JPH0680745B2 - Method of manufacturing integrated circuit container - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing an integrated circuit container for mounting a semiconductor chip. More specifically, the present invention relates to a method of manufacturing an integrated circuit made of a metal material.

(Prior Art) As shown in FIGS. 1 (a) and 1 (b), a ceramic integrated circuit container currently in use has a recessed portion 2 at the center of a rectangular ceramic plate 1, A chip (not shown) is mounted in this recess 2 through a glass or noble metal layer. A lead frame (not shown) is mounted on the peripheral surface portion 3 surrounding the recess via sealing glass and connected to the leads of the semiconductor chip. As shown in a perspective view in FIG. 2, a container lid 4 ′ having a structure similar to such a container 4 and having a recessed portion and a peripheral surface portion surrounding the recessed portion is used as the recessed portion and the peripheral surface portion of the container 4. The lead frame 5 has a container 5 and a container lid 4 '
It is taken out from the long side between and. Like the container 4, the container lid 4'is also a ceramic sintered body. Since the container and the container lid have substantially the same shape, both the container and the container lid are collectively referred to as a container in the present specification.

However, the ceramic container has the following drawbacks.

Since they are vulnerable to impact, there is a great risk that they may collide with each other to cause chipping during the transportation process. If sintering is incomplete, cracks may occur due to thermal shock.

Since the heat dissipation property is insufficient, malfunction is likely to occur when the degree of integration of the semiconductor chips is high and the heat generation is large.

Large shrinkage during firing and poor dimensional accuracy.

Warpage is likely to occur during the cooling process, and there is a problem in the flatness of each part of the container.

In order to overcome these drawbacks, the applicant has already made
In No. 60-146527, we proposed a container using metal as a material. When the container is made of a metal material, it is necessary to cover a portion that may come into contact with the lead frame with an electrically insulating layer. A metal oxide is suitable for the electrical insulating layer in that case. Therefore, the applicant has already proposed in Japanese Patent Application No. 62-68642 that an integrated circuit container made of a metal material having a metal oxide layer on the outermost surface. And its manufacturing method was proposed.

FIG. 3 is an example of the intermediate process product of the container 6, and FIG.
Shows a schematic perspective view, and FIG. As can be seen from this, the plate-shaped metal core material 9a is entirely covered with another metal layer 9b which becomes an oxide, and the recessed portion 7 for mounting a semiconductor chip is formed in the central portion.

The recessed portion 7 is formed by stopping halfway through punching or punching out. By the way, the container 6 shown in FIG. 3 has the following problems.

Since the convex portion 10 is formed on the back surface side of the concave portion 7, the containers may be caught on another object during the transportation.

Due to the springback due to the formation of the recessed portion 7, the fourth
As illustrated, the peripheral surface portion 11 may be warped. The peripheral surface portion 11 is a portion where the lead frame is mounted via the sealing glass layer, and flatness is required. In the case of FIG. 4 (a), the warp is shown, and the same (b) shows the warp. The direction and degree of the warp vary depending on the depth d of the recess 7 and the plate thickness t. According to an experiment by the present inventor, when d is constant, the warp changes from downward warp to upward warp as t increases, and the warp becomes 0 at an appropriate t. That is, t must be determined according to d, and there is a case where an unnecessarily thick material has to be used.
Further, the proper value of t is also affected by the strength of the material, which makes the strength management very troublesome.

The bottom surface of the recessed portion 7 on which the semiconductor chip is mounted via the glass or noble metal layer is required to be flat. The bottom surface 7a is the hole 1 of the die 13.
It will be curved in 3 '. In order to prevent this, a pressure pad is placed in the die hole 13 'as shown in FIG.
By providing 12 and pressing from below, the bottom of the recess
It is necessary to mold 7a while keeping it flat. In addition, when the punch 14 is lifted while the peripheral surface 11 is being pressed by the plate retainer 15 after the recess 7 is formed to a predetermined depth, the recess 12 is pushed back by the pad 12, so the plate retainer 15 is punched 14 It is necessary to raise the punch 14 before raising it, or lowering the pad 12 and then raising the punch 14, which makes the timing difficult and complicates the structure and operation of the mold.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a flatness of a bottom surface of a recessed portion on which a semiconductor chip is mounted and a peripheral surface portion on which a lead frame is mounted without having a convex portion on the bottom surface which obstructs transportation. It is an object of the present invention to provide a method for manufacturing an integrated circuit container, which is capable of extremely easily obtaining

