JP2006186232A - Package, microwave integrated circuit, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce occurrence of cracks of a semiconductor or the like by relaxing stress generated by the mismatch of a thermal expansion coefficient between the semiconductor or the like and a package. <P>SOLUTION: The package 1 is composed by providing a large number of protrusions 2 made of a metallic material having a small rigidity modulus like gold to a mounting face for a component such as the semiconductor of the package 1. When the stress due to the mismatch of the thermal expansion coefficient in between the package 1 is generated in the semiconductor 3, it is possible to reduce the occurrence of cracks of the component such as the semiconductor by relaxing the stress by the composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a package on which a component such as a semiconductor is mounted, and more particularly to a package applicable to a microwave integrated circuit or the like and a manufacturing method thereof.

  FIG. 9 is a diagram showing the configuration of the RF module. An RF module in the microwave and millimeter wave bands is obtained by mounting a semiconductor 6 having a bare chip structure and a microwave transmission line substrate 7 on a metal package 1 in a multichip, and connecting to a peripheral terminal portion 9 by a bonding wire 8. Desired characteristics as an integrated circuit are realized.

By the way, in recent years, there is an increasing demand for higher integration of circuits and higher power in such high-frequency band semiconductors and the like, so that the area is increased and the thickness is reduced.
Therefore, in such a structure, when a stress is applied to a mounted component such as a semiconductor due to mismatch of thermal expansion coefficients between the semiconductor and the package, the component is likely to crack, and the long-term reliability of the RF module, and This is a major factor that reduces the production yield.

  FIG. 10 is a view showing a crack state of an RF module in which components are mounted on a conventional package. As an example, considering the case where the thermal expansion coefficient of the material of the package 5 is larger than the thermal expansion coefficient of the semiconductor 6, when the temperature rises in the RF module, the mismatch between the thermal expansion coefficients of the joint surfaces of the package 5 and the semiconductor 6 occurs. Depending on the stress, a crack 11 is generated in the semiconductor 6 when the stress reaches a certain limit value.

  As mentioned above, stress on mounting components such as semiconductors is caused by mismatch in thermal expansion coefficient with the mounting package, so conventionally, a material close to the thermal expansion coefficient of the semiconductor mounted as a material such as a metal package has been used. It is used to take measures against cracks. However, since a metal material having the same thermal expansion coefficient as a semiconductor is a special metal, it becomes a major obstacle in terms of the cost of the RF module.

  Therefore, even when a metal material with low cost and excellent workability is used, the structure of the package that can reduce the occurrence of cracks in the semiconductor, etc., without depending on the consistency of the thermal expansion coefficient of the semiconductor, etc. with the package Is required.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and is to reduce the occurrence of a crack in a semiconductor or the like by relaxing the stress even if a stress caused by a mismatch of thermal expansion coefficients occurs.

  The present invention has an effect of reducing the occurrence of cracks in a component such as a semiconductor when the stress caused by the mismatch of thermal expansion coefficients between the package and a mounted component such as a semiconductor occurs. The present invention relates to a package structure, a microwave integrated circuit using the package, and a manufacturing method thereof.

  The package of the present invention is a package on which a component is mounted. The component can be mounted and fixed on the top on the component mounting surface side, and is sufficiently smaller than the fixing surface of the component. A plurality of protrusions that relieve stress generated due to a difference from the coefficient, and the protrusions have an unevenness formed on the mounting surface side of the component and a rigidity higher than that of the package material that covers the unevenness. It is formed of a low material, and the unevenness is formed by forming a plurality of grooves on the mounting surface side of the component. A metal material is used as a package material, and the rigidity is higher than that of the metal material covering the unevenness. The low material is formed by metal plating. Furthermore, a microwave integrated circuit is configured by mounting high frequency components using the above package.

  The method for manufacturing a package of the present invention is a method for manufacturing a package on which a component is mounted, and includes a step of forming a plurality of minute unevenness on the mounting surface side of the component of the package, and the unevenness is more rigid than the package material. A plating step of plating with a metal material having a low rate, and the plating step further includes a step of performing electroplating of gold.

