JP2010067678A - Junction structure and package for storing semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of cracks in a ceramic mold and to obtain sufficient joint strength in disposing the ceramic mold (or a metal mold) in a recess of a metal mold (or a ceramic mold) to join the molds with each other with a brazing filler metal. <P>SOLUTION: A junction structure includes: a first mold 104 with the recess 103 defined by a bottom face 103a and side faces 103b and a metal part formed on a bottom surface of the recess 103; a second mold 105 disposed inside the recess 103 and adjacent to the side face 103b of the recess with a metal part formed on the side of the first mold 104; and the brazing filler metal 107 disposed between the metal parts of the first mold 104 and the second mold 105. In the junction structure, the second mold 105 has a chamfered part 110 on the side of the recess side face 103b of the first mold 104 and the surface of the chamfered part 110 has a metal part. A package for storing a semiconductor element has the junction structure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a joining structure used when a ceramic member and a metal member are joined with a brazing material in a semiconductor element housing package, and a semiconductor element housing package using such a joint structure.

  In a semiconductor element housing package or the like, a ceramic member and a metal member are joined using a brazing material (see, for example, Patent Documents 1 and 2).

  FIG. 3 shows an example of a bonded structure using such a bonding technique. On a base 1 made of metal, a molded body 4 made of ceramic having a recess 3 on the upper surface is fixed, and further, A molded body 5 made of metal is disposed in the recess 3 and joined by a brazing material 7. In FIG. 3, reference numeral 8 indicates a metal layer provided for brazing on the bottom surface of the recess 3.

  In such a joined structure, in order to increase the connection reliability of the brazed portion, generally, a fillet 12 of the brazing material 7 is formed from the base outer surface of the metal molded body 5 to the bottom surface of the concave portion 3 of the ceramic molded body 4. Yes. However, although the formation of the fillet 12 of the brazing material 7 is effective in relieving stress concentration at the base end portion of the metal molded body 5, cracks 9 may occur in the ceramic molded body 4 in some cases. there were. In particular, when the distance (d) between the metal molded body 5 and the side surface of the concave portion 3 of the ceramic molded body 4 was short (for example, about 1 mm or less), there was a tendency for cracks 9 to easily occur. This is considered to be due to the following reasons.

  That is, when the distance (d) between the metal molded body 5 and the recess 3 side surface of the ceramic molded body 4 is short, the brazing material is excessive, and the tip of the fillet 12 reaches the recess 3 side surface of the ceramic molded body 4. A large stress concentration occurs. As a result, cracks 9 are likely to occur in the ceramic molded body 4 starting from the side surface of the concave portion 3 where stress is concentrated.

  As a countermeasure against this, it is conceivable to reduce the amount of brazing material used. However, if the amount of brazing material used is reduced, there is a possibility that sufficient bonding strength cannot be obtained. For this reason, even if the distance (d) to the side surface of the concave portion 3 of the metal molded body 5 is short, there is no bonding technology in which cracks 9 do not occur in the ceramic molded body 4 and sufficient bonding strength is obtained. It has been demanded.

For example, as shown in FIG. 4, the above-described crack 9 is generated by placing a ceramic molded body 15 in a recess 13 of a metal molded body 14 having a recess 13 on the upper surface. It was also observed in the joined structure joined by the material 7. In this case as well, as in the joined structure shown in FIG. 3, when the distance (d) between the ceramic molded body 15 and the side surface of the concave portion 13 of the metal molded body 14 is short (for example, about 1 mm or less), cracks 9 enter. An easy tendency was seen. In FIG. 4, reference numeral 8 indicates a metal layer provided for brazing on the bottom surface of the ceramic molded body 15.
JP-A-63-14454 JP-A-6-334057

  The present invention has been made in response to the above-described problems of the prior art, in which a ceramic molded body or a metal molded body is disposed in a recess of a metal molded body or a ceramic molded body, and the ceramic is joined with a brazing material. Bonding structure capable of preventing occurrence of cracks in a molded body and capable of bonding a metal molded body and a ceramic molded body with sufficient bonding strength, and high reliability provided with such a bonded structure An object of the present invention is to provide a package for housing a semiconductor element.

  (1) The invention (joined structure) of claim 1 includes a first molded body that includes a concave portion formed of a bottom surface and a side surface, and a metal portion on the bottom surface of the concave portion, It arrange | positions adjacent to a side surface, and is arrange | positioned between the 2nd molded object which equips the surface by the side of the said 1st molded object with a metal part, and the metal part of the said 1st molded object, and the metal part of the said 2nd molded object. And a brazing material, wherein the second molded body includes a chamfered portion on a side surface of the concave portion of the first molded body, and the surface of the chamfered portion also includes a metal portion. It is characterized by that.

  In the present invention, the second molded body includes a chamfered portion on the side surface of the concave portion of the first molded body, and the surface of the chamfered portion also includes a metal portion. The stress applied to the first molded body or the second molded body when the brazing material between the chamfered portion solidifies and contracts can be reduced, and defects such as cracks due to the stress are caused by the first molded body or the second molded body. Occurrence of the molded body can be prevented. In addition, since the brazing material between the metal portion of the first molded body and the metal portion of the second molded body is not excessive, sufficient bonding strength can be obtained.

  (2) The invention according to claim 2 is the joined structure according to claim 1, wherein the first molded body is formed of a ceramic molded body including a metal layer on a bottom surface of the recess, and the second molded body is It consists of a metal molded body, and the brazing material is arranged between the metal layer of the first molded body and the second molded body.

  In this invention, the 1st molded object consists of a ceramic molded body provided with a metal layer in the bottom surface of a recessed part, and the 2nd molded object is comprised from the metal molded object. In such a bonded structure, cracks may occur in the ceramic molded body constituting the first molded body due to stress when the brazing material solidifies and shrinks. Since the stress applied to the side surface can be reduced, the generation of cracks due to such stress can be prevented.

  (3) The invention according to claim 3 is the joined structure according to claim 1, wherein the first molded body is made of a metal molded body, and the second molded body is a metal layer on the surface on the first molded body side. The brazing material is disposed between the metal layer of the first molded body and the second molded body.

  In the present invention, the first molded body is made of a metal molded body, and the second molded body is made of a ceramic molded body having a metal layer on the surface on the first molded body side. In such a bonded structure, cracks may occur in the ceramic molded body constituting the second molded body due to the stress when the brazing material solidifies and shrinks, but in the present invention, it is added to the second molded body. Since the stress can be reduced, the occurrence of cracks due to such stress can be prevented.

  (4) A fourth aspect of the present invention is the bonded structure according to any one of the first to third aspects, wherein the gap is formed between the concave side surface of the first molded body and the chamfered portion of the second molded body. The brazing material is characterized in that its cross section forms a triangle having a ratio (b / a) of height (b) to base (a) of 1 or less.

  In the present invention, the cross-section of the brazing material between the concave side surface of the first molded body and the chamfered portion of the second molded body has a ratio (b / a) of the height (b) to the base (a) of 1. Since the following triangle is formed, the stress when the brazing material is solidified and contracted can be further reduced, and the occurrence of defects such as cracks due to the stress can be more reliably prevented.

  Here, the above-mentioned “cross section” means that the brazing material between the concave side surface of the first molded body and the chamfered portion of the second molded body is cut by a plane perpendicular to the bottom surface and the side surface of the concave portion of the first molded body. The cross section when it is done.

  (5) A fifth aspect of the present invention is the bonded structure according to any one of the first to fourth aspects, wherein the gap is formed between the concave side surface of the first molded body and the chamfered portion of the second molded body. The surface of the brazing material is a flat surface or an inclined surface recessed inward.

  In the present invention, since the surface of the brazing material in the gap between the concave side surface of the first molded body and the chamfered portion of the second molded body is a flat surface or an inclined surface recessed inward, the brazing material solidifies and shrinks. It is possible to further reduce the stress during the process, and to more reliably prevent the occurrence of defects such as cracks due to the stress.

  (6) The invention of claim 6 (semiconductor element housing package) is characterized by having the joint structure according to any one of claims 1 to 5.

  In the present invention, since there can be provided a bonded structure having no defects such as cracks and sufficient bonding strength, high reliability can be obtained.

  According to the present invention, it is possible to prevent the occurrence of cracks in the ceramic molded body when the ceramic molded body or the metal molded body is disposed in the recess of the metal molded body or the ceramic molded body and joined with the brazing material, In addition, it is possible to provide a bonded structure capable of bonding a metal molded body and a ceramic molded body with sufficient bonding strength, and a highly reliable package for housing a semiconductor element provided with such a bonded structure.

  Embodiments according to the present invention will be described below. Although the description will be made based on the drawings, the drawings are provided for illustration only, and the present invention is not limited to the drawings. It should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Furthermore, in the following description, components having the same or substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a cross-sectional view showing a bonding structure in a package for housing a semiconductor device according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 101 denotes a base made of a copper-tungsten (CuW) alloy. On the metal base 101, a first molded body 104 made of ceramic having a concave portion 103 formed of a bottom surface 103a and a side surface 103b is fixed on the upper surface, and further, in the concave portion 103 of the first molded body 104 made of ceramic. The second molded body 105 made of metal is disposed and joined by a brazing material 107 such as silver brazing.

The first molded body 104 is formed by stacking and firing a plurality of ceramic green sheets made of alumina (Al ₂ O ₃ ), for example. Examples of the material of the first molded body 104 include alumina, mullite, aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), and beryllia. A metal layer 108 made of metallization such as tungsten (W) is provided on the bottom surface of the recess 103 of the first molded body 104. On the surface of the metal layer 108, a metal having excellent wettability with the brazing material 107, for example, a nickel (Ni) layer having a thickness of about 1.0 to 2.5 μm is formed by plating as necessary. A gold (Au) layer having a thickness of about 2 to 3 μm may be further formed on the nickel (Ni) layer by a plating method. The metal layer 108 made of metallization such as tungsten (W), nickel (Ni) layer, gold (Au) layer may be provided on the entire bottom surface of the recess 103, or the brazing material 107 is disposed. It may be selectively provided only in the portion to be provided.

  The second compact 105 is made of an iron-nickel-cobalt (FeNiCo) alloy called Kovar. In addition, the 2nd molded object 105 may be formed with the copper-tungsten (CuW) alloy similarly to the metal base 101, and may be formed with the other metal. On the other hand, the metal base 101 may also be formed of Kovar or other metals. Examples of other metals include a copper-molybdenum (CuMo) alloy and an iron-nickel (FeNi) alloy.

  A metal having excellent wettability with the brazing material 107, for example, a nickel (Ni) layer having a thickness of about 1.0 to 2.5 μm is formed on the bottom surface of the second molded body 105 by a plating method as necessary. The A gold (Au) layer having a thickness of about 2 to 3 μm may be further formed on the nickel (Ni) layer by a plating method.

  The second molded body 105 is disposed in the vicinity of the concave side surface 103 b of the first molded body 104. Here, “arranged closely” means that the distance (d) between the second molded body 105 and the concave side surface 103b of the first molded body 104 is 1 mm or less. In the present embodiment, the second molded body 105 is disposed at a position where the distance (d) is 100 μm.

  Then, on the side of the concave side surface 103b of the first molded body 104 of the second molded body 105, a C chamfered portion 110 having a C chamfer dimension (vertical and horizontal length) in the range of, for example, 0.1 to 0.3 mm. Is formed.

  The brazing material 107 is disposed between the second molded body 105 in which the C chamfered portion 110 is formed and the metal layer 108 formed on the bottom surface of the concave portion 103 of the first molded body 104. By forming the C chamfered portion 110 on the second molded body 105, the following meniscus 112 is formed between the C chamfered portion 110 and the bottom surface 103 a of the concave portion 103 of the first molded body 104. That is, the brazing material 107 between the concave side surface 103b of the first molded body 104 and the C chamfered portion 110 of the second molded body 105 has a cross-sectional ratio of the height (b) to the base (a) ( b / a) is an approximate triangle of 1 or less. Further, the surface of the brazing material 107 between the concave side surface 103b of the first molded body 104 and the C chamfered portion 110 of the second molded body 105 is formed as a flat surface or an inclined surface recessed inward. The ratio (b / a) is preferably 0.8 or less, more preferably 0.5 or less, and even more preferably 0.2 or less.

  In the bonded structure configured as described above, the second molded body 105 is disposed close to the concave side surface 103b of the first molded body 104, but the concave side surface 103b of the first molded body 104 is disposed. In addition, a large stress due to solidification shrinkage of the brazing material 107 as in the prior art is not applied, and the occurrence of cracks due to the stress can be prevented. In addition, since a sufficient amount of brazing material 107 can be disposed between the second molded body 105 and the metal layer 108 of the first molded body 104, the first molded body 104 and the first molded body 104 have sufficient strength. 2 The molded body 105 can be joined. Therefore, the package for housing a semiconductor element of this embodiment provided with such a bonded structure can have high reliability.

  Incidentally, by forming the C chamfered portion 110 on the concave side surface 103b side of the first molded body 104 of the second molded body 105, the joint structure in which the meniscus 112 as described above is formed, and the C surface About the joint structure of the conventional structure similarly comprised except not forming the taking part 110, the joint strength of the 2nd molded object 105 and the 1st molded object 104, and the recessed part side surface 103b of the 1st molded object 104 after brazing When the residual stress was measured, the bonding strength was good. However, the residual stress was reduced by 55% at maximum in the residual structure compared to the conventional structure.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a bonding structure in a package for housing a semiconductor device according to the second embodiment of the present invention.

  As shown in FIG. 2, in the present embodiment, a second molded body 105 made of ceramic is placed in the concave portion 103 of the first molded body 104 made of metal having a concave portion 103 made of a bottom surface 103 a and a side surface 103 b on the upper surface. They are arranged and joined by a brazing material 107 such as silver brazing. The first molded body 104 made of metal is also provided with a through hole 206 that penetrates the bottom surface 103 a of the recess 103.

  The first molded body 104 is made of Kovar. The first molded body 104 may be formed of a copper-tungsten (CuW) alloy, a copper-molybdenum (CuMo) alloy, an iron-nickel (FeNi) alloy, or the like. Further, on the bottom surface of the concave portion 103 of the first molded body 104, a metal having excellent wettability with the brazing material 107, for example, a nickel (Ni) layer having a thickness of about 1.0 to 2.5 μm is provided as necessary. It is formed by a plating method. A gold (Au) layer having a thickness of about 2 to 3 μm may be further formed on the nickel (Ni) layer by a plating method. These nickel (Ni) layer and gold (Au) layer may be provided on the entire bottom surface 103a of the recess 103, or may be selectively provided only on a portion where the brazing material 107 is disposed.

The second molded body 105 is formed by stacking and firing a plurality of ceramic green sheets made of alumina (Al ₂ O ₃ ), for example. Examples of the material of the second molded body 105 include alumina, mullite, aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), and beryllia. A metal layer 108 made of metallization such as tungsten (W) is provided on the bottom surface of the second molded body 105. On the surface of the metal layer 108, a metal having excellent wettability with the brazing material 107, for example, a nickel (Ni) layer having a thickness of about 1.0 to 2.5 μm is formed by plating as necessary. A gold (Au) layer having a thickness of about 2 to 3 μm may be further formed on the nickel (Ni) layer by a plating method. The metal layer 108 made of metallization such as tungsten (W), the nickel (Ni) layer, and the gold (Au) layer may be provided on the entire bottom surface of the second molded body 105. Thus, it may be selectively provided only in the portion where the brazing material 107 is disposed.

  The second molded body 105 is disposed in the vicinity of the concave side surface 103 b of the first molded body 104. Here, “arranged closely” means that the distance (d) between the second molded body 105 and the concave side surface 103b of the first molded body 104 is 1 mm or less. In the present embodiment, the second molded body 105 is disposed at a position where the distance (d) is 100 μm.

  Then, on the side of the concave side surface 103b of the first molded body 104 of the second molded body 105, a C chamfered portion 110 having a C chamfer dimension (vertical and horizontal length) in the range of, for example, 0.1 to 0.3 mm. Is formed. The metal layer 108 described above is also provided on the surface of the C chamfered portion 110, and the surface of the metal layer 108 of the portion has a metal excellent in wettability with the brazing material 107, for example, for example, A nickel (Ni) layer having a thickness of about 1.0 to 2.5 μm can be formed by a plating method, and a gold (Au) layer having a thickness of about 2 to 3 μm is plated on the nickel (Ni) layer. It can be formed by the method.

  The brazing material 107 is disposed between the first molded body 104 and the metal layer 108 formed on the bottom surface of the second molded body 105 in which the C chamfered portion 110 is formed. By forming the C chamfered portion 110 on the second molded body 105, the following meniscus 112 is formed between the C chamfered portion 110 and the concave side surface 103 b of the first molded body 104. That is, the brazing material 107 between the concave side surface 103b of the first molded body 104 and the C chamfered portion 110 of the second molded body 105 has a cross-sectional ratio of the height (b) to the base (a) ( b / a) is an approximate triangle of 1 or less. Further, the surface of the brazing material 107 between the concave side surface 103b of the first molded body 104 and the C chamfered portion 110 of the second molded body 105 is formed as a flat surface or an inclined surface recessed inward. The ratio (b / a) is preferably 0.8 or less, more preferably 0.5 or less, and even more preferably 0.2 or less.

  In the bonded structure configured as described above, the second molded body 105 is formed in spite of the fact that the second molded body 105 made of ceramic is arranged close to the concave side surface 103b of the molded body 104 made of metal. In addition, a large stress due to solidification shrinkage of the brazing material 107 as in the prior art is not applied, and the occurrence of cracks due to the stress can be prevented. Moreover, since a sufficient amount of brazing material 107 can be disposed between the metal layer 108 of the second molded body 105 and the first molded body 104, the first molded body 104 and the first molded body 104 have sufficient strength. 2 The molded body 105 can be joined. Therefore, the package for housing a semiconductor element of this embodiment provided with such a bonded structure can have high reliability.

  The present invention is not limited to the contents described in the embodiment described above, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. For example, in each of the above embodiments, instead of the C chamfered portion 110, an R chamfered portion or a chamfered portion recessed inward may be formed. In general, the C chamfer dimension of the C chamfer 110 is the same in length and width, but the length and width may be different.

It is sectional drawing which shows the junction structure in the package for semiconductor element storage which concerns on 1st Embodiment. It is sectional drawing which shows the joining structure body in the package for semiconductor element accommodation which concerns on 2nd Embodiment. It is sectional drawing which shows an example of the junction structure in the conventional package for semiconductor element accommodation. It is sectional drawing which shows the other example of the junction structure in the conventional package for semiconductor element accommodation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 103 ... Recessed part, 103a ... Bottom face of recessed part, 103b ... Side surface of recessed part, 104 ... 1st molded object, 105 ... 2nd molded object, 107 ... Brazing material, 108 ... Metal layer, 110 ... C chamfering part.

Claims (6)

A first molded body that includes a concave portion including a bottom surface and a side surface, and includes a metal portion on a bottom surface of the concave portion;
A second molded body disposed in the concave portion in proximity to a side surface of the concave portion and having a metal portion on a surface on the first molded body side;
A brazing material disposed between the metal part of the first molded body and the metal part of the second molded body;
A joined structure comprising:
The second molded body includes a chamfered portion on a side surface of the concave portion of the first molded body, and the surface of the chamfered portion also includes a metal portion.   The first molded body is made of a ceramic molded body having a metal layer on the bottom surface of the recess, the second molded body is made of a metal molded body, and the metal layer of the first molded body and the second molded body. The joint structure according to claim 1, wherein the brazing material is disposed between the two.   The first molded body is made of a metal molded body, the second molded body is made of a ceramic molded body having a metal layer on the surface on the first molded body side, and the first molded body and the second molded body The joining structure according to claim 1, wherein the brazing material is disposed between the metal layer and the metal layer.   The brazing material between the concave side surface of the first molded body and the chamfered portion of the second molded body has a cross section with a ratio (b / a) of the height (b) to the base (a) of 1. The joining structure according to any one of claims 1 to 3, wherein the joining structure has the following triangular shape.   The surface of the brazing material between the concave side surface of the first molded body and the chamfered portion of the second molded body is a flat surface or an inclined surface recessed inward. The joining structure according to any one of the preceding claims.   A package for housing a semiconductor element, comprising the bonding structure according to claim 1.

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