Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Of specified configuration
Reexamination Certificate
2000-08-14
2002-07-23
Clark, Jasmine J B (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Of specified configuration
C257S507000, C257S521000, C257S686000
Reexamination Certificate
active
06424048
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a semiconductor chip, a semiconductor device containing such semiconductor chips, a circuit substrate in which such a semiconductor device is incorporated, an electronic apparatus in which such a circuit substrate is mounted, and a method for producing them. Particularly, it relates to processing of through-holes for forming metal bumps.
BACKGROUND ART
The development of multimedia and information apparatuses has been remarkable in recent years. The data processing speed of electronic apparatuses has been improved with the advance of reduction in size and weight and increase in capacity. Micro-processors and memories have been improved in performance correspondingly remarkably. The technical progress of their peripheral equipment, however, has lagged relatively. For example, a CPU clock signal having a frequency over 300 MHz has a tendency to generate wiring noise up to a cache memory, malfunction due to signal delay, and unnecessary radiation. There is the present situation that total system performance is limited by the peripheral equipment.
In order to solve such a problem, it is necessary to improve electric characteristics such as crosstalk, signal delay, etc. As one of approaches to the improvement, there has been proposed a method in which LSI chips and component parts arranged two-dimensionally are mounted three-dimensionally on a substrate to shorten the length of wiring between chips to thereby achieve the improvement in electric performance and the improvement in degree of integration per unit area.
For example, such three-dimensional mounting has been proposed in JP-A-8-264712, JP-A-5-63137, etc. In those proposals, three-dimensional mounting was achieved by connecting electrodes of chips to one another through through-holes each containing an electrically conducting material buried therein by piling up semiconductor wafers. How to form the through-holes was, however, unspecified in those proposals though the through-holes were ones each having a hole size of 10 &mgr;m and a plate thickness (length) of the order of hundreds of &mgr;m.
Laser-processing machining or etching might be conceived for the formation of the through-holes. In the case of laser-processing, however, processing scattered matter (called dross, debris, etc.) was deposited on the neighborhood of the electrodes so that reliability was lowered. Moreover, because it was impossible to make energy per pulse large from the point of view of preventing the substrate from being damaged (breaking or cracking), a large number of pulses were required for the formation of the through-holes. Hence, a long processing time was required. On the other hand, in the case of etching, it was impossible to form a structure of a high aspect ratio because of crystal anisotropy even though an anisotropic etching technique was used.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide: a semiconductor chip having a vertical current conduction structure of a high aspect ratio and high reliability; a semiconductor device, a circuit substrate, and an electronic apparatus each containing such semiconductor chips; and a method for producing them.
(1) According to an aspect of the present invention, a semiconductor chip comprises: a crystalline substrate having a through-hole prepared by laser beam irradiation and anisotropic etching; an electrically insulating film formed on an inner wall of the through-hole; and a metal bump containing an electrically conducting material inserted into the through-hole, for electrically connecting one surface of the crystalline substrate to the other surface of the crystalline substrate through the electrically conducting material.
(2) According to another aspect of the present invention, the semiconductor chip of the above paragraph (1) further comprises an electrode pad formed on the one surface of the crystalline substrate through an electrically insulating film, wherein the metal bump protrudes from the one surface of the crystalline substrate while being electrically connected to the electrode pad and further protrudes from the other surface of the crystalline substrate while piercing the crystalline substrate.
(3) According to a further aspect of the present invention, in the semiconductor chip of the above paragraph (2), the metal bump is formed in the through-hole which is formed to pierce the crystalline substrate in a range of from a portion of the electrode pad on the one surface of the crystalline substrate to the other surface of the crystalline substrate.
(4) According to a further aspect of the present invention, in the semiconductor chip of the above paragraph (3), the metal bump is made of an electrically conducting material provided along the inner wall of the through-hole.
(5) A semiconductor device according to a further aspect of the present invention includes semiconductor chips described in any one of the paragraphs (1) through (4) in the condition that the semiconductor chips are laminated while the metal bumps of the semiconductor chips are connected to one another.
(6) A circuit substrate according to a further aspect of the present invention includes a semiconductor device described in the paragraph (5).
(7) An electronic apparatus according to a further aspect of the present invention includes a circuit substrate described in the above paragraph (6).
(8) A method of producing a semiconductor chip according to a further aspect of the present invention comprises the steps of: forming a prehole in a crystalline substrate by laser beam irradiation; and enlarging the prehole by anisotropic etching to thereby form a through-hole.
(9) A method of producing a semiconductor chip of the above paragraph (8), according to a further aspect of the present invention, further comprises the steps of: forming an electrically insulating film on an inner wall of the through-hole; and forming an electrically conducting material in the through-hole having the electrically insulated inner wall to thereby form a metal bump for electrically connecting one surface of the crystalline substrate to the other surface of the crystalline substrate.
(10) In a method of producing a semiconductor chip of the above paragraph (9), according to a further aspect of the present invention, the leading hole is formed by laser beam irradiation at a portion of an electrode pad portion formed on the crystalline substrate, and the electrode pad is electrically connected to the metal bump.
(11) In a method of producing a semiconductor chip of the above paragraph (9) or (10), according to a further aspect of the present invention, the crystalline substrate is a silicon substrate.
(12) In a method of producing a semiconductor chip of the above paragraph (11), according to a further aspect of the present invention, the silicon substrate is surface-oriented to a (100) face.
(13) In a method of producing a semiconductor chip of the above paragraph (11), according to a further aspect of the present invention, the silicon substrate is surface-oriented to a (110) face.
(14) In a method of producing a semiconductor chip of any one of the above paragraphs (8) through (13), according to a further aspect of the present invention, protective films are formed on one surface of the crystalline substrate and on the other surface of the crystalline substrate, respectively, so that the crystalline substrate is irradiated with a laser beam through the protective films.
(15) In a method of producing a semiconductor chip of the above paragraph (14), according to a further aspect of the present invention, the silicon substrate is irradiated with a laser beam from a surface of the crystalline substrate on which the electrode pad is formed.
(16) In a method of producing a semiconductor chip of the above paragraph (14), according to a further aspect of the present invention, the silicon substrate is irradiated with a laser beam from a surface of the crystalline substrate which is opposite to the surface on which the electrode pad is formed.
(17) In a method of produ
Amako Jun
Arakawa Katsuji
Umetsu Kazushige
Yotsuya Shinichi
Clark Jasmine J B
Seiko Epson Corporation
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