JPH0352240A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To facilitate handling of a semiconductor substrate, to enhance the yield rate and to reduce the cost by fixing the semiconductor substrate to a plate material, dicing a scribing line region on the rear surface of the semiconductor substrate, and separating the semiconductor substrate. CONSTITUTION:The element forming surface side or a semiconductor substrate 1 on which a field effect transistor is formed is stuck to a transparent plate material 8. The rear surface side of the semiconductor substrate 1 is made to be a thin layer having the required thickness. A through hole 12 reaching a source electrode 2a of the field effect transistor is formed on the rear surface side of the semiconductor substrate 1. The entire surface of the rear side of the semiconductor substrate 1 is metallized 13. Plating 15 is applied on the metallized rear surface other than a scribing line region 7. Thereafter the scribing line region 16 undergoes dicing, and the semiconductor substrate is separated. Then the transparent plate material 8 is released from the semiconductor substrate 1, and the semiconductor substrate 1 is made to be chips. Thus, the handling of the semiconductor substrate becomes easy, the yield rate is enhanced and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device, particularly a monolithic microwave integrated circuit (MMIC; MonoHt).
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The present invention relates to a method of manufacturing a semiconductor device having a pier hole intended for high frequency operation such as rcuits.

[Conventional technology]

Gallium arsenide (
GaAs) MMIC is a Schottky barrier field effect transistor (GaAs) MMIC.
) and GaAs diodes, as well as resistors, capacitors,
The operating frequency of this MMTC, which is constructed by combining passive elements such as inductor elements, is 2 GHz.
Because of the above, microstrip lines are widely used as transmission lines as passive circuits. Since a semi-insulating GaAs substrate is used as the dielectric substrate of the microstrip line, the line width of the microstrip line is determined by the thickness of the GaAs substrate, and it is necessary to make the GaAs substrate thinner for higher integration. There is. Further, it is necessary to reduce parasitic impedance not only in MMICs for low noise amplification and MMICs for high output. This parasitic impedance has a particularly large effect on the characteristics of the source inductance, so it is essential to reduce the parasitic impedance by forming a via hole (opening) for leading out the back side of the source electrode during the manufacturing process. be.

At present, wet etching and RIE (Reactive JonE) are used to form this hole.
However, in order to shorten the etching time of higher holes and reduce the area of the opening, the GaAs substrate is thinned by methods such as physical polishing and chemical etching. Usually, a pier hole is formed from the This G a.
The thickness of the As substrate is, for example, approximately 100 μm to 150 μm in a low-noise amplification MMIC, and approximately 30 μm to 50 μm in a high-output MMIC. 1
If the substrate thickness is 00 μm or more, it is possible to form a via hole on the GaAs substrate alone with careful handling, but if the thickness is less than 50 μm, it is possible to form a hole on a silicon (Si) wafer. It is usual to form the GaAs substrate by reinforcing the GaAs substrate.

[Problem to be solved by the invention]

However, in order to form the semiconductor substrate thinly in this way, there is the problem of chipping or cracking of the semiconductor substrate when handling it with a bin set or the like in the via hole formation process or subsequent manufacturing process. There was.

Further, when handling the completed chips, chip chipping and the like tend to occur, resulting in a significant decrease in yield, making it difficult to reduce manufacturing costs. Furthermore, in order to convert an integrated semiconductor substrate into a chip, the scribe line area is removed by wet etching or the like at the same time as the via hole is formed. For this reason, it was necessary to have a wide two-scribe line area, and there was also the problem that high integration of the circuit could not be achieved.

The present invention has been made in order to solve these problems, and allows handling of semiconductor substrates and chipped semiconductor devices in the manufacturing process to be easily carried out without requiring special attention, resulting in a high manufacturing yield. The present invention provides a manufacturing method that allows a semiconductor device to be obtained at low cost, and also provides a manufacturing method that allows a semiconductor device with a high degree of integration to be obtained.

