JP2846456B2 - Chip carrier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chip carrier used when connecting a terminal portion of a semiconductor chip such as an IC or an LSI to a terminal portion of an external container (so-called package) or a circuit board. It is.

[Background Art] Conventionally, a semiconductor device chip has been connected to a lead frame of a package accommodating the chip or a terminal portion of a circuit board on which the chip is mounted, by a bonding wire, a tape carrier, or a chip carrier such as a batch. The usage of the bonding wire and the chip carrier depends on the pitch between the pins of the semiconductor device chip. For example, when the pitch is 200 to 300 μm or less, a chip carrier is generally used.

In the conventional tape carrier shown in FIG. 3, device holes 303 into which semiconductor device chips 306 are inserted are formed at a predetermined pitch in a flexible tape 302 made of a polyimide film, a polyester film, or the like. On one surface of the flexible tape 302, a predetermined metal wiring 301 having an inner lead portion 301a radially arranged around the opening of the device hole 303 is formed.

As shown in FIG. 3, the inner lead portion 301a is in a state of protruding from the opening of the device hole 303 (a so-called overhang structure), and a state in which the semiconductor device chip 306 is inserted in the device hole 303. With the inner lead portion 301a and the bump 307 of the semiconductor device chip 306
Is bonded.

By the way, in recent years, the tendency of high integration of semiconductor device chips is remarkable, and accordingly, the number of input / output pins has been increased, and semiconductor device chips having an inter-pin pitch of 100 μm or less are now in the stage of practical use. ing.

However, it is very difficult to manufacture a chip carrier such as a tape carrier having a fine inner lead portion capable of coping with a semiconductor device chip having such a very narrow pitch between pins.

That is, a general method of forming the metal wiring of the chip carrier is to laminate a copper foil of about 35 μm on a flexible film member,
Alternatively, a copper foil piece is stuck and formed by etching this copper foil, or a catalytically active layer for electroless plating is provided in a predetermined shape on the surface of a flexible film member, and then copper plating is performed. However, when the pitch between pins is made very narrow, the above-described problem occurs.

In the case of the former etching method, for example, the pitch between pins is reduced.
When the thickness is 70 μm, the width of the conductor is about 35 μm. However, when the thickness of the copper foil layer is 35 μm, the ratio of the conductor width / conductor thickness is 1
In such a case, sand etching is remarkable, and the cross-sectional shape of each wiring becomes trapezoidal.

Also, in the case of the latter plating method, there is a possibility that a bump may stick out from the stacked plating and short-circuit between the wirings, and the size of the bump is, for example, 20 μm when the copper plating thickness is 35 μm.
It becomes about μm.

In order to solve such a problem, it is desired to reduce the thickness of the metal wiring in any of the above methods. In other words, if the thickness of the copper foil layer is small in the method by etching, sand etching progresses very much,
If a wiring having a substantially rectangular cross section can be obtained and the plating thickness is small even in the plating method, the bumps do not grow much and the danger of a short circuit is small.

However, since the inner lead portion of the conventional metal wiring has an overhang structure protruding from the opening of the device hole as described above, the pressing force at the time of bonding the semiconductor device chip must withstand the metal wiring alone. No. It is said that the pressure resistance (hereinafter, referred to as “finger strength”) at this time is required to be 5 to 15 g. However, the copper foil layer is made thin, for example, a finger of copper foil wiring having a width of 25 μm and a thickness of 18 μm. The strength is 12 g, and the metal wiring having such a reduced thickness cannot withstand the bonding of the semiconductor device chip.

The present invention has been made in view of such a point,
By providing a chip carrier that allows finer metal wiring, has sufficient finger strength, and has excellent bonding processability, and combines this chip carrier with a highly integrated semiconductor device chip It is an object of the present invention to facilitate the use of highly integrated semiconductor device chips.

DISCLOSURE OF THE INVENTION In the present invention, a chip carrier on which a semiconductor device chip is mounted on a metal wiring forming surface is provided with a device hole including an inner lead portion without providing a device hole as in the related art. A film portion having a thickness smaller than the second thickness of the surrounding second region is formed in the first region (i.e., corresponding to a conventional device hole perforated portion) as a first region, The above object is achieved by the thin film portion in the first region.

