JPS62177934A - Mounting method for semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a constraint to electrode density, and to enable mounting having high density by preparing an insulating sheet with a metal penetrated up to both upper and lower surfaces and projection solder on the end surfaces of the metals, holding the insulating sheet between a semiconductor element and a substrate and melting and solidifying the projection solder. CONSTITUTION:Metals 13 such as Ni are buried where corresponding to foundation metals 11 in an insulating sheet 12, and the sheet 12 is dipped in molten solder and hemispherical solder 14 by surface tension is fitted only on both upper and lower surfaces of the metals 13. A semiconductor element 10, the sheet 12 ad a substrate 15 on which a conductive pattern 16 is shaped are superposed in the order and heated. The sheet 12 is held between the element 10 and the substrate 15, and fixed through the metals 13. Accordingly, mounting having high density is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method for packaging IC chips of a semiconductor device having a large number of electrodes at high density.

[Prior art and its problems]

Conventional methods for mounting IC chips in semiconductor devices include wire bonding and accommodating them in packages, and face mounting methods such as 7-lip chips, in which protruding electrodes provided on the element surface and the substrate surface face each other and are connected without using wires. Daunobo/Ding etc. are known. Regarding these mounting methods, in order to achieve higher density mounting, for example, in wire bonding, if the spacing between electrode pads is narrowed, inconveniences such as wires touching each other occur, so it is necessary to improve reliability and reduce bonding man-hours. A flip-chip method in which bump electrodes are formed has also come to be widely used in order to reduce the amount of damage.

For example, FIG. 3 is a schematic cross-sectional view showing only the process of forming bump electrodes of a flip chip, and other manufacturing processes are omitted. In FIG. 3(a), this device is constructed by disposing an oxide film (S) on a silicon substrate 1 having a necessary conductive shadow area.
After forming a nitride film (SisNn) 4 on it and opening a window, Ti5 and Cu6 are deposited as base metals at the required locations, and Cu6 is formed. This is a process in which Ni plating 8 was applied on top using resist 7 as a plating mask, and then solder plating 9 was applied.

FIG. 3(b) shows the process of subsequently removing the resist 7 and etching the Ti5, followed by heat treatment to reflow the solder plating 9 to form a hemispherical protruding electrode 9a. As can be seen from the process from FIG. 3(a) to K in FIG. It must be placed much larger than the outer diameter of the electrode 9a. For example, the outer diameter of the protruding electrode 9a is 160 μm.
When the height is 100 μm, the outer diameter of the solder plating 9 is required to be 260 μm. As described above, the 7-lip chip also has drawbacks such as there are limitations due to dimensional constraints in the process of forming the protruding electrodes in order to achieve high-density packaging, and the number of steps required to form the protruding electrodes is large, resulting in poor yields.

Therefore, a method is desired that increases the manufacturing efficiency of semiconductor devices having protruding electrodes such as flip chips and enables higher density packaging.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and an object thereof is to provide a method that facilitates the formation of protruding electrodes of a flip chip and allows high-density packaging.

[Key points of the invention]

The present invention does not require forming protruding electrodes on the flip chip from the beginning, but instead prepares an insulating sheet with a separate electrode section.
By placing this insulating sheet between the semiconductor element and the substrate, and bonding the semiconductor element and the substrate so that the electrode portions of the insulating sheet are positioned respectively on the underlying metal of the semiconductor element and the conductive pattern of the substrate, This enables high-density mounting without restrictions on the number of electrodes in the process of forming protruding electrodes and without reducing production water retention.

[Embodiments of the invention]

The present invention will be explained below based on examples.

FIG. 1 is an exploded sectional view of a semiconductor device to which the present invention is applied. In FIG. 1A, 10 is a semiconductor element, and 11 is a base metal on which, for example, Ti, Cu, Ni, etc. are deposited. 12 in FIG. 1B is an insulating sheet such as a polyimide film. After embedding a metal such as Ni 13 in the insulating sheet 12 at a position corresponding to the base metal 11, the insulating sheet 12 is immersed in molten solder, and hemispherical solder 14 is applied only to the upper and lower surfaces of the metal Nt 13 by surface tension. This is provided. In FIG. 1C, a conductive pattern 16 made of Ag-Pd or the like is deposited on a substrate 15 made of ceramic or the like at a position corresponding to the base metal 11. In FIG.

