JPH03265162A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To restrain water from entering inside a package and to improve reliability of humidity resistance by arranging a sealing resin layer of a pair of plate materials which is formed by laminating a sealing resin layer, a metallic layer and an insulating layer one by one in opposition to the side of a semiconductor element and by sealing it by heat bonding. CONSTITUTION:Two sheets of plate material 4 are manufactured, which are formed by laminating an insulating layer 1, a metallic layer 2 and a sealing resin layer 3 one by one. Sealing resin layers 3 of the two sheets of plate material 4 are arranged in opposition each other and a semiconductor element 5 attached to a lead frame 4 is arranged between them. Then, sealing is carried out by heat bonding using upper and lower heating plates.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a resin-sealed semiconductor device.

(Prior art) In recent years, in the field of resin encapsulation of semiconductor devices,
BACKGROUND OF THE INVENTION As semiconductor devices become more highly integrated, various functional units on the device are becoming smaller and the size of the device itself is rapidly increasing. In addition, ASIC (Application Specification)
Processes such as vapor phase reflow, infrared reflow, and solder immersion are used when mounting surface mount packages such as gate arrays called fic ICs and standard cell type LSIs. In these steps, the package is exposed to high temperatures (5 to 260° C. for two steps). For this reason, in a resin-sealed semiconductor device sealed with epoxy resin, a small amount of moisture that penetrates the resin and enters the interior rapidly evaporates, causing cracks in the sealing resin layer. As a result, if the cracks reach the outside, a serious problem arises in that cross-resistance reliability cannot be guaranteed. Also,
There is also a phenomenon in which the resin bulges and cannot be mounted. Furthermore, PSG (phosphosilicate glass) is used as a passivation film for wiring layers such as aluminum.
Problems such as cracks forming in 5iN (silicon nitride) and disconnection of Au bonding wires occur frequently.

As a countermeasure for these, 1) the stress on the internal encapsulation of the sealing resin is reduced, and the PSGSSi on the sealing resin and the element is reduced;
Demands such as increasing adhesion with N, polyimide films and lead frames; ■ providing high-temperature strength and moisture-absorbing high-temperature strength corresponding to the mounting temperature, and reducing heat absorption; are increasing demands for sealing resins for large packages. It is becoming more and more central.

From these viewpoints, examples of sealing resins include maleimide resins, PPS (polyphenylene sulfide), and PPO (polyhydroxyphenylene ether).
The practical application of liquid crystal polymers and liquid crystal polymers is being considered. Furthermore, recently, a resin that is a combination of a maleimide resin and an epoxy resin, or an aminobismaleimide resin that is a combination of a bismaleimide resin and 4,4-diaminodiphenylmethane has been proposed as a sealing resin. However, when transfer molding is performed using these resins, a problem arises in that improved adhesion to lead frames and the like conversely impedes release from the mold.

Therefore, these resins have not been able to satisfy the contradictory characteristics of improved adhesion to lead frames and the like and ease of release from the mold.

On the other hand, resin-sealed semiconductor devices (for example, Japanese Patent Laid-Open No. 60-20884
No. 7) has been proposed. In this semiconductor device, a cylindrical or polygonal hole is provided in the mold resin (sealing resin) below the die pad to form an extremely thin part or a part without mold resin, and when heated, the inside of the mold resin is heated. The structure allows the gas generated by the evaporation of water to escape from the extremely thin portions mentioned above. Another possibility is a resin-sealed semiconductor device in which a metallic coating layer is formed on the package surface using a transfer molding method to prevent cracks from reaching the outside and improve moisture resistance reliability. However, none of the resin-sealed semiconductor devices was fully satisfactory in terms of productivity and moisture resistance reliability.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned problems.
The present invention aims to provide a resin-sealed semiconductor device that is easy to manufacture, suppresses the intrusion of moisture into the package, prevents cracks in the resin during heating during mounting, and has good moisture resistance reliability.

[Structure of the Invention (Means for Solving the Problems)] The present invention provides a plate material in which a sealing resin layer, a metal layer, and an insulating layer are laminated in this order so that the sealing resin layer faces the semiconductor element side. This is a resin-sealed semiconductor device, characterized in that the semiconductor device is placed in a resin-sealed semiconductor device and sealed by heat and pressure bonding.