That is, in the present invention, the inner lead portion of the metal wiring does not have an overhang structure as in the prior art, is formed on the thin film portion formed in the first region, and is supported and fixed by this. In addition, even if the thickness of the metal wiring is reduced, it can sufficiently withstand the heating and pressing in the bonding step. For this reason, the metal wiring can be thinned without lowering the finger strength, so that it is possible to make the metal wiring ultrafine, which has been impossible in the past.

Further, in the present invention, since the thickness of the flexible film portion in the first region corresponding to the conventional device hole equivalent portion is reduced, the heat generated due to the difference in the coefficient of thermal expansion between the thin film portion and the metal wiring is reduced. The stress is small, and deformation or the like of the inner lead portion hardly occurs due to heating in the bonding step.

Furthermore, since the inner lead portion is fixed on the thin film portion, it comes into contact with any object, etc.
Accidents such as deformation of the inner lead portion and contact (short circuit) with the adjacent inner lead portion due to disturbance of the tip portion are unlikely to occur, and the inner lead portion is orderly from the time of manufacturing the chip carrier to the time of bonding with the semiconductor device chip. Is maintained.

Further, since the second thickness of the second region is formed larger than the first thickness, the film strength required as a chip carrier can be maintained. In particular, when a tape carrier is used as the chip carrier, even if a long tape member is used as the flexible film member and a plurality of chip mounting portions are provided, the strength as the tape member is increased by the second thickness. Therefore, the tape winding step and other handling performed from the time of tape manufacture to the time of bonding with the semiconductor device chip can be easily performed.

In the case where an opening is provided in a region (region A) inside the tip of the inner lead portion, the opening functions as a conventional device hole and supports a portion where the conventional inner lead portion is overhanged. Area (first
Since the flexible film portion (region B) of the region (excluding the region A) is thinned in a range where a predetermined finger strength is obtained, the coefficient of thermal expansion between the thin film portion and the metal wiring is reduced. The thermal stress generated due to the difference is small, and by the heating in the bonding step as in the above invention,
Deformation of the inner lead portion is unlikely to occur.

Further, since the opening is provided in the region A and the flexible film member is not formed, the impurity ions contained in the flexible film member migrate to the semiconductor chip and the semiconductor device chip is destroyed. It is also advantageous in preventing

In addition, in the third region including the outer lead portion, the flexible film member may be deleted as necessary, or a thin film portion may be formed in the same manner as in the first region.

This is a problem in a case where a semiconductor device chip is mounted on the chip carrier to form a semiconductor device and then connected to a terminal portion of an external circuit device or the like. For example, the terminal portion is directly bonded by a mechanical device or the like. In this case, it is desirable to form a thin film portion also in the third region in order to increase the finger strength of the outer lead portion. In addition, when selling as a general semiconductor device, for example, when the arrangement of the terminal portion of the external circuit device and the arrangement of the outer lead portion are different, or when the bonding position is on the back surface side, etc. It is desirable not to form a flexible film member in the third region in consideration of the bending property of the portion, the electrical joining conditions, and the like.

Note that the first region and the third region may be combined, a thin film portion may be formed in the entire region including the metal wiring portion, and a thick portion may be formed around the thin film portion as the second region.

Although the method for manufacturing the chip carrier according to the present invention is not particularly limited, a thin film portion which is finally thinner in the first region of the flexible film member than the surrounding second region is formed. I just need.

For example, it can be manufactured by the following method.

First, one side of a flexible film having a thickness of about 10 to 200 μm made of a material having excellent heat resistance, such as polyimide, polyphenylene sulfide, polyethylene terephthalate, or liquid crystal polymer, is formed to a thickness of 0.1 to 1 by a sputter deposition method.
A μm metal film (copper, chromium, nickel, etc.) is formed.

Then, further apply copper plating as needed, 1 ~ 20μ
m is a metal foil layer mainly composed of copper, and this metal foil layer is etched or, after forming a metal film, an unnecessary portion is masked (masked with a negative pattern) and plated with copper, and then the metal film is flashed. The metal wiring is formed by etching.

