JP2892087B2 - Resin-sealed semiconductor device and method of manufacturing the same - Google Patents

Description

The present invention relates to a resin-sealed semiconductor device and a method of manufacturing the same.

(Prior Art) In recent years, in the field of resin encapsulation of a semiconductor device, miniaturization of various functional units on an element and enlargement of the element itself have been rapidly progressing along with high integration of a semiconductor element.
Also, when mounting a surface mount package represented by a gate array called an ASIC (Application Specific IC) or a standard cell LSI, processes such as vapor phase reflow, infrared reflow, and solder immersion are employed. . In these processes, the package is hot (21
5 to 260 ° C). For this reason, in a resin-sealed semiconductor device sealed with an epoxy resin, a small amount of moisture permeating through the resin and entering the interior is rapidly vaporized, and a clutch enters the sealing resin layer. As a result, when the crack reaches the outside, there is a large problem that the moisture resistance reliability cannot be guaranteed. In addition, a phenomenon occurs in which the resin cannot be mounted due to swelling of the resin. Further, cracks occur in PSG (phosphosilicate glass) or SiN (silicon nitride) used as a passivation film of a wiring layer of aluminum or the like, and problems such as disconnection of an Au bonding wire frequently occur.

As a countermeasure, reduce the stress of the sealing resin against the internal enclosure, and use PSG, SiN,
Improve adhesion with polyimide film and lead frame;
Demands for providing high-temperature strength and high-moisture-absorbing high-temperature strength corresponding to the mounting temperature and reducing the amount of moisture absorption are increasing, mainly for sealing resins for large packages.

From these viewpoints, as the sealing resin, for example, maleimide resin, PPS (polyphenylene sulfide)
Practical use of a liquid crystal polymer, a PPO (polyhydroxyphenylene ether), or a liquid crystal polymer is being studied. Further, recently, a resin obtained by combining a maleimide resin and an epoxy resin, or an aminobismaleimide resin obtained by combining a bismaleimide resin and 4,4-diaminodiphenylmethane has been proposed as a sealing resin. However, when transfer molding is performed using these resins, there arises a problem that improvement in adhesion to a lead frame or the like adversely inhibits mold release. Therefore, these resins could not satisfy the contradictory characteristics of improvement in adhesion to a lead frame or the like and ease of mold release.

On the other hand, a resin-encapsulated semiconductor device in which mounting problems have been improved with a package structure (for example, Japanese Patent Application Laid-Open No. 60-208847)
Has been proposed. In this semiconductor device, a column or a polygonal hole is provided in a molding resin (sealing resin) portion on a lower side of a die pad to form an extremely thin portion or a portion having no molding resin. The structure is such that gas generated by the evaporation of moisture escapes from the extremely thin portion described above. Further, a resin-encapsulated semiconductor device in which a metallic coating layer is formed on a package surface by a transfer molding method to prevent the occurrence of cracks reaching the outside and improve the moisture resistance reliability is also conceivable. However, none of the resin-encapsulated semiconductor devices has been sufficiently satisfactory in terms of productivity and moisture resistance reliability.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned problems, and has been proposed in order to prevent moisture from entering the inside of a package and to prevent cracking of a resin upon heating during mounting. It is an object of the present invention to provide a resin-encapsulated semiconductor device having good characteristics and a method for easily manufacturing such a semiconductor device.

[Configuration of the Invention] (Means for Solving the Problems) A resin-encapsulated semiconductor device according to the present invention includes a semiconductor element to which an external lead is connected, and at least a surface of the semiconductor element including a connection portion of the external lead. And an insulating layer laminated on the sealing resin layer via a metal layer.

In another resin-encapsulated semiconductor device according to the present invention, a plate material in which an encapsulation resin layer, a metal layer, and an insulation layer are laminated in this order is formed by opposing a semiconductor element having the encapsulation resin layer to which external leads are connected. And at least the surface of the semiconductor element including the connection part of the external lead is sealed by heat compression.

The method for manufacturing a resin-encapsulated semiconductor device according to the present invention includes:
A step of preparing a plate material in which a sealing resin layer, a metal layer, and an insulating layer are laminated in this order; and the sealing resin layer includes a connection portion of the external lead to a semiconductor element to which the plate material is connected to an external lead. And arranging at least so as to face the surface, followed by heat-pressing and sealing.