(Means for Solving the Problems) Thus, the gist of the present invention is to provide a method for manufacturing an integrated circuit container having a recess for mounting a semiconductor chip and a peripheral surface surrounding the recess in a plate. Prepare a long narrow plate-shaped material in which the peripheral surface of a metal core material is coated with a metal that forms an oxide, and the width is approximately equal to the width of the container. Punching step in which through holes are formed at predetermined intervals in the longitudinal direction, and the perforated long plate material thus obtained is coated with another metal forming an oxide on the peripheral surface of a plate-shaped metal core material. The process of stacking long narrow plate-shaped materials of the same width and heating and rolling to integrate the coating metal on the mating surfaces, and the recesses and dents formed in the thus obtained mating material. A step of cutting the laminated material at an intermediate position between the metal core material and the peripheral surface of the metal core material And a step of oxidizing a metal.

The oxidation step is performed as a final finishing step, but if the oxidation treatment can be performed in a continuous line, the oxidation step may be performed before the cutting of the laminated material.

The metal that coats the metal core may be any metal that easily forms an oxide. Aluminum is usually preferred. The coating can be performed by an appropriate means such as electroplating or vapor deposition. There is no particular limitation.

(Operation) Next, the method for manufacturing the integrated circuit container according to the present invention will be described in more detail with reference to the accompanying drawings.

6 (a) and 6 (b) are a perspective view and a sectional view, respectively, showing an example of the structure of an integrated circuit container manufactured by the method according to the present invention. As described above, the container in the present invention means both the container and the lid, and the container and the lid have the same structure.

As shown in FIGS. 6A and 6B, the container 16 is an upper layer plate 16
a, a double structure in which the lower plate 16b is joined, and the combined surface
40 is the joint surface. A portion where the mounted lead frame (not shown) and the container 16 may come into contact with each other is electrically insulated by the metal oxide layer. Referring to FIG. 6, the peripheral surface portion 32 on which the lead frame is mounted, the upper layer plate and the lower layer plate 16 to which the lead frame bent as shown in FIG.
The long sides of a and 16b and the back surface 33. In the figure, the thicknesses of the upper and lower layers 16a and 16b are represented by ta and tb, and the lengths of their long sides and short sides (16a ', 16b') are represented by 1 and b, respectively. ing.

FIG. 7 shows the long-sized laminated material 17 before the formation of the metal oxide, the width dimension is the same as that of the container b, and the recessed portions 7 correspond to a predetermined pitch (for example, the container length 1). length)
It is provided in. This is cut along the broken line YI between the recesses and oxidized by an appropriate means such as anodic oxidation to manufacture the container 16 as shown in FIG.

In FIG. 7, a long laminated material 17 is obtained by joining a long upper layer plate 18 and a long lower layer plate 19. Each of the lower layer plate 19 and the upper layer plate 18 is formed by coating the metal core material of the plate material with another metal that will be an oxide film. 8 (a) and 8 (b) are long upper layer plates 18
3 is a perspective view and a cross-sectional view showing an example of the structure of FIG. FIG. 8B is a cross-sectional view taken along the line of FIG. 8A. A plate-shaped metal core 18a and a coating metal layer 18b are formed, and through holes 21 having a predetermined size are formed at a predetermined pitch. The side lengths m ', n'and the pitch l'of the rectangular through holes 21 will be described later.

The material before forming the through holes 21 is a plate-shaped hoop material having the same width b ′ in which the peripheral surface of the metal core material 18a is covered with the coating metal layer 18b.
It is manufactured by a method of rolling a rod-shaped clad material having a circular cross section into a rectangular cross section or by a method of forming a coating metal layer 18b on a metal core material 18a by plating or vapor deposition. Through hole 2
Since the processing of 1 is performed by punching and the recessed portion 7 as shown in FIG. 3 seen in the above-mentioned conventional example is not formed, the flatness of the peripheral surface portion 22 is limited as long as the peripheral surface portion 22 of the through hole 21 is constrained and punched. No defects occur.

9 (a) and 9 (b) are a perspective view and a cross-sectional view, respectively, showing the elongated lower layer plate 19, in which the peripheral surface of a plate-shaped metal core material 19a is covered with another metal layer 19b. The manufacturing method thereof is the same as that of the long upper layer plate 18 before processing the through holes.

