JP2568584C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having high reliability, particularly excellent reliability even in a high-temperature atmosphere. [Prior Art] Semiconductor elements such as transistors, ICs and LSIs are generally encapsulated with an epoxy resin composition to form semiconductor devices. The epoxy resin has its electrical properties,
Since it has good moisture resistance and adhesiveness, it is used for encapsulation of semiconductor devices and has achieved good results. However, in recent years, as semiconductor devices are used in large quantities in many outdoor devices, such as automobiles, heat resistance is higher than ever,
Particularly, storage reliability at high temperatures, which has not been a problem in the past, has been required for many semiconductor devices. [Problems to be Solved by the Invention] In order to improve such heat resistance, conventionally, it has been carried out by increasing the flame retardancy of an epoxy resin used for sealing. That is, by combining the brominated epoxy resin and antimony oxide into the epoxy resin composition, the flame retardancy of the cured epoxy resin composition is increased, thereby improving the heat resistance of the sealing resin. I'm wearing The combination of the above brominated epoxy resin and antimony oxide shows good results in terms of flame retardancy. However, there is a problem in terms of storage stability at high temperatures. That is, in a high temperature state, hydrogen bromide is generated due to the thermal decomposition of the brominated epoxy resin, and this hydrogen bromide reacts with the junction between the gold wire of the semiconductor element and the aluminum pad to promote the formation of an alloy. This leads to an increase in the electric resistance value, resulting in poor conduction. In addition, there are more opportunities to use the semiconductor device at high temperatures, and the mounting time is 215 to 26.
Since the entire package may be exposed to a soldering temperature of 0 ° C., excellent mechanical properties under high temperature conditions are also required at the same time. The present invention has been made in view of such circumstances, and provides a semiconductor device that exhibits excellent reliability even when left in a high-temperature atmosphere for a long time, and has a small decrease in mechanical characteristics under a high-temperature atmosphere. For that purpose. [Means for Solving the Problems] To achieve the above object, a semiconductor device of the present invention encapsulates a semiconductor element using an epoxy resin composition containing the following components (A) to (D). Take the configuration to do. (A) An epoxy resin other than a novolak type epoxy resin having at least three epoxy groups in one molecule. (B) A phenolic resin other than a novolak type phenolic resin having at least three phenyl groups in one molecule. (C) Brominated epoxy resin. (D) at least one compound selected from the group consisting of Bi hydroxide, Bi oxide, Al hydroxide and Al oxide. In other words, the present inventors have conducted a series of studies to achieve the above object, and as a result, have found that a halogenated compound gas generated during the thermal decomposition of a brominated epoxy resin as a flame retardant is converted into Bi, Al water. It has been found that oxides and oxides trap and trap the reliability under high-temperature atmosphere without any effect. Further, regarding the mechanical properties under a high-temperature atmosphere, by using the specific epoxy resin and the phenol resin, it becomes possible to obtain a cured epoxy resin composition having excellent mechanical properties under a high-temperature atmosphere. The inventors have arrived at the present invention. The epoxy resin composition used in the semiconductor device of the present invention comprises a specific epoxy resin (component A), a specific phenol resin (component B), and a brominated epoxy resin (component C).
And a compound (component (D)) composed of hydroxides and oxides of Bi and Al, and is usually in the form of powder or tablet. The epoxy resin serving as the component A of the epoxy resin composition is an epoxy resin other than the novolak type epoxy resin and has at least three epoxy groups in one molecule. That is, the present inventors have conducted a series of studies on the improvement of the mechanical properties of the sealing resin under a high-temperature atmosphere. It has been found that the mechanical properties at high temperatures are reduced. Epoxy resins and phenol resins containing such a component having two or less nuclei are of the novolak type. Epoxy resins other than the novolak type epoxy resin have three epoxy groups in one molecule. It has been found that if the epoxy resin has more than two nuclei, it hardly contains components of two or less nuclei. Examples of such an epoxy resin include the following. Such epoxy resins may be used alone or in combination. The phenolic resin of the component B is a phenolic resin other than the novolak type phenolic resin similarly to the epoxy resin, and is a phenolic resin having at least three phenyl groups in one molecule. This phenolic resin is also a phenolic resin that contains almost no binuclear component or less like the epoxy resin. This phenol resin acts as a curing agent for the epoxy resin of the component A. Representative examples of such a phenol resin include those exemplified in the following (1) to (4). Such a phenol resin may be used alone or in combination. It is desirable that the brominated epoxy resin of the component C has an epoxy equivalent of 420 or more, preferably 420 to 550. In particular, the use of a brominated bisphenol-type epoxy resin gives good results. If the epoxy equivalent is less than 420, not only does the resin have a tendency to be inferior in heat resistance, but also a hydrogen halide gas is easily generated. The amount of such a brominated epoxy resin used is preferably set within a range of 1 to 10% by weight (hereinafter abbreviated as "%") in the resin component (A + B + C component) of the epoxy resin composition. That is, if the amount of the brominated epoxy resin is less than 1%, the effect of improving the heat resistance becomes insufficient, and if it exceeds 10%, the generation of hydrogen halide gas increases, which tends to adversely affect the semiconductor element. Because. The mutual use ratio of the phenolic resin and the epoxy resin is appropriately selected from the relationship with the epoxy equivalent of the epoxy resin, and is set so that the equivalent ratio of the phenolic hydroxyl group to the epoxy group is in the range of 0.5 to 1.5. Is preferred. If the equivalent ratio is out of the above range, the heat resistance of the cured epoxy resin composition obtained tends to decrease. One or both of the epoxy resin and the phenol resin as described above have the following general formula (1) It is preferable to use one that has reacted with the organosiloxane represented by By using such an epoxy resin, crack resistance and temperature cycle resistance are improved. However, it is disadvantageous in terms of heat resistance. However, D used in the present invention