After that, when the opening is formed, the flexible film member is removed by etching or the like in a region A surrounded by the inner lead portion of the metal wiring and inside the tip of the inner lead portion. Form a hole. Here, the inner region from the tip of the inner lead portion, the effect of the present invention is sufficiently exhibited if the distance from the tip of the inner lead portion is about 5 mm or less, but more preferably from the tip of the inner lead portion. It is preferably within about 2 mm.

After that, the first wire including the inner lead portion of the metal wiring
In a region or a region excluding the region A from the first region, the thickness of the flexible film member is reduced from the side where the metal wiring is not formed, and a thin film portion is formed in the first region.

In the case where all of the flexible film member is removed or the thin film portion is formed in the third region including the outer lead portion, it can be performed according to the above method.

Here, as a method of reducing the thickness of the flexible film member made of a polymer film, for example, there is a plasma etching as a dry etching method. In this method, a plasma-activated gas is sprayed on the surface to be etched by ECR plasma or the like, thereby removing the polymer film in that portion and forming a thin film portion.

In the case where the flexible film member is made of a polyimide film, wet etching using a mixed solution of hydrazine and ethylenediamine, a solution in which an alkaline chemical such as potassium hydroxide is dissolved in ethanol or water, or the like is also preferable. The result is obtained.

At this time, the thickness of the thin film portion formed in the first region of the flexible film member is desirably about 5 μm or more in order to secure sufficient finger strength. Is preferably equal to or smaller than the thickness of the metal wiring. For example, when the flexible film member is made of a polyimide film, the finger strength is 5 to 25 μm.
It is desirable to be within the range.

As described above, in the present invention, since the inner lead portion of the chip carrier is reinforced by the thinned flexible film portion, even when the thickness of the metal wiring is significantly thinner than before, the bonding process is It is difficult for the inner lead portion to be broken or the inner lead portion to be deformed by thermal stress due to the heating and pressurizing, and the bonding processability is very excellent.

In addition, since the inner lead portions are fixed on the thin film portion of the flexible film, an orderly arrangement of the inner lead portions is always maintained. This is advantageous in performing a proper bonding.

According to the present invention, it is possible to realize a chip carrier such as a tape carrier having an extremely fine inner lead portion, which has been impossible in the past, so that it is possible to mount a semiconductor device chip having a very narrow pitch between pins. This is very useful as the degree of integration of a semiconductor device chip is significantly increased.

Furthermore, if a product as a semiconductor device is created by combining with a semiconductor device chip using this chip carrier, the number of steps and costs in the manufacturing stage can be reduced,
Moreover, since the occurrence of defective products is reduced, the cost of the product can be reduced.

In addition, a device having an opening in the first region can use the opening as a device hole similar to the conventional one, and the semiconductor device chip is destroyed by the influence of impurity ions contained in the flexible film member. It is effective to prevent

Further, the thin film portion formed on the outer lead portion has extremely excellent bonding workability when connected to a terminal portion of an external circuit device or the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a partial cross section of a chip carrier according to a first embodiment of the present invention, FIG. 2 shows a partial plan view of a tape carrier obtained by applying this embodiment, FIG. 3 shows a partial cross section of a conventional chip carrier, FIG. 4 shows a partial cross section of a chip carrier according to a second embodiment of the present invention, and FIG. FIGS. 6, 7, 8 and 9 show a partial cross section of the structure of a chip carrier according to another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1 and 2 are a partial sectional view and a partial plan view of a tape carrier according to a first embodiment of the present invention. In this embodiment, first, a 0.2 μm copper film is adhered to one surface of a flexible tape 2 made of a polyimide film having a thickness of 50 μm by a sputter deposition method, and further subjected to electrolytic copper plating to form a 10 μm thick film. A copper foil layer was formed.

Then, the copper foil layer is etched using an aqueous ferric chloride solution, and the conductor width (FIG. 2A) is 25 μm and the conductor pitch (second
FIG. B) A plurality of sets of 50 μm metal wires 1 were formed at a predetermined pitch in the longitudinal direction. In FIG. 2, only one set of metal wiring is illustrated, and the number of wirings is omitted.