Examples of the sealing resin forming the sealing resin layer include epoxy resins, phenol resins, maleimide sealing resins, silicone sealing resins, and other thermoplastic resins and engineering plastics. It will be done. Among these, from the viewpoint of further improving moisture resistance reliability, it is desirable that the resin has high adhesion to semiconductor elements and metals, and the resin itself has a small amount of moisture absorption. The thickness of the sealing resin layer is appropriately set depending on the thickness of the package. However, the lower limit of the thickness of the sealing resin layer needs to be set to a thickness that can prevent contact between the metal layer and the bonding wire of the semiconductor element during the heat-pressing process.

Examples of the metal forming the metal layer include iron, nickel, copper, gold, silver, aluminum, tin, silicon, stainless steel, lead, and alloys thereof. Among these, those that can be processed into a thin shape and are lightweight are desirable. The thickness of such a metal layer is desirably 1000 μM or less.

Examples of the insulating layer include a metal oxide layer and a polyimide film. The metal oxide layer may be a metal oxide film formed by oxidizing the surface of the metal layer. Such an insulating layer has a volume and a resistivity of 1.0 from the viewpoint of ensuring sufficient insulation. It is desirable that the resistance is OX 108Ω·cm or more. Further, it is desirable that the thickness thereof be 5 μm or less. Note that the insulating layer may be provided in the form of an oxide film or the like on both surfaces of the metal layer.

The plate material can be produced by, for example, laminating a metal layer and an insulating layer in advance and then laminating a sealing resin layer on the metal layer side. The method of laminating the sealing resin layer includes a method of coating the surface of the metal layer with the sealing resin, a method of powder coating the surface of the metal layer with the sealing resin, and a method of applying a compression molded body of the sealing resin to the surface of the metal layer. Examples include a method of heat fusion.

The resin-sealed semiconductor device according to the present invention has a form in which a semiconductor element is sealed from one side with one plate material, and a form in which a semiconductor element is sealed from both sides with two plate materials. These forms are selected depending on the mounting state of the semiconductor element. For example, when a semiconductor element is bonded to a lead frame, these members are sandwiched between two plate materials. When a semiconductor element is bonded to a film carrier, a plate material is placed on one side of these members (the bonding surface of the element with the film carrier), or these members are sandwiched between two plate materials. When a semiconductor element is mounted on a circuit board, a plate material is placed on the side of the element. Methods for manufacturing such resin-sealed semiconductor devices will be specifically exemplified below as methods (1) to (4).

(1) As shown in FIG. 1(a), an insulating layer 1, a metal layer 2
, and a sealing resin layer 3 are arranged in this order so that the sealing resin layers 3 face each other, and a semiconductor element 5 is arranged between these plate materials 4. The semiconductor element 5 is placed on a lead frame 6, and the electrodes on the upper surface are bonded to the leads 7 with wires 8. Next, the sealing resin layers 3 of the two plate materials 4 are heated by plate heating or infrared heating to soften and melt, and the semiconductor element 5 is sandwiched between the two plate materials 4 and pressed together. The softened and molten state of the sealing resin layer 3 at this time is usually adjusted within a range such that the sealing resin does not drip from the plate material and the bonding wire etc. do not deform when crimped.

Through these steps, as shown in FIG. 1(b), the semiconductor element 5, die pad 6, and wire 8 are sealed in the sealing resin layer 3, and the metal layer 2 and the insulating layer 1 are gradually disposed outside of the sealing resin layer 3. A resin-sealed semiconductor device is obtained.

(2) As shown in FIG. 2(a), the TAB (Tape) bonded to the film carrier 10 through the bump 9
The process is carried out in the same manner as the method (1) above, except that the semiconductor element 5 of the Automated Bonding (Automated Bonding) type is used.

Through these steps, as shown in FIG. 2(b), the semiconductor element 5 and the bumps 9 are sealed in the sealing resin layer 3, and the resin sealing layer with the metal layer 2 and the insulating layer 1 gradually arranged on the outside thereof. A stop type semiconductor device is obtained.

(3> As shown in Fig. 3(a), insulating layer 1, metal layer 2
, and a plate material 4 in which the sealing resin layer 3 is laminated in this order.
are arranged so that the sealing resin layer 3 faces the bonding side of the TAB type semiconductor element 5. Next, the sealing resin layer 3 of the plate material 4 is heated to a softened and molten state, and then press-bonded. Through these steps, as shown in FIG. 3(b), the bonding surface and side surfaces of the semiconductor element 5, as well as the bumps 9, are sealed in the sealing resin layer 3, and a sealing resin layer is formed on the bonding surface side of the semiconductor element 5. A resin-sealed semiconductor device is obtained in which the metal layer 2 and the insulating layer (are gradually disposed through the metal layer 2 and the insulating layer 3 are disposed gradually).

