JPH01152731A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To accurately isolate filmy chips of semiconductor substrate which is reduced in thickness by forming an isolating groove having a predetermined depth on the outer periphery of a first covering layer which covers the element forming region of the surface of the substrate. CONSTITUTION:A plurality of element forming regions 2 are respectively covered with first coating layers 3, and with the layers as masks an isolating groove 4 having a predetermined depth is formed on a semiconductor substrate 1. A wax layer 5 is formed on the whole surface, a glass plate 6 is adhered in an inverted shape through the layer 5, the substrate 1 is etched until the surface of the layer 5 is exposed to be reduced in its thickness, and a conductive layer 7 is formed on its whole surface. A second covering layer covering part of the layer 7 is formed on the exposed layer 5, with the layer as a mask a thick plated layer 9 is selectively formed on the exposed part of the layer 7, with the layer as a mask the layers 8, 7 are removed, isolated from the plate 6, the layers 5, 3 are simultaneously removed, and the chips are isolated. Thus, the accuracy and controllability of the groove are improved, thereby reducing the irregularity in the shapes of the isolated chips.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for manufacturing a semiconductor device having a semiconductor substrate on which a thin and thick plating layer is selectively formed.

[Conventional technology]

Generally, in high-output semiconductor devices, the issue of their heat dissipation characteristics is an important issue. It is known that one of the measures for achieving good heat dissipation is to make the semiconductor substrate very thin and to cover it with an fL heat dissipator. .

However, when the semiconductor substrate is heated up, it is affected by the heat dissipation body, causing large warpage in the semiconductor substrate, making it difficult to separate it into individual semiconductor devices (hereinafter referred to as chips).

FIG. 2 is a side view of a main part showing a state in which the above-described semiconductor substrate is warped, in which a metal heat sink 12 is selectively broken to a thin semiconductor device 11. As shown,
The semiconductor substrate 11 is composed of this semiconductor substrate 11 and the metal heat sink 1.
Warpage occurs in response to the difference in thermal expansion coefficients between the two. As a method of separating such a semiconductor substrate 11 into individual chips, there is a method of separating the semiconductor substrate 11 into individual chips by using a scribe or a Guinong saw, but in either case, handling of the semiconductor substrate 11 formed into an r1j film is extremely difficult. Occasionally, cracks or cracks occur in the semiconductor substrate 11, which is a major factor in reducing the chip yield. 1, numeral 13 is an element forming region, and numeral 14 is a conductive layer. .

To solve this problem, a method has been proposed in which chips are separated by etching at the wafer process stage, as shown in FIG. A semiconductor substrate 21 is attached in an inverted manner through a wax layer 25te, and an element forming region 23 is formed on the surface of the semiconductor substrate 21. 22 and then
As shown in FIG. 3(b), the heat sink 22 is used as a mask,
The semiconductor substrate 21 is separated from the surface by etching 7, where 24 is a conductive layer.

[Problem that the invention seeks to solve]

17 However, in this method, the semiconductor substrate 21
The variation within the semiconductor substrate 21 that occurs when forming the 'f4 film causes the variation in side etching during etching, so the non-uniformity of the semiconductor substrate 21 during thinning deteriorates the female shape of the chip. This is a factor that reduces yield.

This invention was made in order to solve the above-mentioned problems, and it is aimed at manufacturing a semiconductor device that can realize chip separation of a thin semiconductor substrate with high accuracy by attaching a heat dissipating body. The purpose is to obtain a method.

[Means for solving problems]

A method for manufacturing a semiconductor device according to the present invention includes the step of covering each of a plurality of element formation regions formed on the surface of a semiconductor substrate with a first coating layer, and using the first coating layer as a mask to cover the semiconductor substrate with a predetermined depth. Step 2 of forming separation grooves: Forming a sock layer on the entire surface of the semiconductor substrate, including the separation grooves, and pasting the semiconductor substrate upside down on a glass plate through this wax layer, until the surface of the wax layer is exposed. A step of etching to make a thin layer, and a step of forming a conductive layer on the entire surface of the i-substituted semiconductor substrate, including the exposed wax layer.

4 on the wax j- exposed due to thinning of the semiconductor substrate
Part of the electric layer I! forming a second covering layer;
A step of selectively forming a thick plating layer on the exposed parts of the conductive layer using the second coating layer as a mask.After removing the second coating layer and the conductive layer using the thick plating layer as a mask, peeling it off from the glass plate. At the same time, the wax layer and the first coating layer are removed, and the chips are separated.

[Effect]

In this invention, a separation groove of a predetermined depth is formed in the outer periphery of the first HPIiT layer that covers the element formation region on the surface of the semiconductor substrate, and a wax layer is formed on the entire surface including the separation groove. ) After pasting on the glass substrate through the WANOX layer, the surface side of the semiconductor substrate is etched until the WANOX layer surface is exposed, and then the chips are separated, so the semiconductor substrate surface has good flatness. Since the in-plane uniformity of the separated separation grooves is good, the shape of the separated chips also has little variation and has good controllability.

[Embodiment] FIGS. 1(n) to 1(h) are cross-sectional views showing the main steps of an embodiment of the method for manufacturing a semiconductor device of the present invention.