The metal wiring 1 in the present embodiment is an inner lead portion bonded to the bump 7 of the semiconductor device chip 6.
As shown in FIG. 2, they are arranged radially with the inner lead 1a inside and the outer lead 1b connected to the terminal of the package or the external circuit board outside.

Note that, in the metal wiring 1 of the present embodiment, an outer lead portion 1b corresponding to the inner lead portion 1a is provided in one-to-one correspondence, and each outer lead portion 1b is connected to a terminal portion of an external circuit device such as a circuit board. , But is not limited to this.

That is, the metal wiring formed on the tape carrier according to the present invention is not limited to the case where the wiring having the inner lead portion at one end and the outer lead portion at the other end are arranged at a predetermined pitch as shown in FIG. In some cases, the outer lead portions and the inner lead portions correspond one-to-many, or the inner lead portions may be connected to a predetermined circuit formed outside thereof. Further, in this embodiment, only one set of inner leads for bonding a semiconductor device chip is formed on one set of metal wiring. However, in some cases, a plurality of sets of inner leads are formed on one set of metal wiring. It may be formed.

Thereafter, the portion surrounded by the dotted line (including the inner lead portion 1a of the metal wiring 1) in FIG. 2 on the back surface (the surface on which the metal wiring is not formed) of the flexible tape 2 is formed. The entire surface of the flexible tape 2 is protected with an alkali-resistant etching resist except for the first region surrounding the mounting region (1), and the tape 2 is placed in a 5N aqueous potassium hydroxide solution at 50 ° C. for 1 hour. After immersion for a time, it was washed with water. As a result, the remaining polyimide thickness in the portion not protected by the etching resist was 9 μm. That is, in this embodiment, the thickness of the region surrounding the mounting region of the chip 6 including the inner lead portion 1a of the flexible tape 2 is reduced from the back surface (back side of the paper) of the flexible tape 2 by wet etching, and the thin film portion 3 ( In FIG. 2, a portion surrounded by a dotted line) was formed.

Note that the sprocket hole 5 continuously provided at a predetermined pitch in the longitudinal direction of both sides of the tape 2 and the outer lead hole 4 formed at a portion corresponding to the outer lead portion 1b are:
It is not necessary.

For example, the tape may be conveyed without using the sprocket holes 5, or the outer lead portion 1b may be joined to a terminal portion such as a circuit board with a flexible tape attached. However, when it is necessary to provide these holes, for example, the portions other than the holes are protected by an alkali-resistant etching resist, and the holes are formed by etching with the same alkaline solution used to form the thin film portion. Can be.

Also, in the portion corresponding to the outer lead hole 4,
By forming a thin film portion in the same manner as the inner lead portion 1a, along with miniaturization of the metal wiring of the outer lead portion 1b, the strength required as connection wiring to the terminal portion of the external circuit device is maintained, and the size is reduced. High bonding workability can be obtained regardless of wiring.

In this example, Mitsubishi Kasei Kogyo Co., Ltd., trade name "NOVAX" is used as the flexible film member, because it has excellent anti-etching properties and is translucent as described above. This is because image processing and the like in alignment at the time of bonding can be easily performed.

Therefore, when another product or the like is used as the flexible film member, the etching conditions and the like are different.

About the tape carrier produced as described above,
As shown in the enlarged sectional view near the inner lead portion in FIG. 1, the semiconductor device chip 6 is attached to the inner lead portion 1a.
When the bump 7 was bonded, since the inner lead portion 1a was supported by the thin film portion 3 of the flexible tape 2, the inner lead portion 1a did not bend due to pressure. Further, since the thin film portion 3 was as thin as 9 μm, the inner lead portion 1a was not deformed by the thermal stress, and the bondability was very good.

Here, in the embodiment of the present invention, the semiconductor device chip 6 is located on the surface of the tape 2 where the metal wiring 1 is formed.

 Next, a second embodiment of the present invention will be described.