[Means to solve the problem]

The present invention includes a process of attaching the element forming side of a semiconductor substrate on which a field effect transistor is formed to a transparent plate material and thinning the back side of the semiconductor substrate to a desired thickness; A step of forming a through hole reaching the source electrode of the field effect transistor, a step of metalizing the entire back side of this semiconductor substrate, a step of plating the metallized back side except for the scribe line area, and this step. This method includes a step of separating the semiconductor substrate by dicing the scribe line area, and a step of peeling off a transparent plate material from the semiconductor substrate to form the semiconductor substrate into chips.

r effect] Since the semiconductor substrate is manufactured by being fixed to a plate material, the thin semiconductor substrate is reinforced and its handling becomes easy. Further, since the semiconductor substrate is separated by dicing the scribe line area on the back side of the semiconductor substrate, the spread of the scribe line portion is suppressed.

〔Example〕

FIG. 1 is a cross-sectional view of the manufacturing process of MMNC according to an embodiment of the present invention.

A silicon oxide (SiO 2 ) film, a silicon nitride (Si3N4) film, or the like is formed on the GaAs semiconductor substrate 1 to protect the surface of the semiconductor substrate. Further, on the semiconductor substrate 1, a source electrode 2a and a gate electrode 2b are provided.
, and a drain electrode 2c is formed. Further, an electrode 3a serving as one terminal of a capacitor which is a passive element and a resistor It! 14 are formed,
These are formed together with MESFETs which are active elements. Further, an electrode 3 that becomes the other terminal of the capacitor is provided on the insulating film 5.
b is formed (see FIG. 1(a)).

A photoresist 6 is formed on this element portion, patterning is performed in a scribe line region 7, and the insulation M5 in the scribe line region 7 is removed by dry etching such as RIE. (See figure (b)).

Thereafter, a quartz plate 8, which is a transparent and hard plate material, is attached to the element formation surface of the semiconductor substrate 1 using an adhesive 9. This adhesive 9 needs to be made of a thin material that can withstand the heat applied in each process and the chemicals used in each process during the manufacturing of semiconductor devices. Blue wax (trade name) etc. are used. The back surface of the semiconductor substrate 1 attached to the quartz plate 8 is polished by a method such as back grinding or chemical polishing, and the semiconductor substrate 1 is thinned to a thickness of 50 to 100 μm (as shown in the figure). (C
)reference).

Next, apply photoresist on the back side of the semiconductor substrate 1. 0 is formed, and a double-sided mask aligner is used to pattern a via hole that is electrically connected to the source electrode 2a of the FET. That is, while the pattern on the element formation surface of the semiconductor substrate 1 is visually confirmed through the transparent quartz plate 8, the pattern 11 for the via hole is formed on the photoresist 10 formed on the back surface (see FIG. 10(d)). ). At this time, the photoresist 10 is OMR8B (product name) or OFPR, which has excellent chemical resistance.
800 or the like, and the quartz plate 8 also has excellent chemical resistance and is not attacked by the chemicals used to form the pipe holes in the next step.

Using the pattern 11 as a mask, for example, sulfuric acid (H2S0
4) By wet etching using a phosphoric acid (H3PO4) based or phosphoric acid (H3PO4) based etchant, or by wet etching using a chlorine (CI) based etchant.
(2) A via hole 12 is formed from the back surface side of the semiconductor substrate 1 by dry etching using a gas, boron trichloride (BCl3) gas, etc. (see FIG. 4(e)). In addition, as a mask for the shape of Pyre Hole 12, is there a mask? Instead of -1, S t O 2 and S 3N4, which have good adhesion to the semiconductor substrate and excellent chemical resistance, can be used.
An insulating film such as the above may also be used.

Thereafter, the photoresist 11 is removed by a method such as oxygen (0) ashing, and the entire back surface of the semiconductor substrate 1 is covered with T.
i/A u metal 13 by sputtering about 50
Deposit about 0A/IOOOA.