As a sealing resin for forming the sealing resin layer, an epoxy resin, a phenol resin, a maleimide sealing resin,
Examples include silicone-based sealing resins, and further include other thermoplastic resins, engineering plastics, and the like. Among these, from the viewpoint of further improving the moisture resistance reliability, those having high adhesion to the semiconductor element and the metal and having a small amount of moisture absorption by the resin itself are desirable. The thickness of the sealing resin layer is appropriately set according to the thickness of the package. However, the lower limit of the thickness of the sealing resin layer needs to be a thickness that can prevent contact between the metal layer and a bonding wire or the like of a semiconductor element in the thermocompression bonding step.

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 which can be processed to be thin and are lightweight are desirable. It is desirable that the thickness of the metal layer be 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 a surface of the metal layer. From the viewpoint of securing sufficient insulating properties, such an insulating layer desirably has a volume resistivity of 1.0 × 10 ⁸ Ω · cm or more. Also,
It is desirable that the thickness be 5 μm or less. In addition,
The insulating layer may be provided on both surfaces of the metal layer in the form of an oxide film or the like.

The plate material can be produced, for example, by laminating a metal layer and an insulating layer in advance, and then laminating a sealing resin layer on the metal layer side. As a method of laminating the sealing resin layer, a method of coating the sealing resin on the surface of the metal layer, a method of powder coating the sealing resin on the surface of the metal layer, and a compression molding of the sealing resin on the surface of the metal layer For example, a method of heat fusion may be used.

The resin-sealed semiconductor device according to the present invention includes 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 modes are selected according to the mounting state of the semiconductor element. For example, in a state where the semiconductor element is bonded to the lead frame, a mode is adopted in which these members are sandwiched between two plate materials. In the state where the semiconductor element is bonded to the film carrier,
Either a plate material is disposed 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. In a state where the semiconductor element is mounted on the circuit board, a form in which a plate material is arranged on the element side is adopted. The method for manufacturing such a resin-encapsulated semiconductor device will be specifically described below as methods (1) to (4).

(1) As shown in FIG. 1 (a), two plate materials 4 in which an insulating layer 1, a metal layer 2, and a sealing resin layer 3 are laminated in this order so that the sealing resin layer 3 faces each other. The semiconductor elements 5 are arranged between the plate materials 4. The semiconductor element 5 is mounted on a die pad 6 of a lead frame, and an electrode on the upper surface is bonded to a lead 7 with a wire 8. Then, two plate materials 4
The sealing resin layer 3 is heated by plate heating or infrared heating so as to be in a softened and molten state, and the semiconductor element 5 is sandwiched between two plate materials 4 and pressed. The softening and melting state of the sealing resin layer 3 at this time is usually adjusted within a range where the sealing resin does not drop from the plate material and the bonding wires and the like do not deform when pressed. Through these steps, as shown in FIG. 1 (b),
The semiconductor element 5, the die pad 6, and the wire 8 are sealed in the sealing resin layer 3, and a resin-sealed semiconductor device in which the metal layer 2 and the insulating layer 1 are gradually disposed outside the semiconductor element 5, the die pad 6, and the wire 8 is obtained.

(2) As shown in FIG. 2 (a), TAB (Tape Automated) bonded to the film carrier 10 by the bump 9
Bonding) is performed in the same manner as in the method (1) except that the semiconductor element 5 is used. By these steps, as shown in FIG. 2 (b), the semiconductor element 5 and the bump 9 are sealed in the sealing resin layer 3, and the metal layer 2 and the insulating layer 1 are gradually disposed outside the resin sealing. A semiconductor device having a stop type is obtained.

(3) As shown in FIG. 3 (a), a plate material 4 in which an insulating layer 1, a metal layer 2, and a sealing resin layer 3 are laminated in this order is used. 5 so as to face the bonding side. Next, the sealing resin layer 3 of the plate material 4 is heated to be in a softened and molten state, and then pressed. Through these steps, as shown in FIG. 3 (b), the bonding surface and side surfaces of the semiconductor element 5 and the bumps 9 are sealed in the sealing resin layer 3, and the semiconductor element 5
To obtain a resin-sealed semiconductor device in which the metal layer 2 and the insulating layer 1 are gradually arranged on the bonding surface side via the sealing resin layer 3.

(4) As shown in FIG. 4 (a), a plate material 4 in which an insulating layer 1, a metal layer 2, and a sealing resin layer 3 are laminated in this order is applied to the sealing resin layer 3 on the upper surface side of the semiconductor element 5. They are arranged so as to face each other. The semiconductor element 5 is mounted on a substrate 11, and electrodes on the upper surface are bonded to wires 12 on the substrate 11 by wires 8. Next, the sealing resin layer 3 of the plate material 4 is heated to be in a softened and molten state, and then pressed. By these steps, as shown in FIG. 4 (b), the semiconductor element 5, the wires 8, and the wirings 12 are sealed on the substrate 11 by the sealing resin layer 3, and the sealing resin layer is formed on the upper surface of the semiconductor element 5. A resin-sealed semiconductor device in which the metal layer 2 and the insulating layer 1 are gradually arranged via 3 is obtained.