By using a compound consisting of the hydroxides and oxides of the components Bi and Al, the phenomenon of lowering the heat resistance is eliminated, and good heat resistance can be obtained. The D component is a hydroxide of Bi, an oxide of Bi, a hydroxide of Al, and an oxide of Al. Representative examples of such compounds include bismuth hydroxide, aluminum hydroxide, bismuth trioxide, and dialuminum trioxide. The above compounds may be used alone or in combination. However,
It is preferable that the content of the D component is set such that the D component accounts for 1 to 10% of the resin component of the epoxy resin composition. That is, if the content is 1
If it is less than 10%, the effect of improving the high-temperature storage characteristics will not be sufficiently exhibited, and if it exceeds 10%, a phenomenon of lowering the moisture resistance will be observed. It is preferable that the compound of the component D is fine particles having an average particle size of 0.5 to 30 μm and a maximum particle size of 74 μm or less. If the particle size is larger than this, the dispersibility tends to be remarkably reduced, and the effect of improving the high-temperature storage characteristics tends to be hardly obtained. The epoxy resin composition used in the present invention contains, if necessary, other additives conventionally used in addition to the above-mentioned components A to D. In particular, in order to improve the flame retardancy in addition to the reliability when left at high temperature, antimony oxide powder is included. Examples of the other additives include a curing accelerator, a release agent, a colorant, and a silane coupling agent. Examples of the curing accelerator include tertiary amines, quaternary ammonium salts, imidazoles, organic phosphorus compounds and boron compounds, and can be used alone or in combination. Examples of the release agent include conventionally known long-chain carboxylic acids such as stearic acid and palmitic acid, metal salts of long-chain carboxylic acids such as zinc stearate and calcium stearate, and waxes such as carnauba wax and montan wax. Can be used. The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, the above-mentioned A to D components and the above-mentioned other additives are appropriately blended, and the mixture is melted and mixed in a kneading machine such as a mixing roll machine in a heated state,
This can be obtained by a series of steps of cooling to room temperature, pulverizing by a known means, and tableting if necessary. The sealing of the semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding. The semiconductor device obtained in this way has sufficient reliability when left at high temperatures and does not show any deterioration in mechanical properties at high temperatures. [Effects of the Invention] As described above, the semiconductor device of the present invention provides the above-described specific epoxy resin (A component).
And a specific phenol resin (component B), a brominated epoxy resin (component C),
It is sealed using a special epoxy resin composition containing a compound (component D) such as hydroxide or oxide of i and Al. The components are trapped, so that excellent reliability can be maintained when left at high temperatures. In addition, the specific epoxy resin (A component) and the phenol resin (B component) minimize the decrease in mechanical strength of the sealing resin, sufficiently exert the protection of the semiconductor element at high temperatures, and provide the halogen compound. It is excellent in reliability at high temperature, in conjunction with the trapping effect. Next, examples will be described together with comparative examples. Examples 1 to 9 and Comparative Examples 1 to 3 Raw materials as shown in Table 1 below were prepared. Next, these raw materials were blended at the ratios shown in Table 2 below, kneaded with a mixing roll machine, cooled and pulverized to obtain a desired powdery epoxy resin composition. A semiconductor element was sealed using the powdered epoxy resin composition obtained as described above, and the characteristics of the obtained semiconductor device were examined. The results are shown in Table 3 below. In Table 3, the bending strength was measured with a Tensilon universal tester (manufactured by Toyo Baldwin Co., Ltd.). The measurement of element failure in a high temperature state was performed by assembling a semiconductor device by sealing a semiconductor element with a resin, exposing a total of 20 devices to a high temperature, and determining and evaluating the number of defective conduction. From the results shown in Table 3, it can be seen that the product of the example is superior to the product of the comparative example in terms of the number of defective elements and the high-temperature strength and has high reliability at high temperatures.

Claims (1)

(1) A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (D). (A) An epoxy resin other than a novolak type epoxy resin having at least three epoxy groups in one molecule. (B) A phenolic resin other than a novolak type phenolic resin having at least three phenyl groups in one molecule. (C) Brominated epoxy resin. (D) at least one compound selected from the group consisting of Bi hydroxide, Bi oxide, Al hydroxide and Al oxide. (2) At least one of the epoxy resin (A) and the phenol resin (B) is represented by the following general formula (1) 2. The semiconductor device according to claim 1, wherein said semiconductor device is one which has reacted with an organopolysiloxane represented by the following formula.