FIG. 4 and FIG. 5 are a partial sectional view and a partial plan view of a tape carrier according to a second embodiment of the present invention. Formation of the flexible tape 402 and its surface in this embodiment,
The method of forming the metal wiring 401 is the same as that of the previous embodiment, and the metal wiring 401 has the inner lead portion 401a bonded to the bump 407 of the semiconductor device chip 406 inside, and the terminal portion of a package or a circuit board. They are arranged as shown in FIG. 5 with the outer lead portion 401b to be connected facing outward.

The relationship between the inner lead portion a and the corresponding outer lead portion 401b in the metal wiring 401 of this embodiment is the same as that of the previous embodiment.

Next, the entire surface of the flexible tape 402 is protected with an alkali-resistant etching resist except for a region (region A) surrounded by the inner lead portion 401a and 1 mm inside from the tip of the inner lead portion 401a. Was immersed in a 5N aqueous solution of potassium hydroxide at 50 ° C. for 1.5 hours, and then washed with water. As a result, the polyimide in the region A not protected by the etching resist was removed, and the device hole 408 was formed.

Thereafter, the surface of the flexible tape 402 was protected with an alkali-resistant etching resist except for a region B (shown by hatching in FIG. 5) further including the inner lead portion 401a and the mounting region of the semiconductor device chip 406. In a state, the tape 402 is placed in a 5N aqueous solution of potassium hydroxide at 50 ° C. for 1 hour.
After immersion for a time, it was washed with water. As a result, the flexible tape 402 in the region B, which is the portion that reinforces the inner lead portion 401a, is half-etched as shown in FIG.
Was formed. In this embodiment, the thickness of the thin film portion 403 (controlled by etching conditions) is set to 12 μm.

In FIG. 5, a sprocket hole 405 and an outer lead portion 4 are continuously provided at a predetermined pitch in the longitudinal direction of both sides of the tape.
The outer lead hole 404 formed in the portion corresponding to 01b is the same as in the previous embodiment.

About the tape carrier produced as described above,
As shown in the enlarged sectional view near the device hole 408 in FIG. 4, the inner lead portion 401a and the semiconductor device chip 40
When the bump 407 of No. 6 was bonded, the inner lead portion 1a was reinforced by the thin film portion 403 of the flexible tape 402 in the region B, so that the inner lead portion 401a did not bend by pressure. .

Also, there was almost no deformation of the inner lead portion 401a due to thermal stress, and the bonding processability was very good.

In addition, in this embodiment, since the device hole 408 is provided, when performing resin fixing at the product stage,
Since the adhesive fixing resin is poured using the device holes 408, there is an advantage that the operation can be easily performed.

In the above embodiment, the copper metal wiring is formed. However, the metal wiring of the present invention is not limited to copper, and may be formed of a two-layer structure of copper and another metal or a metal other than copper. Needless to say, it's good.

Here, as a method of forming a thin film portion in the first region,
In addition to the above, the following method may be used.

First, as shown in FIG.
When the first region is etched, it may be difficult to form a thin film having a small thickness by half-etching.
After completely removing the flexible film member 602 in the first region by etching or other methods, a new thin film may be formed in the first region. Further, as shown in FIG. 7, instead of forming a metal foil layer on the flexible film member 702, a metal foil piece 701 having the same thickness as described above may be attached. At this time, the flexible film member 702 may be subjected to the etching treatment in the same manner as described above, but the flexible film member 702 having an opening in the first region or a region corresponding to the device hole (region A) is used. Can be.

The thin film 704 may be formed on a portion of the metal foil piece 701 or the like facing the opening. The material of the thin film 704 preferably has properties similar to those of the flexible film member.

As a method of forming the thin film portions 604 and 704, for example, it can be easily formed by applying a resin to the thin film only on the opening or on the entire surface.

On the other hand, when the thin film forming material has an adhesive property,
As shown in the figure, when the metal foil piece 801 is applied, the thin film portion 804 can be easily formed in the opening by applying and applying the metal foil piece 801 to the entire surface of the application surface.