(Operation) 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 heated and pressed from the sealing resin layer side to a semiconductor element to seal the semiconductor element. In addition, the penetration of moisture into the package can be suppressed by the metal layer. As a result, cracks in the sealing resin layer due to rapid evaporation of a small amount of residual moisture upon heating during mounting can be prevented, and a resin-encapsulated semiconductor device having excellent moisture resistance reliability can be obtained. Further, since the metal layer is covered with the insulating layer, malfunction due to contact with a pin or the like can be prevented.

Furthermore, by using the above-mentioned plate material, it is not necessary to consider the mold separation of the sealing resin as in the conventional transfer molding method, so that the sealing resin has excellent adhesion to a semiconductor element or a bonding wire. Can be selected. As a result, the moisture resistance reliability can be improved from this point as well. In addition, since molding can be performed in a shorter time as compared with the transfer molding method, it can be easily manufactured.

(Example) Hereinafter, an example of the present invention will be described in detail.

Example 1 The die pad size is 15.5 mm square and the plate thickness is 150 μm
A semiconductor element (15 mm square chip size, passivation film: surface polyimide film) bonded to a 4.2 alloy lead frame by a bonding wire having a diameter of 25 μm was prepared. An epoxy resin composition having the physical properties shown in Table 1 below is coated on one side of an aluminum plate (metal layer) having a thickness of 400 μm, the surface of which is covered with an oxide layer (insulating layer) by alumite treatment, and sealed. Two plate materials were produced by forming a resin stopper layer.

Next, as shown in FIG. 1 (a), the two plate materials having the above structure were arranged so that their sealing resin layers 3 face each other, and were attached to a lead frame between these plate materials 4. The semiconductor element 5 was arranged. Then, the upper and lower heating plates (not shown) were heated and pressed under a temperature of 170 ° C. and a pressure of 5 kg / cm ² , and then sealed at 175 ° C.
After curing for 4 hours, the sealing resin is sufficiently cured, and the package shape shown in FIG. 1 (b) is 32 mm × 32 mm × 3.
A 6 mm QFP 184-pin resin-sealed semiconductor device was manufactured.

Example 2 One side of an aluminum plate (metal layer) having a thickness of 400 μm was coated with a polyimide resin as an insulating layer to a thickness of 5 μm, and the other side of the aluminum plate was coated with an example 1
Two plate materials were produced by heating and coating the same epoxy resin composition as in Example 1 to form a sealing resin layer. Other than the above, FIG.
Was manufactured.

Example 3 A resin-encapsulated semiconductor shown in FIG. 1 (b) in the same manner as in Example 1 except that the sealing resin layer of the plate material of Example 1 was thinned to make the package shape 32 mm × 32 mm × 2 mm. The device was manufactured.

Example 4 A resin-encapsulated semiconductor shown in FIG. 1 (b) in the same manner as in Example 1 except that the sealing resin layer of the plate material of Example 1 was thinned to make the package shape 32 mm × 32 mm × 1 mm. The device was manufactured.

Example 5 One side of a copper plate (metal layer) having a thickness of 200 μm was coated with a polyimide resin as an insulating layer at a thickness of 5 μm, and the other surface of the copper plate was the same epoxy resin composition as in Example 1. An object was heated and coated to form a sealing resin layer, thereby producing two plate materials.
Except for this, the resin-encapsulated semiconductor device shown in FIG. 1B was manufactured in the same manner as in Example 1.

Example 6 One side of a stainless steel plate (metal layer) having a thickness of 150 μm was coated with a polyimide resin as an insulating layer at a thickness of 5 μm, and the other surface of the stainless steel plate was the same epoxy resin composition as in Example 1. An object was heated and coated to form a sealing resin layer, thereby producing two plate materials. Except for this, the first method is the same as in the first embodiment.
A resin-sealed semiconductor device shown in FIG.

Comparative Example 1 The epoxy resin composition used in Example 1 and 0.4 parts by weight of carnauba wax as an internal mold release agent added thereto were used as a sealing resin, and the transfer was performed by a transfer molding method at a mold temperature of 170 ° C. The same semiconductor element as in Example 1 is sealed in a sealing resin layer, and the package shape is 32 mm × 32 mm × 3.6 mm
Manufactured a resin-sealed semiconductor device with 184 pins of QFP.

