JPS5923466B2 - Manufacturing method of flip-chip transistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a flip-chip transistor.

Regarding the structure of conventional flip-chip transistors of this type, lateral Schottky barrier gate field effect transistors (hereinafter referred to as SB and F) using gallium arsenide (GaAs)
(abbreviated as ET) will be explained as an example.

1 and 2 show the general structure of a flip-chip type SB/FET chip.

1 and 2, 1 is a semi-insulating GaAs substrate, 2 is an active layer formed on this substrate 1 by selective epitaxial growth, and 3 and 4 are on this active layer 2. A source electrode and a drain electrode are formed in ohmic contact, and 5 is a gate electrode formed on the active layer 2 between the source electrode 3 and the drain electrode 4 to have a Schottky contact therewith, and 5 is a gate electrode formed in a Schottky contact with the active layer 2 between the source electrode 3 and the drain electrode 4; is on the substrate 1. Thick plated electrodes 6, T and 8 are selectively formed on the bonding pads of the source, drain and gate electrodes 3, 4 and 5 by electrolytic gold plating.

The flip-chip type SB obtained in this way
-FET chips, as shown in Figures 3 and 4,
Mounted on a flip chip carrier.

That is, in these FIGS. 3 and 4, 9 denotes the source thick plating electrode 6 shown in FIGS. 1 and 2 above.
, drain thick plated electrode T and gate thick plated electrode 8
A flip-chip type SB-FET chip with The thick plated drain and gate electrodes 7 and 8 are bonded onto the strip lines 12 and 14 which serve as the drain and gate electrode terminals of the soldered MIC substrates 11 and 13, respectively.

This is a flip-chip type SB-F configured like this.
The operating mechanism of ET is well known, so I will not discuss it again, but it is a normal upside-up type SB-FE.
As with T, since no lead wire is used, the inductance component is extremely small, and especially when used as an amplifier, a reduction in source inductance is directly linked to an improvement in amplification gain, making it possible to achieve high gain. It is effective for

However, on the other hand, in order to uniformly bond the chip 9 to the carrier 10, the thickness of the MIC substrates 11 and 13 on each side of the drain and gate of the carrier 10 and the height of the protrusion on the source side must be adjusted as much as possible. The maximum tolerance is approximately ±0.005 mm, which is an order of magnitude stricter than general machining accuracy, making it extremely difficult to manufacture and mass production. It had the disadvantage of being lacking in sex. This invention aims to improve the inconveniences seen in conventional flip-chip transistors of this type.The present invention aims to improve the inconveniences found in conventional flip-chip transistors. thickly plated electrodes are provided on all of the flip-chip transistors, and when each thickly plated electrode is connected to a corresponding electrode terminal of a flip-chip carrier or package main pair, the electrode terminal corresponding to the intermediate thickly-plated electrode of the flip-chip transistor is The height is formed lower than the electrode terminals on both sides,
A buffer electrode is interposed between the intermediate thick plated electrode and the electrode terminal corresponding to the thick plated electrode, and the electrode terminals are bonded under heat and pressure.

Hereinafter, details of one embodiment of the method of the present invention will be explained using a flip-chip type SB-FET as an example in the same manner as described above.

5a to 5d sequentially show the manufacturing process of the flip-chip type SB-FET according to this embodiment, and in the figures,
The same reference numerals as in FIGS. 1 to 4 above indicate the same or corresponding parts.

In this FIG. 5a-d, this embodiment is shown in FIG.
The height of the protrusion 15 to which the source thick plating electrode 6 of the main body 10 is bonded is formed to be lower than the thickness of the MIC substrates 11 and 13 having the same thickness, and as shown in FIG. The buffer electrode 16 is placed and temporarily bonded.