First, as shown in FIG. 1(a), a first covering layer 3 is formed, which covers an element formation region 2 formed on a semiconductor substrate 1 and exposes a part of the semiconductor substrate 1 on the outer periphery.・Form the pattern of the strike layer. Next, the first il[l15
As shown in FIG. 1B, using 3 as a mask, a separation groove 4 having a depth (for example, 30u+n) such that the bottom substrate thickness is approximately the same as the final substrate thickness is formed by, for example, a wet etching method.

After that, as shown in FIG. 1(c), the element formation region 2 is
A wax layer 5 is formed over the first target ffJda over the separation ma, and a glass plate 6 is formed through this wax layer 5.
Paste it upside down. Subsequently, as shown in FIG. 1(d), the semiconductor substrate 1 is thinned from one surface of the semiconductor substrate 1 by lapping, etching, etc. until the surface of the wax layer 5 is completely exposed.

This divides the semiconductor substrate 1 into individual chips and knobs.
It has a t-shape. Next, as shown in FIG. 1 (Q), the thickness required for forming the plating layer 9 to be formed in a later process is applied to the entire surface of the semiconductor substrate 1 including the surface of the wax layer 5 which is not exposed due to thinning from the back surface of the semiconductor substrate 1. For example, a conductive layer 7 made of Ti/Au or the like is formed.

Subsequently, as shown in FIG. 1(f), a second coating layer 8, for example, a back layer of an L-rest layer is formed on a part of the conductive layer 7 on the wax layer 5 corresponding to the outer periphery of the element forming area 2. Then, as shown in FIG. 1(g), a second covering lid is applied.
Using 8 as a mask, a thick plating Ifi 9 is selectively formed as a heat sink via a conductive layer 7.

Then, using the thick plating layer 9 as a mask, the second coating 8 and the conductive layer 7 are sequentially removed, and finally the glass plate 6 is peeled off, and the wax layer 5 and the first coating layer 3 are removed. , obtain a structure as shown in Figure 1(h).

In the present invention as described above, since the chips are separated from one surface side of the semiconductor substrate 1, the accuracy and controllability of the separation grooves 4 are improved, so that variations in the shape of separated chips can be reduced to low IT. , an improvement in the yield of chives and whelks can be achieved.

In the above embodiment, the groove 4 is formed by the Uerito edging method, but it is also possible to use the Dra, Ienochinog,
There is no problem with the ding-and-saw method, etc.

[Effects of the Invention] This invention (as explained above, each of the plurality of element formation regions formed on the surface of the semiconductor substrate is connected to the first ?!!!)
Step of covering the first covering layer with a mask and step 17 of forming an isolation groove of a predetermined depth in the semiconductor substrate. Step 2: Forming a wax JIV# on the entire surface of the semiconductor substrate including the isolation groove, and Attach the semiconductor substrate upside down to a glass plate through the wax layer. Step 2: Process the semiconductor substrate until the surface of the wax layer is exposed.
A process of making the semiconductor substrate thinner by sowing, a process of forming a conductive layer on the entire surface including the exposed wax layer of the thinned semiconductor substrate, and a part of the conductive layer on the wax layer exposed by thinning the semiconductor substrate. a step of forming a second coating layer; a step of selectively forming a thick plating layer on the exposed portion of the conductive layer using the second mm layer as a mask; After removing the chips, the wax layer and the first coating layer are removed from the glass plate at the same time, and the chips are separated. This improves the precision and controllability of the separation grooves and reduces shape variations in the separated chips. This has the effect of reducing chip yield and improving chip yield.

[Brief explanation of the drawing]

FIGS. 1(a) to (h) are cross-sectional views of main steps for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention, FIG. 2 and FIGS. ) is a cross-sectional view of main steps for explaining a conventional method for manufacturing a semiconductor device. In the figure, 1 is a semiconductor substrate, 2 is an element formation region, 3 is a first covering layer, 4 is a separation groove, 5 is a wax layer, 6 is a glass plate, 7 is a conductive layer, 8 is a second Wi layer, and 9 is a thick plating layer. Note that the same reference numerals in each figure indicate the same or equivalent parts.
. Agent: Masuo Oiwa (2 others) b Glass temporary soldering thick plating layer

Claims (1)

[Claims] a step of covering each of a plurality of element formation regions formed on a surface of a semiconductor substrate with a first coating layer; a step of forming a separation groove of a predetermined depth in the semiconductor substrate using the first coating layer as a mask; A step of forming a wax layer on the entire surface of the semiconductor substrate including the grooves and attaching it to a glass plate in an inverted manner through the wax layer, and a step of etching the semiconductor substrate until the surface of the wax layer is exposed to make it a thin film. , forming a conductive layer on the entire surface of the thinned semiconductor substrate including the exposed wax layer; forming a second covering layer covering a part of the conductive layer on the wax layer exposed by the thinning of the semiconductor substrate; a step of selectively forming a thick plating layer on the exposed portion of the conductive layer using the second covering layer as a mask; using the thick plating layer as a mask, removing the second covering layer and the conductive layer. After that, simultaneously removing the wax layer and the first coating layer from the glass plate,
A method for manufacturing a semiconductor device, the method comprising the step of separating chips.