Comparative Example 2 The package shape was reduced by reducing the thickness of the sealing resin layer of Comparative Example 1 to 32.
A resin-encapsulated semiconductor device was manufactured in the same manner as in Comparative Example 1 except that the size was changed to mm × 32 mm × 2 mm.

Comparative Example 3 The package shape was reduced by reducing the thickness of the sealing resin layer of Comparative Example 1 to 32.
A resin-encapsulated semiconductor device was manufactured in the same manner as in Comparative Example 1 except that the size was changed to mm × 32 mm × 1 mm.

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

With respect to the resin-encapsulated semiconductor devices of Examples 1 to 6 and Comparative Examples 1 to 3, the water absorption of the encapsulating resin, the adhesion with the polyimide film which is the passivation film of the semiconductor element, and the adhesion with the lead frame were examined. Was. In addition, after performing moisture absorption treatment at a temperature of 85 ° C and relative humidity of 85% for 200 hours, VPS treatment (vapor phase reflow treatment) is performed at 215 ° C. Examined. Further, a moisture resistance reliability test was performed in a pressure cooker at a temperature of 121 ° C. and a pressure of 2 atm, and occurrence of defective products was examined. The results are shown in Table 2 below.

As is clear from Table 2, the resin-sealed semiconductor devices of Examples 1 to 6 have a metal layer, so that the invasion of water is suppressed, and the resin-sealed semiconductor devices of Comparative Examples 1 to 3 are sealed. It can be seen that the water absorption of the resin is small. Examples 1 to 6
In the resin-sealed type semiconductor device described above, there is no need to use a sealing resin with good mold release, so that a sealing resin having excellent adhesion to a semiconductor element and a bonding wire can be used.
As a result, VP caused by rapid vaporization of the water inside the package
It can be confirmed that the occurrence of cracks reaching the outside after the S treatment is small and that the moisture resistance reliability is excellent. Further, Examples 1 to
It can be seen that the resin-encapsulated semiconductor device of No. 6 can be easily manufactured in a shorter molding time than the transfer molding method.

[Effects of the Invention] As described in detail above, according to the present invention, the invasion of moisture into the package is suppressed, and the occurrence of cracks in the resin at the time of heating during mounting is prevented. It is possible to provide a resin-encapsulated semiconductor device that can sufficiently cope with an increase in the size and thickness of the device, and a method that can easily manufacture such a resin-encapsulated semiconductor device.

[Brief description of the drawings]

1 (a) and 1 (b) are cross-sectional views showing a manufacturing process of a resin-sealed semiconductor device according to the present invention, and FIGS. 2 (a) and (b) are resin-sealed semiconductor devices according to the present invention. 3 (a) and 3 (b) are cross-sectional views showing another manufacturing process of the resin-sealed semiconductor device according to the present invention, and FIGS. 4 (a) and 4 (b) () Is a cross-sectional view showing another manufacturing step of the resin-encapsulated semiconductor device according to the present invention. 1 ... insulating layer, 2 ... metal layer, 3 ... sealing resin layer, 4 ...
... Plate material, 5 ... Semiconductor element, 6 ... Die pad, 7 ... Lead, 8 ... Wire, 9 ... Bump, 10
…… Film carrier, 11… Substrate, 12… Wiring.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akira Zenzumi 1 Toshiba Research Institute, Komukai-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Kao-Min-Thai Thailand Komukai, Sachi-ku, Kawasaki-shi, Kanagawa No. 1, Toshiba Town Inside Toshiba Research Institute, Inc. (56) References JP-A-63-250847 (JP, A) JP-A-58-199543 (JP, A) JP-A-57-79651 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) H01L 23 / 28,21 / 56

Claims (3)

(57) [Claims] A semiconductor element to which an external lead is connected; a sealing resin layer sealing at least a surface of the semiconductor element including a connection portion of the external lead; and a metal layer interposed on the sealing resin layer. A resin-encapsulated semiconductor device, comprising: an insulating layer laminated by stacking. 2. A plate material in which a sealing resin layer, a metal layer, and an insulating layer are laminated in this order is disposed so that the sealing resin layer faces a semiconductor element to which external leads are connected, and is heated and pressed. A resin-encapsulated semiconductor device, wherein at least a surface of the semiconductor element including a connection portion of the external lead is sealed. 3. A step of producing a plate material in which a sealing resin layer, a metal layer, and an insulating layer are laminated in this order; and said sealing resin layer is attached to a semiconductor element to which an external lead is connected. A step of arranging at least a surface including the connection portion and facing the surface, and then performing heat-compression bonding to seal the resin-sealed semiconductor device.