Then, as shown in Figure c, the flip-chip type SB
- By aligning the EFT chip 9, temporarily bonding the source thick plating electrode 6 onto the buffer electrode 16, and then heat-pressing the chip 9 to the main body 10, as shown in FIG. , the buffer electrode 16 is crushed and automatically corresponds to the height of the MIC substrates 11, 13, and at the same time each thick plated electrode 6, 7, 8 has a protrusion which is the corresponding electrode terminal. 15 and the strip lines 12 and 14. That is, in this embodiment, even if there is a step between the upper surface of the protrusion 15 of the carrier body 10 and the upper surface of each MIC substrate 11, 13, the function of the buffer electrode 16 interposed on the protrusion 15 is improved. Accordingly, each thick plated electrode 6, 7, 8 of the flip-chip type SB-FET chip 9 is attached to the corresponding main body 1.
It is possible to uniformly adhere the protrusion 15 and the strip lines 12 and 14, which are the electrode terminals of the carrier body 10 and the chip 9, thereby eliminating the need to strictly maintain the machining accuracy of the carrier body 10 and, by extension, the chip 9. This type of flip-chip type SB/FET with high gain can be easily and stably manufactured with good reproducibility.

In the above embodiment, the buffer electrode is arranged only on the source electrode, but it may also be applied to the drain and gate electrodes, and the number of buffer electrodes may be one or more, and the shape The shape may be any shape such as a rod, a wire, a ribbon, or a sphere, and the material may be appropriately selected depending on the purpose, such as an alloy of Au or In.

Furthermore, in the above embodiment, the case where the present invention is applied to a lateral shot barrier gate type field effect transistor using GaAs has been described, but it goes without saying that the present invention can be applied to all other flip-chip type transistors.

As detailed above, according to the method of the present invention, when connecting the thick plated electrodes formed on each source electrode, gate electrode, and drain electrode of a flip-chip transistor to the corresponding electrode terminal of the flip-chip carrier or package, The height of the electrode terminal corresponding to the intermediate thickly plated electrode of the flip-chip transistor is formed lower than the next electrode terminals on both sides, and the height of the electrode terminal corresponding to the intermediate thickly plated electrode and the thickly plated electrode is Since it is bonded by heat and pressure with a buffer electrode interposed between it and the terminal, it is easy to process and manufacture, and it is possible to provide this type of flip-chip transistor with good reproducibility, and is expected to improve yields and lower prices. It has the following features:

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of a general flip-chip type SB-FET chip, FIG. 2 is a sectional view taken along the line shown above, and FIG. 3 is a plan view showing the configuration of a conventional flip-chip type SB-FET. FIG. 4 is a cross-sectional view taken along the line ``--'' and FIGS. 5A to 5D are cross-sectional views sequentially showing manufacturing steps according to an embodiment in which the method of the present invention is applied to a flip-chip type SB-FET. 1...GaAs substrate, 2...active layer,
3... Source electrode, 4. ．． ．．・．． ．． Drain electrode, 5...gate electrode, 6...source thick plating electrode, 7...drain thick plating electrode,
8...Gate thickness plated electrode, 9...Flip chip type SB-FET chip, 10...
Carrier body, 11... Drain side MLC substrate, 12... Strip line of drain side MLC substrate, 13. ．． ．． ．． ．． ．． Gate side MIC board, 14.
・・・・・・Stripline of gate side MIC board, 1
5...Protrusion of main body, 16...Buffer electrode.

Claims (1)

[Claims] 1 Thick plated electrodes are provided on all of the source electrode formed in the middle of the surface to which the flip-chip transistor is to be bonded, and the gate and drain electrodes formed on both sides thereof, and each of the thick plated electrodes is used for flip-chip use. When connecting to a corresponding electrode terminal of a carrier or a package body, the height of the electrode terminal corresponding to the intermediate thick plated electrode of the flip-chip transistor is formed lower than the electrode terminals on both sides thereof, and the 1. A method of manufacturing a flip-chip transistor, comprising: interposing a buffer electrode between an intermediate thick plated electrode and the electrode terminal corresponding to the thick plated electrode, and bonding them under heat and pressure.