By the way, the container 16 shown in FIG. 6 needs to have an overall linear expansion coefficient substantially equal to the linear expansion coefficient of the lead frame. This is because no thermal stress is generated between the container 16 and the lead frame. When thermal stress occurs, there is a risk that the adhered glass may crack. Therefore, for the metal core material 18a of the long upper layer plate 18 shown in FIG. 8 and the metal core material 19a of the long lower layer plate 19 shown in FIG. 9, for example, the same metal as the lead frame is used. Aluminum is suitable for the coating metal layers 18b and 19b from the viewpoint of ease of bonding and cost, which will be described later.

Next, the long upper layer plate 18 and the long lower layer plate 19 are overlapped, and 300
It is heated to ˜500 ° C. and rolled by a pair of upper and lower rolls 24 as shown in FIG. 10 to join the coating metal (eg, aluminum) layers on the mating surfaces. FIG. 11 shows a cross section in the width direction after joining, in which the covering metal (eg, aluminum) layer of the long upper layer plate 18 and the covering metal layer of the long lower layer plate 19 are integrated.

The reduction rate required for joining by such hot rolling increases as the heating temperature decreases. According to the experience of the present inventor, heating to 300 ° C. may be about 30%, and 500 ° C. may be about 20%. As shown in FIG. 10, the thickness ta ′ of the long upper layer plate 18 (see FIG. 8) and the thickness tb ′ (the ninth lower layer plate 19
(See the figure). Further, since the dimensions m'and n '(see FIG. 8) of the through holes 21 of the long upper layer plate 18 are changed by rolling, the flat dimensions m, n of the recessed portion 7 shown in FIG. 7 are obtained after rolling. Then, the plane dimensions m ′ and n ′ of the through hole 21 are determined.
Since the dimensional change in the width direction due to rolling is small, n '
Is almost the same as n. The width b ′ of the long upper layer plate 18 and the long lower layer plate 19 may be substantially the same as the width b of the long laminated plate 17.

The thickness ts ₁ of the coating metal layer of the long upper layer plate 18 (see FIG. 8),
The thickness ts ₂ (see FIG. 9) of the coating metal layer of the long lower layer plate 19 is determined from the required rolling joint strength and the thickness after joining. If it is too thin, the bonding will be incomplete and the electrical insulation after the oxidation treatment described below will be insufficient. If the bonding is insufficient, peeling may occur, and even if peeling does not occur, the semiconductor chip is mounted in the recess as described below, and the semiconductor chip after sealing the container lid is completely removed from the outside air. You will not be able to shut off. Conversely, if it is too thick, it is difficult to substantially match the linear expansion coefficient of the container and the lead frame when the linear expansion coefficient of the coated metal layer is larger than that of the metal core material made of the same material as the lead frame. Become. According to the experience of the present inventor, it is suitable that both ts ₁ and ts ₂ are 10 to 50 μm.

The thickness ta '(see FIG. 8) of the long upper layer plate 18 is such that the depth of the recessed portion 7 after rolling and joining is the depth d of the recessed portion of the container (see FIG. 11).
To be The thickness tb 'of the long lower layer plate 19 (9th
(See the drawing) is determined so that the thickness of the bottom of the recessed portion 7 after the rolling and joining becomes a predetermined dimension T (see FIG. 11). At the time of roll-bonding, the bottom of the recess is not directly pressed by the roll,
Since there is an influence of the elongation in the rolling direction of the part to be rolled,
T <tb '. The bottom thickness T of the recess is preferably thin from the viewpoint of heat dissipation of the semiconductor chip, but 0.1 to 0.3 mm is appropriate in consideration of the rigidity of the chip mounting part.

Next, the long laminated material 17 manufactured by rolling joining,
As shown in FIG. 7, the coating metal layer 20 is cut at the position indicated by the broken line ii, and the coating metal layer 20 is oxidized to provide electrical insulation. An example of the oxidation treatment is anodization treatment that is performed electrochemically.

According to the example of FIG. 11, the oxide film is formed by the coating layer 20a on the peripheral surface surrounding the recess 7 and the coating layer 2 on the bottom of the recess 2.
0d, the coating layer 20c on the peripheral portion, the back surface coating layer 2 on the side opposite to the recessed portion
It is 0b. Since the short sides 16a ', 16b' of the container 16 shown in FIG. 6 are cut edges, the metal cores 18a ', 19a' shown in FIG.
Is exposed. When the corrosion resistance of these metal core materials 18a ', 19a' is insufficient, a heat resistant resin coating is applied. The reason why this resin coating material is required to have heat resistance is that it is necessary to withstand heat in a mounting process and a sealing process of a semiconductor chip and a lead frame described later.