  A method for manufacturing a microwave integrated circuit according to the present invention is a method for manufacturing a microwave integrated circuit in which a component is mounted on a package, and includes a step of forming a plurality of minute unevenness on the mounting surface side of the component of the package, A plating step of plating the unevenness with a metal material having a lower rigidity than a package material to form a projection, and a mounting step of mounting a high-frequency component on the top of the projection and fixing by thermocompression bonding, and The plating step includes a step of performing gold electroplating.

  According to the present invention, a component can be mounted on the top side of a package on the mounting surface side of a component such as a semiconductor, and is sufficiently smaller than the mounting and fixing surface of the component, and is generated due to a difference in thermal expansion coefficient between the package material and the component. Since a plurality of protrusions that relieve stress is provided, it is possible to relieve stress caused by mismatch of thermal expansion coefficients between the mounted component and the package, and prevent cracks in components such as semiconductors. be able to.

  Further, since it is not necessary to make the thermal expansion coefficients of the package and the parts coincide, it is possible to sufficiently improve the reliability even if parts such as semiconductor devices of different materials are mounted in the same package.

  In addition, since restrictions on the thermal expansion coefficient of the package material are relaxed, the selection range of the package material is widened, and the cost can be reduced.

  Further, by solving the problem of cracks when mounting a component such as a semiconductor, the area of the entire component such as a semiconductor can be increased, and higher integration can be achieved.

  Furthermore, the package having the projection of the present invention and the microwave integrated circuit using the package are manufactured through a process of plating the component mounting surface of the package having the projections and depressions by electrolytic plating or the like. Since the protrusions at the position can be formed thicker (higher), it is possible to form a plurality of protrusions suitable for stress relaxation, and it is also possible to manufacture a package having protrusions such as gold at a low cost. It is.

  As described above, the present invention is extremely effective in preventing cracks in not only components such as semiconductors to be mounted but also high frequency components such as microwave integrated circuits.

(Description of configuration)
FIG. 1 is a diagram showing a configuration of a package according to an embodiment of the present invention. In this embodiment, an example of mounting a semiconductor as an electronic component is shown. In FIG. 1, reference numeral 1 denotes a plate-like or substrate-like package made of a metal material or the like, and has a step for engaging a cover (not shown) around the mounting surface side. It has a semiconductor etc. and a lead electrode which penetrates from the lower part so that wiring is possible. Reference numeral 2 denotes a large number of protrusions which are formed on the mounting surface of the semiconductor or the like of the package 1 and are smaller than the size of the lower surface of the semiconductor or the like (component) mounted on the top.

  FIG. 2 is a schematic diagram focusing on the bonding surface between the package and the semiconductor. In the present embodiment, the projection 2 is formed on the mounting surface of the semiconductor 3 of the package 1 by a metal material having a lower rigidity than the package material, such as gold, and the top (projection) of the projection 2 has a bare structure or the like. The semiconductor 3 is mounted and bonded, and has a structure having a slight gap between the package 1 and the lower surface of the semiconductor 3.

  With this structure, when a stress is generated due to mismatch of thermal expansion coefficients between the semiconductor 3 and the package 1, the stress is relieved and the occurrence of cracks in the semiconductor 3 can be reduced.

FIG. 3 is a view showing a package structure of the present invention and a method for manufacturing a microwave integrated circuit.
(1) Step of forming irregularities on the semiconductor mounting surface of the package 1 (irregularity forming step)
A large number of irregularities 21 that are sufficiently small with respect to the area of the semiconductor are formed on the semiconductor mounting surface of the package 1. For example, as shown in FIG. 3A, irregularities 21 are regularly or irregularly formed on the semiconductor mounting surface by cutting in the surface treatment of the package or pressing with a pressing die. The uneven shape may be, for example, a triangular pyramid, a triangular prism, a bell shape, a trapezoidal shape, a rectangular shape, or the like in cross section.

(2) A process of forming protrusions on the semiconductor mounting surface of the package 1 (plating process)
Next, a gold plating process is performed on the surface of the package 1 on which the unevenness 21 is formed, and a thick gold protrusion 2 is formed on the unevenness 21 as shown in FIG.

When the package 1 having the projections and depressions 21 is subjected to metal plating by electrolytic plating or the like, more metal is formed on the projections of the projections and depressions 21 than in other portions in a thick film. This is based on the phenomenon that electrolysis concentrates on the convex and concave portions of the unevenness and the plating becomes thick, and in the present embodiment, this phenomenon is actively used to form the gold protrusion 2. The gold protrusions 2 are sufficiently small with respect to the mounting area of a semiconductor or the like to be mounted, and are formed in large numbers so as not to harm the ground state in both direct and alternating currents when the semiconductor is mounted.
(3) A process of mounting and fixing a semiconductor on the top of the protrusion of the package 1 (mounting process)
Further, as shown in FIG. 3C, a semiconductor, a substrate of a microwave transmission line, or the like is mounted on the projection 2 on the semiconductor mounting surface of the package 1 and fixed by thermocompression bonding. Subsequently, a desired microwave integrated circuit or the like is configured by electrically connecting a mounting component such as a semiconductor and surrounding electrodes (connection terminals) by wire bonding.

(Description of operation)
Next, with respect to the function for mismatching the thermal expansion coefficients of the package 1 and the semiconductor 3 according to the present embodiment, a stress relaxation operation applied to the semiconductor when the package 1 has a larger expansion coefficient than the semiconductor 3 will be described as an example.
FIG. 4 is a view showing a state in which a semiconductor 3 is mounted on a package 1 on which a metal protrusion 2 having a small rigidity such as gold is formed by thermocompression bonding, and FIG. 5 is an expanded state of the package 1 due to a temperature rise. FIG. 6 is a diagram showing an operation in a contracted state of the package 1 due to a temperature drop.

  First, when the temperature rises in the package 1, the package 1 expands from the state shown in FIG. 4 as shown in FIG. 5, and stress in the direction of arrow A acts on the bonding surface of the semiconductor 3. In this case, since the metal projection 2 having a small rigidity is fixed to the semiconductor 3 with a relatively small expansion amount at the top of the joint surface between the package 1 and the semiconductor 3, as shown in FIG. Since the side is pulled and deformed with little movement to the outside, the stress applied to the semiconductor 3 at the joint surface between the package 1 and the semiconductor 3 is relaxed.

  Next, when the temperature of the package 1 decreases, the package 1 contracts as shown in FIG. 6 from the state shown in FIG. 4 or 5, and stress in the direction of arrow B acts on the bonding surface of the semiconductor 3. In this case, since the metal protrusion 2 having a small rigidity is fixed to the semiconductor 3 having a relatively small amount of contraction at the top of the joint surface between the package 1 and the semiconductor 3, as shown in FIG. The side is deformed by being pulled inward with little movement inward, so that the stress applied to the semiconductor 3 at the bonding surface between the package 1 and the semiconductor 3 is relaxed.

  As described above, when the stress in any direction acts on the semiconductor 3, the stress on the joint surface between the package 1 and the semiconductor 3 is relieved by the deformation of the metal protrusion 4 having a small rigidity.

  Therefore, the stress at the joint surface between the package 1 and the semiconductor 3 caused by the mismatch of the thermal expansion coefficients of the metal protrusions 2 having a small rigidity is alleviated, and the occurrence of cracks in the semiconductor is suppressed.

(Another embodiment of the invention)
In the above embodiment, the example in which a large number of projections based on a large number of projections and depressions smaller than the bonding surface of the semiconductor are formed on the semiconductor mounting surface of the package 1, but other shapes are adopted as such projections. Is possible.