Here, the reason why the vapor deposition method is not used is that the softening point of the adhesive 9 bonding the semiconductor substrate 1 and the quartz plate 8 is about 80°C to 10°C.
Since the temperature is approximately 0° C., this is to prevent heat from being applied to the adhesive 9 as much as possible. Thereafter, a mask pattern corresponding to the scribe line area 7 formed on the front surface of the semiconductor substrate 1 is formed on the back surface side of the semiconductor substrate 1 using the double-sided mask aligner again. In other words, the semiconductor substrate l
A pattern of photoresist 14 made of OMR 83 or the like is formed on the back surface of semiconductor substrate 1 opposite to scribe line region 7 while visually confirming scribe line region 7 formed on the front surface of semiconductor substrate 1 through quartz plate 8 .

(See figure (f)).

Next, using this photoresist] 4 as a mask, Au metal 15 is selectively plated. This plating grows to a thickness of about 2 μm. Thereafter, the photoresist 14 is removed by a method such as ashing to form a scribe line area 16 on the back side (see (g) in the same figure).
reference).

Next, a cut 17 is made from the back side of the conductor substrate 1 along this scribe line area 6 using a dicer, and the semiconductor substrate is separated (see FIG. 6(h)).

Note that the precision of the dicer is ±1 μm, and the accuracy of the dicer is ±1 μm.
is adhered to the quartz plate 8, and the thickness of the adhesive is approximately 10 μm.
The quartz plate 8 is not damaged by this dicing.

Thereafter, the adhesive 9 is dissolved by immersing the device in an organic solvent such as trichlorethylene, and the semiconductor substrate 1 and the quartz plate 8 are separated. As a result, MMI of chipped structure
You can get C.

(See figure (i)).

As described above, according to this embodiment, each manufacturing process can be carried out with the semiconductor substrate 1 attached to the quartz plate 8 from the time when the semiconductor substrate 1 is thinned to the time when it is made into chips. Therefore, the semiconductor substrate 1 can be easily handled in each manufacturing process or even after being made into chips.

For this reason, chips and cracks on the semiconductor substrate 1 due to handling errors, etc., will no longer occur as in the past.
Yield is significantly improved.

Further, since the semiconductor substrate 1 is separated by dicing, the spread of the removed portion of the scribe line region 17 is suppressed. As a result, the area required for the scribe line region 17 is reduced, which in turn makes it possible to improve the degree of device integration.

〔Effect of the invention〕

As explained above, according to the present invention, since the semiconductor substrate is manufactured by being fixed to a plate material, the thin semiconductor substrate is reinforced and its handling becomes easy. Further, since the semiconductor substrate is separated by dicing the scribe line area on the back side of the semiconductor substrate, the spread of the scribe line portion is suppressed.

This makes it easier to handle semiconductor substrates and chipped semiconductor devices during the manufacturing process without requiring special care, resulting in higher manufacturing yields and lower cost semiconductor devices. have an effect.

Further, the area required for the scribe line region is reduced, and a semiconductor device with a high degree of integration can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of each manufacturing process according to an embodiment of the present invention. 1... Semiconductor substrate, 2a, b, c... Source electrode of FET, gate electrode 1 Drain electrode, 3a, b...
Capacitance, 4... Resistive film, 5... Insulating film, 6.10...
・Photoresist, 7...Scribe line area on the side of the element shape, 8...Transparent quartz plate, 9...Adhesive, 1
2... Pier Hall, 13... T i / A u
Metal, 15...Au metal, 16...Scribe line area on the back side, 17...Notch for element isolation. Manufacturing process according to example (@half) Sagi 1 figure (1) (f) (9) Manufacturing process according to actual example (a half) Information 1 figure (2)

Claims (1)

[Claims] A step of attaching the element forming side of a semiconductor substrate on which a field effect transistor is formed to a transparent plate material and thinning the back side of the semiconductor substrate to a desired thickness, and the thinned semiconductor substrate. forming a through hole reaching the source electrode of the field effect transistor on the back side of the semiconductor substrate; metallizing the entire back side of the semiconductor substrate in which the through hole is formed; plating the back surface except for the scribe line area, dicing the scribe line area to separate the semiconductor substrate, and peeling the transparent plate material from the semiconductor substrate to form the semiconductor substrate into chips. A method for manufacturing a semiconductor device, comprising the steps of: