of the upper layer and the lower layer module have the same circular shape and are arranged at equal intervals in almost the same size. Therefore, the above- However, in this embodiment, as shown in Fig. 4, the opening 30 of the lower layer module to which the upper layer module PK22 is connected is polygonal, and the circular shape of the first connection terminal 2 of the lower layer module is different in shape And its external shape is larger than the diameter of the first connection terminal 2 of the lower layer module, so that it can be easily discriminated in transmission observation.

When the upper-layer module having the general-purpose ball-shaped connecting terminal 30 is bonded and laminated to the lower-layer module as described above, the bottom surface of the connection terminal 30 of the upper-layer module is formed into a polygonal shape , And the unjoined portion remains in a circular shape. And is larger than the diameter of the connection terminal 30 of the upper layer module. Therefore, the presence or absence of bonding can be clearly identified in the transmission inspection from the top by X-rays or the like.

If the diameter is not larger than the diameter of the connection terminal 30, when viewed from the upper side, the polygonal shape of the bottom surface is not exposed to the connection terminal 30 itself, and the circular shape of the terminal diameter is seen as a transmission image, Can not be determined. Since the shape of the bottom surface of the connection terminal is changed before and after the connection, that is, only before and after the lamination, there is no special process in the manufacturing process of each semiconductor module, and only the polygonal shape as described above is used. , It is also easy to use general purpose modules. Further, when the opening portion and the terminal for external connection are viewed on the projection plane, if the straight portion or the corner portion of the polygonal shape of the opening portion is visible, the difference between the opening and the circular shape is clear and easy to understand. That is, the shape of the opening 3 is polygonal, and the bottom surface of the connection terminal 30 is also polygonal. And the size thereof is larger than the diameter of the connection terminal 30 of the upper layer module. Or the diameter of the first connection terminal 2 of the lower layer module. Further, it may be larger than both.

The outer shape of the opening portion 3 is larger than that of the first connection terminal 2 in the foregoing embodiments but the shape of the opening portion 3 is not limited to the plane shape of the first connection terminal 2, The outer shape of the opening portion 3 is the same as that of the first connection terminal 2 in the state in which the plane shape is different from the plane shape of the first connection terminal 2 and the transmission inspection is performed in the lamination direction of the first connection terminal 2 and the opening portion 3. 2, the same effect can be expected.

The planar shape of the opening portion 3 is different from the planar shape of the connection terminal 30 and the planar shape of the first connection terminal 2 formed on the other surface of the first substrate 11, The other end of the connection terminal 30 connected to the second substrate 25 is melted and solidified to be bonded to the pad 15 while satisfying the opening portion 3 and the outer shape of the opening portion 3 is connected to the connection terminal 30 and The planar shape of the opening portion 3 is larger than the planar shape of the connection terminal 30 and the planar shape of the first connection terminal 2 formed on the other surface of the first substrate 11, And the other end of the connection terminal 30 connected to the second substrate 25 is melted and solidified to meet the opening portion 3 and is bonded to the pad 15. The first connection terminal 2, Even if the outer shape of the opening portion 3 protrudes from the connection terminal 30 and the first connection terminal 2 in the state of being inspected in the stacking direction of the connection terminal 3 The same effect can be expected.

In each of the above-described embodiments, the outer shape of the pad opening for upper-layer module connection is connected to the inter-module connection port in a state in which the inter-module connection terminals are inspected in the lamination direction of the external connection terminal and the upper- Terminal and the external connection terminal. In this case, since it is possible to determine the defects of all the objects to be inspected by the simple penetration test, it is possible to completely eliminate the electrical inspection of the open or short.

When the openings of the upper layer module connection pads are a combination of the circular shape and the deformed portion, the projected portion in the transmissive state includes the deformed portion with the external connection terminal. Thereby, even if a localized part of a deformed image is provided due to design constraints, it can be discriminated by the penetration inspection even though it is a limited area. For example, the projecting portion may have a linear shape with respect to the circular shape of the external connection terminal.

The height of the opening of the upper layer module connection pad may be set to be equal to or smaller than half the height of the module connection terminal. More specifically, the height of the connection terminals between the modules is 300 mu m to 400 mu m, and the height of the pad opening to the surface of the bed is 5 mu m to 20 mu m. By thus sufficiently lowering the pad opening height, the following effects can be obtained.

As a characteristic connection failure of the multilayer module, the terminal contacts the surface of the upper layer module connection pad to temporarily maintain the electrical connection. This phenomenon occurs when the solder of the terminal is heated and melted and then hardened without being wetted by the pad and maintained almost in its original terminal shape at a position where it is in contact with the surface of the bed. In the case where the height of the pad opening is a height close to the connection terminal, since the connection terminal is melted along the side surface of the pad opening portion even when the pad is not wetted and extended, the transmission shape from the upper surface shows the shape of the pad opening portion, The phenomenon can not be distinguished in the penetration test. On the other hand, according to the present invention, since the height of the pad opening is less than half the height of the connection terminal, have.

INDUSTRIAL APPLICABILITY The present invention contributes to improvement in reliability of various small electronic apparatuses such as small devices, cellular phone apparatuses, digital still cameras, video cameras, and the like.

Claims (14)

A first substrate on which a first semiconductor chip is mounted on one side and a second substrate on which a second semiconductor chip is mounted on the one side of the first substrate, and a first substrate and a second substrate are connected by a second connection terminal, A semiconductor module comprising:
Providing a pad electrically connectable to the second substrate in addition to the holding region of the first semiconductor chip on the one surface of the first substrate;
An opening is formed in the insulating film formed on the one surface of the first substrate so as to cover a part of the pad, the opening being opened to expose the pad;
The planar shape of the opening differs from the planar shape of the second connection terminal and the planar shape of the first connection terminal formed on the other surface of the first substrate;
The other end of the second connection terminal once connected to the second substrate is melted and solidified to be bonded to the pad so as to satisfy the opening, and in a state of conducting transmission inspection in the stacking direction of the first connection terminal and the opening,
The planar shape of the opening is different from the planar shape of the first connection terminal,
The pitch of the openings is equal to the pitch of the first connection terminals,
Wherein a planar shape of the opening is such that the arrangement of the openings and the arrangement of the first connection terminals are parallel but different from each other and a part of the opening is protruded from the first connection terminal. The method according to claim 1,
In a state in which transmission inspection is performed in the lamination direction of the first connection terminal and the opening,
Wherein the planar shape of the opening is a polygonal shape, and the planar shape of the first connection terminal is a circular shape. The method according to claim 1,
In a state in which transmission inspection is performed in the lamination direction of the first connection terminal and the opening,
Wherein the planar shape of the opening is polygonal, and the planar shape of the first connection terminal is circular, and the outer shape of the opening is larger than the diameter of the first connection terminal. The method according to claim 1,
In a state in which transmission inspection is performed in the lamination direction of the first connection terminal and the opening,
And the arrangement of the openings is located on the outer peripheral side of the first substrate with respect to the arrangement of the first connection terminals. delete delete delete delete delete delete delete delete delete delete

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