(4) As shown in FIG. 4(a), the insulating layer 11 metal layer 2
, and a plate material 4 in which the sealing resin layer 3 is laminated in this order.
are arranged so that the sealing resin layer 3 faces the upper surface side of the semiconductor element 5. The semiconductor element 5 is mounted on the substrate 11, and the electrode on the upper surface is bonded to the wiring 12 on the substrate 11 with a wire 8. Next, plate material 4
The sealing resin layer 3 is heated to a softened and molten state, and then press-bonded. Through these steps, as shown in FIG. 4(b), the semiconductor element 5, the wire 8, and the wiring 12 are sealed in the sealing resin layer 3 on the substrate 11, and the sealing resin layer is formed on the upper surface side of the semiconductor element 5. A resin-sealed semiconductor device is obtained in which the metal layer 2 and the insulating layer 1 are gradually disposed through the metal layer 2 and the insulating layer 1.

(Function) According to the present invention, a plate material in which an insulating layer, a metal layer, and a sealing resin layer are laminated in this order is sealed by heat-pressing and bonding the semiconductor element from the sealing resin layer side. The metal layer can prevent moisture from entering the package. As a result, it is possible to prevent the generation of cracks in the sealing resin layer due to rapid vaporization of minute amounts of residual moisture during heating during mounting, and it is possible to obtain a resin-sealed semiconductor device with excellent moisture resistance and reliability. Furthermore, since the metal layer is covered with the insulating layer, malfunctions due to contact with pins or the like can be prevented.

Furthermore, by using the above-mentioned plate material, there is no need to consider separation of the sealing resin from the mold as in the conventional transfer molding method, so the sealing resin has excellent adhesion to semiconductor elements and bonding wires. can be selected. As a result, moisture resistance reliability can be improved from this point as well.

Furthermore, since molding can be performed in a shorter time than with transfer molding, manufacturing is easier.

(Example) Examples of the present invention will be described in detail below.

Example 1 A lead frame made of 4.270 mm with a die pad size of 15.5+n+n square and a plate thickness of 150μ is 25μ
A semiconductor element (chip size: 15 mm square, passivation film, polyimide film on two surfaces) bonded with m-diameter bonding wire was produced. In addition, the thickness of the plate whose surface is covered with an oxide layer (insulating layer) due to alumite treatment is 40 mm.
Two plate materials were prepared by heating and coating one side of a 0 μm aluminum plate (metal layer) with an epoxy resin composition having the physical properties shown in Table 1 below to form a sealing resin layer.

Next, the two plate materials having the above-mentioned configuration are
As shown in Figure (a), these sealing resin layers 3 were arranged so as to face each other, and a semiconductor element 5 attached to a lead frame was arranged between these plate materials 4. Next, the sealing was carried out by heating and pressure bonding using upper and lower heating plates (not shown) at a temperature of 170°C and a pressure of 5 kg/cm2, and after-curing was performed at 175°C for 4 hours to sufficiently harden the sealing resin. The package shape shown in figure (b) is 32
A resin-sealed semiconductor device with a size of 1×32+n+n×3.6 mm and 84 QFPI bottles was manufactured.

Table 1 Example 2 One side of an aluminum plate (metal layer) with a thickness of 400 μm was coated with polyimide resin to a thickness of 5 μm as an insulating layer, and the other side of the aluminum plate was coated with Example 1.
Two plate materials were prepared by heating and coating the same epoxy resin composition as above to form a sealing resin layer. Other than this, the procedure was the same as in Example 1, as shown in FIG. 1(b).
A resin-sealed semiconductor device shown in Figure 1 was manufactured.

Example 3 A resin-sealed semiconductor device shown in FIG. 1(b) was produced in the same manner as in Example 1, except that the sealing resin layer of the plate material of Example 1 was made thinner and the package shape was changed to 32+ nm x 32 m1 x 2 mn+. Manufactured.

Example 4 A resin-sealed semiconductor device shown in FIG. 1(b) was produced in the same manner as in Example 1 except that the sealing resin layer of the plate material of Example 1 was made thinner and the package shape was 32 mm x 32 mm x 1 mm. Manufactured.

Example 5 One side of a copper plate (metal layer) with a thickness of 200μ0 was coated with polyimide resin to a thickness of 5μm as an insulating layer, and the other side of the copper plate was coated with the same epoxy resin composition as in Example 1. Two plate materials were prepared by heat coating the material to form a sealing resin layer.

Except for this, the resin-sealed semiconductor device shown in FIG. 1(b) was manufactured in the same manner as in Example 1.