For example, an epoxy, polyimide, or polyester-based curable material becomes a flexible film member and has adhesiveness, so that it can be used as an adhesive layer at the same time as forming a thin film portion.

In the case where the thin film forming material has no adhesive property,
As shown in the figure, a coating layer 904 is provided on the entire surface of the metal foil piece 901 side,
By forming the adhesive layer 909 on the entire surface of the film member, a thin film portion can be formed in the first region.

Further, a thin film may be formed by a combination of the above-described methods. A thin film may not be applied to an unnecessary portion in advance, or a flexible film may be formed by using a photosensitive material such as photosensitive polyimide as a material of the thin film portion. After the application, the thin film can be left only in a desired portion by lithography.

[Industrial Applicability] The present invention is mainly used in a manufacturing process of a semiconductor device using a semiconductor device chip.

Claims (10)

(57) [Claims] A plurality of sets of metal wires including an inner lead portion to be connected to a terminal portion of a semiconductor device chip are directed to a region where the chip is to be mounted on one surface side of a flexible film member. A chip carrier formed radially, wherein in the chip mounting area, an inner lead portion of a metal wiring contacts a terminal portion of a semiconductor device chip on the one surface side, and the back surface on the one surface side is The film member has a first thickness in a limited first region including the inner lead portion and surrounding the placement region, and has a second thickness in a second region around the first region. A chip carrier, wherein the first thickness is smaller than the second thickness. 2. The semiconductor device according to claim 1, wherein the film member is in the form of a long flexible tape, and a plurality of areas on which semiconductor device chips are to be mounted are arranged on the tape. A plurality of sets of metal wirings having inner lead portions connected to the terminal portions are formed on one surface side of the flexible tape, respectively, and for each of the mounting regions, the mounting region includes the inner lead portion. 2. The chip carrier according to claim 1, wherein the tape has a relatively thinner thickness in the surrounding first area than in the surrounding second area. 3. The flexible film member according to claim 1, wherein the flexible film member has an opening in a region inside a tip of the inner lead portion in the first region.
A chip carrier according to claim 1. 4. The chip carrier according to claim 1, wherein the first region of the film member is reduced in thickness on a side opposite to a surface on which the metal wiring is located. . 5. The semiconductor device according to claim 1, wherein the metal wiring has an outer lead portion to be connected to an external circuit device.
The third region including the outer lead portion has a third thickness, and the third thickness is smaller than the second thickness. 5. The chip carrier according to 4. 6. A plurality of sets of metal wiring having an inner lead portion connected to a terminal portion of a semiconductor device chip are formed radially toward a region where the chip is to be mounted, and are formed of a flexible film member. A semiconductor device comprising a combination of a chip carrier and the semiconductor chip mounted on the mounting area on the metal wiring forming surface side of the carrier and having its own terminal portion electrically connected to the inner lead portion. The film member has a first thickness in a first region including the inner lead portion and surrounding the placement region, and has a second thickness in a second region around the first region. A semiconductor device, wherein the first thickness is smaller than the second thickness. 7. The film member is in the form of a long flexible tape, on which a plurality of regions on which semiconductor device chips are to be mounted are arranged, and the mounting region of each chip is arranged in each mounting region. A chip carrier in which a plurality of sets of metal wirings each having an inner lead portion connected to a terminal portion are formed on one surface side of a flexible tape; and a plurality of semiconductor chips mounted in each of the mounting regions. 7. The semiconductor device according to claim 6, comprising: 8. The flexible film member is not removed or preliminarily formed in a region inside the tip of the inner lead portion in the first region, and an opening is formed in the inside region. Claim 6 or Claim 7
3. The semiconductor device according to claim 1. 9. The chip carrier according to claim 6, wherein the first region of the film member of the chip carrier is reduced in thickness on a side opposite to a surface on which metal wiring is provided. 13. The semiconductor device according to claim 1. 10. The semiconductor device according to claim 3, wherein the metal wiring of the chip carrier has an outer lead portion connected to a terminal portion of an external circuit device, and the film member includes the outer lead portion.
10. The semiconductor device according to claim 6, wherein the region has a third thickness, and the third thickness is smaller than the second thickness.