Semiconductor element 10 with base metal 11 prepared in advance as described above. Insulating sheet 12 and conductive pattern 16 with hemispherical solders 14 on both end faces of gold@Ni 13
When the substrates 15 on which are formed are stacked in this order and passed through a heating furnace, the solder 14 melts, the base metal 11 and the conductive pattern 16 aligned at this point are soldered together, and the insulating sheet 12 is Semiconductor element 10 and substrate 15
It is sandwiched between and fixed via gold JiiNi 13.

FIG. 2 shows a cross-sectional view of a semiconductor device mounted in this way, and parts common to those in FIG. 1 are denoted by the same reference numerals. As can be seen from FIG. 2, the method of the present invention uses as a spacer an insulating sheet 12 containing metal, which will serve as an electrode portion, and bonding the semiconductor element 10 and the substrate 15 so that this sheet is interposed between the semiconductor element 10 and the substrate 15. Therefore, it is possible to perform batch bonding on 7-lip chips, and the constituent members of these semiconductor devices can be manufactured separately, which also has the advantage of conventional wire bonding in that the bonding material is separated from the semiconductor element. In addition, since the outer diameter of the electrode is determined by the size of the base metal [11] provided on the semiconductor element 10, the electrode density is increased and high-density packaging is possible. In addition, the protruding electrodes of the conventional 7-lip chip are equivalent to the inexpensive insulating sheet 12.
Since the protruding electrodes can be easily formed, the yield for forming the protruding electrodes is good, the number of mounting steps is reduced, and an economically advantageous semiconductor device can be obtained. In addition, since the sheet containing the constituent material of the electrode part can be rolled up when using polyimide film, etc., it is also possible to automate the bonding by using it as a tape carrier, etc., which is expected to further reduce the number of man-hours. Ru.

〔Effect of the invention〕

7 When performing lip chip bonding, it was necessary to apply solder plating that had a larger area than the base metal of conventional protruding electrodes, so there were restrictions on electrode density due to factors such as electrode diameter and distance between electrodes. However, as explained in the embodiment, the present invention has a problem in that the mounting density is determined by the outer diameter of the solder plating.However, as explained in the embodiment, the present invention has a solder plate that penetrates both the top and bottom sides separately from the semiconductor element and the board. N
An insulating sheet with solder protrusions on the end face of the i is prepared, and during mounting, this insulating sheet is sandwiched between the semiconductor element and the substrate, the solder protrusions are melted and solidified, and the base metal of the semiconductor element and the substrate are bonded. Since the electrode is bonded to the conductive pattern, the outer diameter of the electrode is almost the same as the underlying metal on the semiconductor element from the beginning, making it possible to implement higher-density mounting without restrictions on electrode density. .

In addition, many electrodes can be bonded simultaneously by interposing an insulating sheet between the semiconductor element and the substrate without providing protruding electrodes on the semiconductor element in advance, which has the advantage of reducing manufacturing man-hours and improving yield. It is something that you have.

[Brief explanation of drawings]

FIG. 1 is an exploded sectional view of a semiconductor device to which the present invention is applied;
FIG. 2 is a cross-sectional view of a semiconductor device mounted according to the present invention;
FIG. 3 is a cross-sectional view of a semiconductor device showing a conventional process of forming protruding electrodes. 5...'rt, 6...cu, 8...Ni plating,
9...Solder plating, 10...Semiconductor element, 11.
...Base metal, 12...Insulating sheet, 13...Metal Ni, 14...Semispherical solder, 15...Substrate, 16
...conductive pattern. Figure 1

Claims (1)

[Claims] 1) When collectively bonding a large number of electrode base metals provided on the main surface of a semiconductor element and a conductive pattern formed on a substrate, the position of the base metal and the conductive pattern is determined. A method for mounting a semiconductor device, comprising sandwiching an insulating sheet having protruding electrodes on both upper and lower surfaces that can be matched together between the semiconductor element and the substrate, and melting and solidifying the protruding electrodes. 2) In the method according to claim 1, the protruding electrodes are solder formed on both end surfaces of metal embedded through the insulating sheet to the upper and lower surfaces. Method.