Example 6 One surface of a stainless steel plate (metal layer) with a thickness of 150 μm was coated with polyimide resin to a thickness of 5 μm as an insulating layer, and the same epoxy resin as in Example 1 was coated on the other surface of the stainless steel plate. Two plate materials were prepared by heat coating the composition to form a sealing resin layer.

Except for this, the resin-sealed semiconductor device shown in FIG. 1(b) was manufactured in the same manner as in Example 1.

Comparative Example 1 Implementation f! Using the epoxy resin composition used in IJ1 to which 0.4 parts by weight of carnauba wax, which is an internal mold release agent, was added as a sealing resin, the same molding as that of Example 1 was performed using a transfer molding method at a mold temperature of 170°C. The same semiconductor element is sealed in a sealing resin layer and the package size is 32mmX.
A resin-sealed semiconductor device of 4 bottles of QFPIli was manufactured using 32m+IIX 3.6+n+n.

Comparative Example 2 The sealing resin layer of Comparative Example 1 was made thinner, and the package shape was changed to 32 mm.
A resin-sealed semiconductor device was manufactured in the same manner as in Comparative Example 1 except that the dimensions were mmX 32+nmX 2mm.

Comparative Example 3 The sealing resin layer of Comparative Example 1 was made thinner and the package shape was changed to 32 mm.
Comparative example 1 except that maX 32m1X lff1m
A resin-sealed semiconductor device was manufactured in the same manner as above.

Table 2 below shows the package molding times in the sealing process during manufacturing of the resin-sealed semiconductor devices of Examples 1 to 6 and Comparative Examples 1 to 3.

Regarding the resin-sealed semiconductor devices of Examples 1 to 6 and Comparative Examples 1 to 3, the water absorption rate of the sealing resin, the adhesion to the polyimide film that is the passivation film of the semiconductor element, and the adhesion to the lead frame were investigated. Ta.

In addition, after 200 hours of moisture absorption treatment at a temperature of 85℃ and relative humidity of 85%, vPS treatment (paper phase reflow treatment) was performed at 215℃, and we observed the occurrence of cracks that reached the outside immediately after VPS treatment to check for the occurrence of defective products. Examined. Furthermore,
A moisture resistance reliability test was conducted in a pressure cooker at a temperature of 121°C and a pressure of 2 atm to investigate the occurrence of defective products. These results are shown in Table 2 below.

As is clear from Table 2, since the resin-sealed semiconductor devices of Examples 1 to 6 have a metal layer, moisture infiltration is suppressed;
It can be seen that the water absorption rate of the sealing resin is lower than that of the resin-sealed semiconductor devices of Comparative Examples 1 to 3. Further, in the resin-sealed semiconductor devices of Examples 1 to 6, there is no need to use a sealing resin with good mold layering, so a sealing resin with excellent adhesion to the semiconductor element and bonding wire can be used. . As a result, vPS due to rapid vaporization of water city inside the package
It can be confirmed that there are few cracks that reach the outside after treatment, and that the product has excellent moisture resistance and reliability.

Furthermore, it can be seen that the resin-sealed semiconductor devices of Examples 1 to 6 can be easily manufactured in a shorter molding time than the transfer molding method.

[Effects of the Invention] As detailed above, according to the present invention, moisture intrusion into the inside of the package is suppressed, cracks in the resin are prevented during heating during mounting, and the package has excellent moisture resistance and reliability, and is easy to manufacture. Therefore, it is possible to provide a resin-sealed semiconductor device that can fully respond to future trends toward larger and thinner semiconductor elements.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are cross-sectional views showing the manufacturing process of a resin-sealed semiconductor device according to the present invention, and FIGS. 2(a) and (b) are cross-sectional views of the resin-sealed semiconductor device according to the present invention. FIG. 3(a) is a sectional view showing another manufacturing process. (b) is a sectional view showing another manufacturing process of the resin-sealed semiconductor device according to the present invention, and FIGS. 4(a) and (b) are other manufacturing steps of the resin-sealed semiconductor device according to the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Insulating layer, 2... Metal layer, 3... Sealing resin layer, 4... Plate material, 5... Semiconductor element, 6...
・Die pad, 7...Lead, 8...Wire
9... Bamboo, 10... Film carrier, 11.
... Board, 12... Wiring.

Claims (1)

[Claims] A resin seal characterized in that a plate material in which a sealing resin layer, a metal layer, and an insulating layer are laminated in this order is arranged so that the sealing resin layer faces the semiconductor element side, and sealed by heat-pressing. Stop type semiconductor device.