The above is the method for manufacturing the integrated circuit container of the present invention, but the mounting of the semiconductor chip, the lead frame, and the sealing of the container and the container lid will be supplementarily described.

These are the same as the conventional method.

That is, as shown in FIG. 12, first, the semiconductor chip adhesive layer 24 made of glass or noble metal is formed on the bottom surface of the recess of the container 16. Next, glass powder for hermetic sealing is applied on the metal oxide layer 20a of the peripheral surface portion 32 by screen printing, and calcination is performed to form the sealing glass layer 26. One of the reasons why aluminum is used as the coating metal in the preferred embodiment is that the oxide layer has good adhesion to glass.

The semiconductor chip 27 is embedded by heating and melting the adhesive layer 24, and the lead frame 33 is embedded by heating and melting the sealing glass layer 26. The leads of the semiconductor chip 27 and the lead frame are connected by wires 29. Next thirteenth
As shown in the figure, the container 16 is covered with a container lid 16 ', and both sealing glass layers 26, 26' are heated and melted to be integrated and sealed. The reference numerals in the figure are the same as in FIG.

(Effects of the Invention) As described in detail above, the integrated circuit container manufactured by the manufacturing method of the present invention has no protrusions that hinder transportation and has a semiconductor chip formed on the peripheral surface part on which the lead frame is mounted. It can be made flat irrespective of the depth of the recessed part to be mounted and the thickness of the metal plate material to be used, and the characteristics of the metal container are that it is strong against impacts and can quickly dissipate the heat generated in the semiconductor chip. It has different characteristics.

[Brief description of drawings]

1 (a) is a schematic plan view of a conventional ceramic integrated circuit container; FIG. 1 (b) is a cross-sectional view taken along the line Loro of FIG. 1; FIG. 2 is FIG. A schematic perspective view of a package obtained by assembling a semiconductor chip into the container shown in FIG. 3; FIG. 3 (a) is a schematic perspective view of a conventional product; FIG. 3 (b) is a schematic perspective view of FIG. FIG. 4 (a) and FIG. 4 (b) are schematic explanatory views showing how upward warp and downward warp are formed during molding of the recessed portion; FIG. 5 (a), (B) is a schematic explanatory view showing a state of forming a recessed part; FIGS. 6 (a) and 6 (b) are respectively a perspective view and a roro line of an integrated circuit container manufactured by the method of the present invention. FIG. 7 is a schematic perspective view of the long laminated material; FIGS. 8A and 8B are schematic perspective views and sectional views showing the structure of the upper layer plate of the long laminated material, respectively. Fig. 9 (a) and (b) are perspective views and cross-sectional views of the long lower layer plate, respectively. Fig. 10 is a long laminated material obtained by rolling the long upper layer plate and the long lower layer plate together. FIG. 11 is a cross-sectional view of a laminated material obtained by rolling; and FIGS. 12 and 13 are assembling semiconductor chips into a package using the container manufactured according to the present invention. 3A and 3B are schematic sectional views respectively illustrating 7: Recessed part, 16: Container 16a: Upper layer plate, 16b: Lower layer plate 17: Long laminated material, 18a: Metal core material 18b: Coated metal layer, 21: Through holes 32, 22: Peripheral surface part

Claims (3)

[Claims] 1. A recess for mounting a semiconductor chip,
In a method for manufacturing an integrated circuit container having a peripheral surface portion surrounding the recess, a long narrow width in which the peripheral surface of a plate-shaped metal core material is coated with a metal forming an oxide, and the width is approximately equal to the width of the container. A plate-shaped material is prepared, and a punching step in which through holes that are the bases of the recesses are formed at predetermined intervals in the longitudinal direction in the material, and a perforated long plate material obtained in this manner A step of superimposing a long narrow plate-shaped material having the same width, in which the peripheral surface of the metal core material is coated with another metal forming an oxide, and heating and rolling to integrate the coated metal on the mating surface. And a step of cutting the mating material at an intermediate position between the recesses formed in the mating material thus obtained and a step of oxidizing the coating metal on the peripheral surface of the metal core material. A method of manufacturing an integrated circuit container, comprising: 2. The method according to claim 1, wherein the step of oxidizing the coating metal is performed prior to the step of cutting the laminated material. 3. The method according to claim 1, wherein the metal coating the peripheral surface of the metal core material is aluminum.