  FIG. 7 is a view showing a package according to another embodiment of the present invention. In the present embodiment, a plurality of mountain-shaped projections 4 adjacent to the mounting surface side of the package, such as a semiconductor, are formed. This is suitable when the aspect ratio of the size of the semiconductor to be mounted on the package is large and stress relaxation in one direction such as the long side direction (longitudinal direction) is required. By forming unevenness on the package 1, it is possible to reduce the stress due to the coefficient of thermal expansion in that direction.

  FIG. 8 is a view showing a package according to still another embodiment of the present invention. The protrusion 4 formed by the groove shape is divided into a plurality of pieces in the groove direction, thereby enabling stress relaxation in the short side direction.

  In any case, as in the embodiment shown in FIG. 1, a step of forming irregularities by small grooves in advance on the semiconductor mounting surface side of the package, and a protrusion that absorbs stress by electroplating gold on the surface, etc. It is realizable by the process to perform.

  Further, in the above embodiment, the example in which the protrusions are formed by metal plating has been described. However, the protrusions are directly formed as a large number of small protrusions having a necessary height on the surface of the package by cutting or pressing without using metal plating. It is also possible. In this case, the protrusion has the same rigidity as the package material, but it is possible to effectively relieve the stress generated by the difference from the thermal expansion coefficient of the semiconductor etc. by setting its height, width, shape, etc. It is.

It is a figure which shows the structure of the package of one embodiment of this invention. It is a figure which shows the schematic diagram which paid its attention to the junction surface of a package and a semiconductor. It is a figure which shows the manufacturing method of the package of this invention, and a microwave integrated circuit. It is a figure which shows the state which mounted the semiconductor 3 in the package 1 in which protrusion was formed by thermocompression bonding. It is a figure which shows the operation | movement at the time of expansion of the package 1 by a temperature rise. It is a figure which shows the operation | movement at the time of shrinkage | contraction of the package 1 by a temperature fall. It is a figure which shows the package of other embodiment of this invention. It is a figure which shows the package of other embodiment of this invention. It is a figure which shows the structure of the conventional RF module. It is a figure which shows the mode of the crack of RF module which mounted components in the conventional package.

Explanation of symbols

1, 5 Package 2, 4 Protrusion 3, 6 Semiconductor 7 Microwave transmission line substrate 8 Bonding wire 9 Electrode 10 Lead wire 11 Crack 21 Concavity and convexity A, C Stress direction (expansion)
B Stress direction (compression)

Claims (9)

  A package for mounting a component, on which a component can be mounted and fixed on the mounting surface side of the component, and is sufficiently smaller than the fixing surface of the component, and the package material and the thermal expansion coefficient of the component A package comprising a plurality of protrusions that relieve stress generated by the difference.   The package according to claim 1, wherein the protrusion is formed of unevenness formed on the mounting surface side of the component and a material having a lower rigidity than the package material covering the unevenness.   3. The package according to claim 2, wherein the irregularities are formed by forming a plurality of grooves on the component mounting surface side.   4. The package according to claim 2, wherein a metal material is used as the package material, and the material having a lower rigidity than the metal material covering the irregularities is formed by metal plating.   6. A microwave integrated circuit comprising a high-frequency component mounted on the package according to claim 1.   A manufacturing method of a package on which a component is mounted, wherein a step of forming a plurality of minute unevenness on the mounting surface side of the component of the package, and plating in which the unevenness is plated with a metal material having a lower rigidity than the package material And a process for manufacturing the package.   The package manufacturing method according to claim 6, wherein the plating step includes a step of performing electroplating of gold.   A method for manufacturing a microwave integrated circuit in which a component is mounted on a package, wherein a step of forming a plurality of minute irregularities on a mounting surface side of the component of the package, and a metal whose rigidity is lower than that of a package material. A method of manufacturing a microwave integrated circuit, comprising: a plating step of plating with a material to form a protrusion; and a mounting step of mounting a high-frequency component on the top of the protrusion and fixing by thermocompression bonding.   9. The method of manufacturing a microwave integrated circuit according to claim 8, wherein the plating step includes a step of performing electroplating of gold.

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